554

An important task in postal automation technology is determining the position and orientation of the destination address block in the image of a mail piece such as a letter, magazine, or parcel. The corresponding subimage is then presented to a human operator or a machine reader (optical character reader) that can read the zip code and, if necessary, other address information and direct the mail piece to the appropriate sorting bin Analysis of physical characteristics of mail pieces indicates that in order to automate the addressfinding task, several different image analysis operations are necessary Some examples are locating a rectangular white address label on a multicolor background, progressively grouping characters into text lines and text Lines into text blocks, eliminating candidate regions by specialized detectors (fol example, detecting regions such as postage stamps), and identifying handwritten regions. A typical mail piece has several regions or blocks that are meaningful to mail processing, for example, address blocks (destination and return), postage [meter mark or stamp) as well as extraneous blocks WINTER 1987 25 Figure 1. The heuristics listed in the previous section suggest that the design of ABLS consist of several specialized tools that are appropriately deployed. Rule R2 suggests the need for a tool to detect postage fluorescence, rule R3 a tool for isolating blocks of a certain color, rule R4 for discriminating between handwriting and print, and so on.