JPH0131345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for transmitting all-white block information in one scanning line to a receiving side in a facsimile transmission system.

Background of the Technology, Prior Art and Problems Generally, in a facsimile, an original image is sequentially scanned line by line, and signals corresponding to the black and white of the pixels are sent to the receiving side. In this case, to deal with the appearance of an all-white state, a so-called all-white line skip method is used in which all-white appearance information is sent to the receiving side. unit 1
There is an all-white block skip method in which the line is divided into several blocks and each block is divided into blocks. As shown in Figure 6, this all-white block skip method is used to perform facsimile transmission of a document with the word FAX written in black on white manuscript paper, for example, by dividing one scanning line into 10 blocks from 1 to 10. Block 2, which includes black,
Only image signals 4, 7, 8, and 10 are transmitted, thereby reducing the transmission time. In this case, the block numbers containing black signals in the block information part of the transmission signal are 2, 4, 7, 8, and
Contains a signal indicating that it is 10. 〓In the conventional all-white block skip method, as shown in Figure 1, each line of the original image is
The image signal of each line is divided into blocks, and a block code signal (BCD) indicating whether the block is completely white or contains black is placed at the beginning, followed by all bit information about only the blocks containing black. It is formed as an array of (BLK INF). Assume that the block code signal (BCD) indicates, for example, that the upper level indicates that the block is completely white, and the lower level indicates that the block contains black.
In Figure 1, the 2nd, 5th, 7th, 8th, and 10th blocks are completely white, and the
An example is shown in which the 9th and 9th areas are black. In such conventional systems, if an error occurs in the judgment of the block code signal due to noise, for example, an error will also occur in the judgment of subsequent signals based on the block code signal, causing confusion in signal transmission. . As described above, the conventional system has a problem in that it is difficult to accurately perform all-white block skipping in facsimile transmission.

OBJECTS OF THE INVENTION In view of the problems with the conventional type described above, an object of the present invention is to provide information indicating the location where the determination content of whether all bits of a block are white or whether the block includes black bits is inserted in an image signal. Based on the concept of including the synchronization signal and transmitting it from the transmitting side, even if an error occurs in the block code signal of the transmitted image signal, the receiving side can correct it by using the synchronization signal at the next blanking time. The subsequent block code signal position is specified again, and from then on, the block code signal is accurately determined based on the newly specified block code signal position, and recovery from the error is realized. To enable recovery from errors during blanking time and to accurately perform all-white block skipping in facsimile transmission.

Structure of the Invention In order to achieve the above object, the present inventor has proposed that in a facsimile device that transmits image information using a so-called block skip method, a block code is inserted and transmitted asynchronously with a synchronization signal, and the position of this block code is Consideration has been given to transmitting position (address) information where a block code exists between adjacent synchronization signals by attaching it to a position corresponding to a synchronization signal such as a blanking period.

In the present invention, block code information indicating whether or not each block obtained by dividing one line into a plurality of blocks is an all-white block, and all bit information for a block including black are asynchronously transmitted between periodic signals of a constant period. This is a facsimile transmission method in which a block code is inserted between the synchronization signals, and the generated position information is placed at a position corresponding to the synchronization signal. There is provided a facsimile transmission method characterized in that the facsimile transmission method is characterized in that the information is transmitted by attaching the same.

Embodiment of the Invention FIG. 2 shows a facsimile transmission circuit used in a facsimile transmission system as an embodiment of the present invention. A scanning signal is generated by a charge coupled device (CCD) 1 which receives reflected light from the original screen, and an output signal is obtained which is binarized in accordance with the black and white of the pixel in an amplifier 2. The binarized output signal is supplied to a random access memory (RAM) 3 and also to an identification circuit 5 for identifying all-white blocks. Identification circuit 5
are flip-flop 51 and shift register 5
It has 2. Corresponding to the number of divided blocks in one line, signals BLC0, BLC1, ..., BLC indicating that the block is completely white are sent from the shift register 52.
15 (in the case of 1 line and 16 blocks as an example) are supplied to the microcomputer 6. The microcomputer 6 sends an image signal memory write command PIXW and an image signal send command to the counter 4.
Supply PIXS. The number of the block to be sent is the line BLA~BLD from the microcomputer 6.
It is outputted through the counter 4 and the memory 3, and is led to the memory 3 via the changeover switches 7a to 7d interposed between the counter 4 and the memory 3. The lines BLA to BLD are connected to the memory 3 in response to the sending of the image signal sending command PIXS. The microcomputer 6 is further provided with a signal transmission path SD, and this signal transmission path SD switches the signal that defines the blanking time (BT), the synchronization signal (SYNC), and the block code signal (BCD). It is led to a transmission line 9 via a switch 8.

The operation of facsimile transmission by the second circuit is shown in the signal sequence diagram of FIG. There is a blanking time (BT) between one image signal and the next image signal.
is set. As an example of a picture signal, a block code signal BCD1 giving all-white block number information,
Scanning signals of blocks containing black, e.g. G1, G
2, G5, G7 (when the first, second, fifth and seventh blocks contain black), the next block code signal BCD2, and the scanning signal of the block containing black, for example G3 (when the third block contains black). ) is shown. The block code signal BCD1 is a binary signal as shown in FIG. 4, and the upper level indicates that the block is completely white, and the lower level indicates that the block contains black. In the first image signal section following the left synchronization signal SYNC in FIG. 3, the blocks containing black are G1, G2, G5, and G7 for the first scan line, and G3 for the next scan line. , right sync signal
In the next picture signal interval following SYNC, the blocks containing black are G7 and G9 for the first scan line. Correspondingly, the first, second, fifth, and seventh positions are at the lower level as shown in BCD1 of FIG. The location is on the lower level.

As shown in FIG. 3, the image signal portion includes a block code signal BCD, a block scanning signal G1,
G2, . Based on this fact, in the present invention, the synchronization signal (SYNC) generated during the blanking time BT provided between one picture signal section and the next picture signal section is A signal indicating the position of the block code signal in the block code signal, that is, a block code address is included. In Fig. 3, the first synchronization signal SYNC located at the beginning of the first picture signal section, the next synchronization signal SYNC located at the beginning of the next picture signal section, and the following picture signal section. A block code address instruction signal, which is a signal indicating the position of block codes BCD1, BCD2, and BCD3, is included. In other words, as shown in 3 in Fig. 4, the block code in the first image signal section
Since BCD1 is at block position 0 and 1, and block code BCD2 is at block position 6 and 7, the waveform indicating the BCD position in the first SYNC is at position 0 and 6 as shown in 3 in Figure 4. Since the block code BCD3 in the next picture signal section is at the 2nd or 3rd block position, the waveform indicating the BCD position in the next SYNC is at the 2nd position as shown in 4 in Figure 4. is at the lower level. In this way, the synchronization signal (SYNC) that appears at the blanking time (BT) that occurs at regular intervals clearly indicates the position of the block code signal (BCD), so it is possible to avoid errors in the judgment of the block code signal due to noise etc. Even if something like this occurs, the subsequent block code signal (BCD) position is specified again on the receiving side by the synchronization signal (SYNC) at the next blanking time (BT), and from then on, the block code signal (BCD) position is specified again. Block Code Signal (BCD) Revealed
Block code signal (BCD) based on position
is determined accurately, and all-white block skips are performed accurately. In this way, even if an accidental error occurs in the judgment of the block code signal, recovery from the error is realized in the next blanking period, and the negative effects of one error persist indefinitely. will not occur.

Next, the operation in FIG. 2 will be explained. As mentioned above, the microcomputer 6 receives the signal BLA...
...Since the address of the block to be transmitted is given by BLD, and the number of blocks to be transmitted is determined by the signals BLC0 to BLC15 of the shift register 52, the remaining number of blocks to be transmitted can be determined by calculation. can get.

Therefore, when the blanking period comes when the image signal of a block is sent out, the microcomputer calculates the number of remaining blocks, adds +1 to the remaining number of blocks, and calculates the address of the block code. Thereafter, the address of the block code obtained by the calculation is outputted to the terminal 9 via the switch 8 during the synchronization signal period of the blanking period as a position signal of the block code. As a result, the start address of the block code is inserted and transmitted during the synchronization signal period.

Note that this address signal may be obtained by transmitting a numerical value obtained by calculation one bit at a time from the lower bit, or by using a code having as many bits as the number of blocks that fit between the pair of synchronization signals, and using the above-mentioned block code. Similarly, the signal may be such that only the bit at the block position corresponding to the address is set to logic 1.

= In the circuit shown in Figure 2, one block in the image signal section is made up of 108 bits, one line of document scanning is made up of 1728 bits, one line is divided into 16, and each of the 16 blocks resulting from the 16 divisions is divided into black pixels. The case of transmitting a block containing a block will be explained using FIG.

In the circuit shown in Figure 5, the image signal sending command PIXS
Switches 7a to 7d are switched in accordance with the output of 4-bit parallel outputs BLA to BLD.
is supplied to RAM3. The microcomputer 6 is provided with a signal transmission path SD, which transmits the following signals: (1) a signal specifying the blanking time BT, (2) a synchronization signal SYNC, and (3) a block code. Signal BCD (4) A block code address signal (a number representing the arrangement of BCD within the picture signal section) is routed to the transmission line 9 via the changeover switch 8.

Memory 3 is 1-bit addressable RAM
Each line of 1728 bits is divided into 16 blocks of 108 bits, and each block is divided into 000, 100,
200,...Stored at the address starting with E00, F00 (hexadecimal). The output signals on the output lines BLA to BLD are the upper digits of 0, 1, and 2 in RAM3.
...Specify the block numbers of E and F, and specify the address of the picture signal within the block using the lower digits.

Effects of the Invention According to the present invention, even if an error occurs in the block code signal of the transmitted image signal, on the receiving side, the subsequent block code signal position can be reset using the synchronization signal at the next blanking time. After that, the block code signal is accurately determined based on the newly specified block code signal position, recovery from the error is realized, and all-white block skipping in facsimile transmission is accurately performed. Furthermore, in the case of facsimile transmission in which all-white blocks often appear, the efficiency of the facsimile transmission system is increased because the ratio of blanking time to the image signal is relatively small. In this way, it is possible to contribute to improving the practicality of the facsimile transmission system.

[Brief explanation of drawings]

FIG. 1 is a signal sequence diagram explaining a conventional facsimile transmission system, FIG. 2 is a block circuit diagram of a facsimile transmission circuit used in a facsimile transmission system as an embodiment of the present invention, and FIG. 4 is a waveform diagram of the block code signal and block code signal address instruction signal in FIG. 3, and FIG. 5 is a circuit specifically explaining the circuit of FIG. 2. 6 are diagrams for explaining the all-white block skip method. (Explanation of symbols), 1...CCD, 2...Amplifier,
3...RAM, 4...Counter, 5...Identification circuit, 51...Flip-flop, 52...Shift register, 6...Microcomputer, 7a,
7b...Switch switch, 8...Switch switch, 9
...Transmission line.

Claims (1)

[Claims] 1. Block code information indicating whether each block obtained by dividing one line into a plurality of blocks is an all-white block and all bit information for blocks including black are asynchronously inserted between synchronization signals of a constant period. This is a facsimile transmission method that uses means for generating position information indicating the position of a block code inserted between the synchronization signals, and transmits the generated position information by attaching it to a position corresponding to the synchronization signal. A facsimile transmission method characterized by: