Information transmission method and apparatus

• US 5,751,743 A
• Filed: 10/01/1992
• Issued: 05/12/1998
• Est. Priority Date: 10/04/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takizawa, Hiroshi
• Primary Examiner(s): NGO, CHUONG D
• Application Number:
  US07/955,035
• Time in Patent Office: 2,049 Days
• Field of Search: 371/5.5, 371/37.1, 371/41, 358/433, 358/426, 375/8, 375/109, 341/67
• US Class Current: 714/774
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04N 1/00095 Systems or arrangements for the transmission of the picture signal
• CPC Class Codes: H04N 1/333 Mode signalling or mode changing; Handshaking therefor
• CPC Class Codes: H04N 1/417 using predictive or differential encoding

Abstract

In an information transmission method and apparatus, information is transmitted in units of a block including information codes and error-correcting check codes, and the transmission speed is switched by changing the number of blocks to be transmitted per unit time without changing the amount of information of the information codes and the amount of information of the error-correcting check codes within each block.

Claims

1. An image information method for transmitting image information at a plurality of transmission speeds, said method comprising the steps of:

setting a desired transmission speed from the plurality of transmission speeds;

transmitting information in units of a fixed-length block including image information codes and error-correcting check codes for correcting errors of the image information codes, the image information codes being obtained by performing variable-length encoding of image signals in a frame of image data which are encoded to be a predetermined total amount of codes; and

changing a number of blocks to be transmitted per unit time without changing a code amount of the image information codes and a code amount of the error correcting check codes within each block in accordance with the set transmission speed.

2. A method according to claim 1, wherein each information code comprises a code obtained by performing variable-length encoding of an image signal for every predetermined number of picture elements.

3. A method according to claim 1, wherein the number of blocks is changed so that a ratio of the number of blocks before the change to the number of blocks after the change is equal to a ratio of a total amount of codes to be transmitted per unit time before the change to a total amount of codes to be transmitted per unit time after the change.

4. An image data transmission apparatus for transmitting image data at a plurality of transmission speeds, said apparatus comprising:

setting means for setting a desired transmission speed from the plurality of transmission speeds;

encoding means for encoding image data so as to provide a predetermined total amount of codes in a frame of the image data;

dividing means for dividing the encoded frame of image data into blocks of image data, each such block having a fixed number of codes of image data;

error-correcting encoding means for forming error-correcting check codes for each block of image data produced by said dividing means;

formation means for forming fixed-length blocks of data, each such block including a block of image data produced by said dividing means and the error-correcting check codes formed for the block of image data by said error-correcting encoding means; and

output means for outputting the fixed-length blocks of data formed by said formation means and for changing a number of blocks of data output per unit time in accordance with the transmission speed set by said setting means.

5. An apparatus according to claim 4, wherein said encoding means includes quantization means for quantizing the image signals and variable-length encoding means for encoding the image signals quantized by said quantization means.

6. An image information transmission apparatus for transmitting image information at a plurality of transmission speeds, said apparatus comprising:

setting means for setting a desired transmission speed from the plurality of transmission speeds;

input means for inputting a plurality of blocks of data, each of the blocks of data including a fixed code amount of image information codes and a fixed code amount of error correction check codes, the image information codes being variable-length encoded so that the amount of codes obtained when image data in a frame of image data is encoded is set to be a predetermined total amount of codes; and

output means for outputting the block data and for controlling the number of blocks output per unit time in accordance with the transmission speed set by said setting means.

7. An apparatus according to claim 6, wherein each information code comprises a code obtained by performing variable-length encoding of an image signal for every predetermined number of picture elements.

8. An image data transmission apparatus for transmitting image data at variable transmission speeds, said apparatus comprising:

setting means for setting a desired transmission speed from the plurality of transmission speeds;

encoding means for encoding image data so as to provide a predetermined total amount of codes in a frame of the image data;

error-correcting encoding means for forming error-correcting check codes for the encoded image data;

formation means for forming fixed-length block data including the encoded image data and the error-correcting check codes formed by said error-correcting encoding means, each of the fixed-length block data including a fixed code amount of the encoded image data and a fixed code amount of error correction check codes; and

output means for outputting the block data formed by said formation means and for controlling the number of blocks output per unit time in accordance with the transmission speed set by said setting means.

9. An apparatus according to claim 8, wherein said encoding means comprises quantization means for quantizing the image signals and variable-length encoding means for encoding the image signals quantized by said quantization means.