Image processor normalising and enhancing image contrast - uses programme statistical pipe-line processor to calculate new brightness for each point in image

摘要

The image processor normalises and enhances the contrast of an image using a pipe-line processor programmed to perform a statistical function on each image poit to yield a new value. For each image point the mean amplitude and the variance of the immediately neighbouring points are calculated in two processors. A histogram of mean amplitudes is stored, as is a histogram of amplitude variance, above a threshold. For each image point these histograms are combined in a statistical function whose form is determined by a read-only-memory. From the results of this process a look up table is derived which is used to transform each incoming image point into an enhanced point.