1. A method of finding stable keypoints in a picture image using localized scale space properties, comprising: calculating by at least one processor an integral image of an input image; constructing by the at least one processor a scale space pyramid layer representation of the input image at multiple scales, wherein at each scale, a set of specific filters are applied to the input image to produce an approximation of at least a portion of the input image; combining by the at least one processor the output of each of the filters together to form a single function of scale and space; identifying by the at least one processor stable keypoint locations in each scale as pixel locations at which the single function attains a local peak value; and storing by the at least one processor the stable keypoint locations in a memory storage; wherein the constructing of the scale space pyramid representation of the input image at multiple scales includes scaling up the filters, wherein each successive filter is a scaled up version of a previous filter.