Physical processes involved when seeing, and comparisons between with other light detection systems. Includes questions about the eye, optical nerve, brain, corrective lenses, etc.

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1answer
83 views

White LEDs and colour perception

I’m very interested in LED lighting and the different spread of wavelengths that are produced compared to other types (like tungsten). Given that a White LED bulb actually produces 3 different peaks ...
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1answer
8 views

What equation should I use to determine retinal image size generated by 10 micron DIA input beam?

If I plot the effective focal spot diameter (S) achieved by using the popular expression: S = (4L/pi)(F/D), where L is input beam wavelength, F is the focal length of the lens, and D is the input ...
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0answers
409 views

Why can I turn light red or blue by holding my finger up to it?

This is a difficult phenomenon to explain. Imagine you have an opaque object partially covering a very bright light source, for example, an object held up against the sky. The left hand diagram is ...
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0answers
51 views

What happens at the point of welding iron?

What is the physics behind welding iron? It is obviously the electricity that causes the two metal parts to fuse but what is the role of the welding rod and why is it said to damage your eyes when you ...
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0answers
51 views

Terminology - optical (visual) properties of a structure

I am trying to understand few terminological problems that I encounter. Without knowing keywords it is hard to perform search for literature or publications in the area. The area relates to the ...
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0answers
80 views

What is the minimal size of the spec of dust I can see with naked eye?

When sun directly shines thru the window - I can see small specs of dusts in the air. All specs have different sizes. Assuming direct sun luminosity is 100kLux, spec is a perfect sphere, reflection ...
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0answers
123 views

How do I translate from CIE xyY color space to combinations of monochromatic wavelengths

Let's say I have a chromaticity point, on the CIE xyY color space that falls within the real colors. (Like y:0.1, x:0.4 Y:1 -- magenta)[1] I also know that humans can perceive the same color, when ...
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0answers
14 views

Total uncertainty of multiple stereo camera depth measurements

I have a stereo camera that measures depth for a rectangular area of pixels in a single image. Each depth measurement is obtained independently (this goes back to the stereo matching algorithm used). ...
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0answers
29 views

Modeling total absorption using absorbance of multiple visual layers

I have a question involving light absorbance versus absorption. It applies to a stack of different photoreceptor types. I understand the difference between absorbance, which is basically equal to ...
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142 views

How to convert a hologram into an image?

Suppose one knows in full detail the phase and intensity of monochromatic light in a plane. This is basically what a hologram records, at least for some section of a plane. By using this as the ...