Bildsystem mit programmierbarer Steueranlage

摘要

A module of a programmable controller is adapted to process a video image to evaluate characteristics of an object within the image. A processor (100) converts an analog video signal into four binary images. A memory (124) stores data defining a separate sensor region for each binary image. A set of four counters (152) is provided to tabulate the pixels of one color in each binary image that lie within the associated sensor region. A video signal sensor (68) measures variation of the luminance of the video signal. The processor (100) uses the luminance variation measurement to adjust the binarization of the video signal to produce normalized binary images under varying lighting conditions.