What is Image Processing. Image Process
- 1. UNIT 2 Introduction to Image Processing
- 2. What is Image Processing ? Applications Purpose of Image Processing Types of Image Processing Components of Image Processing Future Scope Advantages Disadvantages
- 3. Image Processing is any form of signal processing for which our input is an image, such as photographs or frames of video and our output can be either an image or a set of characteristics or parameters related to the image.
- 4. Image Processing generally refers to processing of two dimensional picture and by two dimensional picture we implies a digital image. A digital image is an array of real or complex numbers represented by a finite number of bits. But now in these days optical and analog image processing is also possible.
- 5. Face detection Feature detection Non-photorealistic rendering Medical image processing Microscope image processing Morphological image processing Remote sensing Automated Sieving Procedures Finger print recognization
- 6. Visualization - Observe the objects that are not visible. Image sharpening and restoration - To create a better image. Image retrieval - Seek for the image of interest. Measurement of pattern – Measures various objects in an image. Image Recognition – Distinguish the objects in an image.
- 7. Analog Image Processing Digital Image Processing Optical Image Processing
- 8. Image Sensors Image Displays Image Processing Software(OpenCV,Matlab,CIMG) Image Processing Hardware Memory
- 9. We all are in midst of revolution ignited by fast development in computer technology and imaging. Against common belief, computers are not able to match humans in calculation related to image processing and analysis. But with increasing sophistication and power of the modern computing, computation will go beyond conventional, Von Neumann sequential architecture and would contemplate the optical execution too.
- 10. This one is more accurate than the overlapping method because it is based upon minutia. It is an interactive method for recognizing fingerprints.
- 11. It is more time consuming as compared to the former. More complex program.
- 12. - Structure of the Human Eye - Image Formation in the Eye - Brightness Adaptation and Discrimination
- 13. Eye characteristics – nearly spherical – approximately 20 mm in diameter – three membranes • cornea (transparent) & sclera (opaque) outer cover • choroid contains a network of blood vessels, heavily pigmented to reduce amount of extraneous light entering the eye. Also contains the iris diaphragm (2-8 mm to allow variable amount of light into the eye) • retina is the inner most membrane, objects are imaged on the surface.
- 14. Retinal surface is covered in discrete light receptors Two classes – Cones • 6-7 million located primarily near the center of the retina (the fovea) • highly sensitive to color • can resolve fine details because each is attached to a single nerve ending • Cone vision is called photopic or bright-light vision – Rods • 75-150 million distributed over the retinal surface • multiple rods connected to a single nerve ending • give a general overall picture of the field of illumination • not color sensitive but are sensitive to low levels of illumination • Rod vision is called scotopic or dim-light vision
- 15. Rods are thin cells with slender rodlike projections that are the photoreceptors for: Black and white vision Vision in dim light Cones are the receptors for: Color vision Visual acuity There are three types of cones, each with a different visual pigment One sensitive to green light One sensitive to blue light One sensitive to red light The perceived color of an object depends on the quantity and combination of cones that are stimulated In very dim light, cones do not function Color blindness occurs because there is an absence or deficiency of one or more of the visual pigments in the cones. So the person cannot distinguish certain colors.
- 17. Pupil allows varying amounts of light to enter the eye. Cornea is a transparent structure that covers the iris and pupil Cones are concentrated in the center of the retina - the fovea Lens helps to focus light on the retina. Retina includes - Rods (94%) (light sensitive) - Cones (6%) (color sensitive)
- 18. •Fovea size is 1.5 mm in diameter •1.5 mm 1.5 mm square contain 337000 cones 5mm 5mm CCD imaging chip CONT’D…
- 19. 2.1- Elements of Visual Perception 2.2- Light and the Electromagnetic Spectrum 2.3- Image Sensing and Acquisition 2.4- Image Sampling and Quantization 2.5- Some Basic Relationships Between Pixels 2.6- An Introduction to the Mathematical Tools Used in Digital Image Processing The principal difference between the lens of the eyee and an ordinary optical lens is that the former is flexible. The radius of curvature of the anterior surface of the lens is greater than the radius of its posterior or surface. The shape of the lens is controlled by tension in the fibers of the ciliary body. To focus on distant objects, the controlling muscles cause the lens to be relatively flattened. Similarly, these muscles allow the lens to become thicker in order to focus on objects near the eye. The distance between the center of the lens and the retina (called the focal length) varies from approximately 17mm to about 14mm, as the refractive power of the lens increases from its minimum to its maximum. When the eye focuses on an object farther away than about 3m, the lens exhibits its lowest refractive power. When the eye focuses on a nearby object, the lens is most strongly refractive. This information makes it easy to calculate the size of the retinal image of any objects.
- 20. Draw an image similar to that below on a piece of paper (the dot and cross are about 6 inches apart) Close your right eye and focus on the cross with your left eye Hold the image about 20 inches away from your face and move it slowly towards you The dot should disappear! Blind-Spot Experiment
- 22. Example: Calculation of retinal image of an object 15/100=h/17 or h=2.55 mm - Muscles within the eye can be used to change the shape of the lens allowing us focus on objects that are near or far away - An image is focused onto the retina causing rods and cones to become excited which ultimately send signals to the brain Light receptor radiant energy electrical impulses Brain
- 23. Range of light intensity levels to which HVS (human visual system) can adapt: on the order of 1010 _ from the scotopic threshold to the glare limit. Subjective brightness (i.e. intensity as perceived by the HVS) is a logarithmic function of the light intensity incident on the eye. • The visual system does not operate simultaneously over the 1010 range. It accomplishes this large variation by changes in its overall sensitivity, a phenomenon known as brightness adaptation. For any given set of conditions, the current sensitivity level of HVS is called the brightness adaptation level. mL = millilambert
- 24. • Brightness discrimination is the ability of the eye to discriminate between changes in light intensity at any specific adaptation level. • The quantity Ic/I, where Ic is the increment of illumination discriminable 50% of the time with background illumination I, is called the Weber ratio. A small value of Weber ratio, means good brightness discrimination. The eye also discriminates between changes in brightness at any specific adaptation level. ratio Weber I Ic Where: ∆𝐼𝑐: the increment of illumination discriminable 50% of the time I : background illumination
- 25. Typical Weber ratio as a function of intensity CONT’D Weber ratio (the experiment) Ic/I I: the background illumination Ic : the increment of illumination Small Weber ratio indicates good discrimination Larger Weber ratio indicates poor discrimination • Brightness discrimination is poor at low levels of illumination. The two branches in the curve indicate that at low levels of illumination vision is carried out by the rods, whereas at high level by the cones.
- 26. Thanks