The image projected onto the retina is essentially 2D (two-dimensional).
While the external world is three-dimensional, and we perceive it as such, the process of vision involves projecting that 3D world onto a flat surface – the retina. The following points elaborate on this concept:
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Flat Image Projection: As stated in the provided reference, the image of the external world on the retina is essentially flat or two-dimensional. This is similar to how a camera lens projects a 3D scene onto a flat sensor.
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Depth Perception: Despite the 2D image on the retina, our brains are remarkably capable of interpreting this information to create a 3D perception of the world.
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Cues for 3D Perception: The brain uses various cues to reconstruct the 3D world from the 2D retinal image. These cues include:
- Binocular vision: The slight difference in images received by each eye provides depth information (stereopsis).
- Motion parallax: As we move, objects at different distances appear to move at different speeds.
- Accommodation: The eye muscles adjust the lens to focus on objects at different distances.
- Linear perspective: Parallel lines appear to converge in the distance.
- Texture gradient: Textures appear finer and more densely packed in the distance.
- Occlusion: Objects that block our view of other objects are perceived as being closer.
- Relative size: Objects of known size appear smaller when they are farther away.
In summary, while the initial image captured on the retina is two-dimensional, our brains utilize various cues to construct a three-dimensional representation of the world around us.
