An Introduction to Video Principles-Part 2

Dr. Mohieddin Moradi
mohieddinmoradi@gmail.com
Dream
Idea
Plan
Implementation
1

2
https://www.slideshare.net/mohieddin.moradi/presentations

− Elements of High-Quality Image Production
− Human Visual System and Color Perception
− A Short History of Film
− Mechanism of CCD and CMOS Sensors
− Television System History
− Color Video Signal Formats
− The Color Bars Test Signal Specifications
− CIE Color Spaces and Color Gamut Specifications
− Analog to Digital Conversion and Color Sub-Sampling
Outline
3

− The highest point on each curve is called the “peak wavelength”, indicating the wavelength of radiation that the cone is
most sensitive to it.
Normalized Human Cone Sensitivity
Human Cone Sensitivity
7
S : 420~440 nm (closed to blue) (2%)
M: 534~545 nm (green) (33%)
L : 564~580 nm (closed to red) (65%)
S = Short wavelength cone
M = Medium wavelength cone
L = Long wavelength cone
Rod cells
S-cone
M-cone
L-cone

Human Cones Sensitivity and Human Eye Sensitivity to Brightness
8
M-Cone cells L-Cone cells
S-Cone cells
450 500 550 600 650 700
Wavelength (nm) 450 500 550 600 650 700
Wavelength (nm)
• The human eye sensitivity to brightness as a function of the wavelength is
expressed by the sensitivity characteristic or luminosity curve.
• This characteristic indicates how bright the individual spectral colors
appear to the eye when all of them have the same energy level.
It can be seen from
this characteristic
that certain colors
appear dark (e.g.
blue) and others
bright (e.g. green).

9
Spectral Flux (W/nm)
Wavelength (nm)
Area under this part of the curve =
𝑇𝑜𝑡𝑎𝑙 𝑅𝑎𝑑𝑖𝑎𝑡𝑒𝑑 𝐸𝑛𝑒𝑟𝑔𝑦
𝑠
within visible range
= 8.4 J/s or W
Spectral Luminous Flux Example
Wavelength (nm)
Spectral Luminous Flux (W/nm)
Area under this part of the curve =
𝑇𝑜𝑡𝑎𝑙 𝐿𝑢𝑚𝑖𝑛𝑜𝑢𝑠 𝐸𝑛𝑒𝑟𝑔𝑦
𝑠
within visible range
= 2.4 J/s or W
Relative Human Sensitivity to Brightness
Wavelength (nm)
450 500 550 600 650 700
Wavelength (nm)

10
Y: Luminance Signal or Brightness Signal
If you take equal amounts of green, red, and
blue light energy and superimpose the rays from
these lights on the screen, you will see white.
More saturated green
Less saturated green
100%B (Bright)
Equal amounts of green, red, and blue light energy
465nm
540 nm
610 nm
• According to the brightness sensitivity test, the eye is more sensitive
to green than to red and more sensitive to red than to blue.
• If you then look at each light separately, the green appears to be
twice as bright as the red and six times as bright as the blue.
Contribution of each color in white with 100% bright

11
47%
92%
17%
Peak Sensitivity at 555 nm
47
.
0
92
.
0
17
.
0
92
.
0
59
.
0
47
.
0
92
.
0
17
.
0
47
.
0
3
.
0
47
.
0
92
.
0
17
.
0
17
.
0
11
.
0









Y=0.11B+0.3R+0.59G (SDTV)
465 540 610
Sensitivity to brightness

− Mathematically (in SD camera), the black and white or monochrome portion of the total color signal is formed by taking
• 59 percent of the signal coming from the green camera tube
• 30 percent of the signal developed by the red camera tube
• 11 percent of the signal output of the blue camera tube
− This particular combination was chosen because it closely follows the color sensitivity of the human eye.
− That is, if you take equal amounts of green, red, and blue light energy and superimpose the rays from these lights on the
screen, you will see white.
− However, if you then look at each light separately, the green appears to be twice as bright as the red and six
times as bright as the blue. This is because the eye is more sensitive to green than to red and more sensitive to red than to
blue. Alternate names for the monochrome signal are luminance signal and brightness signal.
12
Y=0.11B+0.3R+0.59G

− Colour pictures can be broken down into three primaries.
Red Green Blue
− Original plan to use these primaries in colour television.
− The colour are called components.
Color Video Signal Formats
13
Y=0.11B+0.3R+0.59G (SDTV)

− RGB signals offer the most faithful reproduction in both image brightness and color depth.
− This is because they are obtained right after the R, G, and B imagers with minimum video processing in
between.
− Each one of the RGB signals contains information on brightness and color in the same channel.
− RGB signals are also called full bandwidth signals because they are not limited in bandwidth, which is the
case with other signal formats. This is another reason why RGB signals provide the best video quality.
RGB Signals
14

Camera
Monitor
Transmission
RGB Signals
17

18
Y=0.11B+0.3R+0.59G
RGB Signals

− There was many black-&-white television customers when colour TV was introduced.
• Needed to keep these customers happy when colour TV was introduced.
− Old black and white signal is needed.
− Matrix in the camera converts from RGB to
• Y
• (R-Y)
• (B-Y)
− Y is the black-&-white signal.
− (R-Y) and (B-Y) are two colour difference signals
19
Y/R-Y/B-Y Signals

Matrix
R B
G
Y R-Y B-Y
Old Black & White televisions ignore
the colour components and only use
the monochrome component
20
Y=0.11B+0.3R+0.59G
Y/R-Y/B-Y Signals

– The Y/R-Y/B-Y signal is called the component signal.
– The Y/R-Y/B-Y signal is obtained by feeding the RGB signal to a matrix circuit, which separates it into color
information and brightness information.
– This makes the signal easier to process.
– Information on the total brightness of the three RGB signals is combined into one signal called the
luminance signal (Y), while information on color is packed into two signals called the color difference
signals (R-Y/B-Y).
– Information on luminance is not bandwidth-restricted and is equivalent to that of the RGB signal.
– Information on color (R-Y/B-Y) is bandwidth-limited to a certain extent, but kept sufficient for the human
eye’s sensitivity to fine color detail, which is less than that to brightness.
21
Y/R-Y/B-Y Signals

22
700 mV
0 mV
620 mV
-620 mV
491 mV
-491 mV
𝑅′
− 𝑌′
𝐵′
− 𝑌′
𝑌′
700 mV
0 mV
700 mV
0 mV
700 mV
0 mV
𝑅′
𝐺′
𝐵′
Matrix
Y/R-Y/B-Y Signals
Y=11B+0.3R+0.59G

Unsuitability of G – Y Signal for Transmission
− The proportion of G in Y is relatively large (59%) in most cases
− The amplitude of (G – Y) is small
− The smaller amplitude together with the need for gain in the matrix would make S/N ratio problems more
difficult then when (R – Y) and (B – Y) are chosen for transmission.
24
Y=0.11B+0.3R+0.59G
G-Y=G-0.11B-0.3R-0.59G
G-Y=0.31G-0.11B-0.3R

Y/C or S-Video Signal
25
− The Y/C signal packs the R-Y/ B-Y channels into one signal
called the C signal (color signal).
− Available on standard-definition NTSC and PAL devices only.
− This is achieved by modulating (quadrature modulation) the
R-Y/B-Y signals on
 a 3.58 MHz sub-carrier for NTSC
 a 4.43 MHz sub-carrier for PAL
− In the Y/C signal, the bandwidth of the luminance signal (Y)
is the same as that of the component signal.
− The bandwidth of the C signal is usually limited and slightly
distorted due to the quadrature modulator and band-pass
filter used to eliminate high-frequency harmonics.

– This is achieved in such a way that the bandwidth of the chrominance signal overlaps with that of the luminance signal.
– This allows the composite signal to provide both luminance and chrominance information (color images) using the same
bandwidth as the black and white signal.
– Technically, this is achieved by modulating the color signals on a carrier signal (= color subcarrier) that does not interfere
with the luminance signal’s spectrum.
– The frequency of the color carrier signal is determined so its spectrum interleaves with the spectrum of the luminance.
 For NTSC video, this is approximately 3.58 MHz.
 For PAL video ,this it is approximately 4.43 MHz.
– This prevents the chrominance (C) and luminance signals (Y) from mixing with each other when they are added together
to form the composite signal.
– The composite signal can be separated back into its luminance and chrominance components using special filters,
known as comb filters. 26
Composite Color Video Signal (CCVS)
– The composite signal is obtained by adding the
luminance (Y) and chrominance (C) signals of the
Y/C signal to form one signal, which contains both
brightness and color information.

27
− The chrominance signal is combined with the composite video signal (CVS) to form the composite color video
signal (CCVS).

Front Porch
700 mv
300 mv
BackPorch
28
Front Porch
Active Line or Vision
12 µs 52 µs
700 mv
300 mv
4.7 µs
BackPorch
Horizontal Blanking
Amplitude → Color Saturation
(chroma saturation)
Phase Difference → Color Hue
(chroma Phase)
A B

Colour Television Standards
PAL
1963
NTSC
1953
SECAM
1958~ 1967
Color System Frame per
Second
Lines
Quantity
Bandwidth
(MHz)
B &W
Modulation
Color
Modulation
Audio
Modulation
NTSC 30 525 6 AM QAM FM
PAL 25 625 7-8 AM QAM FM
SECAM 25 625 7-8 AM FM FM
29

− Improved European colour television standard.
− Co-designed in Germany and England.
− More complex than NTSC, but better colours.
− 625 total lines in each frame.
− 576 picture lines and 720 pixels in each line
− Interlaced scanning at 25 frames per second.
− 50 fields per second.
PAL = Phase Alternation by Line
PAL Colour Signal
30

− The PAL signal, mainly used in Europe, China, Malaysia, Australia, New Zealand, the Middle East, and parts
of Africa.
− PAL stands for Phase Alternation by Line, which describes the way color information is encoded on the
sub-carrier.
− PAL signals employ an interlace scanning system with 625 scanning lines per frame, displayed at a rate of
25 frames per second.
− Color information is encoded and transmitted together with the luminance information using a 4.43-MHz
sub-carrier, which is flipped (phase alternated) by 180 degrees every other scanning line.
 This reduces the chance of color distortions when the phase of the sub-carrier shifts due to electrical or
mechanical reasons, during transmission or in video devices.
PAL Colour Signal
31

B-Y, U=0.493 (B’-Y’)
R-Y, V=0.877 (R’-Y’)
Chroma
32
𝜑
U and V in PAL System

− The CCVS is amplitude-modulated onto the RF vision carrier. The full level of the colour difference signals would cause
overmodulation of the RF vision carrier by the chrominance signal for certain coloured patterns.
− Αs a compromise between overmodulation on the one hand and degradation of signal-to-noise ratio on the other, an
overmodulation of 33% in both directions with fully saturated colours has been permitted since, in practice, fully saturated
colours hardly ever occur.
33
U and V in PAL System
• Amplitude modulation of RF vision carrier by
CCVS without reducing color difference
signals.
 In particular, the periodic suppression of
the RF carrier and its falling short of the
10% luminance level would cause heavy
interference.
 For this reason, the chrominance signal
amplitude has to be reduced.
Small Overmodulation
Latge Overmodulation

U=0.493 (B’-Y’)
V=0.877 (R’-Y’)
These particular weighting factors ensure
that
• the subcarrier excursions are around
33% (700mV×1.33= 934 mV) above
white level for saturated yellow and
cyan color bars
• the subcarrier excursions are around
33% (700mV×0.33=235 mV⇒ -235 mV)
maximum white level below black
level for red and blue bars.
34

PAL Encoder
37
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Color Y B-Y R-Y U V Amplitude Angle (°)
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
𝐔 𝒄𝒐𝒔 𝝎𝒔𝒄𝒕
U
V
± 𝑽𝒔𝒊𝒏 𝝎𝒔𝒄𝒕
𝒇𝒔𝒄 = 4.43 𝑀𝐻𝑧
Gate
Command at
back porch
BURST
± 𝒔𝒊𝒏 𝝎𝒔𝒄𝒕
𝒄𝒐𝒔 𝝎𝒔𝒄𝒕
Front Porch
700 mv
300 mv
BackPorch

Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
PAL Encoder
38
𝝋 = 𝟏𝟔𝟕°
-0.4388
+0.0965
S=0.44
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

PAL Encoder
39
𝝋 = 𝟐𝟖𝟑°
+0.1479
-0.6139
S=0.63
Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

PAL Encoder
40
𝝋 = 𝟐𝟒𝟏°
-0.2909
-0.5174
S=0.59
Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

PAL Encoder
41
𝝋 = 𝟔𝟏°
+0.2909
+0.5174
S=0.59
Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

PAL Encoder
42
𝝋 = 𝟏𝟎𝟑°
-0.1479
+0.6139
S=0.63
Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

PAL Encoder
43
𝝋 = 𝟑𝟒𝟕°
+0.4388
-0.0965
S=0.44
Front Porch
700 mv
300 mv
BackPorch
𝑼
𝑽
𝟎 ≤ 𝒀, 𝑹, 𝑮, 𝑩 ≤ 𝟏
Yellow 0.89 -0.89 0.11 -0.4388 0.0965 0.44 167
Cyan 0.7 0.3 -0.7 0.1479 -0.6139 0.63 283
Green 0.59 -0.59 -0.59 -0.2909 -0.5174 0.59 241
Magenta 0.41 0.59 0.59 0.2909 0.5174 0.59 61
Red 0.3 -0.3 0.7 -0.1479 0.6139 0.63 103
Blue 0.11 0.89 -0.11 0.4388 -0.0965 0.44 347
White 1.0 0 0 0 0 0 ---
Black 0 0 0 0 0 0 ---
S
U
M
PAL
B.M
B.M
Y
U
V
Gate
Command at
back porch
BURST

44
PAL Color Bar Signal
2
Y=0.620 V
U=0.306 V
V=0.070 V
Y=0.491 V
U=0.103 V
V=0.430 V
Y=0.411 V
U=0.202 V
V=0.360 V
Y=0.289 V
U=0.202 V
V=0.360 V
Y=0.209 V
U=0.103 V
V=0.430 V
Y=0.080 V
U=0.306 V
V=0.070 V

45
Cb Y Cr Y
Cb Y Cr Y
Y
𝑃′
𝑏
𝑃′
𝑟
SD-SDI Color Bars Signal
700 mV
0 mV
700 mV
0 mV
350 mV
700 mV
0 mV
350 mV
𝑌′
𝐶𝑟
′
𝐶𝑏
′
700 mV
0 mV
700 mV
0 mV
700 mV
0 mV
𝑅′
𝐺′
𝐵′
700 mV
0 mV
620 mV
-620 mV
491 mV
-491 mV
𝑅′
− 𝑌′
𝐵′
− 𝑌′
𝑌′

PAL Chrominance Vectors
0.25 0.5 0.75
-0.75 -0.5 -0.25
0.75
0.5
0.25
-0.25
-0.5
-0.75
-U +U
-V
R
B
Cy
Mg
Y
+Burst
-V
G
46

Line A Chrominance Vectors
0.25 0.5 0.75
-0.75 -0.5 -0.25
0.75
0.5
0.25
-0.25
-0.5
-0.75
-U +U
-V
R
B
Cy
Mg
Y
+Burst
-V
G
47

Line B Chrominance Vectors
0.25 0.5 0.75
-0.75 -0.5 -0.25
0.75
0.5
0.25
-0.25
-0.5
-0.75
-U +U
-V
-V
g
b
cy
mg
y
r
-Burst
48

Line A and B Chrominance Vectors
0.25 0.5 0.75
-0.75 -0.5 -0.25
0.75
0.5
0.25
-0.25
-0.5
-0.75
-U +U
-V
R
B
Cy
Mg
Y
+Burst
-V
g
b
cy
mg
y
r
G
-Burst
49

PAL Color TV Signal
50
Parameter Value
Picture Size 720×576
Frame Rate / Field Rate 25 frame per second /50 field per second
Field Frequency (𝒇𝒗) 50 Hz
Line Frequency (𝒇𝒉) 625×25=15625 Hz
Audio Sub Carrier Frequency (𝒇𝑺𝑪,𝒔𝒐𝒖𝒏𝒅) 5.5 MHz
Color Sub Carrier Frequency (𝒇𝑺𝑪) 283.75 x 𝒇𝒉 +25 = 4.43361875 MHz
Video
Carrier
0
Audio
Sub-Carrier
5.5 MHz
Color
Sub-Carrier
4.43 MHz
Chrominance Signal V
Chrominance Signal U
Audio
Signal
Video
Signal
-1.25 MHz
8 MHz

NTSC Color Signal
 NTSC is a standard-definition composite video signal format primarily used in North America, Japan, Korea,
Taiwan, and parts of South America.
 Its name is an acronym for National Television Systems Committee.
 Tends to suffer from bad colours.
• Nicknamed “Never The Same Colour”!
 525 total lines in each frame.
• 480 picture lines and 720 pixels in each line.
 Interlaced scanning at 30 frames per second.
• Actually 29.97 frames per second to be exact.
• 60 fields per second.
 Color information is encoded on a 3.58-MHz sub-carrier, which is transmitted together with the luminance
information.
51

52
+I
33°
33°
-Q
-I
R-Y
B-Y
Burst Phase
+Q 𝑨𝒓𝒄𝒕𝒂𝒏 (𝑸/ 𝑰) = 𝑯𝒖𝒆
𝑺𝒒𝒖𝒂𝒓𝒆 (𝑰 𝟐 + 𝑸 𝟐) = 𝑺𝒂𝒕𝒖𝒓𝒂𝒕𝒊𝒐𝒏
C
I: Orange-Cyan Q: Green-Purple

• The positive polarity of Q is purple, the negative is green. Thus, Q is often called the "green-purple" or "purple-
green" axis information.
• The positive polarity of I is orange, the negative is cyan. Thus, Q is often called the "orange-cyan" or "cyan-
orange" axis information.
• The human eye is more sensitive to spatial variations in the "orange-cyan" (the color of face!) than it is for the
"green-purple“. Thus, the "orange-cyan" or I signal has a maximum bandwidth of 1.5 MHz and the "purple-green"
only has a maximum bandwidth of 0.5 MHz.
• Now, the Q and I signals are both modulated by a 3.58 MHz carrier wave. However, they are modulated out of
90 degrees out of phase (QAM). These two signals are then summed together to make the C or chrominance
signal.
• The nomenclature of the two signals aids in remembering what is going on.
 The I signal is In-phase with the 3.58 MHz carrier wave.
 The Q signal is in Quadrature-phase with the 3.58 MHz carrier wave.
NTSC Color Signal
53

− Position the band limited chrominance at the high end of the luminance spectrum, where the luminance
is weak, but still sufficiently lower than the audio (at 4.5 MHz).
− The two chrominance components (I and Q) are multiplexed onto the same subcarrier using QAM.
− The resulting video signal including the baseband luminance signal plus the chrominance components
modulated to fc is called composite video signal.
NTSC Color Signal
54

− New chrominance signal (formed by Q and I) has the interesting property that the magnitude of the signal
represents the color saturation, and the phase of the signal represents the hue.
Phase = Arctan (Q/ I) = hue
Magnitude = Square (I 2+ Q 2) = saturation
− Now, since the I and Q signals are clearly phase sensitive -- some sort of phase reference must be
supplied. This reference is supplied after each horizontal scan and is included on the "back porch" of the
horizontal sync pulse as a color burst.
NTSC Color Signal
55
Q: Green-Purple
I: Orange-Cyan

0
20
40
60
80
100
IRE
Color burst
Phase=0°
White
level
Black
level
Blank
level
Sync
level
White
Yellow
Green
Magenta
Red
Blue
Black
Phase=167°
Phase=241°
Phase=61°
Phase=103°
Phase=347°
Blanking Interval Visible Line Interval
9 cycles
-20
- 40
Cyan
Phase=283°
Backporch
NTSC/EIA 75% Color Bar Signal
56
E’CB = 0.564 (E’B-E’Y)
(also known as PB in North America)
E’CR = 0.713 (E’R-E’Y)
(also known as PR in North America)

Monochrome NTSC Signal
− Early TV systems used local power line frequency as the field rate reference (Europe used 50 Hz, the USA used 60 Hz)
− Originally, black and white video ran at a true 30 fps.
− In the NTSC monochrome system the luminance signal is AM/VSB (Amplitude Modulation/Vestigial Sideband) modulated
onto the video carrier
57
0
VSB
6 MHz
Video Carrier
0
Audio Sub-Carrier
4.49999 MHz
Audio Signal
Video Signal
-1.25 MHz
Parameter Value
Frame Rate / Field Rate 30 frame per second /60 field per second
Field Frequency (𝒇𝒗) 60 Hz
Line Frequency (𝒇𝒉) 525×30=15750 Hz
Audio Sub Carrier Frequency (𝒇𝑺𝑪,𝒔𝒐𝒖𝒏𝒅) 4.5 MHz

NTSC Color Signal
− When color video was introduced, the frame rate slowed to 29.97 fps to allow color television to run on black-and-white
receivers ⇒ Compatibility with black and white receiver
− The audio subcarrier frequency required integer relationship to color subcarrier to prevent interference (due to the
physical limitations of the black and white circuits in older television sets, and issues involving sound waves).
− Reducing field rate from 60 to 59.94 Hz, allowed integer value of 4.49999 MHz possible for audio subcarrier.
58
Parameter Value
Frame Rate / Field Rate 59.94 frame per second /29.97 field per second
Field Frequency (𝒇𝒗) 59.94 Hz
Line Frequency (𝒇𝒉) 525×29.97=15734.25 Hz
Audio Sub Carrier Frequency (𝒇𝑺𝑪,𝒔𝒐𝒖𝒏𝒅) 286×𝒇𝒉= 4.49999 MHz (closed to 4.5 MHz)
Color Sub Carrier Frequency (𝒇𝑺𝑪) 227.5 x 𝒇𝒉 = 3.579545 MHz
Video Carrier
0
Audio Sub-Carrier
4.49999 MHz
Color Sub-Carrier
3.579545 MHz
Chrominance Signal Q (0.4 MHz)
Chrominance Signal I (1.4 MHz)
Audio Signal
Video Signal
Q: Green-Purple
I: Orange-Cyan
-1.25 MHz
VSB
286×15750= 4.504500 MHz
(not closed to 4.5 MHz)
𝒇𝒉 in Monochrome NTSC

NTSC Color Signal Compatibility Issue
Compatibility issue with black and white receiver
– Initially, black and white video ran at 30 fps. When color video was introduced, the frame rate slowed to
29.97 fps to allow color television to run on black-and-white receivers.
Disparity between real-time and video time
– This created a disparity between real-time and video time, as a fraction of a frame cannot be produced
in one second.
– In one hour, the difference between a 30 fps video and a 29.97 fps video is 108 frames ⇒ creating a lag
between video time and real time.
Ex:
– After 60 real-time minutes, a video playing at a frame rate of 29.97 fps will only read 00:59:56:12
59

– Frame rate is the measurement of individual images, known as frames created by an imaging device.
– Drop frame and non-drop frame were created before High Definition (HD), but the same rules still
apply.
SMPTE (Society of Motion Picture and Television Engineers)
29.97 fps NDF Color 60Hz Non-Real Time
29.97 fps DF Color 60Hz Real Time
30 fps NDF Black & White 60Hz Real Time
59.94 fps NDF Color HD 60Hz Non-Real Time
59.94 fps DF Color HD 60Hz Real Time
60 fps NDF Color HD 60Hz Real Time
EBU (European Broadcasting Union)
25 fps NDF Color 50Hz Real Time
50 fps NDF Color HD 50Hz Real Time
Film
24 fps NDF Color N/A Real Time
23.98 fps NDF Color HD 60Hz Non-Real Time
Frame Rate Standards
60
30
1.001
= 29.97
60
1.001
= 59.94

SMPTE Timecode
SMPTE (Society of Motion Picture and Television Engineers) timecode
– A standard for labeling frames of video or film for accurate editing, synchronization, and identification of
media.
– The final part of the SMPTE timecode reflects the frame number; this number can only go as high as the
frame rate.
61
t

Non-Drop Frame Time Code
Reducing Frame rate (30/1.001=29.97, 60/1.001=59.94) ⇒ Compatibility with black and white receiver
– Color video required that the frame rate be slowed to 29.97 fps.
– In one hour, the difference between a 30 fps video and a 29.97 fps video is 108 frames.
⇒ The disparity between real time and the measurement of video time
(as a fraction of a frame cannot be produced in one second)
• A video with 29.97 fps after 60 real-time minutes ⇒ Time code read 00:59:56:12
⇒ lag between video time and real time.
• A program using non-drop timecode ⇒ 3.6 seconds shorter per every hour
62

Drop Frame vs. Non-Drop Frame
63
Drop Frame Timecode
Non Drop Frame Timecode
– Drop frame and non-drop frame timecode do not alter the visual image in any way.
– No frames or images are lost in drop frame; it is simply a way of labeling every frame.
– They are methods of counting (you are not losing frames, the way they are being
counted has been changed).
– Two frame numbers are removed per minute, except every 10th minute, to make the
video 108 frames shorter within one hour , allowing the video to end in real time.

Drop Frame Time Code
Drop frame (DF) timecode
– Drop frame is a standard for broadcast using NTSC due to correlation with real time.
– It was introduced in an attempt to make 29.97 fps video indicate real-time to alleviate disparity between
real time and video time.
– DF does not actually remove any frames from your video; instead, it effectively drops a frame number
every time the remaining 0.03 of a frame adds up to a full frame (once every 33.33 seconds).
– In one hour, the difference between a 30 fps video and a 29.97 fps video is 108 frames.
– So, within that hour, DF video removes 108 frame numbers so that a 29.97 fps video will finish at 01:00:00:00
instead of 00:59:56:12.
64
𝟎. 𝟎𝟑 𝒐𝒇 𝒐𝒏𝒆 𝒇𝒓𝒂𝒎𝒆 × 𝟑𝟑. 𝟑𝟑 𝒔𝒆𝒄 ⇒ 𝟏 𝑪𝒐𝒎𝒑𝒍𝒆𝒕𝒆 𝑭𝒓𝒂𝒎𝒆 𝑫𝒖𝒓𝒂𝒕𝒊𝒐𝒏

Drop Frame and Non-Drop Frame in Editing System
– If two projects were created with identical cuts, both timelines in the software would be identical. Since
this does not affect the picture, choosing between drop or non-drop frame can be determined by
• the specifications of the editing system
• distribution media
• video editor’s preference
– Understanding frame rate helps us understand why these two methods exist.
– One format is not better than the other when it comes to your editing system.
– You can even toggle between drop frame and non-drop frame in most non-linear timelines.
– Adobe Premiere Pro CS3:
• In the title bar: Window > Window Options > Timeline Window Options ⇒ 30 fps Non-Drop Frame Timecode or
Drop Frame and click OK.
65

Drop Frame and Non-Drop Frame in Editing System
66

Drop Frame or Non-Drop Frame Captions
– NDF files (colon) ⇒ (hh:mm:ss:ff)
– DF files (a semi-colon or a period) ⇒ (hh:mm:ss;ff or hh:mm:ss.ff)
– Not all 29.97 fps video is drop frame!!!. Some 29.97 fps or 59.94 videos are non-drop frame (NDF), which
means that the timecode does not account for the difference in video time vs. real time.
– If you are captioning your video, it is important to know whether your video file is drop frame or non-drop
frame so that your captions are accurately synched with the timing of the media.
• At the end of a real-time hour, a DF video will have run 01:00:00:00
• At the end of a real-time hour, an NDF video will have run 00:59:56:12
– If you caption a DF video with NDF captions, the captions will not be synched with the video and will get
more and more out of sync as time goes on.
67

69
Different Formats Component Signals

70
(SDTV)
Y=0.11B+0.3R+0.59G
The Color Bars Test Signal

− Color-bar signals are used as an absolute color reference to maintain consistent
color reproduction throughout the entire production chain.
− Very common professional test signal.
− 8 bars with White, Black and all 6 primaries.
− Brightest bar on the left (White) and darkest on the right (Black)
• Each bar is a darker colour from left to right.
− Useful to check connections, colour, quality an many other things.
The Color Bars Test Signal
71
White, Yellow, Cyan, Green, Magenta, Red, Blue, Black

− In 100% color bar Each color (including the white bar) is a combination of equally adding the three
primary colors R, G, B and all have 100% saturations.
− The 75% color bar has the same 100% white bar but the levels of R, G and B for the colored bars is 75%.
− This maintains the level of the peak to 700 mV but reduces the saturation of the color bars.
The Colour Bars Test Signal
72

73
75 /0/75/0 100 /7.5/100/7.5 75 /7.5/75/7.5 100/0/75/0 100/7.5/75/7.5
100 /0/100/0
/ / /
100 0 100 0

74
100 /0/100/0 75 /0/75/0 100 /7.5/100/7.5 75 /7.5/75/7.5 100/0/75/0 100/7.5/75/7.5
1st number: white amplitude (white bar)
• The primary color signal level during the transmission of the white bar, that is, the maximum value of 𝑬𝑩
′
, 𝑬𝑮
′
, and 𝑬𝑹
′
.
2nd number: black amplitude (black bar)
• The primary color signal level during the transmission of the black bar, that is, the minimum value of 𝐄𝐁
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
.
3rd number: white amplitude from which color bars are derived
• The maximum level of the primary color signal during the transmission of the colored color bars, that is, the maximum value of 𝐄𝐁
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
.
4th number: black amplitude from which color bars are derived
• The minimum level of the primary color signal during the transmission of the colored color bars, that is, the minimum value of 𝐄𝐁
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
.

75
The Colour Bars Test Signal, 100% Bars (PAL) PAL 100/0/100/0
color bars signal waveform
− A fully saturated color bars signal with maximum
signal levels of 100% and minimum signal levels of
0%.
• 100% and 0% of the maximum value of 𝐄𝐁
′
, 𝐄𝐆
′
, and
𝐄𝐑
′
signal for white and black bars respectively.
′
, 𝐄𝐆
′
, and
𝐄𝐑
′
signals for colored bars.

− A fully saturated color bar signal with maximum signal
levels of 75% and minimum signal levels of 0%
− They are representative of the signals used to feed a
PAL encoder and would be obtained at the output of
a properly adjusted PAL decoder (625/50 countries).
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signal for white and black bars respectively.
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signals for colored bars.
76
PAL 75/0/75/0
75% amplitude
100% saturation with white and black
The Colour Bars Test Signal, 75% Bars (PAL)
The dotted outline of the luminance bar
represents a 100/0/75/0 color bars signal.

77
Graphic representation of the formation of 100/0/100/0 color bars Y signal from the primary Green, Blue and Red signals

78
Graphic representation of the formation of 100/0/100/0 color bars blue color difference signal from the primary Green, Blue and Red signals
E’B-Y = 0.493 (E’B-E’Y) (Called E’U in PAL)

79
Graphic representation of the formation of 100/0/100/0 color bars red color difference signal from the primary Green, Blue and Red signals
E’R-Y = 0.877 (E’R-E’Y) (Called E’V in PAL)

100% amplitude for white and black bars
100% amplitude for other bars
80
100% amplitude for white and black bars
75% amplitude for other bars
75% and 100% Bars

81
− A fully saturated color bar signal with maximum signal levels of
100% and minimum signal levels of 7.5%.
• 100% and 7.5% of the maximum value of 𝐄𝐁
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signal for
white and black bars respectively.
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signals for
colored bars.
The Colour Bars Test Signal, 100% Bars (NTSC) NTSC 100/7.5/100/7.5

82
− A fully saturated color bar signal with maximum signal levels of 75%
and minimum signal levels of 7.5%.
− These types of color bar signals were used in 525/60 countries except
Japan.
− They are representative of the signals used to feed an NTSC encoder
using the original philosophy behind the 1953 NTSC standard.
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signal for
white and black bars respectively.
′
, 𝐄𝐆
′
, and 𝐄𝐑
′
signals for
colored bars.
The Colour Bars Test Signal, 75% Bars (NTSC)
The dotted outline of the luminance bar
represents a 100/7.5/75/7.5 color bars signal.
NTSC 75/7.5/75/7.5

100% White PLUGE
75% Contrast Color Bars
10% Purple Chip
(+Q)
20% Blue Chip
(-I)
0% Black chip 0% Black chip
3.5 IRE 7.5 IRE +11.5 IRE
White
Castellation
Blue
castellation
Cyan
Castellation
Magenta
Castellation
83
SMPTE Color Bar for NTSC
Super-black
"blacker than black“
-I
Very dark
blue
+Q
Very dark
purple
+I
33°
33°
-Q
-I
R-Y
B-Y
Burst Phase
+Q
Setup level
(Black Level)

SMPTE Color Bar for NTSC
− NTSC Setup level (Black Level) is 7.5 IRE (7.5 %).
(In HD test signals Setup level (Black Level) is 0 IRE)
− PLUGE ("Picture Line-Up Generation Equipment")
• An intensity 4 IRE (4%) above black level, i.e. 11.5 IRE, in SD
in the rightmost (+3.5 IRE in HD)
• A middle one with intensity exactly equal to black level,
i.e. 7.5 IRE, in SD (0 IRE in HD)
• A leftmost one with intensity 4 IRE (4%) below black (super-
black or "blacker than black“, i.e., 3.5 IRE, in SD (-3.5 IRE in
HD)
− The top two-thirds of the television picture contain seven
vertical bars of 75% intensity.
− When using this test signal to set Brightness, Contrast, and
Chroma, all you really need to concern yourself with are the
75% Color Bars, 100% White Chip, and Pluge.
84
3.5 IRE: Super-black or "blacker than black“
PLUGE ("Picture Line-Up Generation Equipment")
It is with lifted blacks so you can see the pluge better.
100%
White PLUGE
75% Contrast Color Bars
10%
Purple Chip
(+Q)
20%
Blue Chip
(-I)
0%
Black chip
0%
Black chip
3.5 IRE 7.5 IRE +11.5 IRE
White
Castellation
Blue
castellation
Cyan
Castellation
Magenta
Castellation

+Q
A square of very
dark purple
-I
A square of very
dark blue
-I
Very dark
blue
+Q
Very dark
purple
In-phase and +Quadrature signals with the same gain as the color burst signal
− Analog NTSC Video Applicaion
⇒ To ensure properly demodulating of 3.58 MHz color subcarrier in receiver.
⇒ The vectors for the -I and +Q blocks should fall exactly on the I and Q axes.
− HDTV Video Application
⇒ For verification that the color information in the test signal is accurately centered on the scope.
85

86
The Colour Bars Test Signal, PAL and NTSC Color Bar

87
Cb Y Cr Y
Cb Y Cr Y
Y
𝑃′
𝑏
𝑃′
𝑟
SD-SDI Color Bars Signal
700 mV
0 mV
700 mV
0 mV
350 mV
700 mV
0 mV
350 mV
𝑌′
𝐶𝑟
′
𝐶𝑏
′
700 mV
0 mV
700 mV
0 mV
700 mV
0 mV
𝑅′
𝐺′
𝐵′
700 mV
0 mV
620 mV
-620 mV
491 mV
-491 mV
𝑅′
− 𝑌′
𝐵′
− 𝑌′
𝑌′

88
PAL CVBS output levels NTSC-M CVBS output levels
The Colour Bars Test Signal, PAL and NTSC Color Bar

90
Color Spectrum Seen by Passing White Light through a Prism.

− The color matching experiment was invented
by Hermann Graßmann (Grassmann) (1809 -
1877) about 1853.
− The observer adjusts the intensities of the red,
green, and blue lights, called primaries, until
the mixture matches the unknown.
91
Color Matching Test
546.1nm
435.8nm
700nm

Color Matching, Ex. 1
• Variable Power
• Fixed wavelength
92
546.1nm
435.8nm
700nm

93
p1 p2 p3
546.1nm
435.8nm
700nm

94
p1 p2 p3
546.1nm
435.8nm
700nm

Amount of the primary colors
needed for matching
95
p1 p2 p3
546.1nm
435.8nm
700nm

96
546.1nm
435.8nm
700nm

p1 p2 p3
97
546.1nm
435.8nm
700nm

98
p1 p2 p3
546.1nm
435.8nm
700nm

p1 p2 p3
A “negative” amount
of p2 is needed for
matching
p1 p2 p3
Amount of the primary colors
needed for matching
99
p1 p2 p3
546.1nm
435.8nm
700nm

100
546.1nm
435.8nm
700nm

True Color Matching Functions
• The amounts of primaries (700 nm (red), 546.1 nm (green) and 435.8 nm (blue)) needed to match the
monochromatic test color at a given wavelength.
103
546.1nm
435.8nm
700nm
CIE RGB Color Space (CIE 1931 RGB Color Space)

− The CIE 1931 RGB color space is created by the
International Commission on Illumination (CIE) in 1931.
− Rather than specify the brightness of each primary, the
curves are normalized to have constant and equal area
beneath them.
− This area is fixed to a particular value by specifying that
Color Matching Functions
• The normalized weight factors ത
𝒓 𝝀 , ഥ
𝒈 𝝀 and ഥ
𝒃 𝝀 are
called CIE color matching functions.
CIE RGB Color Space
The CIE 1931 RGB color matching functions
(Stiles and Birch 1931 color matching functions).
Relative intensity (amounts of normalized primaries)
104
546.1
435.8 700
න
0
∞
ҧ
𝑟 𝜆 𝑑𝜆 = න
0
∞
ҧ
𝑔 𝜆 𝑑𝜆 = න
0
∞
ത
𝑏 𝜆 𝑑𝜆

105
Cone Sensitivity and CIE RGB Color Matching Function
CIE RGB Color Space

− The resulting normalized color matching functions are then scaled in the r:g:b ratio of 1:4.5907:0.0601 for
source luminance to reproduce the true color matching functions (72.0962:1.3791:1 for source radiance).
CIE Standard Primaries
− In the diagram the height represents the contribution to the luminance for source luminance.
− Three lamps with spectral distributions R, G, B and weight factors R,G,B {=0…100} generate the color
impression C.
R=1 ത
𝒓 𝝀 = 𝟕𝟎𝟎
G=4.5907 ഥ
𝒈 𝝀 = 𝟓𝟒𝟔. 𝟏
B=0.0601 ഥ
𝒃 𝝀 = 𝟒𝟑𝟓. 𝟖
106
R,G,B
C=RR+GG+BB
Ratio 1:4.5907:0.0601
CIE RGB Color Space

R, G and B Tristimulus Values
• Using CIE color matching functions ത
𝒓 𝝀 , ഥ
𝒈 𝝀 and ഥ
𝒃 𝝀 , the R, G and B tristimulus values for a color with a
spectral power distribution 𝑺 𝝀 or 𝑷 𝝀 would then be given by (K is a scaling factor (usually 1 or 100)).
• For a spectral pure color C with a fixed wavelength λ with normalized weight factors ത
𝒓 𝝀 , ഥ
𝒈 𝝀 and ഥ
𝒃 𝝀 .
107
C=ത
𝒓 𝝀 R+ഥ
𝒈 𝝀 G+ഥ
𝒃 𝝀 B
R = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑟 𝜆 𝑑𝜆 G = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑔 𝜆 𝑑𝜆 B = 𝑘 න
0
∞
𝑆 𝜆 ത
𝑏 𝜆 𝑑𝜆
CIE RGB Color Space
C=RR+GG+BB
R,G,B
𝑺 𝝀
R
G
B
න
×

Example: The pure spectral color associated with 600nm an (R, G, B) coordinate of (0.34, 0.062, 0.00).
108
CIE RGB Color Space
C 𝝀 =ത
𝒓 𝝀 R+ഥ
𝒈 𝝀 G+ഥ
𝒃 𝝀 B
C 𝝀 =𝟎. 𝟑𝟒R+𝟎. 𝟎𝟔𝟐G+𝟎. 𝟎𝟎B

109
C 𝝀 =ത
𝒓 𝝀 R+ഥ
𝒈 𝝀 G+ഥ
𝒃 𝝀 B
C 𝝀 =−𝟎. 𝟕𝟐R+𝟎. 𝟖𝟓G+𝟎. 𝟒𝟖B
CIE RGB Color Space
Example: The pure spectral color associated with 500nm has an (R, G, B) coordinate of (-0.72, 0.85, 0.48)

110
C=RR+GG+BB
C=1R+0.8G+0.2B
R,G,B
R = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑟 𝜆 𝑑𝜆 G = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑔 𝜆 𝑑𝜆 B = 𝑘 න
0
∞
𝑆 𝜆 ത
𝑏 𝜆 𝑑𝜆
𝑆 𝜆
Example: R,G and B extraction for a point on the lemon
− By taking the area under the curve of the product of the spectral curve and the color matching functions,
we’re left with an (R, G, B) triplet (1.0, 0.8, 0.2) uniquely identifying this color.
CIE RGB Color Space

111
Perceptible Colors by Human Eye
CIE xy Chromaticity Diagram (CIE 1931 xy Chromaticity Diagram )

This triangle slice of the cube has the property that R+G+B=1, and we can use R+G+B as a crude approximation of lightness.
113
R,G and B: o to 1
CIE RGB Color Space

114
CIE RGB Color Space
A side view of triangular slice
r+g+b=1

The RGB primaries can be interpreted as unit
vectors emanating from the origin of the cube.
115
CIE RGB Color Space and RGB Color Cube
− In terms of digital image processing, the hardware-oriented
models most commonly used in practice are the RGB model
for color monitors and a broad class of color video cameras.
− Each color appears in its primary spectral components of red,
green, and blue.
− The RGB primary values are at three corners.
− The grayscale (points of equal RGB values) extends from
black to white along the line joining these two points.
− For convenience, the assumption is that all color values have
been normalized in the range [0, 1].

116
− The number of bits used to represent each pixel is called the pixel depth.
− 8-bit for each of the R, G, and B ⇒ each RGB color pixel [that is, a triplet of values (R, G, B)] has a depth of 24 bits
− The total number of possible colors in a 24-bit RGB image is 283
= 16, 777, 216.

117

• A normalized orthogonal space, with R/G/B as the three basis.
• We can plot all colors in 3D space constructed by RGB.
118
CIE RGB Color Space
(Stiles and Birch 1931 color matching functions).
Negative values for R
Some negative
values for G
g
b
r

119
CIE RGB Color Space
Negative values for R
− Because sometimes, people only need to care about the hue and saturation of the color, ignoring the intensity, meaning
we can reduce the dimensionality by dropping one dimension.
• This is usually done by projecting the curve onto the plane r+g+b=1.
• Another way to think about it is to shoot a ray from the original to every point on the curve, find the intersection set
of these rays with the plane r+g+b=1, which is also a curve.
g
b
r g
b
r
Some negative
values for G

− The total color space of the human eye is
greater than the experimental results of CIE RGB.
− CIE RGB was not perfect, but considering the
technology available at the time you could say it
was a wonderful effort.
− Illuminant E is an equal-energy radiator;
• It has a constant SPD (Spectral Power
Density) inside the visible spectrum.
• It is useful as a theoretical reference
• An illuminant that gives equal weight to all
wavelengths, presenting an even color.
Gamut of the CIE RGB primaries and location of
primaries on the CIE 1931 xy chromaticity diagram.
The triangle is CIE RGB.
Out of CIE RGB
space.
CIE 1931 xy chromaticity diagram
CIE RGB
120
CIE RGB Color Space
Primaries White
Red Green Blue Illuminant E
x y x y x y x y
0.7347 0.2653 0.2738 0.7174 0.1666 0.0089 1/3 1/3

121
𝑟 =
𝑅
𝑅 + 𝐺 + 𝐵
𝑔 =
𝐺
𝑅 + 𝐺 + 𝐵
𝑏 =
𝐵
𝑅 + 𝐺 + 𝐵
𝑟 + 𝑔 + 𝑏 = 1
𝑏 = 1 − 𝑟 − 𝑔
rg Chromaticity Diagram (two dimensions of the normalized RGB)
The CIE RGB space can be used
to define chromaticity (hue and
saturation) in the usual way.

− The chromaticity specifies the hue and
saturation, but not the lightness.
− The chromaticity coordinates are r, g and b
where
− The chromaticity coordinates are 𝒓 , 𝒈 and are
extracted from CIE RGB space by normalization.
− It is a two-dimensional color space in which
there is no intensity information.
122
𝑟 =
𝑅
𝑅 + 𝐺 + 𝐵
𝑔 =
𝐺
𝑅 + 𝐺 + 𝐵
𝑏 =
𝐵
𝑅 + 𝐺 + 𝐵
𝑟 + 𝑔 + 𝑏 = 1
𝑏 = 1 − 𝑟 − 𝑔

E Point
− White point where r,g are equal and have a value of 1/3.
𝒈 + 𝒓 = 𝟏 (𝒚 + 𝒙 = 𝟏 )
− As the x (red) increases the y (green) decreases by the
same amount.
− Any point on the line has no b information and formed by
some combination of r and g.
− In computer vision and digital imagery only the first
quadrant is used because a computer cannot display
negative RGB values. The range of RGB is 0-255 for most
displays.
− When trying to form color matches using real stimuli,
negative values are needed to match all possible colors.
− This is why the rg chromaticity diagram extends in the
negative r direction.
123
.E
(𝒚 + 𝒙 = 𝟏)
𝑟 + 𝑔 = 1
𝑟 =
𝑅
𝑅 + 𝐺 + 𝐵
𝑔 =
𝐺
𝑅 + 𝐺 + 𝐵
𝑏 =
𝐵
𝑅 + 𝐺 + 𝐵
𝑟 + 𝑔 + 𝑏 = 1
𝑏 = 1 − 𝑟 − 𝑔

− The CIE 1931 XYZ color space is created by the International Commission on Illumination (CIE) in 1931.
− In order to avoid negative RGB numbers, the CIE consortium had introduced coordinate system XYZ.
− The CIE XYZ color space encompasses all color sensations that are visible to a person with average
eyesight. That is why CIE XYZ is a device-invariant representation of color.
X=0.49000R+0.31000G+0.20000B
Y=0.17697R+0.81240G+0.01063B
Z=0.00000R+0.01000G+0.99000B
X , Y and Z Tristimulus Values
RGB base vectors and
color cube in XYZ system
CIE XYZ Color Space (CIE 1931 XYZ Color Space)
124
X=2.36461R-2.36499G+0.00031B
Y=-0.89654R+6.54822G-0.00087B
Z=-0.46807R+0.40747G+0.06065B
X,Y, X: Imaginary or Synthetically Primaries
ҧ
𝑥 𝜆 = 2.7688 ҧ
𝑟 𝜆 + 1.7517 ത
𝑔 𝜆 + 1.1301ത
𝑏(𝜆)
ത
𝑦 𝜆 = 1.0000 ҧ
𝑟 𝜆 + 4.5906 ത
𝑔 𝜆 + 0.0601ത
𝑏(𝜆)
ҧ
𝑧 𝜆 = 0.0000 ҧ
𝑟 𝜆 + 0.0565 ത
𝑔 𝜆 + 5.5942ത
𝑏(𝜆)
CIE 1931 XYZ Color-matching functions
C=XX+YY+ZZ

125
− The CIE XYZ color space encompasses all color sensations that are visible to a person with average
eyesight. That is why CIE XYZ is a device-invariant representation of color.
− The RGB system is essentially defined by three non-orthogonal base vectors in XYZ.
CIE XYZ Color Space
RGB base vectors and
color cube in XYZ system

CIE XYZ Color Space
126
Human Visible Part of CIE XYZ
Color Space
510nm
500nm
460nm
480nm
540nm
560nm
580nm
620nm
600nm
Can be reconstruct by R,G and B
The RGB system is essentially defined by
three non-orthogonal base vectors in XYZ.
Color Space

CIE XYZ Color Space
127
Color Space
510nm
500nm
460nm
480nm
540nm
560nm
580nm
620nm
600nm
Triangle plane
𝑥 + 𝑦 + 𝑧 = 1

− In 1931, based on the results of the CIE RGB version of the human eye, CIE
mathematically determined a color space called the CIE XYZ 1931 color space.
• XYZ is not RGB, they are imaginary or synthetically primaries.
• The primaries X,Y,Z are sums of delta functions.
• X and Z do not contribute to the luminance. This is a special trick in the CIE
system. The integrals are zero, here represented by the sum of the heights.
• The luminance is defined by Y only.
128
R,G,B
X=2.36461R-2.36499G+0.00031B
Y=-0.89654R+6.54822G-0.00087B
Z=-0.46807R+0.40747G+0.06065B
CIE XYZ Color Space
X,Y,Z: Imaginary or Synthetically Primaries

Relative sensitivity
129
ҧ
𝑥 𝜆 = 2.7688 ҧ
𝑟 𝜆 + 1.7517 ҧ
𝑔 𝜆 + 1.1301ത
𝑏(𝜆)
ത
𝑦 𝜆 = 1.0000 ҧ
𝑟 𝜆 + 4.5906 ҧ
𝑔 𝜆 + 0.0601ത
𝑏(𝜆)
ҧ
𝑧 𝜆 = 0.0000 ҧ
𝑟 𝜆 + 0.0565 ҧ
𝑔 𝜆 + 5.5942ത
𝑏(𝜆)
CIE XYZ Color Space
CIE 1931 XYZ Color-matching (Standard Observer ) functions

− X, Y and Z are extrapolations of RGB and created mathematically to avoid negative numbers and are called X, Y
and Z Tristimulus Values and can be calculated from R , G and B Tristimulus Values.
130
• Y means luminance
• Z is somewhat equal to blue
• X is a mix of cone response curves chosen to be orthogonal to luminance and non-negative.
X=0.49000R+0.31000G+0.20000B
Y=0.17697R+0.81240G+0.01063B
Z=0.00000R+0.01000G+0.99000B
CIE XYZ Color Space

− A given spectral color distribution P(λ) or S(λ) delivers the three coordinates XYZ by
these integrals in the range from 380nm to 700nm or 800nm (Mostly, the arbitrary factor
k is chosen for a normalized value Y=1 or Y=100)
− For a given spectral color distribution P(λ) or S(λ)
− For a spectral pure color C with a fixed wavelength λ with normalized weight factors
ҧ
𝑥 𝜆 , ത
𝑦 𝜆 and ҧ
𝑧 𝜆 .
131
X = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑥 𝜆 𝑑𝜆 Y = 𝑘 න
0
∞
𝑆 𝜆 ത
𝑦 𝜆 𝑑𝜆 Z = 𝑘 න
0
∞
𝑆 𝜆 ҧ
𝑧 𝜆 𝑑𝜆
C=ഥ
𝒙 𝝀 X+ഥ
𝒚 𝝀 Y+ത
𝒛 𝝀 Z
CIE XYZ Color Space
X=2.36461R-2.36499G+0.00031B
Y=-0.89654R+6.54822G-0.00087B
Z=-0.46807R+0.40747G+0.06065B
C=XX+YY+ZZ
S(λ)
Spectral Color Distribution
×
X
Y
Z
න

Reflective
3
Spectral Reflectance
S(λ)
Reflection
1- Emissive Case: Spectral Radiance Le,Ω,λ(λ)
2- Transmissive case: Spectral Transmittance S(λ)
3- Reflective Case: Spectral Reflectance S(λ)
132
CIE XYZ Color Space
Transmissive
Spectral Transmittance
S(λ)
2
Transmission
Spectral Power Distribution (SPD) of the Illuminant
I(λ)
Black body radiation in different temperatures
1
Emissive
Le,Ω,λ(λ)

I. X, Y and Z in Emissive Case
− The tristimulus values for a color with a spectral radiance Le,Ω,λ(λ) are given by:
133
CIE XYZ Color Space
×
CIE 1931 XYZ Color-matching functions (Standard Observer Functions)
Relative
sensitivity
Black body radiation in different temperatures
Le,Ω,λ(λ)
C=XX+YY+ZZ
X
Y
Z
න
X = න
0
∞
𝐿𝑒,Ω,𝜆 𝜆 ҧ
𝑥 𝜆 𝑑𝜆 Y = න
0
∞
𝐿𝑒,Ω,𝜆 𝜆 ത
𝑦 𝜆 𝑑𝜆 Z = න
0
∞
𝐿𝑒,Ω,𝜆 𝜆 ҧ
𝑧 𝜆 𝑑𝜆

II. X, Y and Z in Reflective and transmissive cases:
− The spectral reflectance S(λ) or spectral transmittance S(λ) of the object being measured, multiplied by
the spectral power distribution (SPD) of the illuminant I(λ).
− K is a scaling factor (usually 1 or 100), and the standard limits of the integral are [380,780].
134
CIE XYZ Color Space
C=XX+YY+ZZ
X
Y
Z
න
X =
𝐾
𝑁
න
0
∞
𝑆 𝜆 𝐼 𝜆 ҧ
𝑥 𝜆 𝑑𝜆 Y =
𝐾
𝑁
න
0
∞
𝑆 𝜆 𝐼 𝜆 ത
𝑦 𝜆 𝑑𝜆 Z =
𝐾
𝑁
න
0
∞
𝑆 𝜆 𝐼 𝜆 ҧ
𝑧 𝜆 𝑑𝜆 𝑁 = න
0
∞
𝐼 𝜆 ത
𝑦 𝜆 𝑑𝜆
×
I(λ)
Spectral Power Distribution (SPD)
S(λ)
×
Spectral Reflectance

135
CIE XYZ Color Space
X, Y and Z Calculation Example
(XYZ)

136
CIE XYZ Color Space
S(λ)
I(λ)
S(λ)
I(λ)

137
C=XX+YY+ZZ
CIE XYZ Color Space
X
Y
Z

CIE XYZ Color Space and rg Chromaticity Diagram
− Diagram in CIE rg chromaticity space showing the
construction of the triangle specifying the CIE XYZ
color space.
− The triangle Cb-Cg-Cr is just the xy = (0, 0), (0, 1),
(1, 0) triangle in CIE xy chromaticity space.
• Cb=(x=0,y=0)
• Cg=(x=0, y=1)
• Cr=(x=1,y=0)
− Notice that the spectral locus passes through
• rg = (0, 0) at 435.8 nm
• rg = (0, 1) at 546.1 nm
• rg = (1, 0) at 700 nm.
− The equal energy point (E) is at rg = xy = (1/3, 1/3).
138
CIE XYZ color space
𝑟 =
𝑅
𝑅 + 𝐺 + 𝐵
𝑔 =
𝐺
𝑅 + 𝐺 + 𝐵
𝑏 =
𝐵
𝑅 + 𝐺 + 𝐵
𝑟 + 𝑔 + 𝑏 = 1
𝑏 = 1 − 𝑟 − 𝑔
(x=1,y=0)
(x=0, y=1)
(x=0,y=0)

1- CIE 1931 2° Standard Observer (CIE 2° Standard Observer)
− Due to the distribution of cones in the eye, the tristimulus values depend on the observer's field of view.
− To eliminate this variable, the CIE defined a color-mapping function called the 2° Standard (colorimetric) Observer, to
represent an average human's chromatic response within a 2° arc inside the fovea (by Stiles and Birch 1931).
− This angle was chosen owing to the belief that the color-sensitive cones resided within a 2° arc of the fovea.
CIE Standard Observers
139
CIE 1931 XYZ Color-matching
(Standard Observer ) functions

2- CIE 1964 10° Standard Observer (CIE 10° Standard Observer)
− In 1964, the CIE defined an additional standard observer, this time based upon a 10 field of view; this is referred to as the
10 Supplementary Standard Observer.
− A more modern but less-used alternative Standard Observer, which is derived from the work of Stiles and Burch and
Speranskaya.
− For the 10° experiments, the observers were instructed to ignore the central 2° spot. The 1964 Supplementary Standard
Observer function is recommended when dealing with more than about a 4° field of view.
140
The CIE XYZ standard observer
color matching functions

141
− At normal viewing distance of 50 cm, the circle on the top represents the 2° field on which the CIE 1931
standard observer is based.
− The figure at the bottom is the 10° field on which the 1964 CIE supplementary standard observer is based.
CIE 1931 2° Standard Observer
CIE 1964 10° Standard Observer:

− It is important to make separate the concept of chromaticity (which defined how colorful a color is) from
the concept of a color's brightness.
− The CIE 𝑥𝑦𝒀 color space was developed in order to be able to separate these two properties and use only
two components (x and y) to encode the color's chromaticity and keep the Y value from the XYZ
tristimulus values to encode the color's brightness or value.
− The idea is simple. It consists of normalizing the three components of a XYZ color by the sum of these
components.
− In the CIE 𝑥𝑦𝒀 color space, x and y are normalized values.
− Because it is important to keep track of the original color's brightness, we will also store the original Y value
from the CIE XYZ color next to the x and y values.
− In the XYZ color space, Y represents the color's brightness.
− In the CIE 𝑥𝑦𝒀 color space, the xy values can be seen as a representation of the color's chromaticity while
the Y values can be seen as a representation of the color's intensity or brightness value.
CIE xyY Color Space (CIE 1931 xyY Color Space)
142

− The chromaticity values 𝒙, 𝒚, 𝒛 are independent of the luminance by
− All the values are on the triangle plane 𝒙 + 𝒚 + 𝒛 = 𝟏, projected by a line
through the arbitrary color XYZ and the origin, if we draw XYZ and 𝑥𝑦𝑧 in
one diagram.
− This is a planar projection.
− The center of projection is in the origin.
− The chromaticity values 𝒙, 𝒚 𝒂𝒏𝒅 𝒛 depend only on
• the hue (dominant wavelength)
• the saturation
Projection and chromaticity plane
Triangle plane
(𝑥, 𝑦, 𝑧)
143
𝑥 + 𝑦 + 𝑧 = 1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍
𝒛
𝒚
𝒙
XYZ
𝑥 + 𝑦 + 𝑧 = 1
CIE xyY Color Space
𝒁
𝒀
𝑿

− The CIE 𝑥𝑦𝒀 color space is a transformation of the CIE XYZ
color space onto 2 dimensions.
− The vertical projection onto the 𝑥𝑦-plane is the chromaticity
diagram CIE 𝑥𝑦𝒀 (view direction).
XYZ color space extraction from CIE 𝒙𝒚𝒀 color space
− To reconstruct a color triple XYZ from the chromaticity values
𝑥𝑦, we need an additional information, the luminance Y.
− The 𝑋 and 𝑍 tristimulus values can be calculated back from
the chromaticity values 𝑥 and 𝑦 and the 𝒀 tristimulus value as
144
𝑌
𝑍 =
𝑌
𝑦
𝑧 =
𝑌
𝑦
(1 − 𝑥 − 𝑦)
𝑋 =
𝑌
𝑦
𝑥
All visible (matchable) colors which
differ only by luminance, map to the
same point in the chromaticity diagram.
𝑋
𝑥
=
𝑌
𝑦
=
𝑍
𝑧
CIE xyY Color Space
𝑥
+
𝑦
+
𝑧
=
1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍
Triangle plane
(𝑥, 𝑦, 𝑧)
𝒛
𝒚
𝒙
XYZ
𝑥 + 𝑦 + 𝑧 = 1
Chromaticity Diagram xyY
𝒁
𝒀
𝑿

145
CIE xyY Color Space
y
y
2D View of CIE xyY Color Space

146
CIE xyY Color Space
cvc
v
𝑌
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑌
𝑥
𝑦
y
y
Chromaticity Diagram xyY
2D View of CIE xyY Color Space

148
Linear y-axis
Logarithmic y-axis
nit
CIE xyY Color Space

151
Wide Color Gamut (WCG) and High Dynamic Range (HDR)

CIE xy (or xyY) Chromaticity Diagram (CIE 1931 xy (or xyY) Chromaticity Diagram )
152
𝑥 + 𝑦 + 𝑧 = 1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍
• Y means luminance
• Z is somewhat equal to blue
• X is a mix of cone response curves chosen to be
orthogonal to luminance and non-negative.
The CIE 1931 color space
chromaticity diagram
locus of non-spectral purples
𝑥
𝑦
The chromaticities of black-body light
sources of various temperatures, and lines
of constant correlated color temperature
− Using normalized stimulus values 𝑥, 𝑦, 𝑧, a CIE 1931
color space chromaticity diagram is produced.
− The chromaticity of a color is specified by two
derived parameters x and y

153
CIE xy (or xyY) Chromaticity Diagram

154
y
x
CIE RGB
Locus of spectral
(monochromatic) colors
𝑥
𝑦
Z
X
Y
The CIE primaries X, Y, and Z
− Since the coordinates x and y tell us the
chromaticity of a color, we can use a chart
with x and y as its axes to plot points that
indicate chromaticity, usually called the CIE x-
y chromaticity diagram.
− Adding the chromaticity of the three imaginary
primaries of the CIE XYZ color space, X, Y, and
Z on the x-y chromaticity diagram (these
primaries don’t really have a chromaticity
because we can not see them by eye!!).
− Even though primaries X, Y, and Z have no
physical reality, they participate just fine in the
mathematics by which a set of X, Y, and Z
values define a color.
1
1
X=2.36461R-2.36499G+0.00031B
Y=-0.89654R+6.54822G-0.00087B
Z=-0.46807R+0.40747G+0.06065B

X+Y=1,X=Y=0.5 Point:
• To find the chromaticity of the color that would
be produced by adding equal amounts of
primary X and primary Y if we could actually do
that.
• X=Y=0.5, X+Y=1
• A bit outside of the visual gamut
X+Y+Z Point:
• Adding same amount of primary Z
• X=Y=Z=1/3
• The equal amounts of primary X,Y and primary Z
• Inside of the visual gamut
• White point of this color space
155
y
x
X+Y=1
CIE RGB
CIE 1931 xy
X=1/3
Y=1/3
(X+Y)+Z Point
Locus of spectral
𝑥
𝑦
X+Y=1, X=Y=0.5 Point
1
1
X
Z
Y

• The chromaticity diagram might look two-dimensional but it is really three dimensional.
• The diagram is only the most ‘widely used’ cross section of it.
156
Human Visible Part of
CIE XYZ Color Space
510nm
500nm
460nm
480nm
540nm
560nm
580nm
620nm
600nm
y
x
X+Y=1
CIE RGB
CIE 1931 xy
Locus of spectral
Part of CIE XYZ 1931 color space (2D View)
𝑥
𝑦
Z
X
Y
X+Y=1, X=Y=0.5 Point
1
1
𝑥 + 𝑦 + 𝑧 = 1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍

− The biggest issue with CIE 1931 is the uniformity with chromaticity, the 3D color space is not visually uniformed.
− The CIE 1976 (CIELUV) was created by the CIE as a simple-to-compute transformation of the 1931 CIE XYZ color.
− It was put forward in an attempt to provide a more uniform color spacing than CIE 1931 for colors at approximately the
same luminance.
− UCT: Uniform Chromaticity Scale
157
CIE 1976 UCS chromaticity diagram
((u′, v′) chromaticity diagram)
CIE 1976 L*u*v* or CIELUV Color Space, CIE 1976 UCS Chromaticity Diagram
Perceptually more uniform
BT.709
BT.2020
BT.709
BT.2020
CIE (x,y) chromaticity diagram

− It is extensively used for applications such as computer graphics
which deal with colored lights.
− The key advantage of this color space is that the distance
between two points is approximately proportional to the
perceived color difference.
− The same distance between any two points are presumed to be
perceptually equal.
− In CIE 1931 color space, the color resulting from the addition of
two different colors will fall on a connecting line.
− In CIELUV color space, the color resulting from the addition of
two different colors will fall on a connecting line when the
mixtures are constant in lightness.
• So, it is intended to provide a perceptually more uniform
color spacing for colors at approximately the same
luminance.
158
CIE 1976 uniform chromaticity scale (UCS) diagram
Distance ⇒ Proportional to the
perceived color difference

159
CIE 1976 CIE 1931

160
A perceptually more uniform color
spacing for colors at approximately
the same luminance.

RGB Color Cube in the CIE LUV Color Space
− The RGB-representable colors occupy only part of the LUV color space limited by the nominal ranges,
therefore there are many LUV combinations that result in invalid RGB values.
161

sRGB (Standard RGB)
− sRGB is a standard color space, defined by
companies, mainly Hewlett-Packard (HP) and
Microsoft.
− sRGB is a color space that defines a range of
colors that can be displayed on screen or in print.
− It is the most widely used color space and is
supported by most
• operating systems
• software programs
• monitors
• printers
− The sRGB specification make sure colors are
represented the same way across different
software programs and devices.
162

− sRGB uses the ITU-R BT.709 primaries, the same
as in studio monitors and HDTV, a transfer
function (gamma curve) typical of CRTs, and a
viewing environment designed to match typical
home and office viewing conditions.
− This specification allowed sRGB to be directly
displayed on typical CRT monitors of the time,
which greatly aided its acceptance.
sRGB (Standard RGB)
163
Parameter Values
Opto-electronic transfer
characteristics before
non-linear pre-correction
Assumed linear
Primary colours and
reference white
Chromaticity coordinates
(CIE, 1931)
x y
Red primary (R) 0.64 0.33
Green primary (G) 0.30 0.60
Blue primary (B) 0.15 0.06
Reference white (D65) 0.3127 0.3290

− YPbPr is the analog version of the YCbCr color space.
− The term invalid refers to RGB components outside the normalized RGB limits of (1, 1, 1).
− When processing information in a non-RGB color space (such as YUV, or YCbCr), care must be taken that combinations
of values are not created that result in the generation of invalid RGB colors.
− Only about 25% of all possible signal values in the YPbPr domain are used to present the complete gamut of colors in the
R'G'B' domain.
− The converting the color values from R'G'B' space to YPbPr space limits the range of colors.
− Care must be taken when translating between formats to ensure that the dynamic gamut of the signal is not exceeded.
Digital quantization of analog component signals
Definition of luminance and color-difference signals
Y'P'bP'r Color Cube (Color Space)
165
Y'P'bP'r
R'G'B'
Y'
P'b
P'r
RGB normalized limits transformed into the YPbPr color space

Y, U, and V components
Y, Cb and Cr components 166
YCbCr and YUV Color Models
B-Y,
U=0.493
(B’-Y’)
R-Y, V=0.877 (R’-Y’)
Chroma
𝜑

– The colour space in PAL is represented by YUV, where Y represents the luminance and U and V represent
the two colour components.
– The basis YUV colour space can be generated from gamma-corrected RGB (referred to in equations as
R’G’B’) components as follows:
– The Y'U'V' notation means that the components are derived from gamma-corrected R'G'B'.
– Initially YUV is
1) the re-coding of RGB for transmission efficiency (minimizing bandwidth)
2) and for downward compatibility with black-and white television (analogue color TV broadcasting).
– The principal advantage of the YUV model in image processing
⇒ decoupling of luminance and color information
⇒ the luminance component of an image can be processed without affecting its color component
YUV Color Model (Color Space)
167
𝒀′ = 𝟎. 𝟐𝟗𝟗 𝑹′ + 𝟎. 𝟓𝟖𝟕 𝑮′ + 𝟎. 𝟏𝟏𝟒 𝑩′
𝑼′ = −𝟎. 𝟏𝟒𝟕 𝑹′ − 𝟎. 𝟐𝟖𝟗 𝑮′ + 𝟎. 𝟒𝟑𝟔 𝑩′ = 𝟎. 𝟒𝟗𝟐 (𝑩′ − 𝒀′)
𝑽′ = 𝟎. 𝟔𝟏𝟓 𝑹′ − 𝟎. 𝟓𝟏𝟓 𝑮′ − 𝟎. 𝟏𝟎𝟎 𝑩′ = 𝟎. 𝟖𝟕𝟕 (𝑹′ − 𝒀′)

RGB Colors Cube in the YUV Color Space
– There are many combinations of YUV values from nominal
ranges that result in invalid RGB values, because the possible
RGB colors occupy only part of the YUV space limited by
these ranges.
– Figure shows the valid color block in the YUV space that
corresponds to the RGB color cube RGB values that are
normalized to [0..1].
168
YUV Color Model (Color Space)
𝒀′ = 𝟎. 𝟐𝟗𝟗 𝑹′ + 𝟎. 𝟓𝟖𝟕 𝑮′ + 𝟎. 𝟏𝟏𝟒 𝑩′
𝑼′ = −𝟎. 𝟏𝟒𝟕 𝑹′ − 𝟎. 𝟐𝟖𝟗 𝑮′ + 𝟎. 𝟒𝟑𝟔 𝑩′ = 𝟎. 𝟒𝟗𝟐 (𝑩′ − 𝒀′)
𝑽′ = 𝟎. 𝟔𝟏𝟓 𝑹′ − 𝟎. 𝟓𝟏𝟓 𝑮′ − 𝟎. 𝟏𝟎𝟎 𝑩′ = 𝟎. 𝟖𝟕𝟕 (𝑹′ − 𝒀′)
𝑹′ = 𝒀′ + 𝟏. 𝟏𝟒𝟎 𝑽′
𝑮′ = 𝒀′ − 𝟎. 𝟑𝟗𝟒 𝑼′ − 𝟎. 𝟓𝟖𝟏 𝑽′
𝑩′ = 𝒀′ + 𝟐. 𝟎𝟑𝟐 𝑼′ " RGB Colors Cube in the YUV Color Space"
(valid color block in the YUV space)

– The YCbCr color space was developed as part of ITU-R BT.601 during the development digital component video
standard. YCbCr is a scaled and offset version of the YUV color space.
– The colour space recommended by CCIR-601 is very close to the PAL system.
– The precise luminance and chrominance equations under this recommendation are as follows (SDTV):
– The slight departure from the PAL parameters is due to the requirement that in the digital range
• Y should take values in the range of 16–235 quantum levels (8-bit).
• U and V are centered on the grey level 128, and the range is defined from 16 to 240 (8-bit).
– The reasons for these modifications are
– to reduce the granular noise of all three signals in later stages of processing
– to make chrominance values positive to ease processing operations (e.g. storage)
169
YCbCr Color Model (Color Space)
𝒀′ = 𝟎. 𝟐𝟓𝟕 𝑹′ + 𝟎. 𝟓𝟎𝟒 𝑮′ + 𝟎. 𝟎𝟗𝟖 𝑩′ + 𝟏𝟔
𝑪𝒃
′
= −𝟎. 𝟏𝟒𝟖 𝑹′ − 𝟎. 𝟐𝟗𝟏 𝑮′ + 𝟎. 𝟒𝟑𝟗 𝑩′ + 𝟏𝟐𝟖 = 𝟏𝟐𝟔 𝑩′ − 𝒀′ + 𝟏𝟐𝟖
𝑪𝒓
′ = 𝟎. 𝟒𝟑𝟗 𝑹′ − 𝟎. 𝟑𝟔𝟖 𝑮′ − 𝟎. 𝟎𝟕𝟏𝑩′ + 𝟏𝟐𝟖 = 𝟏𝟔𝟎 𝑹′ − 𝒀′ + 𝟏𝟐𝟖
𝒀′ =
𝟔𝟓. 𝟕𝟑𝟖
𝟐𝟓𝟔
𝑹′ +
𝟏𝟐𝟗. 𝟎𝟓𝟕
𝟐𝟓𝟔
𝑮′ +
𝟐𝟓. 𝟎𝟔𝟒
𝟐𝟓𝟔
𝑩′ + 𝟏𝟔
𝑪𝒃
′
= −
𝟑𝟕. 𝟗𝟒𝟓
𝟐𝟓𝟔
𝑹′
−
𝟕𝟒. 𝟒𝟗𝟒
𝟐𝟓𝟔
𝑮′
+
𝟏𝟏𝟐. 𝟒𝟑𝟗
𝟐𝟓𝟔
𝑩′
+ 𝟏𝟐𝟖
𝑪𝒓
′
=
𝟏𝟏𝟐. 𝟒𝟑𝟗
𝟐𝟓𝟔
𝑹′
−
𝟗𝟒. 𝟏𝟓𝟒
𝟐𝟓𝟔
𝑮′
−
𝟏𝟖. 𝟐𝟖𝟓
𝟐𝟓𝟔
𝑩′
+ 𝟏𝟐𝟖

A/D (Coding) in Rec BT-601
– Digital Standard for Component Video, 27 MHz stream of 8 / 10 bit 4:2:2 Samples
– 8 bit range, 219 levels black to white (16-235)
– 8 bit range, 224 levels black to white (16-240)
– Sync/Blanking replaced by SAV & EAV signals
128
16
235
0 & 255
Y Cr (from R-Y)
Cb (from B-Y)
170
240
Fs=13.5 MHz Fs=6.75 MHz
700 mV
0 mV
700 mV
0 mV
350 mV
700 mV
0 mV
350 mV
𝑌′
𝐶𝑟
′
𝐶𝑏
′

171
D/A (Decoding) in Rec BT-601
– Multiple A/D and D/A conversion generations should be avoided
Display
𝑌, 𝐶𝑟, 𝐶𝑏
DAC
DAC
DAC
𝑺𝒊𝒏𝒙
𝒙
𝑺𝒊𝒏𝒙
𝒙
𝑺𝒊𝒏𝒙
𝒙
Filter
Filter
Filter
MATRIX
AMPLIFIER

RGB Colors Cube in the YCbCr Space
– Possible RGB colors occupy only part of the
YCbCr color space limited by the nominal
ranges, therefore there are many YCbCr
combinations that result in invalid RGB values.
172
𝒀′ = 𝟎. 𝟐𝟓𝟕 𝑹′ + 𝟎. 𝟓𝟎𝟒 𝑮′ + 𝟎. 𝟎𝟗𝟖 𝑩′ + 𝟏𝟔
𝑪𝒃
′
= −𝟎. 𝟏𝟒𝟖 𝑹′ − 𝟎. 𝟐𝟗𝟏 𝑮′ + 𝟎. 𝟒𝟑𝟗 𝑩′ + 𝟏𝟐𝟖
𝑪𝒓
′
= 𝟎. 𝟒𝟑𝟗 𝑹′ − 𝟎. 𝟑𝟔𝟖 𝑮′ − 𝟎. 𝟎𝟕𝟏𝑩′ + 𝟏𝟐𝟖
𝑹′ = 𝟏. 𝟏𝟔𝟒 (𝒀′ − 𝟏𝟔) + 𝟏. 𝟓𝟗𝟔 (𝑪𝒓
′ − 𝟏𝟐𝟖)
𝑮′ = 𝟏. 𝟏𝟔𝟒 (𝒀′ − 𝟏𝟔) − 𝟎. 𝟖𝟏𝟑 (𝑪𝒓
′
− 𝟏𝟐𝟖) − 𝟎. 𝟑𝟗𝟐 (𝑪𝒃
′
− 𝟏𝟐𝟖)
𝑩′ = 𝟏. 𝟏𝟔𝟒 (𝒀′ − 𝟏𝟔) + 𝟐. 𝟎𝟏𝟕 (𝑪𝒃
′
− 𝟏𝟐𝟖)

Gamut of a color space
− The Gamut of a color space is the complete range of
colors allowed for a specific color space.
− It is the range of colors allowed for a video signal.
− No video, film or printing technology is able to fill all the
colors can be see by human eye.
− Outside edge defines fully saturated colours.
− Purple is “impossible”.
− Each corner of the gamut defines the primary colours.
173
Color Gamut
Chromaticity coordinates of Rec. 2020 RGB primaries and
the corresponding wavelengths of monochromatic light
Parameter Values
Opto-electronic transfer
characteristics before
non-linear pre-correction
Assumed linear
Primary colours and
reference white
Chromaticity coordinates
(CIE, 1931)
x y
Red primary (R) 0.708 0.292
Green primary (G) 0.170 0.797
Blue primary (B) 0.131 0.046
Reference white (D65) 0.3127 0.3290

Color Gamut
174
𝑥 + 𝑦 + 𝑧 = 1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍

175
CIE x CIE y
Red 0.708 0.292
Green 0.170 0.797
Blue 0.131 0.046
White 0.3127 0.3290
ITU-R BT.2020
CIE x CIE y
Red 0.640 0.330
Green 0.300 0.600
Blue 0.150 0.060
White 0.3127 0.3290
ITU 709-5 & sRGB Gamut
CIE x CIE y
Red 0.630 0.340
Green 0.310 0.595
Blue 0.155 0.070
White 0.3127 0.3290
ITU 601 Gamut
Color Gamut

176
CIE XY Coordinates for Various Color Gamut
CIE several standard white points sources illuminant values
A color gamut range is bounded by the xy coordinates of the primary red, green, and blue
colors within the color space. The xy coordinates for these primary colors is given in table.
Color Gamut

Color Gamut
177
Waveform Monitor
𝑥 + 𝑦 + 𝑧 = 1
𝑥 =
𝑋
𝑋 + 𝑌 + 𝑍
𝑦 =
𝑌
𝑋 + 𝑌 + 𝑍
𝑧 =
𝑍
𝑋 + 𝑌 + 𝑍

178
YPbPr View RGB View
YRGB View Composite View
Gamut Monitoring - the Traditional Way RGB Domain

179
Maximum
Gamut
Minimum
Gamut
Gamut Monitoring - the Traditional Way RGB Domain
The maximum (“brightest”) and minimum
(“darkest”) values of the three
components R, G, B define a volume in
that space known as the “color volume”.

Legal/Illegal Signal
180
700 mV
0 mV
700 mV
0 mV
700 mV
0 mV
A Legal/Illegal Signal
− A signal is legal if it stays within the gamut appropriate for the format in use.
− A legal signal stays within the voltage limits specified for all signal channels
for a given format (it does not exceed the voltage limits specified for the
format of any signal channel).
− An illegal signal is one that is, at some time, outside the limits in one or
more channels.
− A signal can be legal but still not be valid.
 The allowed range for R'G'B' channels and Y‘C'bC'r ' channels
• 0 to 700 mV
 The allowed ranges for Y'P'bP'r
• 0 to 700 mV for the luma (Y') channel
• ±350 mV for the color difference (P'b/P'r) channels

181
A signal can be legal in one color space but not legal when converted to another
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Converted back
to RGB
D Illegal
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Distorted
Color Difference
C Legal
Legal RGB
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
A
Legal/Illegal Signal

Valid Color Gamut
− It is defined as all colors represented by all
possible combinations of legal values of an
R'G'B' signal.
− Signals in other formats (YUV, YCrCb, …) may
represent colors outside valid gamut, but still
remain within their legal limits.
− These signals, when transcoded to the R'G'B'
domain, will fall outside legal R'G'B' limits.
− This may lead to clipping, crosstalk, or other
distortions.
Valid Color Gamut
182
(Valid color gamut for YCrCb)
Inside Valid
Gamut
Outside Valid
Gamut
Outside Valid
Gamut

Legal Signal and Valid Signals
183
A Valid Signal
− A video signal where all colors represented lie
within the valid color gamut.
− For YCbCr, it means all Y, Cb and Cr signals that
falls into valid color gamut of YCbCr color space.
− A valid signal will remain legal when translated to
R'G'B' or other formats.
− A valid signal is always legal, but a legal signal is
not necessarily valid.
− Signals that are not valid will be processed
without problems in their current format, but may
encounter problems when translated to another
format.
(Valid color gamut for YCrCb)
Legal Signal
Valid Signal
Legal Signal
Invalid Signal
Illegal Signal
Invalid Signal

EBU R103: Video Signal Tolerance in Digital Television Systems
184
System Bit Depth Range in Digital sample (Code) Values
Nominal Video Range Preferred Min./Max. Total Video Signal Range
8-bit 16-235 5-246 1-254
10-bit 64-940 20-984 4-1019
12-bit 256-3760 80-3936 16-4079
16-bit 4096-60160 1280-62976 256-65279
Preferred Min.
Preferred Max.
− Television and broadcasting do not
primarily use the “full range” of digital
sample (code) values available in a given
format.
− This is often referred to as “Narrow Range”
or “Video Range” in television and
broadcasting.
− Another term, “extended range” is not
formally defined but is sometimes used for
the range 64 – 1019 (10-bit), so including
super-whites, whilst maintaining sub-
blacks.
• SDI always reserves some code values for its
own signal processing requirements.
(Narrow Range)
Extended
Range

− An incorrect interpretation of the video range values used in SDI links and compression technologies for
contribution and distribution can seriously compromise the images.
− Any signals that contain values that exceed the total video signal range will be clipped (application-
specific).
− Such clipping can cause harmonic distortion and alias artefacts in the video signal, which manifests as
compression artefacts and the potential for increased data rates both for contribution and distribution.
185
8-bit 16-235 5-246 1-254
10-bit 64-940 20-984 4-1019
12-bit 256-3760 80-3936 16-4079
16-bit 4096-60160 1280-62976 256-65279

Video Signal
− In a video signal, each primary component should lie between 0 and 100% of the Narrow Range (Video Range) between
black level and the nominal peak level (R and G and B).
− When television signals are manipulated in YUV form, it is possible to produce "illegal" combinations that, when de-
matrixed, would produce R, G or B signals outside the range 0% - 100%.
HDR to SDR Color Volume Conversion
− It is expected that some colours that are present in the HDR colour volume when converted to SDR will be outside of the
ITU-R BT.709 volume Nominal Range but within the Preferred Range.
− This allows conversion processing to maintain the saturation and brightness of colours already within the Nominal Range
target colour volume.
186
8-bit 16-235 5-246 1-254
10-bit 64-940 20-984 4-1019
12-bit 256-3760 80-3936 16-4079
16-bit 4096-60160 1280-62976 256-65279

Video Signal Tolerance
− In practice it is difficult to avoid generating signals slightly out of range, and it is considered reasonable to allow a small
tolerance.
− Therefore, the EBU recommends that, the RGB components and the corresponding Luminance (Y) signal should not
normally exceed the “Preferred Minimum/Maximum” range of digital sample levels.
− Any signals outside the “Preferred Minimum/Maximum” range are described as having a gamut error or as being “Out-of-
Gamut”.
− Signals shall not exceed the “Total Video Signal Range”, overshoots that attempt to “exceed” these values may clip.
187
8-bit 16-235 5-246 1-254
10-bit 64-940 20-984 4-1019
12-bit 256-3760 80-3936 16-4079
16-bit 4096-60160 1280-62976 256-65279

Out-of-Gamut
− The term “Out-of-Gamut” refers to code values that exceed the Preferred Min / Max
values in table.
− Certain operations and signal processing may produce relatively benign gamut
overshoot errors in the picture.
− Therefore, the EBU further recommends that measuring equipment should indicate
an “Out-of-Gamut” occurrence only after the error exceeds 1% of the image.
(signals outside the active picture area shall be excluded from measurement).
− Experience has shown that colour gamut "legalisers" should be used with caution as
they may create artefacts in the picture that are more disturbing than the gamut
errors they are attempting to correct.
− It is advisable not to “legalise” video signals before all signal processing has been
carried out.
188

Legalisation:
− Gamut legalisation ensures that both the HD and SD outputs of the unit meet specified color limits.
− The available selections are:
⇒ Off: This selection disables gamut legalisation.
⇒ 700mV: RGB Lo 0mV, RGB Hi 700mV, will comply with area mask set to 1% or greater.
⇒ 721mV: RGB Lo -21mV, RGB Hi 721mV, will comply with area mask set to 0% or greater.
⇒ 735mV: RGB Lo -35mV, RGB Hi 735mV, will comply with area mask set to 0% or greater.
− Note: The 735mV selection should be used in conjunction with the luma clipper (set at presets) to generate images that
adhere to EBU R103-200 specification.
189
Example: Alchemist Ph.C-HD LIVE
Area mask defines the percentage of total pixels in the image
that may be out of gamut without reporting that the signal has
a RGB gamut error.

Luma Clipper
− When luminance levels are too high or too low devices such as encoders and displays can have problems.
− The luma clipper is used to limit signals above and below predefined limits.
− Minimum and maximum limits can be set, in addition a knee allows for a graduated transition to the limit.
190
White Max
Black Min
White Knee
Black Knee
Luma Clip Input
Luma Clip Output
White Soft Clip Region
Black Soft Clip Region

191
To achieve a hard white clip set the White
Max and White Knee to the same value.
Luma Clipper
⇒ White Max
• This sets up the upper limit (hard clip point) of the clipper. The range is minimum 90% (852 digital 10-bit value) to maximum 109% (1019) with
increments of 1%. Preset is 103% (966).
⇒ White Knee
• This sets up the knee for the maximum white limit of the clipper. This can be set up to give a “soft clip” from this knee point to the hard white
clip point. The range is minimum 60% (590) to maximum 109% (1019) with increments of 1%. Preset is 100% (940).
White Max
Black Min
White Knee
Black Knee
Luma Clip Input
Luma Clip Output

192
To achieve a hard black clip set the Black
Min and the Black knee to the same value.
Luma Clipper
⇒ Black Min
• This sets up the lower limit (hard clip point) of the clipper. The range is minimum -7% (4) to maximum 10% (152) with increments of 1%. Preset is -
1% (55).
⇒ Black Knee
• This sets up the knee for the minimum black limit of the clipper. This can be set up to give a “soft clip” from this knee point to the hard black clip
point. The range is minimum -7% (4) to maximum 60% (590) with increments of 1%. Preset is 0% (64).
White Max
Black Min
White Knee
Black Knee
Luma Clip Input
Luma Clip Output

Lightning Display
− Lightning display is developed to provide both amplitude and inter-channel timing information for the
three channels of a component signal within a single display.
− This unique display requires only a single test signal, standard color bars, to make definitive measurements.
− Increasing luma is plotted upward in the upper half of the screen and downward in the lower half.
The bright dot at the center
of the screen is blanking
(zero signal level).
194

Luma amplitude error
P’b amplitude error
195
Lightning Display

196
The P'b signal is leading
the luma signal.
The P'b signal is delayed with
respect to the luma signal.
Lightning Display

− Determine where transitions intersect the delay scales and derive the timing error in nanoseconds, as deflected from the
center mark, using the following guidelines.
⇒ The center mark of the nine marks spanning each green-magenta transition is the zero error point.
⇒ Alignment to a mark toward black means the color-difference signal lags with respect to luma.
⇒ Alignment to a mark toward white means the color-difference signal leads the luma signal.
⇒ The upper half of the display measures the Pb to Y timing; the bottom half measures the Pr to Y timing.
⇒ The + tic marks on the graticule indicate the following timing errors:
197
Lightning Display

Diamond Display
199
This version facilitate observation of
gamut errors within the black region

200
Configuration Menu
Selectable Gamut Thresholds
Gamut
Limits
Diamond Display

201
Diamond Display
Example A:
• R - Ok
• G > 700 mV
• B - Ok
Example B:
• R - Ok
• G - Ok
• B > 700 mV
Example C:
• R - Ok
• G - Ok, 350 mV
• B < 0 mV

Diamond Display
Correct Diamond Display An amplitude error within the green channel
202

Diamond Display
203
4
An amplitude error within the red channel
• In this example using a high definition format, the NTSC SMPTE color bars signal is not
legal when converted to R'G'B' color space.
• The waveform exceeds the graticules in several areas. This is due to the –I patch having
a red component at –144.6 mV, the +Q patch having a green component at –97.9 mV,
and the –4% black patch of the pluge area having all three components at –28 mV.

There is a minor violation along both the upper and lower G’ axes. A significant red imbalance
204
Diamond Display

205
Diamond Display
A significant blue imbalance A green color imbalance

206
Diamond Display
− The Rainbow pattern contains the
complete range of high definition
colors.
− This color range completely fills the
graticules of the Split Diamond display.
− EBU R103 provides the recommended
tolerance for illegal colors in television.
− Tektronix waveform monitors have
configurable gamut limits, including a
preset for R103 values.
− For RGB, these are 5% to 105% (–35
mV to 735 mV)
− For the luma signal the limits are –1%
to 103% (–7 mV to 721 mV).

207
White
White
Black
• Luma produces vertical straight line on Diamond Display
• Black at center of double Diamond
• White at apex of double Diamond
Diamond Display

208
• The Diamond display can be an essential tool for
simplifying camera balancing.
• When the value of R'=G'=B', this produces a gray
value.
• A resulting gray scale will therefore produce a
vertical line in both upper and lower diamonds,
provided the signal is aligned correctly.
• Any deviation can easily be observed within the
Diamond display.
• In this case, the camera has a red imbalance that is
shown by the deviation of the lower diamond from
the vertical axis toward the red axis.
• The camera should be adjusted to correct for this
imbalance.
• With the lens of the camera capped, the signal should
be black and the Diamond display should show a dot
at the center of the graticule.
• In this case, the capping produces a trace along the
red axis in the lower diamond, indicating that the red
channel has a setup error and should be adjusted
until a dot is displayed at the center of the display.
Diamond Display

209
Lens Flare
− Lens flare is the light scattered in lens systems.
− Flare manifests itself as swift in black levels with a change light level.
Diamond Display

210
Blacks Lifted
Slightly Cool
Green-Blue White Points slightly Blue
Green-Red White Points slightly Green
Green-Blue
White Point
Green-Red
White Point
Diamond Display
Flare Adjustment
• Iris down the camera
• Set black level to 0mv
• Adjust Iris so white chip is 1 to
2 f-stop above 700mv
• Adjust the flares for black chip
to 0mv
Black
Lift
Chip Chart

211
Diamond Display
Video Session Display
− Lower case and uppercase letters indicate which
gamut limits have been exceeded.
− In the case of RGB gamut errors
• the uppercase letters “R---B” show the upper limit
of gamut have been exceeded for red and blue
• the lowercase letter “-r---b” shows that the lower
gamut limit has been exceeded for the red and
blue channel
− In the case of composite and luma gamut errors
• upper case “L” and “C” indicate the Luma or
Chroma limit have been exceeded
• lower case letters “l” and “c” indicate the lower
limit have been exceeded.
− The user can use this information to make adjustment
of the appropriate component in error.
The image shows the status bar with Luma, RGB and
Composite gamut errors highlighted in red.

215
Luma Qualified Vector Display

Analog to Digital Conversion
221

Fs=f
T=1/f
T
Sampling Frequency
222

223

Sampling Frequency
Fs=2f
T=1/2f
T
224

Minimum Fs restriction:
– Nyquist law (Fs ≥ 2 signal B.W)
Maximum Fs restriction:
– Chanel bandwidth (bit rate)
Ex: for SD Y signal we select Fs=13.5MHz because:
– 13.5MHz ≥ 2×5MHz, SD B.W=5M Hz
– 13.5MHz=864×15625, Line Frequency=15625 Hz
Fs Restriction in Analog to Digital Conversion
225
• The functions in left are totally different, but their
digitized versions in right are identical.
• Aliasing occurs when the samples of two or more
functions coincide, but the functions are different
elsewhere.

Bit resolution=2 4 different digital levels
Bit Resolution Effect (B)
227

Bit resolution=3 8 different digital levels
Bit Resolution Effect (B)
228

Minimum bit resolution restriction:
− Signal to Quantization Noise Ratio
− Peak Signal to Noise ratio
Maximum bit resolution restriction:
− Chanel band width (bit rate)
Ex: for video B=8,10,12,14 bits
Bit Resolution Restriction in Analog to Digital Conversion
230
𝑺𝑸𝑵𝑹 = 𝟏𝟎 𝒍𝒐𝒈
𝑺𝒊𝒈𝒏𝒂𝒍 𝑷𝒐𝒘𝒆𝒓 (𝑹𝑴𝑺)
𝑸𝒖𝒂𝒏𝒕𝒊𝒛𝒂𝒕𝒊𝒐𝒏 𝑵𝒐𝒊𝒔𝒆 𝑷𝒐𝒘𝒆𝒓 (𝑹𝑴𝑺)
= 𝟔𝑩 + 𝟏. 𝟕𝟖 𝐝𝐁
2𝐴
𝑷𝑺𝑵𝑹 = 𝟏𝟎 𝒍𝒐𝒈
𝑺𝒊𝒈𝒏𝒂𝒍 𝑷𝒐𝒘𝒆𝒓 (𝑷𝒆𝒂𝒌)
𝑸𝒖𝒂𝒏𝒕𝒊𝒛𝒂𝒕𝒊𝒐𝒏 𝑵𝒐𝒊𝒔𝒆 𝑷𝒐𝒘𝒆𝒓 (𝑹𝑴𝑺)
= 𝟔𝑩 + 𝟏𝟏 𝒅𝑩

4 levels (2 bits) 16 levels (4 bits) 256 levels (8 bits)
231
Bit Resolution Restriction in Analog to Digital Conversion

4:4:4
Vs
4:2:2
vs
4:2:0
4:2:0
Vs
4:1:1
Color Sampling and Sub-Sampling
232
4:n:n (Y:Cr:Cb)

Full Color Resolution
10 x 3 x1920 x1080 x 25 = 1.448 Gbps (HD)
10 x 3 x 720 x 576 x 25 = 291.99 Mbps (SD)
4:4:4 Line structure
233

4:2:2 Line structure (Co-sited Sampling)
Half Horizontal Color Resolution
10 x 2 x1920 x1080 x 25 = 0.965 Gbps (HD)
10 x 2 x 720 x 576 x 25 = 194.66 Mbps (SD)
234
4:2:2 sampling is used in ITU-R BT601, D-1, D-5, Ampex
DCT, Digital Betacam, Digital S and DVCPRO50

Quarter Horizontal Color Resolution
10 x 1.5 x1920 x1080 x 25 = 0.724 Gbps (HD)
10 x 1.5 x 720 x 576 x 25 = 145.99 Mbps (SD)
235
4:1:1 sampling is used in 525/59.94 (NTSC) DV and
DVCAM and in both 525/59.94 and 625/50 (PAL) DVCPRO

YV Y Only
236
Co-sited sampling for 525/59.94i (NTSC) DV and DVCAM.
Field N Field N+1
YV Y Only
1
2
3
4
[1]
[2]
[3]
[4]
[]
Field 1
Field 2

Half Vertical & Horizontal Color Resolution
10 x 1.5 x1920 x1080 x 25 = 0.724 Gbps (HD)
10 x 1.5 x 720 x 576 x 25 = 145.99 Mbps (SD)
237
4:2:0 sampling is used in 625/50 (PAL) DV and DVCAM
formats. U and V samples are on alternative lines.

YV Y Only
238
4:2:0 Co-sited Sampling in DV and DVCAM for Interlaced Video
Co-sited sampling for 576/50i (PAL) DV and DVCAM formats.
Field N Field N+1
YV Y Only
1
2
3
4
[1]
[2]
[3]
[4]
[]
Field 1
Field 2

4:2:0
YV Y Only
YU Y Only
4:2:0
Y V Y
Y U Y
239
4:2:0 Sampling in MPEG-1 and MPEG-2 for Progressive Video
Downsize chrominance Components.
• 4:2:0 (with chrominance samples centered)
• Requires bilinear interpolation
• Calculated Cr and Cb.
MPEG-2
JPEG/JFIF
H.261/H.263/MPEG-1
Mid-sited Sampling
(interstitial)
Calculated Samples
Downsize chrominance Components.
• 4:2:0 (with chrominance samples centered)
• Requires bilinear interpolation
• Calculated Cr and Cb.

YV Y Only
240
4:2:0 Sampling in MPEG-2 for Interlaced Video
The sampling positions on the active scan lines of an interlaced picture (top_field_first=1)
Field N Field N+1
YV Y Only
Calculated Samples
1
2
3
4
[1]
[2]
[3]
[4]
[]
Field 1
Field 2
Is top field displayed first

YV Y Only
241
The sampling positions on the active scan lines of an interlaced picture (top_field_first=0)
Field N Field N+1
YV Y Only
1
2
3
4
[1]
[2]
[3]
[4]
Calculated Samples
[]
Field 1
Field 2
Is top field displayed first

YV Y Only
242
The sampling positions on the active scan lines of an interlaced picture
1
2
3
4
[1]
[2]
[3]
[4]
Calculated Samples
[]
Field 1
Field 2

− In a 4:2:0 interlaced video sequence, the Y, Cr
and Cb samples corresponding to a complete
video frame are allocated to two fields.
243
The sampling positions on the active scan lines of an interlaced picture

Comparison
Sampling Y R-Y B-Y
4:4:4 1920 1920 1920 Samples on Every line
4:2:0 1920 960
0
0
960
Samples on Alternate lines
244

245

246
− When the block upsamples from one format
to another, it uses interpolation to
approximate the missing chrominance values.
− If, for the Interpolation parameter, you select
Linear, the block uses linear interpolation to
calculate the missing values.
− If, for the Interpolation parameter, you select
Pixel replication, the block replicates the
chrominance values of the neighboring pixels
to create the upsampled image.
Pixel Replication

247

Chroma Downsampling
248
Chroma 4:4:4 Chroma 4:2:2
Chroma 4:2:0i
Chroma 4:2:0p

Chroma Upsampling Back to 4:4:4
249
4:4:4 4:2:2 to 4:4:4
4:2:0p to 4:4:4 4:2:0i to 4:4:4

250
https://www.extron.com/technology/landing/vector4k/
4:4:4

251
https://www.extron.com/technology/landing/vector4k/
4:2:2

253
Chroma Downsampling
The 4:4:4 text is darker than the background, and "4:2:2" should barely be visible.
4:4:4

254
Chroma Downsampling
4:4:4
Far View

255
Chroma Downsampling
The text should be brighter than the background, and the "4:4:4" text should almost blend
into the background. There should be a bright border around the edge of the image.
4:2:2

256
Chroma Downsampling
4:2:2
Far View
Far View
Calculated Samples
Mid-sited Sampling

257
Chroma Downsampling
• The image should just appear to be a solid color with 4:2:0 processing.
• None of the text is clearly visible (it may be faintly visible) and the center of
the image should be dark, with a bright border around the edge of the screen.
4:2:0

258
Chroma Downsampling
4:2:0
Far View
Far View
Same View
Calculated Samples
Mid-sited Sampling

Most TVs Today Allow you to Enable Chroma 4:4:4
259
SONY TVS
− The home view ⇒ settings page ⇒ external inputs ⇒ "HDMI enhanced format" to enable chroma 4:4:4 support.
− Then, go to picture settings and change the picture mode to "graphics."
− As you may notice, some Sony TVs only have this feature enabled on select HDMI ports.
SAMSUNG TVS
− The settings page ⇒ picture settings ⇒ expert settings ⇒ "HDMI UHD color" to select which inputs have this feature enabled.
− You will have to select PC mode for the input as well.
LG TVS
− The picture settings ⇒ "HDMI ULTRA HD deep color."
− Then, press the input button, then select "All inputs."
− Pick the input you would like to enable the feature on then edit the icon.
− Select the PC icon.
When does it matter?
Subsampling Visual Impact
PC 4:4:4 Major
Movies 4:2:0 None
Video Games 4:4:4 Minor
Sports 4:2:0 None
TV Shows 4:2:0 None

260
RTings.com Chroma Test Pattern

261
Samsung UN55JU7100 4k @ 60Hz under PC mode Chroma 4:4:4

262

263

Questions??
Discussion!!
Suggestions!!
Criticism!!
264

An Introduction to Video Principles-Part 2

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An Introduction to Video Principles-Part 2