Image signal encoding method and system

• US 4,811,113 A
• Filed: 06/18/1987
• Issued: 03/07/1989
• Est. Priority Date: 06/18/1986
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kondo, Makio, Ozeki, Yoshiaki, Taniguchi, Hayashi
• Primary Examiner(s): Coles, Sr., Edward L.
• Application Number:
  US07/063,426
• Time in Patent Office: 628 Days
• Field of Search: 358/260, 358/261, 358/262, 340/377 DD, 382/56
• US Class Current: 382/245
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: H04N 1/419 in which encoding of the length of a succession of picture-elements of the same value along a scanning line is the only encoding step H04N1/4135 - H04N1/417 take precedence
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 7/24 Systems for the transmission of television signals using pulse code modulation H04N21/00 takes precedence

Abstract

An encoding/decoding method for carrying out conversion between run lengths and corresponding run length codes is provided. The run length codes has a format including a first part for storing first information and a second part for storing second information. The first information indicates the length of the code and the second information indicates the corresponding run length. The total number of bits of each of the run length codes is set as an integral multiple of a predetermined number of bits. The present encoding/decoding method is suitable for use in an image processing system, such as a facsimile machine.

Claims

1. An encoding/decoding method for carrying out conversion between a run length and a corresponding run length code, said run length code has a format including a first part and a second part which follows said first part, said first part including first information indicating a length of said code and said second part including second information in the binary representation indicating the corresponding run length, said length of code being set an integral multiple of a predetermined number of bits.

2. The method of claim 1 wherein said first information is a predetermined binary data pattern.

3. A method of encoding an image signal using a plurality of predetermined run length codes, comprising the steps of;

scanning an original to produce an image signal;

determining a series of run lengths in said image data; and

converting said series of run lengths into a corresponding series of said run length codes, whereby each of said run length codes has a format including a first part and a second part following said first part, said first part including information indicating the length of the code and said second part including information indicating a corresponding run length, each of said run length codes having a total number of bits which is an integral multiple of a predetermined number of bits.

4. The method of claim 3 wherein said step of scanning is carried out line by line and the set of conversion is also carried out line by line.

5. The method of claim 3 wherein said series of run lengths includes a first kind of run length defined by at least one white pixel and a second kind of run length defined by at least one black pixel.