1
Joan L Mitchell, William B Pennebaker, Jorma J Rissanen: Dynamic model selection during data compression. International Business Machines Corporation, Thomas P Dowd, September 3, 1991: US05045852 (132 worldwide citation)

A system and method for maximizing data compression by optimizing model selection during coding of an input stream of data symbols, wherein at least two models are run and compared, and the model with the best coding performance for a given-size segment or block of compressed data is selected such t ...


2
Cesar A Gonzales, Joan L Mitchell, William B Pennebaker: Adaptive graylevel image compression system. International Business Machines Corporation, Marc A Block, February 16, 1988: US04725885 (92 worldwide citation)

Apparatus and method for modelling differential pulse code modulation (DPCM) input data for entropy coding. In particular, the sign and magnitude of one piece of DPCM data after another are modelled to provide a magnitude state input and a sign state input to provide context for DPCM magnitude input ...


3
Joan L Mitchell, Karen L Anderson: Method for converting an image from a run end or run length representation to a bit map. International Business Machines Corporation, George E Clark, Thomas P Dowd, June 17, 1986: US04596039 (92 worldwide citation)

A method for converting an image from a run representation to a bit map, includes the steps of: storing a plurality of run representations of an image in a buffer; initializing a line of data; converting, by table lookup, each run representation, in said line, to a picture element representation, st ...


4
Joan L Mitchell, William B Pennebaker: Arithmetic coding data compression/de-compression by selectively employed, diverse arithmetic coding encoders and decoders. International Business Machines Corporation, Marc A Block, Thomas P Dowd, January 2, 1990: US04891643 (91 worldwide citation)

A data compression/de-compression system includes a first arithmetic coding encoder, characterized by a first set of encoding conventions, which encoder generates a code stream that points to an interval along a number line in response to decision event inputs. The code stream can be adjusted to poi ...


5
Glen G Langdon Jr, Joan L Mitchell, William B Pennebaker, Jorma J Rissanen: Arithmetic coding encoder and decoder system. International Business Machines Corporation, Thomas P Dowd, February 27, 1990: US04905297 (84 worldwide citation)

Apparatus and method for compressing and de-compressing binary decision data by arithmetic coding and decoding wherein the estimated probability Qe of the less probable of the two decision events, or outcomes, adapts as decisions are successively encoded. To facilitate coding computations, an augend ...


6
Dimitris Anastassiou, Joan L Mitchell: Gray scale image data compression with code words a function of image history. International Business Machines Corporation, Roy R Schlemmer Jr, January 18, 1983: US04369463 (68 worldwide citation)

The present invention relates to a method and apparatus for compacting gray-scale image data which maintains extremely good picture quality and can result in typical images in a compression ratio of 5 to 1 and even better if a final step of arithmetic coding is used. The method is a special applicat ...


7
Karen L Anderson, Ian R Finlay, Joan L Mitchell, Davey S Thornton: Multi-mode data stream generator. International Business Machines Corporation, Mark S Walker, September 20, 1994: US05349348 (65 worldwide citation)

Improved apparatus and method for encoding and decoding information is disclosed herein. The invention uses the same marker segment information to engage an encoder or a decoder. The technique eliminates many of the complexities associated with building parameter lists, and generating various types ...


8
William B Pennebaker, Joan L Mitchell: Probability adaptation for arithmetic coders. International Business Machines Corporation, Marc A Block, Thomas P Dowd, June 19, 1990: US04935882 (53 worldwide citation)

Apparatus and method for adapting the estimated probability of either the less likely or more likely outcome (event) of a binary decision in a sequence of binary decisions involves the up-dating of the estimated probability in response to the renormalization of an augend A. The augend A changes valu ...


9
Scott D Mastie, Joan L Mitchell, Ravi Prakash, Nenad Rijavec: Background data recording and use with document processing. InfoPrint Solutions Company, Duft Bornsen & Fishman, December 25, 2007: US07312902 (53 worldwide citation)

Systems, methods and program products for recording a document's background data during front-end generation of the document, and inserting a background data identifier on the document. In addition, the invention provides for use of the background data for document processing. For example, the inven ...


10
Karen L Anderson, Joan L Mitchell: System for creating transposed image data from a run end or run length representation of an image. International Business Machines Corporation, Thomas P Dowd, November 8, 1988: US04783834 (50 worldwide citation)

A system for formatting electronic binary image data, which may be in compressed raster form, into transposed or rotated raster form for storage or output, such as on a printing device, is disclosed wherein the image data is first assembled in a buffer in the form of vectors of run ends representing ...