Abstract: An improved method is disclosed of compressing, for storage or transmission, the information contained in a bi-level digitized input image by separate handling of a corresponding template image and a compressed image, which method is capable of handling "white-out" areas of the image. In accordance with the method, the template image is subtracted from the input image to generate the compressed image, the subtraction is characterized in that the subtraction step determines, for each pixel, whether the pixel is a "removed pixel" and, if so, the pixel is assigned to be black in the compressed image. A pixel is a "removed pixel" if the corresponding pixel in the template image is black, and the corresponding pixel in the input image is white.

Abstract: A data entry system generates an electronically stored coded representation of a character sequence from one or more electronically stored document images. The system comprising optical character recognition logic for generating, from the document image or images, character data specifying one of a plurality of possible character values for corresponding segments of the document images. The system also has an interactive display means for generating and sequentially displaying, one or more types of composite image, each composite image comprising segments of the document image or images arranged according to the character data, and a correction mechanism responsive to a user input operation to enable the operator to correct the character data associated with displayed segments.