A method and apparatus for localizing an area in relative movement and for
determining the speed and direction thereof in real time is disclosed.
Each pixel of an image is smoothed using its own time constant. A binary
value corresponding to the existence of a significant variation in the
amplitude of the smoothed pixel from the prior frame, and the amplitude
of the variation, are determined, and the time constant for the pixel is
updated. For each particular pixel, two matrices are formed that include
a subset of the pixels spatially related to the particular pixel. The
first matrix contains the binary values of the subset of pixels. The
second matrix contains the amplitude of the variation of the subset of
pixels. In the first matrix, it is determined whether the pixels along an
oriented direction relative to the particular pixel have binary values
representative of significant variation, and, for such pixels, it is
determined in the second matrix whether the amplitude of these pixels
varies in a known manner indicating movement in the oriented direction.
In each of several domains, histogram of the values in the first and
second matrices falling in such domain is formed. Using the histograms,
it is determined whether there is an area having the characteristics of
the particular domain. The domains include luminance, hue, saturation,
speed (V), oriented direction (D1), time constant (CO), first axis
(x(m)), and second axis (y(m)).