Stereo pair - a pair of flat images of the same object (subject), which have differences between the images, designed to create the effect of volume. The effect occurs due to the fact that the parts of the plot located at different distances from the observer when viewed from different points (corresponding to the right and left eyes) have different angular displacement (parallax). When viewing a stereo pair in such a way that each eye perceives only the image intended for it, the illusion of observing a three-dimensional picture is created (see binocular vision). The stereo pair is used to demonstrate spatial images of objects in stereoscopic cinema, stereophotography, stereoscopic television, virtual reality systems, and for scientific purposes.
As a rule, a classical stereo pair consists of images arranged horizontally next to each other at a distance corresponding to the interpupillary distance of a person. To view such a stereo pair, the direction of the eye's gaze has to be placed in parallel, as if we were observing a very distant object, which requires special efforts when viewing stereo pairs. To simplify the perception of a pair of images can be placed with the superimposition of one on the other, while the separation of pairs occurs due to different colors (see anaglyph), of different polarization or time separation (for example, pairs flicker alternately on the screen; special glasses are used to ensure visibility for each of the eyes only at the moment when the desired image is displayed). In the described cases, glasses of various designs are used to observe stereo pairs.
Over Under 3D - frames are arranged horizontally relative to each other. In turn, it is divided into two subspecies: Cross and parallel stereo pairs. Parallel: The left image is for the left eye, and the right image is for the right eye. To view such a stereo pair, the direction of the eye's gaze has to be placed in parallel, as if we were observing a very distant object, which requires special efforts when viewing stereo pairs. Cross: The left image is for the right eye, and the right image is for the left eye. To view such a stereo pair, we have to cross our eyes as if we are observing a very close object, which is easier than when viewing parallel stereo pairs.
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