Vision Flashcards
dog vision
- bad color vision
- can see green byt everything else is grayish
gecko vision
- have really nice color vision
- can see even better than use when it comes to certain things
Snail vision
- sees blobs
- tentacles are important for feeling the environment
bird vision
sharp colors and granularity
snake vision
night vision, reddish hue due to thermal vision
What wavelength is the visible spectrum
- around 400-700
- is the rainbow (far violet to far red and everything in between)
What is the color we see in terms of light?
- the color we see is the light being reflected back to use
- every other color is being absorbed
black vs. white color
- black absorbs all light and reflects none
- white reflects all light and absorbs none
How does a prism work?
- prism separates white light into the colors of the visible light spectrum
- similar to rainbow, when moisture in the air has sunlight (white light) bounce off, the light refracts
Each color in a rainbow corresponds to…
a different wavelength of electromagnetic spectrum
What are photons?
- Particles that form waves
- our vision is dependent on photons
What is brightness?
- number of photons emitted by a source
- more photons=brighter
What is color?
- frequency of photons (wavelength)
- red is longer wavelength/frequency than orange, etc
What is brightness for a pixel?
- for any particular pixel brightness is the number of photons per square unit space
What is color for a pixel?
- color is wavlength of photons
How are pixels brightness and color extracted/determined?
- extracted from comparing across nearby pixels (always in relation to something else/comparison)
- determined by edges, motion, and form
Optical features of the eye
What does the cornea do?
- refracts light
- the first surface that light hits
- covers the whole eye
Optical features of the eye
What is the pupil and what does it do?
- the pupil is an opening in the opaque disc called iris
- it controls light entering the eye
What controls eye movement?
- extraocular muscles control eye movement
- muscles located outside of eye field
What shape is lens for near focus?
globular
What shape is lens for far focus?
flatter
What is accommodation?
- process of focusing by changing the shape of the lens
- why we squint- it changes lense shape via ciliary muscles to make objects appear sharper
What do ciliary muscles in the eye do?
- adjust the focus
- by changing the shape of the pliable lens
What is binocular vision?
- the center region of the visual field
- what is seen by both eyes
Why is binocular vision helpful?
- it allows us to see depth
- animals w eyes on side of head cannot see depth well due to poor binocular vision
What is binocular depth perception correlated with?
positively correlated with the amount of visual field overlap (area seen w both eyes)
What do lateral portions of the retina monitor?
the medial portions of the visual field
Where does visual processing begin?
in the retina
What does the retina contain? Precisely where in the retina are these found?
- photoreceptor cells known as rods and cones
- found deep within the retina (buried under layers of other cells)
What does the ganglion cell layer form?
the optic nerve
what is the bipolar cell layer connected to?
- rods and cones as well as ganglion cell layer (in between the two)
What is targeted when light enters eye in pupil?
- the cells in the very back/last layer of the retina (the rods and cones)
Rods vs. Cones: system type
rods: scotopic system (low-light)
cones: photopic system (light)
Rods vs. Cones: photoreceptor type #
- rods: one type of photoreceptor
- cones: three different photoreceptors
Rods vs. Cones- more common where?
- rods: more common in peripheral parts of retina
- cones: more common in fovea (center of the retina)