METHOD FOR MEASURING THE SPEED OF MOVEMENT OF EXTENDED OBJECTS Russian patent published in 2023 - IPC G01P3/36 

FIELD: digital measuring equipment.

SUBSTANCE: non-contact meters of movement parameters of extended objects. Claimed method for measuring the speed of movement of an extended object is based on projecting its image onto the screen of a radiation receiver (a video camera) and converting image elements into electrical signals. On the current frame, a rectangular area is selected, for which a histogram is calculated, obtained by summing the brightness levels of the pixels of each column with a width of one pixel, on the next frame, a strip is selected, the upper and lower boundaries of which correspond to the selected rectangular area of the current frame with similar coordinates of the upper and lower boundaries, and a histogram is also calculated for the selected band. Next, inside the selected strip, a plausible rectangular area is searched for by the value of the least sum of squares of the difference between the corresponding elements of the histograms of the selected rectangular area of the current frame and sequentially analysed similar areas of the selected strip of the next frame, the position of the rectangular area of the current frame relative to the plausible rectangular area of the next frame corresponds to the image offset value of the extended object for the period of frames, and the found value of the offset is used to calculate the speed of the extended object. At the same time, several analysed image areas are pre-processed, for which, at an additionally introduced preliminary stage, the histograms of brightness levels are calculated, the histogram variance and the correlation coefficient between the histogram of the rectangular area of the current frame and the histogram of the plausible area of the next frame are determined, which determines the most informative area containing an extended moving object, selected by the largest variance of the histogram of brightness levels and a correlation coefficient exceeding the threshold, which is used to measure the value of the displacement of the image of the object over the period of the frame and calculate the speed of the extended object according to the formula: V = K⋅Δs/τ , where K is a constant coefficient characterizing the distance from the video camera to the object, Δs is the offset of the video image of the object, and τ is the period of frames.

EFFECT: improved measurement accuracy (ensuring low measurement error) of the movement speed of an extended object by selecting the most informative area with an extended object.

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