Data communication control apparatus and its control method, image processing apparatus and its method, and data communication system

• US 6,744,927 B1
• Filed: 12/22/1999
• Issued: 06/01/2004
• Est. Priority Date: 12/25/1998
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kato, Masami
• Primary Examiner(s): Chen, Wenpeng
• Application Number:
  US09/469,798
• Time in Patent Office: 1,623 Days
• Field of Search: 382/235, 382/239-250, 382/232, 382/166, 382/251, 358/430, 358/433, 375/240.12, 375/240.26, 370/263, 709/204, 709/203, 709/217
• US Class Current: 382/239
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• CPC Class Codes: H03M 13/00 Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes error detection or error correction for analogue/digital, digital/analogue or code conversion H03M1/00 – H03M11/00; specially adapted for digital computers G06F11/08; for information storage based on relative movement between record carrier and transducer G11B, e.g. G11B20/18; for static stores G11C

Abstract

In video conference system terminals, the conventional difficulty in high-quality display of facial expressions of a plurality of participants is solved. In a multipoint connection device connecting a plurality of video conference terminals, image data transmitted from a terminal is decoded, and a face area in the image data is recognized. Then, quantization coefficients for the face area are set to be greater coefficients than those for other areas than the face area, then the image data is compressed, and delivered to the respective terminals. By this arrangement, in image data, a face area with great significance can be re-compressed without degradation of image quality, while an area with less significance such as background can be compressed with high efficiency. Thus, the total code amount can be reduced. Accordingly, even if the system uses a narrow band communication channel, the significant face area can be clearly displayed at the respective terminals.

Claims

1. A data communication control method in a data communication control apparatus for controlling data communication among a plurality of terminals connected to the apparatus, each of the plurality of terminals being configured to transmit and receive image data to and from the apparatus and to issue an instruction not to perform compression control in accordance with a request of a user, the method comprising the steps of:

(a) receiving image data from one of the plurality of terminals;

(b) determining whether or not compression control is performed on the received image data in accordance with the instruction;

(c) if it is determined in step (b) that the compression control is performed,

(c-1) recognizing a specific area in the received image data,

(c-2) controlling a compression method for compressing the received image data so as to compress the specific area and an other area of the received image data in different compression methods, respectively, and

(c-3) compressing the received image data using the compression method controlled in step (c-2); and

(d) transmitting the image data to at least one of the plurality of terminals.

2. The data communication control method according to claim 1, wherein quantization coefficients are controlled in step (c-2).

3. The data communication control method according to claim 1, wherein, in step (c-2), execution or non-execution of spatial filter processing on the image data is controlled.

4. The data communication control method according to claim 1, wherein, in step (c-2), coefficients of a spatial filter are controlled.

5. The data communication control method according to claim 1, wherein the specific area is an area showing a face of a person.

6. The data communication control method according to claim 1, further comprising the step of:

(c-0) if it is determined in step (b) that the compression control is performed, decompressing the compressed image data prior to performing step (c-1),

wherein step (c-1) further comprises recognizing the specific area in the image data decompressed in step (c-0).

7. The data communication control method according to claim 1, wherein at least one of the plurality of terminals has an image sensing unit for obtaining image data to be transmitted, and wherein the image sensing unit can be operated from another terminal in communication with the one terminal.

8. A data communication system, in which a plurality of terminals are connected via a data communication control apparatus, for performing data communication among said plurality of terminals, wherein each of the plurality of terminals is configured to transmit and receive image data to and from said data communication control apparatus, and to issue an instruction not to perform compression control in accordance with a request of a user, said data communication control apparatus comprising:

a reception unit, adapted to receive compressed image data from one of the plurality of terminals;

a determination unit, adapted to determine whether or not compression control is performed on the received compressed image data in accordance with the instruction;

a decompression unit, adapted to decompress the compressed image data received by said reception unit if the compression control is performed;

a recognition unit, adapted to recognize a specific area in the image data decompressed by said decompression unit;

a compression control unit, adapted to control a compression method for compressing the image data so as to compress the specific area and an other area of the image data in different compression methods, respectively;

a compression unit, adapted to compress the decompressed image data by the compression method controlled by said compression control unit; and

a transmission unit, adapted to transmit the compressed image data to at least one of the plurality of terminals.

9. The data communication system according to claim 8, wherein said compression control unit controls quantization coefficients.

10. The data communication system according to claim 8, wherein said compression control unit controls execution or non-execution of spatial filter processing on the image data.

11. The data communication system according to claim 8, wherein said compression control unit controls coefficients of a spatial filter.

12. The data communication system according to claim 8, wherein the specific area is an area showing a face of a person.

13. The data communication system according to claim 8, wherein at least one of said plurality of terminals has an image sensing unit, adapted to obtain image data to be transmitted, and wherein said image sensing unit can be operated from another terminal in communication with said one terminal.

14. A storage medium containing control program code in a data communication control apparatus for controlling data communication among a plurality of communication terminals connected to said apparatus, wherein each of the plurality of terminals is configured to transmit and receive image data to and from said apparatus, and to issue an instruction not to perform compression control in accordance with a request of a user, said program code including at least code of process procedures for:

(a) receiving image data from one of the plurality of terminals;

(b) determining whether or not compression control is performed on the received image data in accordance with the instruction;

(c) if it is determined in step (b) that the compression control is performed,

(c-1) recognizing a specific area in the received image data,

(c-2) controlling a compression method for compressing the received image data so as to compress the specific area and an other area of the received image data in different compression methods, respectively, and

(c-3) compressing the received image data using the compression method controlled in process procedure (c-2); and

(d) transmitting the image data to at least one of the plurality of terminals.