JPS58215862A - Method for constituting line memory in high speed facsimile or the like - Google Patents

Abstract

PURPOSE:To improve the encoding rate of an encoding section or the like, by discriminating the storage state of picture signals at the transfer to a line memory or from the line memory for displaying the state at a header section. CONSTITUTION:The line memory 2 consists of a picture signal storage section and the header section. In storing the picture signal in the line memory in this constitution, the presence of a line black picture element is detected in parallel and it is displayed on the header section. Since the presence of the black picture element is displayed on the header section without an excessive processing time as to the line stored in the line memory in this way, an encoder recognizes the line without the encoded information by referencing the header section, allowing to eliminate the need for the run lengt count. Thus, the encoding efficiency of the encoder is improved and the stability of the subscanning control system is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the field to which the invention pertains The present invention relates to a method of configuring a line memory used in facsimiles and the like that performs redundancy suppression coding.

(2) Description of conventional technology In facsimiles, etc., which use a continuously variable sub-scanning method in which a line memory is provided between the reading section 9 and the encoder, and the sub-scanning speed is smoothly controlled based on the stored amount, the reading speed is The image signal is stored once in the line memory, read out, encoded by an encoder, and sent to the transmission path. Therefore, when using a conventional line memory, it is difficult to store images that contain black pixels such as between the lines of a document. Even when reading image information that has no black pixels, it is necessary for the encoder to detect the absence of black pixels and send out a code, which causes the problem of lowering the encoding speed and worsening controllability. there were.

(3) Purpose of the Invention The present invention, for example in a facsimile transmitter, takes the trouble of inputting lines with almost no amount of information, such as lines with no black pixels, into an encoder to reduce the encoding speed, and A header is provided in the line memory so as not to reduce the stability of speed control, and the purpose is to use the header to identify lines W without black pixels and operate the encoder efficiently. This will be explained in detail below with reference to the drawings.

(4) Description of structure and operation of the invention FIG. 1 is a block diagram of an embodiment in which the present invention is applied to a facsimile transmitter using a continuously variable sub-scanning method, in which 1 is a reading unit, 2 is 1 shows a line memory section, a 3J/'i encoder, 4 a backup memory, and 5 a sub-scanning speed control section constructed according to the present invention.

The image signal read by the reading section 1 is temporarily stored in the line memory 2, then subjected to redundancy suppression encoding by the encoder 3, and stored in the backup memory 4, and matched with the transmission path. Sent out.

The sub-scanning speed control unit 5 operates to smoothly change the sub-scanning speed using the storage amount of the line memory 2 and buffer memory 4, and prevent overflow and under-70 of the line memory 2 and buffer memory 4. do.

FIG. 2 shows an example configuration of the line memory 2. As shown in FIG.

The line memory 2 is composed of an image signal storage section and a header section. As shown in Fig. 3, when an image signal is stored in a line memory, the presence or absence of a black pixel (indicated by °1'') in that line is detected in parallel, and this is displayed in the header section. In addition, it is possible to display the presence or absence of black pixels in the line stored in the line memory in the header section without extra processing time, so the encoder 3 first looks at the header to determine the encoded information. It is possible to eliminate the need to know which lines are missing and to count their length, thereby improving the encoding efficiency of the encoder and further improving the stability of the sub-scanning control system. Figure 4 shows another embodiment,
By displaying the number of consecutive lines without black pixels in the header, it is possible to further improve the efficiency of the encoder.

FIG. 5 shows still another embodiment, in which one line is divided into four parts, and the presence or absence of black pixels in the corresponding parts is displayed in the header section. Since the encoder 3 only needs to encode blocks containing black pixels, the encoding efficiency is further improved.

Furthermore, if the presence or absence of a change is displayed in the header by referring to the previous line etc. to identify the accumulation state of the image signal of one line, it is possible to improve the coding efficiency in two-dimensional coding. The application example of the transmitter has been explained above, but if the receiver knows in advance that there are no black pixels in that line during recording, that line can be skipped, which improves the efficiency of recording. similar effects can be expected.

Note that the line memory may be a line backer memory attached to an encoder or recording unit. Moreover, the presence or absence of black pixels and white pixels may be omitted if there are more than a certain number of pixels in order to reduce noise.

Furthermore, the present invention is not limited to application to the line buffer of the facsimile machine described above, but can also be applied to the input buffer or screen buffer of a printer or display device. In addition to those that handle coded information such as character codes, or those that handle multiple scanning lines line by line, 0 (5
) Description of effects As explained above, the line memory consists of an image signal storage section and a header section, and the storage state of image signals is identified and displayed in the header section when transferring to or from the line memory. This has the advantage that the encoding efficiency of the encoding unit and the like can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a continuously variable sub-scanning facsimile transmitter to which the present invention is applied, Fig. 2 is a block diagram of an embodiment of a line memory, and Fig. 3 is a diagram between the reading section and line memory section of Fig. 1. FIG. 4 is an explanatory diagram of another embodiment of the present invention, and FIG. 5 is an explanatory diagram of yet another embodiment. In the figure, 1 indicates a reading section, 2 a line memory section, 3 an encoder, 4 a backup memory, and 5 a sub-scanning speed control section. Patent applicant Mori, Patent attorney representing Nippon Telegraph and Telephone Public Corporation 1) Hiro line menu 1st old 2nd figure 3 Riichi Sono □□ Figure 4 Figure 5

Claims (3)

[Claims] (1) - The line memory that stores line image signals is composed of an image signal storage section and a header section, and the characteristics of the image signal stored in the image signal storage section are displayed in a ladder section. Featured line memory configuration method 0 (2) In the first term, n - lines (n≧
1) A line memory configuration method characterized by dividing into blocks and displaying the presence or absence of black pixels or white pixels in each block in a header section. (3) In paragraphs 1 and 2 above, if there are consecutive lines without black pixels or white pixels, the number of consecutive lines is displayed in the header and subsequent lines are omitted. How to configure line memory. (4) In the first, second, and third paragraphs, the line is characterized in that the header section displays whether or not there has been a change when referring to the previous line or even the previous line. Memory configuration method 0