P1254503583TCdYc - PowerPoint PPT Presentation

Title: P1254503583TCdYc


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???????????????????????? Ian Thomas
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Forming Images
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The eye
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The eye
Refractive indices in the eye pre-corneal tear
film 1.3375 cornea 1.3760 aqueous humor
1.3360 crystalline lens 1.4100 vitreous
humor 1.3360
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Seeing in colour
Micrograph of many rods and 2 cones (x 10,000)
Sensitivity of three types of cones.
lamda

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How well can you see?
2020 vision means you can read 20mm high letters
at 20 feet, or 5 of arc.
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What is this picture of?
http//www.sandhillscoutreservation.com/www/images
/Night20Time20With20Trees.JPG
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And this?
http//justinsomnia.org/gallery/tanzania/DCP_4100a
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We have two types of vision using rods and cones.
http//www.siggraph.org/education/materials /Hyper
Vis/vision/twovis.htm
http//www.visualexpert.com/Resources/nightvision.
html
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It takes time to change from one system to
another.
http//www.visualexpert.com/Resources/nightvision.
html
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Some eye problems
Floaters
Optical migraine http//www.dizziness-and-balance.
com/disorders/ central/migraine/migraine_scotoma_o
dc.jpg
http//en.wikipedia.org/wiki/Floater
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???????????????????????? Ian Thomas
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The sensitivity of the eye
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???????????????????????? Ian Thomas
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Arrange from darkest to lightest.
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???????????????????????? Ian Thomas
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Arrange from darkest to lightest.
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???????????????????????? Ian Thomas
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It is easier if they are next to each other, but
we can see bands.
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???????????????????????? Ian Thomas
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Forming digital images Electromagnetic
radiation CCD cameras Flat bed scanners and
drum scanners Television cameras (CRT) Digital
X-ray MRI Non-electromagnetic Ultrasound
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???????????????????????? Ian Thomas
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Charge coupled devices (CCDs)
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???????????????????????? Ian Thomas
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Optical imaging using CCDs
Microscope with CCD camera attached
Colour CCD camera
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???????????????????????? Ian Thomas
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Scanners
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???????????????????????? Ian Thomas
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MRI at Physics Dept., KKU
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???????????????????????? Ian Thomas
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MRI
Coronal image of the brain
Sagittal image of the knee
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???????????????????????? Ian Thomas
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Infra-red imaging
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???????????????????????? Ian Thomas
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X-ray imaging
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http//en.wikipedia.org/wiki/Rainbow
Colour
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Pure colours found in the spectrum
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Colour is used by most animals to find food.
http//www.digital-cameras-help.com/insects.html?i
d27
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What dogs see
What humans see
http//www.veterinaryvision.com/See.htm
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Isiharas colour blindness test
http//www.colourtherapyhealing.com/colour/colour_
blindness.php
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We can only see faint colours in stars.
http//www.geocities.com/ariane1au/Page029b.htm
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Colour can be mixed in two ways, additive and
subtractive
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Hering colour wheel
http//webexhibits.org/causesofcolor/1B.html
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James Clerk Maxwell suggested a way of
representing colour by using a colour triangle
with the three primary colours at the points of
the triangle in 1857.
green
red
blue
http//heritage.scotsman.com/ingenuity.cfm?id6590
02005
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CIE Chromaticity Diagram
Green
Proposed by the Committee International Eclairage
in 1931 and still used today. The primary colours
are 700.0 nm ('red'), 546.1 nm ('green') and
435.8 nm ('blue').
Red
Blue