Vision Sujective and Objective Issues Drl University视觉的主观和客观的问题卓克索大学

1、vision: subjective and objective issuesoleh tretiakmedical imaging systems2002why study vision understand how to display images understand what is seen understand how vision workssources of information physics of vision neurophysiology of vision psychology of vision psychophysicsreferences david hub

2、el, eye, brain, and vision, henry hold & company, 1995 james p. c. southall, physiological optics, dover, 1961 vicki bruce, patrick r. green, mark a. georgeson, visual perception: physiology, psychology, and ecology, psychology press, 1996visual pathway - anatomyvisual pathway - symbolicthe reti

3、na and the eyethe eyeballvision and eye fixation (motion)half-retina mapslayers of the geniculate nucleussection through striate cortexmap from retina to striate cortexstriate cortex input/outputindex of refractioncornea (n2)1.376aqueous humor and vitreous body (n3 = n7)1.336outer portion of lens (n

4、4 = n6)1.386core-lens (n5)1.406the model is due to gullstrand (1924). the power of the eye in this model ranges from 58.64 dptr (diopters) to 70.57 dptr. most of the refraction (43 dptr) is due to the cornea.subjective intensity (contrast) modelsin a model for subjective intensity, let x by the brig

5、htness (power/area) and y the subjective brightness (contrast). both x and y range from 0 to 100. logarithmic model:power law model:on the next slide we show thirty four steps designed to produce uniform contrast with (1) linear, power law with gamma = 1, (2) power law, gamma = 0.7, and (3) logarith

6、mic. note that the appearance of this depends on the transfer function of the display.y =50log10(x), 1 x 100y =100(x/100)gsimultaneous contrast examplesbackground = 245, circles = 210, 225, and 235background = 70, circle = 60the circles have the same objective intensity.typical visual spatial responseobjective value (intensity)subjective (perceived) valuemac