JPS6048663A - Facsimile transmission method - Google Patents

Abstract

PURPOSE:To decrease the transmission time of facsimile communication by inserting intermittently a line synchronizing signal to the converting position of each scanning line of a digital coding picture signal obtained by scanning a picture, modulating the signal together with a coded picture signal and transmitting the result. CONSTITUTION:A reading scanner 12 scans a transmission picture, outputs a digital picture signal to a coder 13 and transmits a control signal to a line synchronizing signal EOL inserting control means 15 according to a prescribed transmission mode. The coder 13 is controlled by the means 15, inserts a signal EOL at each picture signal of the prescribed number of scanning lines, codes the signal and this signal is modulated by an MODEM14 and transmitted. The transmission signal is demodulated by an MODEM17 and reduced to the signal EOL and a coded picture signal. When a decoder 18 detects the signal EOL of a prescribed bit pattern, the decoder activates the number of bits counting means 21 and decodes the coded picture signal into a digital picture signal and outputs the result. The means 21 counts the number of pulse in synchronizing with the number of bits of the picture signal and when said number is dissident with the prescribed number of bits, and the means 21 requests 23 the retransmission of the coded picture signal from the preceding signal EOL via a signal error discriminating means 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention encodes the image signal obtained by scanning a document image on the transmitting side, modulates and transmits it, demodulates the transmitted signal on the receiving side, This invention relates to an IJ transmission method for decoding and obtaining an image signal for recording a raw image.

Conventional configuration and its problems As is clear from the Group 3 facsimile recommendations of the G.O.T. The transmitted digital signals are encoded according to a predetermined sequence to compress the amount of information, and then modulated and transmitted by a high-speed modem. The mainstream method is to recover the image using a modem, decode it, scan the ζj! image on the transmitting side, obtain a digital image signal, and record the reproduced image based on that digital image signal. occupies .

FIG. 1 is a schematic block diagram of this type of facsimile receiving apparatus and receiving apparatus, and FIG. 2 is a human output signal diagram of each block. The scanning device 2 of the facsimile transmitting device 1 reads and scans the transmitted image 3 to obtain a signal as shown in FIG. 2a. In Figure 2 2L (/C), 41 to 15 indicate digital image signals having a predetermined number of bits for each continuous scanning line. If the image resolution is 1,728 bits, and the reading width is B4 size, it is 2,048 bits, which corresponds to black and white.
It is a series of digital signals of "1".

Since this 1-dimensional modulation is performed and transmitted, the redundancy of both L and J digit signals is too large to shorten the transmission time (l does not contribute to this. Therefore, in the encoder 4, this digit signal is By encoding the image signal (-7, reducing redundancy, modulating and transmitting 4, E) j,
Efforts are being made to shorten transmission time.

Figure 2 shows the output signal of the encoder 4, and L1
.about.L6 are not shown in FIG. 2A, but L7 shows all the encoded signals obtained by encoding the digital image signal.

The encoding method of encoder 4 has been proposed as ψume.
Broadly speaking, they can be divided into the following two types.

One is a one-dimensional encoding method, and a typical example thereof is a run-length encoding method. This gin-length encoding method and (d, the weight of one scanning line's worth of digital image signals or the information that changes from black to black or white and the changed black size)
It converts white or continuous length/1111 information into a digital code.

This is a two-dimensional encoding method, and a typical example is the differential encoding method. The encoded 1-yamabutsu number L1 is obtained by encoding using the dimensional coding method, and then the difference information between the digital image signal β1 of the reference line / and the digital image signal 12-kichi of the next line is encoded (-7 Then, the difference information between the digital image signal 12 and the digital image signal C of the next line is encoded to obtain the encoded image signal L3, hereinafter, ii
'iJ, I sent the encoded image signals L4+L5 sequentially.
6. In the case of this encoding method, if a transmission error occurs in the encoded image signal of a certain gine, it will also affect the lines below that tL, so the reference line is
) intervals, so that disturbances on the recording side due to transmission errors can be eliminated midway. In addition, in Fig. 2, the EOLid fin synchronization signal is a digital signal-2 consisting of ten or more bits inserted at each scanning line conversion point of the encoded image signal of each scanning line.
It is J゛.

In this way, the obtained launch signal 1J signal +i is modulated by the modulator 5 and transmitted.

On the other hand, the signal transmitted by the facsimile receiving device 6 is demodulated by the demodulator 7. At the output of the demodulator 7, both encoded signals corresponding to b2 in FIG. 2 are output.
Then, the demodulated coded image signal (decoded in a predetermined procedure in the IM encoder 8) is output. This digital image signal is input to the recording device, and the recording C, image 10 is obtained.The line synchronization signal EOL is deleted in the decoder 8. .

The transmission time for facsimile communication carried out in this manner is i', j, <, such as 12 seconds or 16 seconds for an A4 size standard manuscript.

However, the technical problem of further shortening the transmission time remains as a semi-permanent problem.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to provide a facsimile transmission method that can shorten the transmission time in a facsimile communication system that performs encoded transmission.

Components of the Invention In the facsimile transmission method of the present invention, a digital image signal for each scanning line having a predetermined bi Each image signal is encoded 1. to obtain a signal Mhi1ij-ii'f, and a line synchronization signal is intermittently inserted at the conversion position of each scanning line of the encoded image signal. It modulates and transmits the synchronization signal, and aims to shorten the time between transmission, ipl+, and 'J.

DESCRIPTION OF EMBODIMENTS The present invention will now be described with reference to the drawings. 31.(a) is a schematic block diagram of the facsimile transmitting device and the altruistic device, and FIG. 4 is a signal form diagram of the picture/tall picture signal and the coded picture signal.

In FIG. 3, 11 is a facsimile transmission device;
12 is a reading/scanning device, 13 is an encoder, and 14 is a modem. 15 is an EO that controls the insertion of the line synchronization signal EOL.
This is L insertion control means. On the other hand, 16 is a facsimile receiving device, and 1 is a modem, an 18-digit decoder, and a 19-digit recording/scanning device.

2o is a control means, 21 starts counting the number of focuses of the decoded digital image signal output from the decoder 18 when the decoder 18 detects the line synchronization signal KOL;
It is a bit number counting means that completes counting when the 02 signal unit 18 detects the next line synchronization signal EOL and repeats this process thereafter. Reference numeral 22 denotes a transmission error determining means that determines that a transmission error has occurred when the count result of the bit number and word number means 21 is an integral multiple of the predetermined number of bits included in the digital image signal of one scanning line. 23 transmission error determination means 22
This is a retransmission requesting means for requesting the IJ receiving device to retransmit the part that was missed by 1 or 1 when it is determined that there is a transmission error.

In FIG. 4, 2L indicates a digital image signal as in FIG. 2a, b indicates a conventional encoded signal in the same manner as in FIG. 3 shows an encoded image signal according to a second embodiment of the present invention, and ed illustrates an encoded image signal according to a third embodiment of the present invention.

First, the first embodiment will be described. At the beginning of Fakunmiri communication, the communication control signal is exchanged (-
to determine the transmission mode between sending and receiving. This transmission mode 1
This includes the change Z:a method, transmission speed j, and encoding method, and also includes the line synchronization signal EOL insertion method. In this embodiment, as is clear from FIG. 4, a method is adopted in which a line synchronization signal EOL is inserted for each encoded image signal of four scanning lines.

Next, the reading/scanning device 12 scans the transmitted image and
Digital image signal as shown (l4.β2゜15...
) is output. Under the control of the 13-encoder EOL insertion control means, the digital image signal is encoded according to a predetermined code dead power formula while inserting the line synchronization signal EOL every four scanning lines of the encoded image signal. Line synchronization signal EOL and encoded image signals (Ll, L2, L3...
...) is obtained. The modem 14 uses this line synchronization signal EOL.
and modulates and transmits the encoded image signal.

The transmitted signal is demodulated by the modem 17 of the iJ facsimile receiver 16, and the same line synchronization signal EOL as shown in FIG.
and becomes an encoded image signal. When the decoder 18 detects a line synchronization signal with a predetermined bit pattern from among the input signals, the bit number division means 21 is set to an old mode enable state, and the encoded image signals are sequentially decoded and output as digital image signals. Bit number dividing means 211d counts pulses output from the decoder synchronized with the bit number of this digital image signal.

By the way, the decoder 18 outputs digital image signals in sets such as 4 bits for a certain code and 10 bits for a certain code, but when there is no transmission error, K is At any break in the set of number i, the count value of the bit number means 21 reaches a predetermined value of 1.
This corresponds to an integral multiple of the total number of bits of the digital image signal for the scanning line. As a result, the bit counting means 21
instructs the encoded image signal to be decoded starting from the beginning of the scanning line. In other words, by utilizing the fact that the total number of bits of the digital image signal for one scanning line is fixed at 2, the conversion point of the scanning line of the encoded image signal, which is unknown due to the omission of the line synchronization signal EOL, can be determined. It's clearly j~. However, if a transmission error occurs, the count value of the bit argument means 21 matches an integral multiple of the total number of bits of the digital image signal for one predetermined scanning line at any break H in the set of digital image signals. It may not. At this time, it is determined that there has been a transmission μ↓ error, and the bit number argument means 21 requests retransmission of both encoded signals from the previous line synchronization signal EOL through the transmission error determination means. This retransmission request will be described later. Thereafter, the decoder 18 decodes the encoded image signals L1 to L4 in the same manner.

When the decoder 18 detects the next line synchronization signal EOL, it notifies the transmission error determination means 22 of the count result of the bit number divider means 21, and also sends the count result to the transmission error determination means 22.
When the counting result is equal to an integral multiple of the total number of digital image signal bits for one predetermined scanning line, the transmission error determining means 22 determines that there is no transmission error and operates the recording/scanning device 19. On the other hand, if they are not equal, it is determined that there has been a transmission error, the operation of the recording/scanning device 19 is stopped, and the retransmission requesting means 23 requests the facsimile transmitting device 11 to transmit the encoded image signals L1 to L4 again. request.

For the retransmission request of the encoded image signal, the retransmission request means 23 instructs the modem 1 to send a communication control signal meaning a vC retransmission request, and the modem 14 of the facsimile transmitter 11 detects this communication control signal. f stored in storage device
I ossification signal 'k'11! 3. If a transmission error occurs after several attempts in a row, the transmission speed will be reduced to 71 (~C transmission).

Thereafter, similarly, by decoding the encoded image signal and inputting the digital image signal to the recording/scanning device 19, a recorded image is obtained. Ru.

As described above, even if the line synchronization signal EOL to be inserted before or after the encoded image signal of each scanning line is thinned out, reception is possible and a reception recording surface equivalent to that of the transmission 111i can be obtained. Moreover, as is clear from FIG. 4, the transmission time can be reduced by 1.

Here, we will estimate how much the transmission time will be shortened. For this trial calculation, the following conditions are assumed.

Number of bits of line synchronization signal = 12 bits (A) Transmission speed = 9600bps (B) Original length = 3oovr
m (A 4 size phase A) (C) Scanning line density -7,7
(D) Under the above conditions, the reduction in transmission time according to the first embodiment is approximately 2.2 seconds, and the calculation formula is as follows.

In the first embodiment, a line synchronization signal is inserted before the encoded image signal for every 4 scanning lines, but under the above conditions, a line synchronization signal is inserted before the encoded image signal for every n scanning lines. The shortened transmission time is expressed as follows.

(B) be.

Next, a second example will be described. In the second embodiment, the EOL insertion control means 15 counts the black information included in the digital image signal output from the reading/scanning device 12, and when the counted value exceeds a predetermined value, the EOL insertion control means 15 starts scanning the next digital image signal. 2. Line synchronization (No. 1-4 EOL is inserted at the scanning line conversion point of the encoded image signal) corresponding to the line conversion point. 1
Therefore, as is clear from FIG. 4d, one scanning line t existing between two consecutive line synchronization signals EOL
The number of minus-8 image signals of rj is about to decrease.

In this second embodiment, similarly to the first embodiment,
Even if the line 3EOL is inserted intermittently into the encoded image signal string, it can be decoded by the facsimile receivers 1-4 and the transmission time can be shortened. do not have. Moreover, in this second embodiment, compared to the first embodiment, if the facsimile receiver 1 and the recording/scanning device 19 of the device 16 change the recording time depending on the amount of black information, the black information is In areas where there is a lot of black information, the line sync signal EOL is inserted more frequently, so the time required for recording can be gained. Conversely, in areas where there is less black information, the line sync signal EOL is inserted more frequently.
The office lady's mood is getting a bit high, so I'll have to wait for the recording device.
I like the advantage of being able to save time.

Finally, a third example will be described. 4th>+e
At VrC, L+ + L5+ L9...
-1d, in the two-dimensional encoding method, indicates an image signal encoded by the one-dimensional encoding method with a reference line provided every four scanning lines, R2, R3+ R4+ Rb...... is two-dimensional encoding The figure shows an image signal encoded using the method.

In the third embodiment, the previous line synchronization signal EOL of the coded image signal of the reference line is inserted.

In this third embodiment as well, the first. Similarly to the second embodiment, even if the line synchronization signal EOL is intermittently inserted into the encoded image signal sequence using the one-dimensional and two-dimensional encoding method, the facsimile receiving device receives it and records it. It is no secret that it can be played back and the transmission time can be shortened. Moreover, the feature of this third embodiment is that it is optimal for a two-dimensional encoding method. That is, in the line synchronization signal EOL insertion method that ignores the reference line, when a transmission error occurs, not only the encoded image signal existing between two consecutive line synchronization signals EOL is affected; There is only one record.
The previous encoded picture information-bow is also affected. in this case,
There is a possibility that the image will be distorted. In contrast, in the third embodiment, even if a transmission error occurs, only the encoded image signal existing between two consecutive line synchronization signals 8050 is affected, so it does not affect the recording surface in any way. It doesn't affect me.

Although only three embodiments of the present invention have been described above,
The present invention is not limited only to these examples. That is, it is easy for those skilled in the art to make minor changes and additions without departing from the spirit of the invention.

In particular, there are a wide variety of known encoding techniques and transmission and retransmission techniques, and even if they are used in combination, it does not go against the spirit of the present invention.

Effects of the Present Invention As explained above, according to the present invention, transmission time can be shortened by intermittently inserting a line synchronization signal. By changing the line synchronization signal insertion interval depending on the amount of black information contained in the digital image signal, the recording speed of the recording device in the facsimile receiving device can be leveled out, reducing the load on the recording device. It can be reduced. Furthermore, when using the two-dimensional encoding method, the line before C can be easily detected by inserting the line synchronization signal before the image signal encoded by the one-dimensional encoding method as a reference line. (It is also possible to avoid image distortion even when a transmission error occurs.)

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a facsimile transmitting device and receiving device, FIG. 2 is an input/output signal sequence diagram of the main part thereof, and FIG. 3 is a block diagram of a facsimile transmitting device and receiving device using the facsimile transmission method according to the present invention. Figure 4 is the third
FIG. 3 is an input/output signal sequence diagram of each block in the figure. 11... Facsimile'lJ transmitter, 12...
. . . Reading scanning device, 13 . . . Encoder, 14.
...Modem, 15...EOL inserted! IIJ control means, 16...-Facsimile receiving device, 17.
...Modem, 18...Decoder, 19...
. . . Record scanning means, 20 . . . Control means, 2
1...Bit number counting means, 22...Transmission error determination means, 23...Retransmission requesting means.

Claims (4)

[Claims] (1) Scan a document image to obtain a digital image signal for each scanning line having a predetermined number of bits, encode the digital image signal for each scanning line to obtain an encoded image signal, and encode the digital image signal for each scanning line. A facsimile transmission method characterized in that a line synchronization signal is intermittently inserted at the conversion position of each scanning line of an image signal, and the encoded image signal and line synchronization signal are modulated and transmitted. (2) A facsimile transmission method according to claim 1, characterized in that a line synchronization signal is inserted every N scanning lines. (3) Facsimile transmission according to claim 1, characterized in that a line synchronization signal is inserted at the conversion position of the next scanning line when the black information included in the image signal sequence exceeds a predetermined number. Method. (4) When the encoding method is a two-dimensional encoding method, a line synchronization signal is inserted before the encoded image signal of the reference line encoded using the one-dimensional encoding method. Range 1st term - Facsimile transmission method for number of peaks.