Chapter+Two+-+Environment,+Optics,+Resolution,+Display

=Chapter Two - Environment, Optics, Resolution, Display=

Perception = understanding patterns of light

Ecological optics (developed by JJ Gibson) - Emphasis on perception of surfaces in the environment and its textures - Ambient optic array = different direction of light into the enviro (i.e. absorb, reflect, refract)
 * Changes over time as viewpoint and object moves = flow field develops = optical flow

Surface = unformed patch of light unless it is textured

Paint Model of Surfaces - Lambertian shading - Specular shading - Ambient shading - Cast shadows

Visual angle = angle subtended by an obj at the eye of an observer (defined in gedree, min, sec of arc)

Lens - Human eye contains a compound lens (17 mm focal length with a power of 59 diopters) - Two key elements of the lens = curved front surface of the cornea and crystalline lens - Depth of focus = distance over which objects are in focus without blurring or change in focus

Augmented reality = superimposing reality into virtual imagery using computer graphics Virtual reality = correct depth of focus info is presented by computer generated imagery Chromatic aberration = diff light wavelengths are focused at diff eye distance (ie most see red not blue)

Acuities = measurement of our ability to see detail - Point acuity (1 min of arc) = ability to resolve two distinct point ( . . ) - Grating acuity (1-2 min of arc) = ability to resolve letters (E) - Stereo acuity (10 sec of arc) = ability to measure the difference between 2 angles ( ^^ ) - Vernier acuity (10 sec of arc) = ability to see if 2 line segments are collinear ( _ – )

Spatial contrast sensitivity function - Five ways in which the sine wave grating pattern can be varied (| | | | |)
 * Spatial frequency = # of bars of the grating per degree of visual angle
 * Orientation
 * Contrast = amplitude of the sine wave
 * Phase angle = lateral displacement of the pattern
 * Area covered by the grating pattern