JPS63311871A - Facsimile transmission system - Google Patents

Abstract

PURPOSE:To send picture information with high confidentiality properly by providing a decoded table storage means to store a nonstandard decoding table to a receiver and sending the content of the decoded table to the receiver from a transmitter in the transmission pre-processing. CONSTITUTION:A nonstandard coding table 7 and a nonstandard decoding table 8 to decode the picture information subject to coding and compression based on the nonstandard coding table 7 into an original picture signal are provided to a transmitter TX and a decoding table storage means 27 to store the nonstandard decoding table is provided to a receiver RX. The transmitter TX sends the content of the decoding table 8 to the receiver RX, the receiver RX stores it in the decoding table storage means 27 and the transmitter TX compresses the picture information based on the nonstandard coding table 7 and sends it to the receiver, the receiver RX decodes the signal into the original picture signal based on the decoded table 27. Thus, the picture information with high confidentiality is sent properly.

Description

[Detailed description of the invention] [Technical field] The present invention relates to a facsimile transmission system.

[Prior Art] Generally, facsimile machines have functions that comply with the recommendations of CCITT (Consultative Committee for International Telegraph and Telephone). For example, for Group 3 devices, the device standard is defined by Recommendation 7.4, and the transmission control procedure standard is defined by Recommendation T.30. Data transmission between devices that comply with these recommendations is guaranteed.

However, from the standpoint of maintaining the confidentiality of data transmission,
Important data may be stolen by devices that meet the same standards, creating an undesirable situation.

For example, if a wiretapping device is connected to a telephone line used as a transmission path and the transmission signal is wiretapped, and the transmission signal is given to a facsimile device that has the same standard as the transmitting device, the transmitted image information will be sent to the facsimile device on the wiretapping device side. It can be reproduced with a device.

In this way, conventionally, inconveniences have arisen when transmitting highly confidential information using a facsimile machine.

[Objective] The present invention has been made in order to eliminate the disadvantages of the prior art, and it is an object of the present invention to provide a facsimile transmission system that can appropriately transmit highly confidential image information.

[Configuration] In order to achieve this object, the present invention provides a non-standard encoding table in a transmitting device, and converts the encoded and compressed image information into the original image signal based on the non-standard encoding table. While having a non-standard decoding table for decoding,
The receiving device includes a decoding table storage means for storing a non-standard decoding table, the transmitting device transmits the contents of the decoding table to the receiving device in a pre-transmission procedure, and the receiving device stores the received decoding table. The transmitting device compresses the image information based on the non-standard encoding table and transmits it to the receiving device, and the receiving device stores the received image information in the decoding table storage device. The original signals are decoded based on the decoding table stored in the decoding table.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a facsimile transmitting apparatus (hereinafter simply referred to as transmitting apparatus) TX according to an embodiment of the present invention.

In the figure, a system control unit 1 controls the entire transmitting device TX, a scanner 2 is for reading the transmitted document at a predetermined resolution, and an operation display unit 3
consists of various operation keys and displays necessary to operate the transmitter TX. The image memory 4 is for storing encoded and compressed image information and the like.

The encoding unit 5 encodes and compresses the transmitted image signal,
A standard encoding table 6 for standard encoding and a non-standard encoding table 7 for non-standard encoding are provided. In addition, the non-standard encoding table 8 is for decoding the image information encoded and compressed based on the non-standard encoding table 7 into the original two signals, and is transmitted to the receiving device RX as described later. and then reconfigured at the receiving device.

The communication control unit 9 is for executing a predetermined facsimile transmission control procedure to transmit images to the other party, and the modem IO can use a public telephone line, which is an analog line network, as a transmission line. The network control device 11 modulates and demodulates digital data as shown in FIG.
This is for connecting X to the public telephone line network. Note that this network control device 11 is equipped with an automatic calling function.

In addition, the system control unit 1. Scanner 2, operation display section 3,
The image memory 4, the encoding section 5, the non-standard decoding table 8, and the communication control section 9 exchange data with each other via the system bus 12.

FIG. 2 shows a facsimile receiving apparatus (hereinafter simply referred to as receiving apparatus) RX according to an embodiment of the present invention.

In the figure, the system control unit 21 controls the receiving bag VL.
The plotter 22 is for recording and outputting the received image at a predetermined resolution, and the operation display unit 23 is for controlling the various operation keys necessary to operate this receiving device RX. and display unit. The image memory 24 is for storing encoded and compressed image information and the like.

The decoding unit 25 decodes the received image information into two original signals, and includes a standard decoding table 26 for standard decoding and a non-standard decoding table for non-standard decoding. Non-standard table storage unit 2 for accumulating and reconfiguring
It has 7.

The communication control unit 28 is for executing a predetermined facsimile transmission control procedure to perform image transmission with the other party,
The modem 29 modulates and demodulates digital data so that an analog line network such as a public telephone line can be used as a transmission line, and the network control device 30 is a modem for connecting the receiving device RX to the public telephone line network. It is something. Note that this network control device 30 has an automatic call receiving function.

Also, a system control section 21, a plotter 22, an operation display section 23, an image memory 24. The encoding section 25, the non-standard table storage section 27, and the communication control section 28 are connected to the system bus 31.
They exchange data with each other via.

Here, the standard encoding table 6 of the transmitting device TX and the standard decoding table 26 of the receiving device RX are based on CCITT Recommendation T
This is for realizing the standard one-dimensional encoding method defined in , 4.

Furthermore, the non-standard encoding table 7 and the non-standard decoding table 8 of the transmitting device TX are for realizing highly confidential image information transmission using a non-standard one-dimensional encoding method. As will be described later, the contents of the non-standard decoding table 8 are transmitted to the receiving device RX and reconstructed in its non-standard table storage unit 27, so that the receiving device RX can read the non-standard decoding table 8. Now you can prepare.

The non-standard encoding table 7 stores codes in which the relationship between the code and the run length in the standard encoding table 6 is partially replaced with parts having the same code length,
Examples (parts) are shown in the table below. (Left below) In this way, the relationship between the code length appearance probability and the code length defined in the non-standard encoding table 7 and the non-standard decoding table 8 is the same as the standard encoding table 6 and the standard decoding table. 26, the efficiency of non-standard encoding using non-standard encoding table 7 and non-standard decoding table 8 is equal to that of the standard code. (equivalent to the efficiency of standard encoding using encoding table 6 and standard decoding table 26).

Note that even when using the non-standard encoding table 7, the encoding unit 5 applies the same encoding rules as when using the standard encoding table 6. Further, the decoding unit 25 also uses the standard decoding table 26.

The same decoding rules are applied when using the non-standard decoding table 8 reconfigured in the non-standard table storage unit 27.

A case will be described in which image information is transmitted from the transmitting device TX to the receiving device RX.

If the transmitted image information is highly confidential, the transmitting device T
The operator of X sets the original to be transmitted on the scanner 2 and inputs the destination information, and then instructs the operator from the operation display section 3 to transmit the image in the encrypted mode.

As a result, the system control unit 1 of the transmitting device TX first transfers the destination information to the network control device 11 to make a call to the destination.

As a result, when a transmission path is established between the transmitting device TX and the receiving device RX, the receiving device RX sends a called station identification signal to indicate that its own terminal is a facsimile device, as shown in FIG. CED, a non-standard device signal NSF for notifying the non-standard functions of the own terminal, and a digital identification signal DIS for notifying the standard functions of the own terminal are sequentially transmitted to the transmitting device. . Further, the non-standard device signal NSF includes information indicating that the device has a function of internally reconfiguring the non-standard decoding table 8.

As a result, the transmitting device TX knows that the receiving device RX is equipped with a function that can reconfigure the non-standard decoding table 8, so the non-standard device that placed the contents of the non-standard decoding table 8 in its information frame Setting signal NSS (
T) is transmitted to the receiving device RX.

The receiving device RX receives this non-standard device setting signal N5S(T
) are sequentially added to the non-standard decoding table 8 to the non-standard table storage unit 27? ? Multiply. This results in
The non-standard decoding table 8 is reconfigured in the non-standard table storage unit 27. Additionally, a non-standard device setting signal NSS (T
) is received without error, and if there is no reception error, a reception preparation confirmation signal CFR is sent to the transmitting device TX. Note that the determination of the presence or absence of this reception error is based on the frame check sequence FC added to the signal frame for transmitting the non-standard device setting signal N5S(T).
3 (see CCTTT Recommendation T, 30).

Thereby, the transmitting device TX sends a non-standard device setting signal N5 including setting information of functions for transmitting other image information.
S (S) to the receiving device I\RX to set the transmission function, and at the image information transmission speed set at that time, modem 1
Send training check TCP to train 0.29. This training check TCP
If the reception result is good, the receiving device 8 responds with a reception preparation confirmation signal CFR.

As a result, the system control unit l of the transmitter TX instructs the encoding unit 5 to use the non-standard encoding table 7. Then, the scanner 2 is operated to read the image of the transmitted document, and both signals are encoded by the encoder 5.
The image information PIX thus formed is transferred to the communication control section 9 and sent out to the transmission path.

On the other hand, the system control unit 21 of the receiving device RX instructs the decoding unit 25 to use the non-standard decoding table 8 reconstructed in the non-standard table storage unit 27.

After the received image information is decoded into the original image signal by the decoding section 25, the image signals are sequentially transferred to the plotter 22, and the plotter 22 is caused to record and output the received image.

When the transmission of the image information PIX is completed, the transmitter TX transmits a procedure end signal EOP, and the receiver RX responds with a message confirmation signal MCF. As a result, the transmitting device TX transmits the line disconnection command signal DCN, and then i...i 4
No I, IJ... "The image information transmission ends. The receiving device RX also disconnects the line and ends the image information transmission.

In this way, when the encryption mode is set in the transmitting device TX, image information transmission using non-standard codes is executed in the transmitting device TX and the receiving device RX. As a result, for example, even if a signal on a transmission line is intercepted by an eavesdropping device, the facsimile device on the eavesdropping side will not be able to properly reconstruct the image information.

Confidentiality of image information can be maintained.

By the way, for example, if the receiving device RX determines that the line condition is poor and a reception error has occurred in the received non-standard device setting signal N5S(T), the receiving device RX sends a train failure signal FTT to the transmitting device TX. (See Figure 4).

At this time, the transmitting device TX sends out a line disconnection command signal DCN to terminate image information transmission, calls the same destination again, and performs the same operation as described above.

Therefore, when transmitting image information in encrypted mode,
Since the accurate non-standard decoding table 8 is always reconfigured in the receiving device RX, the receiving device RX can record and output accurate image information.

On the other hand, if the operator did not specify a cipher mode,
The system control unit l of the transmitter TX instructs the encoding unit 5 to use the standard encoding table 6. In this case, the non-standard device setting signal NSS (T) is not transmitted to the receiving device RX.

In this way, the non-standard device setting signal N5S (
T) is not transmitted, the system control unit 21 of the receiving device RX instructs the decoding unit 25 to use the standard decoding table 26.

Thereby, the transmitting device TX and the receiving device RX can perform image information transmission using a standard encoding method.

For example, if the operator inputs the destination information incorrectly and connects to a facsimile machine that does not have the function to internally reconfigure the non-standard decryption table even though the encryption mode has been set, the transmission The device TX discontinues the transmission when it learns that the destination facsimile device does not have the ability to internally reconfigure the non-standard decoding table.

By the way, non-standard encoding tables other than those shown in the embodiments described above can be used. For example, in the standard encoding table, the relationship between codes and run lengths can be configured by replacing all parts where the code lengths are equal.

Further, as in the above-described embodiment, it is preferable to use a code using the same encoding rule as the standard encoding method as a non-standard code, since the encoding/decoding unit can be used in common.

Further, image information transmission using the encrypted mode can also be used for broadcast transmission using the storage function of the image memory.

In addition, in the embodiment described above, the non-standard decoding table is
However, it is also possible to provide two or more non-standard decryption tables and allow the operator to select one of the non-standard decryption tables when transmitting in cipher mode.

[Effects] As explained above, according to the present invention, a transmitting device uses a non-standard encoding table and image information encoded and compressed based on this non-standard encoding table into both original signals. While having a non-standard decoding table for decoding,
The receiving device includes a decoding table storage means for storing a non-standard decoding table, the transmitting device transmits the contents of the decoding table to the receiving device in a pre-transmission procedure, and the receiving device stores the received decoding table. The transmitting device compresses the image information based on the non-standard encoding table and transmits it to the receiving device, and the receiving device stores the received image information in the decoding table storage device. Since the original signals are decoded based on the decoding table stored in the decoding table, the effect is that highly confidential image information can be appropriately transmitted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a facsimile transmitting device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a facsimile receiving device according to an embodiment of the present invention, and FIG. 3 is a block diagram showing an example of transmission control. Time Chart FIG. 4 is a time chart showing another example of transmission control. 1.21... System control unit, 3, 23... Operation display unit, 5... Encoding unit, 7... Non-standard encoding table, 8... Non-standard decoding table, 9. 28...
Communication control unit, 25...Decoding unit, 27...Non-standard table storage unit, TX...Transmitting device, RX...Receiving device. Agent Patent Attorney Crest 1) Makoto Figure 1 RX Figure 2 RX Figure 3 Figure 4

Claims (1)

[Claims] In a facsimile transmission system that encodes and compresses image information before transmitting it, the transmitting device uses a non-standard encoding table and converts the encoded and compressed image information based on this non-standard encoding table into the original image signal. The receiving device includes a decoding table storage means for storing the non-standard decoding table, and the transmitting device performs the decoding in a pre-transmission procedure. The content of the encoding table is transmitted to the receiving device, the receiving device stores the content of the received decoding table in the decoding table storage means, and the transmitting device transmits the image information based on the non-standard encoding table. A facsimile transmission characterized in that the received image information is compressed and transmitted to a receiving device, and the receiving device decodes the received image information into an original image signal based on a decoding table stored in the decoding table storage means. method.