BIJPEG

BIJPEG is a proposed image compression concept within the JPEG family designed to optimize storage and transmission of bi-level (black-and-white) and grayscale images, particularly scanned documents. The idea combines a JPEG-like transform and quantization stage with a specialized bit-plane encoding scheme and context-adaptive arithmetic coding to better capture the statistics of binary images.

The term appears in academic discussions and experimental implementations as researchers explore improvements for document imaging. As of now, there is no formal ISO/IEC standard or widely adopted specification for BIJPEG; it remains primarily in research contexts and open-source experiments rather than in production workflows.

Technically, BIJPEG envisions a workflow that mirrors JPEG for color content while adding a bi-level aware processing path. It may employ a multi-rate bit-plane decomposition of image data, encoding the most significant bitplanes first and using context modeling and arithmetic coding to improve efficiency on text and line art. The format would support lossy and lossless modes, with parameters to control quantization and bitplane depth. A BIJPEG container would include metadata about bit-depth, image properties, and optional OCR-related text blocks to assist downstream processing.

Applications for BIJPEG are mainly in document imaging, archival of scanned records, and environments where OCR accuracy is important. It aims to provide higher compression for binary content than standard JPEG and potentially more robust text restoration than some existing bi-level codecs, but it remains uncommon outside of experimental or academic contexts.

BIJPEG is related in goal to formats like JBIG2 and JPEG-LS, sharing the aim of efficient representation for diverse image classes. This article treats BIJPEG as a conceptual or research-oriented idea rather than a standardized format.