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Human Visual Systems and Perception. C. Edward Chow. Image in Human Eye. Rod and Cone Cell Distribution. Contrast Illusion . Demystify Illusion with Mach Bend Effect. Spatial Frequencies. Image can be considered as superposition of gratings of different spatial frequencies (cycles/degree).
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Human Visual Systems and Perception C. Edward Chow
Image in Human Eye chow
Contrast Illusion chow
Spatial Frequencies • Image can be considered as superposition of gratings of different spatial frequencies (cycles/degree). chow
Contrast Impact chow
Visual Acuity • Visual acuity: the smallest angular separation at which the individual lines can be distinguished. • Depend on contrast ratio and keenness of your eyes. 1.7’ is normal assumption= 60/(2*1.7’)~18 cycles/degree chow
Tristimulus Curves • Devise a system with simple numbers to represents all colors. (How about all positive numbers?) • x,y,z are proportion of X primary, Y primary, Z primary (supersaturated red, green and blue) • x=X/(X+Y+Z); y=Y /(X+Y+Z); z=1-x-y chow
CIE {X,Y,Z} system • CIE: Commission Internationale de I’Eclairage, The International commission on color standards) • Figure 2.17b shows the corresponding amount of primaries needed to match all wavelengths of visible spectrum. chow