Exam 2 Sens.1

Wavelengths

Different colors in the visible spectrum, including red, orange, yellow, green, blue, indigo, and violet.

Principle of Univariance

The response of a photoreceptor cell is based on the amount of light absorbed, not the wavelength of light.

Trichromacy

Theory stating that color vision is based on three primary colors - red, green, and blue, detected by cones in the retina.

Opponent Colors

Color pairs that cannot be perceived simultaneously, such as red/green, blue/yellow, and black/white.

Stereoscopy

Technique creating the illusion of depth in images for binocular vision.

Vieth-Müller Circle

Theoretical construct representing points in space producing the same retinal stimulation for binocular vision.

Disparity

Great for perceiving closeness or farness, less effective for distant objects' shapes due to minimal eye image differences.

Horopter

Surface where all points have zero disparity, crucial for overlapping eye vision and depth perception.

Accommodation

Process of adjusting lens shape for focus adjustment, essential for clear vision.

Stereoblindness

Commonly caused by strabismus, leading to the inability to blend images from both eyes for a clear picture.

Pictorial Depth Cue

Typical depth clue in artworks aiding in perceiving depth through size, position, or occlusion hints.

Motion Parallax

Depth cue arising from motion through the environment, assisting in judging distances.

Convergence

Not a monocular depth cue example, as it involves both eyes moving towards each other for focusing.

Implication of Uni-variance

Different wavelengths can produce the same response.

• Limitations in color perception in low light conditions.

L-cones

The long-wavelength light from a sunset activates which type of photoreceptors most strongly

S-cones

The short-wavelength light from blue sky activates which type of photoreceptors most strongly?

Mesopic

During the day, in bright sunlight, what type of vision is most active?

infinite set of different wavelength-intensity combinations can elicit the same response from a single type of photoreceptor.

The principle of univariance refers to which of the following?

trichromacy

The colour of any light can be defined by three numbers." Which of the following terms is most closely related to this claim?

Metamers

If two mixtures of wavelengths look identical, they are called

Three

What is the smallest number of (correctly chosen) lights that can create all possible colors that humans can see?

New colors generated by combining filters are _______ while new colors generated by mixing lights are _________.

opponent; multiple

Melanopsin

Which photopigment is most important for regulating the circadian clock?

Opponent Processes in the Lateral Geniculate Nucleus

Neurons in the lateral geniculate nucleus respond to opponent colors. They have center-surround receptive fields that respond to color contrasts

Color Contrast and Color Assimilation

occurs when colors appear different due to the influence of surrounding colors. happens when colors appear more similar due to the influence of surrounding colors.

color afterimages

Visual illusions where an image continues to appear after the original image is removed. They occur due to fatigue of specific color receptors in the retina.

color constancy

The ability to perceive the color of an object as constant under different lighting conditions. The brain adjusts for changes in illumination to maintain the perceived color of an object.

the following are opponent colour pairs

blue versus yellow; red versus green; black versus white

impossible colour pair to percieve

greenish red

which of the following is a non-spectral hue

magenta

Which of the following is the inability to perceive colors due to damage to the central nervous system?

achromatopsia

Sometimes the visual system makes colours appear more similar to neighbouring colours than they are. This is called

color assimilation

A colour that can only be seen about other colours, not in isolation, is called:

a related colour

The image seen after the removal of a stimulus is called the:

Afterimage

Unique Blue

refers to a specific shade of blue that is perceived as neither greenish nor purplish. It's called "unique" because it's a hue that cannot be created by mixing other colors. It's one of the unique hues perceived by the human visual system.

Color constancy

is the ability of the human visual system to perceive the consistent color of an object despite changes in lighting conditions. It allows us to recognize objects as having the same color under different illumination.

Spectral power distribution

describes the intensity of light at each wavelength across the visible spectrum. It provides a complete description of the color of light, including its hue, brightness, and saturation.

One absolute metrical depth cue

is known as "familiar size." It refers to the perception of depth based on our knowledge of the size of familiar objects. For example, we can estimate the distance to a car because we know how large cars typically are.

The Vieth-Müller circle

is a theoretical construct in visual perception that represents the locus of points in space that produce the same pattern of retinal stimulation when projected onto the retina. It helps explain certain aspects of binocular vision and the perception of depth.

horopter

is an imaginary surface in space where corresponding points in the two eyes' visual fields are seen single when fixating on a particular point. It represents the locus of points in space that fall on corresponding retinal points in each eye.

Panum's fusional area

refers to the region of space around the horopter within which binocular fusion of images occurs. It represents the range of disparities over which the visual system can fuse images from both eyes into a single percept.

Name the first area in the visual pathway that contains binocular neurons.

The primary visual cortex (V1), located in the occipital lobe, is the first area in the visual pathway that contains binocular neurons. These neurons receive input from both eyes and play a crucial role in processing binocular disparity.

Name and briefly describe two pictorial depth cues.

One pictorial depth cue is linear perspective, which refers to the convergence of parallel lines as they recede into the distance. Another is interposition, which occurs when one object partially blocks another, indicating that the blocked object is farther away.

Diplopia

commonly known as double vision, is a visual phenomenon where a single object is perceived as two distinct images. It can occur when the eyes are misaligned or when there is an issue with binocular vision coordination.

Stereoscopy

is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision.^[2] The word stereoscopy derives from Greek στερεός(stereos) 'firm, solid', and σκοπέω (skopeō) 'to look, to see'.^[3][4] Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope.

Most stereoscopic methods present a pair of two-dimensional images to the viewer. The left image is presented to the left eye and the right image is presented to the right eye. When viewed, the human brain perceives the images as a single 3D view, giving the viewer the perception of 3D depth. However, the 3D effect lacks proper focal depth, which gives rise to the Vergence-Accommodation Conflict.

Stereoscopy is distinguished from other types of 3D displays that display an image in three full dimensions, allowing the observer to increase information about the 3-dimensional objects being displayed by head and eye movements.

Imagine the land squid on planet Nexus has special eyes that can see different colors using three types of cones. To match any color the squid can see, you need at least three different wavelengths of light. But here's the tricky part: there isn't just one single wavelength that looks like white light to the squid.

See, for us humans, white light looks white because it's a mix of all the colors. But for the land squid, their eyes work differently, so they don't have a single wavelength that makes things look white.

Land Squid Vision

With three types of color cells, they can see any color with the right mix of light. They see white with a balance of 500 nm light.