Jian X Lu

US Patent:

6389177, May 14, 2002

Filed:

Jul 2, 1996

Appl. No.:

08/677344

Inventors:

Ke-Chiang Chu - Saratoga CA
Jian Lu - Santa Clara CA
Yu Tina Tian - Stanford CA

Assignee:

Apple Computer, Inc. - Cupertino CA

International Classification:

G06K 940

US Classification:

382268, 382275, 382168

Abstract:

A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

US Patent:

6618509, Sep 9, 2003

Filed:

Apr 9, 2001

Appl. No.:

09/829519

Inventors:

Yu Tina Tian - Stanford CA
Jian Lu - Santa Clara CA
Ke-Chiang Chu - Saratoga CA

Assignee:

Apple Computer, Inc. - Cupertino CA

International Classification:

G06K 900

US Classification:

382239, 382172, 35842614, 3484091

Abstract:

In a digital signal processing system, a method for selecting a transform function to apply to an input signal based on characteristics of the signal, and for self-adjusting criteria which are used in selecting a transform function to apply to a subsequent signal. Characteristics are obtained from the signal. The characteristics are compared to adjustable criteria which are used in selecting a transform function. Differing criteria are maintained for the different selectable transform functions. A record is maintained of transform functions selected and the particular characteristics that caused the selection. Based on the ability of a transform function to minimally define the coded signal, an inverse transform function is selected to decode the signal. The criteria used in selecting a transform function to apply to a subsequent signal are adjusted based on a quality measure of the decoded signal and the record of selected transform functions.

US Patent:

6798918, Sep 28, 2004

Filed:

Apr 17, 2002

Appl. No.:

10/124932

Inventors:

Ke-Chiang Chu - Saratoga CA
Jian Lu - Santa Clara CA
Yu Tina Tian - Stanford CA

Assignee:

Apple Computer, Inc. - Cupertino CA

International Classification:

G06K 940

US Classification:

382268, 382275, 382168

Abstract:

A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

US Patent:

7079695, Jul 18, 2006

Filed:

Aug 7, 2003

Appl. No.:

10/637245

Inventors:

Yu Tina Tian - Stanford CA, US
Jian Lu - Santa Clara CA, US
Ke-Chiang Chu - Saratoga CA, US

Assignee:

Apple Computer, Inc. - Cupertino CA

International Classification:

G06K 9/36
G06K 9/46

US Classification:

382239, 382173, 35842614, 3484091, 37524002

Abstract:

In a digital signal processing system, a method for selecting a transform function to apply to an input signal based on characteristics of the signal, and for self-adjusting criteria which are used in selecting a transform function to apply to a subsequent signal. Characteristics are obtained from the signal. The characteristics are compared to adjustable criteria which are used in selecting a transform function. Differing criteria are maintained for the different selectable transform functions. A record is maintained of transform functions selected and the particular characteristics that caused the selection. Based on the ability of a transform function to minimally define the coded signal, an inverse transform function is selected to decode the signal. The criteria used in selecting a transform function to apply to a subsequent signal are adjusted based on a quality measure of the decoded signal and the record of selected transform functions.

US Patent:

7092580, Aug 15, 2006

Filed:

May 17, 2004

Appl. No.:

10/847988

Inventors:

Ke-Chiang Chu - Saratoga CA, US
Jian Lu - Santa Clara CA, US
Yu Tina Tian - Stanford CA, US

Assignee:

Apple Computer, Inc. - Cupertino CA

International Classification:

G06K 9/40

US Classification:

382268, 382275, 382168

Abstract:

A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

US Patent:

7346106, Mar 18, 2008

Filed:

Dec 30, 2003

Appl. No.:

10/751345

Inventors:

Wenqing Jiang - San Jose CA, US
Jian Lu - Sunnyvale CA, US
Gregory K. Wallace - Palo Alto CA, US
Peter Chou - Mountain View CA, US

Assignee:

Apple Inc. - Cupertino CA

International Classification:

H04N 7/12

US Classification:

37524012

Abstract:

An encoding manager performs a first-pass encoding of a video sequence, collecting modeling data concerning the sequence in the process. The encoding manager utilizes collected data to construct a model concerning the sequence, the model including bit overhead for each frame and data concerning transitions that occur during the sequence. The encoding manager uses the data model to generate a rate profile for the video sequence, avoiding buffer underflow by allocating bits from hard to easy segments as needed. The encoding manager utilizes the rate profile to perform a second-pass encoding of the video sequence, adjusting quantization and bit rate for frames as necessary to avoid underflow and conform to the bit budget for the video sequence.

US Patent:

7577306, Aug 18, 2009

Filed:

May 16, 2006

Appl. No.:

11/436113

Inventors:

Yu Tina Tian - Stanford CA, US
Jian Lu - Santa Clara CA, US
Ke-Chiang Chu - Saratoga CA, US

Assignee:

Apple Inc. - Cupertino CA

International Classification:

G06K 9/36
G06K 9/46

US Classification:

382239, 382232

Abstract:

In a digital signal processing system, a method for selecting a transform function to apply to an input signal based on characteristics of the signal, and for self-adjusting criteria which are used in selecting a transform function to apply to a subsequent signal. Characteristics are obtained from the signal. The characteristics are compared to adjustable criteria which are used in selecting a transform function. Differing criteria are maintained for the different selectable transform functions. A record is maintained of transform functions selected and the particular characteristics that caused the selection. Based on the ability of a transform function to minimally define the coded signal, an inverse transform function is selected to decode the signal. The criteria used in selecting a transform function to apply to a subsequent signal are adjusted based on a quality measure of the decoded signal and the record of selected transform functions.

US Patent:

7746927, Jun 29, 2010

Filed:

Mar 26, 2004

Appl. No.:

10/811427

Inventors:

Eric Hamilton - Los Gatos CA, US
Jian Lu - Sunnyvale CA, US
Gregory K. Wallace - Palo Alto CA, US
Peter Chou - Mountain View CA, US

Assignee:

Apple Inc. - Cupertino CA

International Classification:

H04N 7/18

US Classification:

37524002, 37524003

Abstract:

An encoding manager facilitates robust single-pass variable bit rate video encoding of a video sequence. Before encoding the video sequence, the encoding manager determines the size of a buffer to use for keeping track of over/under used bits generated during encoding. The encoding manager uses the target bit rate for the video sequence and the length of the video sequence to determine the size of the buffer. After allocating bits to a frame of the sequence, the encoding manager determines the quant to use to encode that frame. The determination of a quant to use to encode a frame is informed by the fullness of the buffer. The encoding manager adjusts the quant to use (and thus the aggressiveness of its encoding) in response to the amount of overflow generated thus far by the encoding of the video sequence.