Fast Segmentation of JPEG-Compressed Documents

We present a novel technique for segmentation of a JPEG-compressed document based on block activity. The activity is measured as the number of bits spent to encode each block. Each number is mapped to a pixel brightness value in an auxiliary image which is then used for segmentation. We introduce the use of such an image and show an example of a simple segmentation algorithm, which was successfully applied to test documents. The document is segmented into characteristics regions labeled as background, half- tones, text, graphics, and continuous tone images. The key feature of the proposed framework is that the desired region can be identi- fied and cropped (or removed) from the compressed data without decompressing the image. © 1998 SPIE and IS&T.