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Published byShannon Lyons Modified over 9 years ago
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Vision 153-158
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Structure of the Eye
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We only use light energy to see.
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Wavelength The distance from the peak of one light wave to the peak of the next. The distance determines the hue (color) of the light we perceive.
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Intensity The amount of energy in a light wave. Determined by the height of the wave. The higher the wave the more intense the light is.
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Vision – front of eyeball – phase 1 Pupil- adjustable opening in the center of the eye Iris- a ring of muscle that forms the colored portion of the eye around the pupil and controls the size of the pupil opening Lens- transparent structure behind pupil that changes shape to focus images on the retina
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Nearsighted Vision
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Farsighted Vision
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Inner eye – phase 2 Accommodation- the process by which the eye’s lens changes shape to help focus near or far objects on the retina Retina- the light-sensitive inner surface of the eye receptor rods and cones layers of neurons that begin the processing of visual information
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The Retina
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Rods and Cones – 125 million rods to 7 million cones per eye! Rods – sensitive to variations in light, helps us adjust to dark. Full adjustment = 30 minutes Cones – sensitive to color, bright light. Full adjustment = 5 minutes
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Retina’s Reaction to Light Optic nerve- nerve that carries neural impulses from the eye to the brain Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there Fovea- central point in the retina, around which the eye’s cones cluster. Greatest visual acuity
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Blind spot
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Processing from retina to the brain – phase 3 Bipolar Cells – preliminary sensory reception area. Raw data Ganglion cells – neurons that are photoreceptive – processes fine details from cones From retina cells go to optic nerve and then optic chiasm
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158-163 Color Processing Trichromatic (three color) Theory Young and Helmholtz three different retinal color receptors red green blue
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Color-Deficient Vision People who suffer red-green blindness have trouble perceiving the number within the design
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Visual Information Processing Opponent-Process Theory- opposing retinal processes enable color vision “ON”“OFF” red green green red blue yellow yellow blue black white white black
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Opponent Process Theory – Afterimage effect
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Feature Detection The concept that specific nerve cells in the brain respond to specific features of the stimulus, such as shape, angle, or movement.
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Parallel Processing The processing of several aspects of a problem simultaneously. Color MotionForm Depth
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