Determining a rectangular box encompassing a digital picture within a

Abstract

An invention for determining a rectangular bounding box encompassing a photograph or object(s) represented within a digital image is disclosed. The rectangular bounding box is determined irrespective of the device used to acquire the digital image. First a set of contrast points is derived; these contrast points representing changes in the characteristics of a pixel from that of a traversed neighbor. After ordering the contrast points according to their radial angle around a central reference point, a list of lines is generated by selecting two points separated by q positions in the ordered list of contrast points. If the four lines generated the most often roughly form a rectangle, then they correspond to the sides of the rectangular bounding box. Else, the line with the highest count is used as a base side of the rectangular bounding box. The slopes of the other sides are readily calculated as they are either perpendicular and parallel to base side, and their positions are then determined with reference to the other lines in the list. Once the rectangular bounding box has been determined, the digital photograph is extracted, or a high-resolution scan is performed and the digital photograph is readily extracted from this new high-resolution image based on the corresponding position and size of the rectangular bounding box.