IDENTIFYING POINTS OF INTEREST IN AN IMAGE

Points of interest are identified in an image to characterize that image by dividing the image tiles consisting of adjacent pixels; finding within each tile the position of a pixel with an extremum value and ascribing that extremal value to the tile; identifying a tile with an extremal value which is more extreme than that of all adjacent tiles; and selecting as a point of interest the position within the image of the pixel with the extremum value in that identified tile.