Abstract: An image processing system is arranged to process an array of pixels. The array is scanned in a sequential manner, pixel by pixel, each pixel being scanned only once. The resulting scan data is processed to identify pixels which contain image information of significance, and to assign these pixels to an image segment which may contain a number of such pixels. The system provides a data output of summary information pertaining to the segment or segments identified in the image. In this way a segmentation scan is performed which is very efficient and which produces summary information without a further processing step.