Pictorial data from a thermal imager is applied on a line to a RAM at which a histogram representing the numerical distribution of pixel values is produced. This is applied to a microprocessor which uses the histogram to produce a transform to control the gain and offset of the data output of the processor....http://www.google.com.tw/patents/US5081693?utm_source=gb-gplus-share專利 US5081693 - Thermal imager arrangements
