JP3211524B2 - Variable code length transmitter for facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a variable code length transmission device obtained by coding an image signal of a facsimile machine.

[0002]

2. Description of the Related Art When transmitting a variable-length code,
It is important to specify the effective code length. Conventionally, encoding is performed with a regularity such that the code length increases, for example, by an integral multiple, and an effective code length is designated by the regularity.

[0003]

However, the conventional method of designating the effective code length by providing regularity has a problem that as the encoding becomes more complicated, it may not conform to the regularity.

The present invention has been made in view of the above points, and provides a variable code length transmitting apparatus of a facsimile apparatus capable of efficiently specifying an effective code length even for a variable length code having no regularity. It is intended to be.

[0005]

In order to achieve the above object, a variable code length transmitting apparatus of a facsimile apparatus according to the present invention comprises a code table for storing variable length data and a code table for storing the variable length data. And two address tables for storing the storage addresses of the respective data.

In the address data stored in the address table, the difference between the address data stored at one address and the address data stored at an address adjacent to the address is code length data. It is configured to be

[0007]

In the facsimile apparatus having the variable code length transmitting apparatus constructed as described above, two tables are provided. First, the table reference method is used, so that the redundancy at the time of encoding is suppressed. By providing an address table characterized in that the effective code length can be specified by the relationship between two adjacent address data, the effective code length can be efficiently specified even for a variable code length having no regularity. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram illustrating an embodiment of a variable code length transmitting apparatus according to the present invention. FIG. 2 shows a configuration of an address table, and FIG. 3 shows a configuration of code data. . An image signal obtained by reading a document is input to the image signal processing unit 1. The image signal processing unit 1 performs predetermined processing such as black-and-white discrimination and black-and-white run length calculation on the input image signal, and then outputs a first address signal a to the address table 2.

The address table 2 stores the address of the code data in the code table 3 as shown in FIG.
It is like the contents. a0 to ak are image signal processing units 1
Are the first address signals output from b0 to bk
Is the address of the code data in the code table 3. Then, two adjacent address data, for example, b0 and b1
Is configured to represent the code length of the code data. For example, (b0-b1) represents the code data stored at the address specified by b0, that is, the code length of c0 in FIG.

When the first address signal a is received, the address table 2 encodes the address data, for example, b0, stored in the area designated by the address signal as a code table.
The address data stored in the next address of the address specified by the address signal, for example, b1 and the address data are output to the subtractor 4. The subtracter 4 obtains the code length 1 from the difference between the two input address data, and outputs the result to the image signal processing unit 1. The code length 1 specifies, for example, the effective code length of the code data (c0 in FIG. 3) stored at the address specified by b0.

The code table receiving the second address signal b as input outputs the code data c stored at the address designated by b to the code register 5. The code register 5 is a shift register having a parallel-serial conversion function. The code data c temporarily stored in the register is shifted one bit at a time in accordance with a clock ck based on the transmission speed from the image signal processing unit 1 and transmitted as a serial signal. Then, when the number of clocks becomes equal to the number of the code length data described above, the encoding is terminated as one transmission of the code is completed.

[0012]

As described above, according to the present invention, in the transmission of a variable code length having no regularity, the designation of the effective code length is performed by referring to the table. A variable code length transmission method can be specified, and efficient code transmission can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an apparatus according to an embodiment of the present invention.

FIG. 2 shows a configuration of an address table proposed in the present invention.

FIG. 3 shows a configuration of a code table proposed in the present invention.

[Explanation of symbols]

 Reference Signs List 1 image signal processing unit 2 address table 3 code table 4 subtracter 5 code register

Claims (1)

(57) [Claims] 1. A variable code length transmitting device of a facsimile apparatus for encoding and transmitting an image signal by a redundancy suppression method, wherein: a first encoding table for storing variable code length data; A second encoding table for storing the address of the code data, wherein the address data stored in the second encoding table is adjacent to the address data stored in a certain address; A variable code length transmitting apparatus in a facsimile apparatus, wherein a difference from address data stored in an address is code length data.