week 4 Flashcards
form and color perception, chapters 5-6
white light composition
- combination of light waveforms spanning the entire visible spectrum
- temperature describing shades based on wavelength distribution (warm/cool white)
darker objects warmer in the sun
- darker objects absorb more light, increased heat absorption
hue
- based on wavelength
saturation
- range from rich to light versions of a hue
non spectral purples
- colors that do not correspond to a single wavelength, created through a combination of wavelengths
2 types of color mixing
additive color mixing
- combining light wavelengths
- adjusting the brightness of red, green and blue diodes to create the perception of various colors
subtractive color mixing
- removing wavelengths through absorption, changes the colors percieved
- eg. paints, dyes
opponent process theory
- humans evaluate colors as combinations of four categories/ 3 channels
- red v green, blue v yellow, black v white
- supported by afterimages, color is perceived after the removal of a colored stimulus, evidence of color opponency
- not widely accepted
color constancy
- ability to perceive objects as having consistent colors despite changes in lighting
- ensures visual stability in different environments
oliver sacks
- the man who mistook his wife for a hat, object agnosia, describe visual features unable to identify or it’s use
- damage to inferior temporal lobe, inability to integrate bottom-up and top down cues for object recognition
object perception flexibility
- identify objects belonging to the same category despite significant variations in appearance eg dog breeds
- schema
shape constancy
- perception that an object retains its shape even when its visual dimensions change as it’s position shifts within the environment
object representation vs object recognition
representation
- encoding an objects features
recognition
- association of these representations within stored memory to identify and understand the object
figure-ground seperation
- distinguishing objects (figures) from the background
- allows us to focus on and interact with specific visual elements
perceptual interpoltion
- visual cortex filling in missing information based on surrounding features and past experiences
illusory contours
- perceived edges or lines that don’t physically exist but are created by the brain to complete the visual image
- necker cube
object processing along the ventral visual stream
- basic stimulus features encoded in the primary visual cortex and passed through areas like V4 and the inferotemporal cortex
- higher-level object processing, such as faces
role of occipital face area in face perception
- determine if an object is a face before passing the information to the fusiform face area for further processing
