DISTANCE CALCULATION BASED ON SPATIAL PHASE MODULATION IN A FOUR STROKE i-ToF SENSOR Russian patent published in 2023 - IPC G01S17/894 

FIELD: processing 3D images.

SUBSTANCE: invention relates, in general, to the field of processing three-dimensional (3D) images, and in particular to a method for calculating distances to scene objects in a 3D image based on spatial phase modulation and a device for its implementation. The technical result is to increase the accuracy of determining the depth in a 3D image. The result is achieved by simultaneously illuminating the scene with the first structured light having the first phase space pattern and the second structured light having the second phase space pattern, wherein each of the first and second structured light is modulated in amplitude with the same carrier and is formed by sections with shift +Δ phases alternating with sections with a shift -Δ phases, phase shifts of the sections of the first and second phase spatial patterns are equal in absolute value and are within 0<Δ<π/2, sections of the first and second phase spatial patterns with phase shifts opposite in sign are superimposed on each other, the spatial frequency of the sections of the first and second phase spatial patterns is higher than the spatial frequency of the scene objects; capturing an image of a scene simultaneously illuminated by the first and second structured light by a four-stroke i-ToF sensor in combination with an array of separators, while the separator array contains a first set of separators and a second set of separators different from the first set of separators, the separators of the first set of separators are arranged in alternation with separators of the second set of separators, one separator from the array of separators is opposite one pixel of the four-stroke i-ToF sensor, and two adjacent pixels of the four-stroke i-ToF sensor form a dual pixel, and if the first and second structured light have different wavelengths and/or different polarization, then the image of the scene is captured by a four-cycle i-ToF sensor through an array of separators; eliminating for at least one pair of consecutive cycles of the first and second pixels in each dual pixel of the four-cycle i-ToF sensor, the background and the global component of the signals; for each dual pixel, the distance to the scene object is calculated for at least one pair of successive cycles of the first and second pixels in the dual pixel.

EFFECT: increase in the accuracy of determining the depth in a 3D image.

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