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L7 Light + Eye - Coggle Diagram
L7 Light + Eye
light
reflect, scatter, absorption occurs
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eyes better at colours w shorter WL in scotopic, longer WL in photopic -> not equally responsive to WL
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threshold detection
detecting stimulus w small ang subtense dep total amount of light collected by retina -> luminous flux
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light level > threshold, visibility related to luminous intensity
ambient -> large ang subtense, visibility dep luminance
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specular reflection
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forward scattered light > veiling glare, less contrast
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whole eye transmittance
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scatter
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due to combo of diffraction, refraction + reflection
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corneal scatter
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diseased, holes, oedema causes more
lens scatter
increase w age, forward > back
forward: veiling glare, back: reduced light entering retina
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fluorescence
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mostly in lens, increase w age + cataract
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lens w tryptophan, fluorogens
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luminous flux F
measure of total amount of light, unit lumen lm
luminou efficacy
lumen to watts ratio, lumens generated per energy watts
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luminous intensity I
measure of pt source brightness, unit candela cd
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luminance L
obj measure of brightness of extended source, unit candela/square metre cd/m^2
sun dep elevation + scatterng, reflection, absorption
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illuminance E
measure of luminous flux density incident on surface, unit lumen per square metre lm/m^2 or lux