Louis Joseph Kerofsky

US Patent:

6622145, Sep 16, 2003

Filed:

Mar 30, 2001

Appl. No.:

09/823854

Inventors:

Louis Joseph Kerofsky - Portland OR

Assignee:

Sharp Laboratories of America - Camas WA

International Classification:

G06F 700

US Classification:

707101, 341 67, 341107

Abstract:

Methods and apparatus for constructing a grafted codebook, encoding symbols using a grafted codebook, and decoding codewords formed using a grafted codebook are disclosed. A grafted codebook is formed by piecewise modeling an input probability distribution on a number of modeling intervals, and then selecting a set of modeling distributions that minimize the redundancy of the piecewise model on the modeling intervals. An infinite code is then selected for each interval, and offsets are calculated for the codes. The codes are then merged into a grafted codebook where each code contributes codewords on its interval. The offsets are used to ensure that the resulting codebook is valid from a cumulative probability standpoint.

US Patent:

6677868, Jan 13, 2004

Filed:

Dec 12, 2001

Appl. No.:

10/017838

Inventors:

Louis J. Kerofsky - Portland OR
Shijun Sun - Vancouver WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H03M 700

US Classification:

341107, 341 51, 341 67, 341 63

Abstract:

The compression efficiency of variable length coding is preserved by altering the syntax of a bit stream input to a variable length coder if the bit stream is likely to include a symbol with a high occurrence probability.

US Patent:

6782052, Aug 24, 2004

Filed:

Mar 16, 2001

Appl. No.:

09/810349

Inventors:

Shijun Sun - Vancouver WA
Louis Kerofsky - Portland OR

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H04N 712

US Classification:

37524012

Abstract:

A method provides a fast motion search in advanced video signal coding systems based on a reference-frame prediction and a block-mode prediction so that a motion search of each block mode and each reference frame is not required. A reference frame prediction f , spaced from the current frame by âpâ number of frames, is determined by: p=min(n , p +max(a,b,c,d)); wherein p is a pre-chosen positive integer, n is the total number of reference frames, wherein A, B, C, and D are image blocks adjacent to a searched block, and wherein the reference image blocks have been chosen from reference frames f , f , f and f. The search is conducted within frames f to f , which is a subset of all the n reference frames, so that the total computational burden is significantly decreased with respect to prior art searches. The mode frequency prediction is based on the frequencies of the block modes: F =Âmin(F , F , F , F ); wherein is a positive parameter less than 1. The block-mode selection is then conducted using the mode-frequency prediction.

US Patent:

6898313, May 24, 2005

Filed:

Mar 6, 2002

Appl. No.:

10/092851

Inventors:

Xin Li - Vancouver WA, US
Louis J. Kerofsky - Portland OR, US
Kristine Elizabeth Matthews - Vancouver WA, US

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

G06K009/34

US Classification:

382176, 382181, 382190, 382232

Abstract:

A data coder prepares a frame of data for transmission over a data channel. The frame is first broken into a series of non-overlapping blocks. The blocks are analyzed to determine if they are a “picture” block or a “non-picture” block. Picture blocks are compressed to produce one or more layers of data, including a base layer and, optionally, one or more enhanced layers. Non-picture blocks are similarly compressed, but according to different compression procedures. Prior to sending the compressed layers of data to a scheduler for transmission on the data channel, the blocks are checked to see if they have changed more than a threshold amount from the last time they were sent. If the block has changed more than the threshold, the changed block is sent to the scheduler, in compressed form. If the block has not changed more than the threshold, only an indication of the block, and not the block itself, is sent to the scheduler.

US Patent:

6956511, Oct 18, 2005

Filed:

Oct 7, 2004

Appl. No.:

10/961453

Inventors:

Renjit T. Thomas - Vancouver WA, US
Louis J. Kerofsky - Portland OR, US

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H03M007/40

US Classification:

341 67, 341 65, 341106, 382233, 382246, 382250

Abstract:

Method and apparatus for use in Huffman decoding are described. In exemplary systems, a JPEG Huffman decoder is capable of simultaneously decoding multiple coefficients and/or symbols in a single table lookup. Methods for designing, building, and using such a table are included. Other embodiments are described and claimed.

US Patent:

7003153, Feb 21, 2006

Filed:

Sep 29, 2000

Appl. No.:

09/676523

Inventors:

Louis Joseph Kerofsky - Portland OR, US

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

G06K 9/00

US Classification:

382168, 382254

Abstract:

Methods and apparatus for video contrast enhancement are disclosed. A pixel level threshold is set for an input video frame in a video sequence. For pixel levels in the input video frame that are below the threshold, an adaptive contrast-enhancing function is applied. For other pixel levels, a scene-stable mapping function is applied. This contrast enhancement method can improve the contrast in darker areas of a scene depicted in the video sequence, without destroying the intended light levels for a scene or causing temporal brightness fluctuations in the enhanced video sequence.

US Patent:

7010043, Mar 7, 2006

Filed:

Apr 22, 2002

Appl. No.:

10/127742

Inventors:

Louis J. Kerofsky - Portland OR, US
Xin Li - Vancouver WA, US

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H04N 7/18

US Classification:

37524019, 37524027

Abstract:

A method in a scalable encoder for reducing the average latency associated with randomly accessing an encoded digital video signal is disclosed. This method may include converting a digital video signal into a first layer having a first degree of quality and a second layer having a second degree of quality that is higher than the first degree of quality. The method may also include encoding the first layer at a first intra-frame rate, and encoding the second layer at a second intra-frame rate that is lower than the first intra-frame rate. A method in a scalable decoder for reducing the average latency associated with randomly accessing an encoded digital video signal is also provided. The method includes accessing a first layer of a digital video signal. The first layer includes the digital video signal encoded at a first degree of quality and a first intra-frame rate. The method also includes accessing a second layer of the digital video signal.

US Patent:

7046852, May 16, 2006

Filed:

Sep 13, 2001

Appl. No.:

09/952643

Inventors:

Louis J. Kerofsky - Portland OR, US

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

G06K 9/36
G06K 9/46

US Classification:

382233, 382246, 382253

Abstract:

A system to decode compressed digital images coded with frequently occurring variable length or other symbols. The disclosed system extracts one or more symbols from the coded compressed image and selects corresponding quantized pixel values for inverse quantization from a table relating the extracted symbols to precalulated quantized pixel values.