Abstract: A image obtained by a camera is segmented into regions. Information about signs of curvature values of an intensity of the image is computed as a function of pixel location. Pixel locations are assigned to different segments, each according to one or more, or a combination of the signs for the pixel location. Preferably, each pixel location is assigned to a respective type of segment according to whether the signs of the curvature values in two mutually transverse directions at the pixel location are both positive or both negative respectively. Preferably spatial low pass filtering is used to control the number of segments that are found in this way.