Patent ID: 6486909
Filing Date: 2002-11-26
Classification: G06K,G06T

Abstract:
A process for identifying relative movement in an input signal, the input signal comprising a succession of frames, each frame comprising a succession of pixels, the process comprising:for each pixel of the input signal, smoothing the input signal using a time constant for such pixel, thereby generating a smoothed input signal; determining for each pixel in the smoothed input signal a binary value corresponding to the existence of a significant variation in the amplitude of the pixel between the current frame and the immediately previous smoothed input frame, and the amplitude of the variation; using the existence of a significant variation for a given pixel, modifying the time constant for the pixel to be used in smoothing subsequent frames of the input signal; for each particular pixel of the input signal, forming a first matrix comprising the binary values of a subset of the pixels of the frame spatially related to such particular pixel, and a second matrix comprising the amplitude of the variation of the subset of the pixels of the frame spatially related to such particular pixel; and determining in the first matrix whether the particular pixel and the pixels along an oriented direction relative to the particular pixel have binary values of a particular value representing significant variation, and, for such pixels, determining in the second matrix whether the amplitude of the pixels along the oriented direction relative to the particular pixel varies in a known manner indicating movement in the oriented direction of the particular pixel and the pixels along the oriented direction relative to the particular pixel, the amplitude of the variation of the pixels along the oriented direction determining the velocity of movement of the pixel and the pixels along the oriented direction relative to the particular pixel.