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The Concepts of 3D Stereo Vision

There are two primary factors to generate a 3D stereo vision, Convergence and Parallax.

Convergence

The convergence is the angle formed by your eyes and the observed object. The higher the angle

value is, the nearer the observed object is to your two eyes, and vice versa.

High Convergence

(Target object is near)

Low Convergence

(Target object is far)

Therefore, when the convergence is fixed, any object between you and the convergence point

will be closer to you, while the object beyond the convergence point will be farther away from

you.

Please note that if the Convergence is higher then 6 degrees, which means the object is too close

to you, then your eyes feel uneasy. On the contrary, when the value is too small, which means

the object is too far, the stereo sensation will be lost.

Parallax

The parallax images are the images passing through to your left and right eyes. All 3D stereomedia contain a pair of parallax images that individually, and simultaneously, pass to your left

and right eyes. This is to convince your brain that there is an existence of depth in the media.

Positive Parallax

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When the target object offsets to the right in the left image, and offsets to the left in the right

image, then your binocular focus is lead to fall behind the display. This phenomena is calledPositive Parallax.

Your convergence point is lead to fall behind

the display.

Positive Parallax

Zero Parallax

When the paired parallax images superimpose on the display, then your binocular focus is lead tofall on the same display, which is the Zero Parallax.

The L and R image lead your convergence

point to fall on the display.

Zero Parallax

Negative Parallax

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When the target object offsets to the left in the left image, and offsets to the right in the right

image, then your binocular focus is lead to fall in front of the display. This phenomena is callNegative Parallax.

The L and R images lead your convergence

point to fall in front of the display.

Negative Parallax