JPS61252750A - Error detection system of storage type facsimile equipment - Google Patents

Abstract

PURPOSE:To decrease the time for error check by providing an extraction detecting means to received compression picture data, discriminating the data depending on the result of detection, informing it to the transmission side when the data is no good and controlling the system so as not to record the data. CONSTITUTION:Compression data received from a line section 15 is stored tentatively in an interface buffer 27 from a gate 23, the content is controlled by a gate 26 to store it in a storage medium 28. A line end pitch is detected from data transferred by a prescribed quantity to an interface buffer 27 through a 2-way gate 26 from the storage medium 28 at each prescribed time or a prescribed capacity by an MPU 21 and the data of next plural lines is decoded by the processor MPU 21 itself to attain error check. The processing above is repeated, the data corresponding to one page is accumulated by (n) times, and the corresponding compression data of one page is discriminated for the propriety depending whether the result is a threshold value or below. Thus, the time for checking the error of the data for the entire page is required in a conventional system, while the same result is obtained only with the accumulated time of the detection of extraction, then the efficient operation is attained.

Description

Detailed Description of the Invention [Summary] The present invention provides a storage type facsimile device that is equipped with a storage device for storing received compressed image data and checks whether the stored data is correct. By providing a sampling detection means for checking for errors by restoring a plurality of lines while placing the data, it is possible to check for errors in a short time and with fewer steps to determine whether or not data for one page, for example, is accepted.

[Industrial application field]

The present invention relates to an error detection method for a storage facsimile, which allows error checking to be performed in a short time and with a small number of steps depending on the contents of a storage device that stores received compressed image data.

C. Prior Art] Conventionally, storage facsimile devices having a storage device such as a magnetic disk for storing received compressed image data have been widely used.

FIG. 1 is an explanatory diagram of the configuration of a storage type facsimile device.

That is, the transmission original is read by the reading section 11 and converted into a digital signal. Next, the compression method specified by the compression unit 12,
For example, MH (Modified Huffman) or M 几 (
compressed using a method such as Modified Read). This compressed data is sent out onto the transmission line via the line section 15.

Conversely, compressed image data from the other party's facsimile is received by the line unit 15, stored in a predetermined amount in the storage storage unit 16, and successively restored by the restoration unit 14 according to the specified restoration method.

The restored data is recorded on paper in the recording section 13. Each of these configurations is independently controlled by the control section 10.

FIG. 2 is a detailed explanatory diagram of the storage section which is the main part of FIG. 1.

In the same figure, to input received data into a storage medium,
The compressed image data received from the line section 15 passes through the one-way gate 23 and is sent to the interface buffer (
The information is temporarily stored in a RAM (RAM) 27, and then stored as a set of contents in a recording medium 28 such as a micro disk or a floppy disk through a bidirectional gate 26. In addition, to send the contents of the storage medium to the restoration unit, use route 9.
The data stored in the storage medium 28 is passed through the two-way gate 26, a set of contents is temporarily stored in the interface buffer 27, and the content is sequentially sent to the restoration unit 14 through the one-way gate 24 for restoration. An error check is then performed. In these cases, the opening/closing control of the one-way gates 23 and 24 is performed via the control logic 22 according to instructions from the microprocessor (MPU) 21, and the control of the two-way gates 26 is performed via the control logic 25.

Further, when the MPU 21 directly reads the contents of the storage medium 28, the contents are temporarily stored in the interface buffer 27 and then read out. In other words, the route (■) is taken.

FIG. 5 is an explanatory diagram of the conventional communication procedure of G5 facsimile including the storage type described above.

In the figure, following a 16H2 paging signal and conversation from the transmitting side, a 2100 Hz response signal (OED) from the called station on the receiving side and a notification of the capabilities of the called station [(N8F
) Ds8) and sends out the response signal (DO8), an affirmative response (OFB) is returned from the receiving side, and if NG, a negative response (FTT) is returned from the receiving side. If OK, write @0101...” at the beginning (margin) of the image signal as shown in the figure.
A training signal consisting of the following data is prefixed, and compressed image data (PBX) is subsequently transmitted. When the image signal ends, a procedure completion signal (GOP) is sent. In response, a response signal (MOP) is returned from the receiving side, and upon confirmation of this, a line disconnection command (DON) is issued from the transmitting side. If the training (TOF) for checking the line state is NG and a negative response (FTT) is returned all three times, the transfer rate is reduced and retransmission is performed.

FIG. 6 is a schematic illustration of a conventional facsimile error check method.

The figure shows the code array for one line, and area 2 has one line.
Compressed data for a line, area 3 contains a fill bit to reduce the time required for one line to 10 m5 or 20 m5,
Area 4 is provided with a line end bit (EOL) followed by a code for the compression method of the next line.

To check for errors in this line bit,
■Check whether the number of restored 12-in bits is less than or greater than 1728 bits.

■A method is adopted to check whether the code is incorrect.

[Problem that the invention seeks to solve]

As described above, in the above configuration, error checking is performed on all received compressed data. Also, since the total time required depends on the slower of the restoration processing time and the recording speed, the transmission speed depends on the line condition! >9600 B/s,
7200B15. -, 2400 BI3 (D species k
The intermittent input of received compressed data and the amount of Batza memory are used to match the transmission speed, restoration, and error checking time.

On the other hand, although the state of error occurrence depends on the line state, a sufficiently accurate judgment result can be obtained by performing sampling detection without performing error checking on all data for one page. This makes it possible to shorten the operation required to check for errors on one page, for example.

SUMMARY OF THE INVENTION An object of the present invention is to provide a storage facsimile error detection method that reduces the time required to restore received compressed data and check for errors in a storage facsimile apparatus.

[Means for solving problems]

In order to achieve the above object, in the present invention, a storage type facsimile restores a plurality of lines of received compressed image data after a predetermined period of time, and controls the data so as not to record the corresponding data.

[For production]

In the above configuration, the head of a line, for example, is detected after waiting a predetermined time for the received compressed data, the error checks for N: fins are accumulated for one page, and this is compared with a preset threshold. The quality of the received and accumulated compressed data is judged. This result is v4 of all data for one page.
The result is the same as that obtained by performing a site search.9 Moreover, the processing time can be significantly shortened.

〔Example〕

FIG. 2 is a diagram illustrating the configuration of an embodiment of the present invention using a facsimile machine having the configuration shown in FIG. 1, and a detailed diagram illustrating the main part of the storage unit. The difference from the conventional example is the control method for checking errors in the storage section shown in FIG. That is, in the figure, the compressed data received from the line section 15 is temporarily held in the interface buffer 27 through the gate 23, and its contents are controlled by the gate 26 and stored in the storage medium 28. In the present invention, the line end bit (EO) described in FIG.
L) and sends the next multiple lines to the processor MPU
21 itself and performs an error check.

This process is repeated to accumulate the external value for one page, and depending on whether this is less than or greater than the threshold value, it is determined whether or not the compressed data for one page is accepted.

If it is less than the threshold, it is normal, so after the communication ends, the storage medium 2
The data is read from 8, restored by the restoration unit 14, and then recorded in the recording unit 13.

In addition, when the threshold value is exceeded, this one page of compressed data is not accepted and the transmitter is notified and retransmission is requested.
The corresponding compressed data in the storage medium 28 is not recorded.

FIG. 3 is an explanatory diagram of a communication procedure according to an embodiment of the present invention, and corresponds to the conventional example shown in FIG.

In Fig. 3, the difference from Fig. 5 is that the received data P
It is after BX. As mentioned above, this PiX section is
This includes the above-mentioned procedure of detecting a plurality of twins at regular intervals, accumulating the errors of one page, and comparing the accumulated errors with a threshold value. At the end of one page, a procedure completion signal (HO
As a result of P) being issued, if there are many errors, a redrain negation signal (RTN) is issued as shown in the figure to notify the transmitting side that there are many errors). Transmitting line disconnection command (DO
N) is sent as a transmission alarm. If the BOP results in fewer errors (OK, the redrain positive signal (RTP
) is issued and communication is completed.

FIG. 4 is a flowchart showing the operation of the main parts of the present invention.

This figure shows the operating procedure of the storage section which is the main part of the present invention. The storage unit knows where the beginning of a page is on the storage medium, so from there it can store, for example, a number,
B explained in Figure 6, which is a line break every 100 bytes.
Detect OL4. BOL is MR with 11 bits of @0” and 1 bit of 11” followed by 1 bit of @0” or ``1''.
or MH can be identified, and N lines are restored by continuing to restore the specified MH1 number of lines from the next data using the MR method. If there is an error during this time, the counter value is incremented. Next, another few hundred bytes of data later! >1OL is detected, and BOL is detected in the same way.
Start restoring from the next data. This is repeated three times for one page, and depending on whether the error count value exceeds a threshold value, it is determined whether or not the data for that one page is accepted. In other words, if it is above the threshold, there will be many errors and N
G to the control unit and requests retransmission.

Furthermore, if there are few errors, the controller is notified that the reception is OK.

In this way, the control unit 10 receives the input compressed data for one page, and before the control unit 10 finishes receiving the input compressed data for one page, the storage unit 10 determines whether the above is OK or NG.
The above information is processed by the MPU 21 in the storage unit, which determines whether to terminate the communication procedure normally or notify the sending side of a retransmission request. It is also possible to configure it so that it can be processed in batches using a processor.

〔Effect of the invention〕

As explained above, according to the present invention, a sampling detection means is provided which restores a plurality of lines of compressed image data received by a storage type facsimile after a predetermined period of time to check for errors; Based on this detection result, it is determined whether, for example, one page of data is accepted. As a result, compared to the conventional method that required time to check all data on one page for errors, the same result can be obtained only in the system time required for sample detection, resulting in much more efficient operation. .

It is also very useful in reducing the processing load on the processor MPU 21 or the control section 10 of the storage section.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of a storage type facsimile machine, Fig. 2 is a detailed explanatory diagram of the main parts of the embodiment, Fig. 3 is an explanatory diagram of the procedure of the embodiment of the present invention, and Fig. 4 is an embodiment of the present invention. 5 is an explanatory diagram of the procedure of the conventional example, and FIG. 6 is a schematic explanatory diagram of the error 9 check method. In the figure, 10 is a control unit;
1 is a reading section, 12 is a compression section, 13 is a recording section, 14 is a decompression section, 15 is a line section, 16 is an accumulation storage section, 21 is a microprocessor (MPU), 22.25 is a control logic, 2
3, 24, and 26 are gates, 27 is an interface buffer, and 28 is a storage medium.

Claims (1)

[Claims] In a storage type facsimile device that is equipped with a storage device for storing received compressed image data and performs error checking on the restored image data, the received compressed image data is restored for a plurality of lines after a predetermined period of time and is checked for errors. If a value obtained by accumulating errors for the plurality of lines multiple times exceeds a threshold value, the storage type is characterized in that it notifies the transmitting side and controls not to record the corresponding data. Error detection method for facsimile machines.