Patent ID: 6061476
Filing Date: 2000-05-09
Classification: G06K,G06T

Abstract:
A method for providing dynamic thresholding in an automated inspection system: said method comprising the steps of:capturing with an image acquisition device a first image comprising a plurality of first image pixels and a second image comprising a plurality of second image pixels;subtracting gray level values of said second image pixels from gray level values of said first image pixels to provide a subtracted image having a plurality of subtracted image pixel values;processing said subtracted image pixel values with a positive image pixel map to generate a positive difference image consisting of positive difference values from said subtracted image pixels values;processing said subtracted image pixel values with a negative image pixel map to generate a negative difference image consisting of negative difference values from said subtracted image pixels values;generating a positive dynamic threshold image as a function of said gray level values of said first image pixels and said gray level values of said second image pixels;generating a negative dynamic threshold image as a function of said gray level values of said first image pixels and said gray level values of said second image pixels;subtracting said positive difference image from said positive dynamic threshold image, to implement thresholding and provide a subtracted positive image;subtracting said negative difference image from said negative dynamic threshold image, to implement thresholding and provide a subtracted negative image;converting said subtracted positive image and said subtracted negative image to provide, respectively, a positive results image and a negative results image wherein pixels that exceed respective threshold values are set to a first number and pixels that do not exceed respective threshold values are set to a second number;merging said positive results image and said negative results image to provide a merged image; andbinarizing said merged image to provide a binarized foreground/background detection output wherein all positive values representing features of interest are set to a first binarization number and all zero values are set to a second binarization number.