Chapter 1 fundamentals of digital imaging
- 2. 1. Computer Graphics Is one of the most effective and commonly used way to communicate the processed information to the user. It displays the information in the form of graphics objects such as pictures,charts,graphs and diagrams instead of simple text.
- 3. Advantages of Computer Graphics 1. It provides tools for producing pictures not only of concrete real world objects but also of abstract, synthetic objects such as mathematical surface in 4D and of data that have no inherent geometry such as survey results. 2. It has the ability to show moving pictures and thus it is possible to produce animations with computer graphics. 3. With computer graphics user can also control the animation speed, portion of the view, the goniometric relationship the object in the scene to one another, the amount of detail shown and on.
- 4. Advantages of Computer Graphics 4. The computer graphics provides tool called motion dynamics. 5. The computer graphics also provides facility called update dynamics. 6. With the recent development of digital signal processing (DSP) and audio synthesis chip the interactive graphics can now provide audio feedback along with the graphical feedbacks to make the simulated environment even more realistic.
- 5. Applications of Computer Graphics User Interface Plotting of Graphics and Charts Office Automation and Desktop Publishing Computer-aided Drafting and Design Simulation and Animation Art and Commerce Cartography
- 6. User Interface User friendliness is one of the main factors underlying the success and popularity of any system. It is now a well established fact that graphical interfaces provide an attractive and easy interaction between users and computers.
- 7. Plotting of Graphics and Chart Is the most commonly used to create 2D and 3D graphs of mathematical, physical and economic functions in form of histograms, bars and pie-charts.
- 8. Office Automation and Desktop Publishing The desktop publishing on personal computers allow the use of graphics for the creation and dissemination of information. It allows the user to create documents which contain text, tables, graphs and other forms of drawn or scanned images.
- 9. Computer-aided Drafting and Design Uses graphics to design components and systems electrical, mechanical, electromechanical and electronic devices such as automobile bodies, structures of building, airplane, ships, very large scale integrated chips, optical systems and computer networks.
- 10. Simulation and Animation Use of graphics in simulation makes mathematic models and mechanical systems more realistic and easy to study. The interactive graphics supported by animation software proved their use in production of animated movies and cartoons films.
- 11. Art and Commerce This allows user to create artistic pictures which express messages and attract attentions. Such pictures are very useful in advertising.
- 12. Cartography Computer graphics is also used to represent geographic maps, weather maps, oceanographic charts, contour maps, population density maps.
- 13. Classification of Computer Graphics Two categories in classification of computer graphics: Passive computer graphics Interactive computer graphics
- 14. Passive computer graphics • A computer graphics operation that transfers automatically without operator intervention. • Non-interactive computer graphics involves one way communication between the computer and the user.
- 15. Interactive computer graphics • In interactive Computer Graphics user have some controls over the picture, the user can make any change in the produced image. • It require two-way communication between the computer and the user.
- 16. Pixel • is a physical point in a raster image, or the smallest addressable element in an all points addressable display device. • it is the smallest controllable element of a picture represented on the screen.
- 17. Bit Depth Refers to the color information stored in an image. The higher the bit depth of an image, the more colors it can store. The simplest image, a 1 bit image, can only show two colors, black and white. An 8 bit image can store 256 possible colors, while a 24 bit image can display over 16 million colors.
- 18. Resolution Is sometimes identified by the width and height of the image as well as the total number of pixels in the image. The more pixel per inch. the higher your image resolution will be.
- 19. Megapixels Image Resolution Maximum Print Size 0.3 Megapixel 640 x 480 1.6" x 2.3" at 300 dpi 1.3 Megapixel 1392 x 1024 3.2" x 4.3" at 300 dpi 2.0 Megapixel 1600 x 1200 4" x 5.3" at 300 dpi 3.3 Megapixel 2080 x 1542 5.1" x 6.8" at 300 dpi 5.0 Megapixel 2580 x 1944 6.4" x 8.5" at 300 dpi 6.0 Megapixel 2816 x 2112 9.4" x 7" at 300 dpi 8.0 Megapixel 3264 x 2448 8" x 11" at 300 dpi 12.5 Megapixel 4080 x 3072 10.24" x 13.6" at 300 dpi 32 Megapixel 6464 x 4864 16" x 21.5" at 300 dpi
- 20. Image Size is the term given to describe the height and width of an image in pixels. Maximum Image Size is determined by the megapixels of a given camera.for example, a 10-megapixel camera will give a maximum image size of 2592 by 3872 pixels.
- 21. Image Resizing is necessary when you need to increase or decrease the total number of pixels, whereas remapping can occur when you are correcting for lens distortion or rotating an image.
- 22. Device Resolution Is the number of pixels on a device found in each dimension that can be displayed on the screen. For example: a device with the resolution of “1024 x 768” has a 1024 pixel width and a 768 pixel height.
- 23. Digital Color This elegant representation of color bridges the gap between additive and subtractive systems of color, and defines the method by which colors are stored, manipulated, and reproduced using computer technology.
- 24. Primary Colors • a set of real colorants or colored lights that can be combined in varying amounts to produce a gamut of colors. • Primary colors include red, blue and yellow.
- 25. Secondary Colors A color produced by mixing two additive primary colors in equal proportions. The secondary colors are cyan, magenta and yellow. Each secondary color is also the complementary color of the primary color whose wavelength it does not contain.
- 26. Color Gamut The term color gamut refers to the range of colors a device can reproduce, the larger or wider the gamut the more rich saturated colors available.
- 27. Color Model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components.
- 28. Color Management is the controlled conversion between the color representations of various devices, such as image scanners, digital cameras, monitors, TV screens, film printers, computer printers, offset presses, and corresponding media.
- 29. 3 Perception of Light Luminance Hue Saturation
- 30. LUMINANCE • Is brightness which corresponds to its physical property. • It measures the total energy in the light. • It is proportional to the area bounded by P (λ) and the λ axis in the 400 to 700 nm range.
- 31. Hue Distinguish a white light form a red light or a green light. When white light is incident on the object , some of its gets reflected.
- 32. Saturation Describes the degree of vividness. Saturation corresponds to the physical property called excitation purity which is defined to be the percentage of luminance that is allocated to the dominant or pure color component.
Editor's Notes
- #3: Computer graphics In computer graphics, pictures or graphics object are presented as a collections of discrete pictures elements called pixels. Take note that computer graphics allows rotation, translation, scaling and performing various projections on the picture before displaying it. It also allows to add effects such as hidden surface removal, shading or transparency to the picture before final representation.
- #5: “Advantages of computer graphics” In short, computer graphics permits extensive, high bandwidth user computer interaction. It significantly enhances the ability to understand information, to perceive trends and to visualize real or imaginary objects either moving or stationary in a realistic environment. “applications of computer graphics” today, computer graphics is used in a variety of fields ranging from routine everyday activities to very specialized area in widely different fields so let us know and discuss some of the major application areas of computer graphics.
- #6: There are 8 major applications of computer graphics first we have user interface….ect.
- #8: These graphs and charts are very useful for decision making.
- #9: Many organizations does the in-house creation and printing of documents. And this is one approach towards the office automation.
- #10: Computer aided design software packages range from 2D vector based drafting systems to 3D solid and surface modellers.
- #14: Computer graphics has been classified into two categories according to the application do main and requirement. They are passive and interactive computer graphics.
- #15: So class picture is produced on the monitor and the user does not have any control over the produced picture. The example of passive computer graphics is screen saver and static website Static website - contains Web pages with fixed content.
- #16: This is also called on-line graphics. This is termed as interactive computer graphics because the user can interact with the machine as per his requirements. The example of interactive computer graphics is Videogames, dynamic websites, special effects in movies, cartoons.
- #17: Pixel are normally arranged in a 2-dimensional grid, and are often represented using dots, squares and rectangles. It is the smallest piece of the display screen which we can control, the control is achieved by setting the intensity and color of the pixel which compose the screen.
- #18: The simplest image, a 1 bit image, can only show two colors, black and white. That is because the 1 bit can only store one of two values, 0 (white) and 1 (black). An 8 bit image can store 256 possible colors, while a 24 bit image can display over 16 million colors. As the bit depth increases, the file size of the image also increases because more color information has to be stored for each pixel in the image. When you save an image as a GIF or a PNG, you can select the bit depth of the resulting file. With certain types of images that naturally have few colors such as logos or simple designs, you may be able to drastically reduce the size of the image file without degrading the quality of the image. With other images reducing the number of colors in an image will severely degrade the image quality.
- #19: More pixel means higher resolution, which creates better image quality because you end up with more realistic representation of colour,better gradations of both individual colors and gray tones and crisper images in general
- #20: To determine what resolution you will need for particular print sizes, see the chart.
- #25: Primary colors cannot be mixed from other colors. They are the source of all other colors.
- #26: A secondary color is a color made by mixing of two primary colors in a given color space Cyan (a mixture of blue and green) Magenta ( mixture of blue and red) Yellow (mix of green and red)
- #27: color gamut is the color pallete that a given technology or process is capable of reproducing. The entire range of colors available on a particular device such as a monitor or printer. A monitor, which displays RGB signals, typically has a greater color gamut than a printer, which uses CMYK inks. When a color is "out of gamut," it cannot be properly converted to the target device; for example, to a different type of printer. RGB-Red- Green- Blue CMYK inks -CMYK refers to the four ink plates used in some color printing: cyan, magenta, yellow, and key (black).
- #28: Tuples -s a finite ordered list (sequence) of elements. Color model is a particular representation of color that is useful for at least one particular application. WE have 7 different color model: RGB model-(red,green,blue),is an additive model in which adding components produces colors , this model used for active displays such as television and computer screens. CMY model (Cyan, magenta and yellow)-this model is useful for describing color output to hard copy devices. CMYK model (Cyan,magenta,yellow and key (black))-works by partially or entirely masking certain colors on the typically white background that is absorbing particular wavelength of light. HSV model (Hue, Saturation and value) is more intuitive than the RGB color model. User specifies a color and the amount of white and black to add to the color to obtain different shakes, tones and tints. YIQ model (black-and-white, orange-blue, purple-green)model – is used in U.S commercial color television broadcasting and is therefore closely related to the color raster graphics. HLS model-(hue,lightness,Saturation)-allows a user to think in terms of making a selected hue darker or lighter. HIS model-respond closely to the way humans perceive color and thus this model is suited for interactive manipulation of color images where changes occur for each variable shift that correspond to what the operator expects.
- #29: Class the primary goal of color management is to obtain a good match across color devices; for example, the colors of one frame of a video should appear the same on a computer LCD monitor, on a plasma TV screen, and as a printed poster. Color management helps to achieve the same appearance on all of these devices, provided the devices are capable of delivering the needed color intensities.
- #30: In computer graphics Light can be characterized in three perceptual terms.
- #31: The higher the luminance the brighter the light to the observer
- #32: The combination of frequencies of the reflected light is called dominant frequency which is responsible for the color of the object. It is called as hue or color of light.
- #33: Vividness means clarity or brightness, like the vividness of a specific, distinct childhood memory or the vividness of a glowing neon sign on a clear night.