I. Human vision and digital image attributes
1. Human eye structure
Sclera: Non-transparent white tissue that protects the eye. The iris is composed of the choroid.
Choroid: rich in pigment, black, shading effect.
Iris: Racial, black, brown, or blue with the round hole in the middle of the iris known as the pupil.
▲ Pupil: The same as the aperture controls the flux of light into the eye. The circular muscles of the iris regulate its size.
Retina: a total of 10 layers, 8 of which are transparent to light that is ineffectual. The ninth layer is the photosensitive layer, which is filled with optic nerve cells. The tenth layer is directly attached to the choroid. To form an optical image on the retina.
Macula: An oval, yellow, pit-shaped area near the center of the retina. Concentrated areas of photoreceptor cells. Each photoreceptor cell corresponds to an optic nerve, which perceives objects with the highest sharpness. On the contrary, the farther away from the macula, the more light sensitive cells are distributed, and the more light sensitive cells correspond to one optic nerve, the lower the clarity.
Photoreceptor cell: to obtain light information, through the optic nerve to the human brain, so that people produce vision
▲ Classification of photoreceptor cells:
| The name of the | Also known as | The number of | function | Condition/premise | distribution |
|---|---|---|---|---|---|
| Columnar cells | Dark vision cell | About 100 million | They can only distinguish between the intensity of light | It only works in low light | Marginal area of retina |
| cones | Bright vision cell | About 7 million | It can distinguish not only the intensity of light but also color | It only works under light | Central retinal area |
[Tip] : column dark cone Ming, dark more Ming less, dark bright, dark edge Ming center
Lens: The flat, spherical, transparent body behind the pupil that acts like the lens of a camera, allowing a scene to be clearly formed on the retina.
Blind spot: All the light-sensitive cells connect to the optic nerve, which converges to a point in the retina that leads to the brain, where there are no light-sensitive cells, known as the blind spot
Anterior ventricle and posterior ventricle:
- The anterior chamber, filled with a clear liquid, has a certain absorption of ultraviolet light.
- The rear chamber, filled with vitreous liquid, has a certain filter protection effect
2. Human vision
Angle of view: The Angle formed when light from two external points converges on the human eye. An eye chart is designed according to the principle of perspective.
▲ The minimum Angle of view of the human eye: 1/60°, that is, 1 ‘[1 degree =60’ (60 points)]
▲ Visual inertia:
Critical flicker frequency:
How the human eye reacts to brightness: