Vision and Lighting

Ellen Rita
Mind Map by Ellen Rita, updated more than 1 year ago
Ellen Rita
Created by Ellen Rita over 4 years ago
2
1

Description

Uni Ergonomics Mind Map on Vision and Lighting, created by Ellen Rita on 12/24/2015.

Resource summary

Vision and Lighting
1 Designing a Petrol Pump
1.1 Visual display
1.1.1 Style of display
1.1.2 Day/Night use
1.1.2.1 Supplementary lighting needed for the display?
1.1.2.1.1 Characteristics of the lighting (sodium)
1.1.2.1.2 Could the lighting affect the identification of the colour of the pump, signage or display?
1.1.3 Glass/plastic covering, reflections from the artificial lighting sun or car headlamps?
1.2 Height of display for users (standing/sitting)
2 How do we see
2.1
2.2 Light rays from an object pass through the pupil apeture, lens and inside of eyeball, converge on the retina. Specific sensors (rods and cones) are stimulated.
2.3 Brain
2.3.1 Controls pupil size
2.3.2 Lens curvature
2.3.3 Eyeball movement
2.3.4 Integrates signals from the eye into a picture (we see)
2.4 Pupil
2.4.1 Controls the amount of light entering the eye
2.5 Cornea and Lens
2.5.1 Refracts the rays of light and focuses them on the retina
3 Basic Human Vision Capabilities
3.1 Visual Acuity
3.1.1 The ability of the eye to discriminate fine detail
3.1.1.1 Vernier acuity
3.1.1.2 Snellen chart
3.1.2 Occurs in the fovea (cones)
3.1.3 Requires accomodation - changes in the curvature of the lens by contractions of the ciliary muscle
3.1.4 Problems
3.1.4.1 Myopia
3.1.4.1.1 Near sightedness (converge infront of retina)
3.1.4.2 Hyperopia
3.1.4.2.1 Far sightedness - converge behind the retina
3.1.4.3 Lens can stiffen with age - problems
3.1.5 Increases with better lighting
3.2 Contrast sensitivity
3.2.1 The ability of the eye to perceive differences in illuminaton
3.2.1.1 Critical for seeing shapes and hazards
3.3 Adaption
3.3.1 The changes in our sensitivity to light. Adapting to different light levels, bright sunshine - x10000000000 brighter than a dark night- can still see from adaption
3.3.1.1 Light to dark
3.3.1.1.1 Very quick to start - could take up to 1 hour for full
3.3.1.2 Dark to light
3.3.1.2.1 Quicker- Full takes a few minutes
3.3.1.3 Vehicles - illuminated instruments (red/yellow light and night-easier to adjust to) - maintains dark adaption of rods - can see black, grey, white on roads.
3.4 Colour Discrimination
3.4.1 Contrast can vary for different colour combinations
3.4.1.1 7-9% males colour deficient (RED-GREEN)
3.5 Rods and Cones
3.5.1 Rods
3.5.1.1 Located through periphery- more common closer to the lens
3.5.1.2 More sensitive to light levels than cones - used for night vision
3.5.2 Cones
3.5.2.1 In fovea
3.5.2.2 Need lots of illumination to operate
3.5.2.3 Provide visual acuity and colour sensitivity
3.6 Eye/Neck/Head movement
3.6.1 Tracking movements
4 Parameters of Light
4.1 Illuminance/Illumination
4.1.1 The amount of light falling onto a surface (lux)
4.2 Luminance
4.2.1 The amount of light emitted from a surface (candela per m^2)
4.3 Reflectance
4.3.1 % = (Luminance / Illuminance) x pi x 100
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