Light and Vision: Photon Direction

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SUMMARY

The discussion centers on how the human eye differentiates light from multiple point sources, specifically addressing the behavior of photons emitted from a pinhole light source. It is established that the lens of the eye converges light rays from each point source to a specific point on the retina, allowing for the perception of directionality. The angle at which light rays enter the eye is crucial for identifying the source of light, as they strike different areas of the retina based on their origin. This mechanism enables the eye to distinguish between closely positioned light sources despite overlapping photon paths.

PREREQUISITES
  • Understanding of basic optics principles
  • Knowledge of human eye anatomy, particularly the lens and retina
  • Familiarity with photon behavior and light dispersion
  • Concept of visual perception and how stimuli are processed
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  • Research the anatomy and function of the human eye, focusing on the lens and retina
  • Study the principles of optics, including light rays and convergence
  • Explore the concept of visual perception and how the brain interprets light stimuli
  • Investigate the physics of photons and their behavior in different mediums
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Students of optics, vision scientists, educators in biology and physics, and anyone interested in the mechanics of human vision and light perception.

clalburn1420
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How is it that light disperses from a point source (like a pinhole w/ a light shining through). From my understanding, photons disperses in all directions at all angles. So than how is it that an eye can differentiate that point from all the other points light around it (say there was another pin hole in a different area of the field of view). Would not the complete dispersal from one point of light hit every photoreceptor cell? And if so, how would it differentiate that stimulus from another point of light?
Thanks very much.
 
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That's what the lens of the eye is for. It converges the light from each point source to a single point on the retina.
 
clalburn1420 said:
How is it that light disperses from a point source (like a pinhole w/ a light shining through). From my understanding, photons disperses in all directions at all angles. So than how is it that an eye can differentiate that point from all the other points light around it (say there was another pin hole in a different area of the field of view). Would not the complete dispersal from one point of light hit every photoreceptor cell? And if so, how would it differentiate that stimulus from another point of light?
Thanks very much.

It is the angle of the rays coming in to your eye that identifies the direction to you.

Think about what you're seeing right now. There's a light ray coming from a window in your peripheral vision. It impinges on your eye near the edge of your cornea and directed into your pupil where it impinges on your retina way over near the edge. A stimulus received at that point on your retina appears in your vision as a source of light in your preipheral vision.
 
Still not sure i understand. Let me try illustrating my understanding, and then correct me one how terribly misinformed i am.

In the attachment i did a rough representation of what I'm talking about. If two points of emitting light are next to each other and near the eye, won't their photons be crossing paths, eventually striking same receptors?
I mean, one point of light does not transmit through the eye in only one direction/angle, does it?
 

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clalburn1420 said:
I mean, one point of light does not transmit through the eye in only one direction/angle, does it?
The purpose of a lens component is that it takes divergent rays coming from a single distant source and focusses them at a point.

See diagram.
 

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Last edited:
I think i get it. Thats pretty amazing. Thanks very much!
 

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