JP2000032274A - Facsimile machine - Google Patents

Abstract

(57) [Summary] To improve the security of communication in closed area communication, increase the compression ratio of binary data, and shorten the communication time. Kind Code: A1 A plurality of Huffman tables, a Huffman table selecting means for selecting an arbitrary Huffman table among the plurality of Huffman tables upon transmission, and compression of binary data with reference to the selected Huffman table. And code / decoding means for restoring code data. In this case, at the transmitter, the Huffman table is selected, and when the binary data is encoded with reference to the Huffman table, unless the selected Huffman table is provided at the receiver, a third party can perform closed communication. You cannot enter. Therefore, communication security in closed area communication can be enhanced, and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus.

[0002]

2. Description of the Related Art Conventionally, a facsimile machine can communicate with anyone by inputting and transmitting a telephone number, but information may be erroneously sent to an unintended communication partner. Communication security is low. Therefore, a facsimile apparatus having a function of performing closed area communication capable of performing communication only with a specific communication partner is provided. Usually, the called facsimile machine in the closed communication, that is, the receiver, is specified by a telephone number. And, the telephone number is usually the T.T. 30, the called station identification signal CSI, the transmitting terminal identification signal TS
I and other frames.

Further, in a facsimile apparatus on the calling side in the closed area communication, that is, a transmitter, image data generated by reading an image of an original is converted into white data and black data in order to shorten the communication time. Is converted to binary data, and the binary data is compressed, that is, encoded to generate code data, and the code data is modulated into modulated data and transmitted to a receiver.
And, in the receiver, upon receiving the modulated data from the transmitter, demodulates the modulated data into code data,
The code data is restored to the original state, that is, decoded to generate binary data.

An MH system, an MR system, an MMR system, and the like are used as a system for generating the code data. The Huffman table defined in 4 is used. FIG. 2 is a first diagram showing a communication procedure of a conventional facsimile machine, and FIG. 3 is a second diagram showing a communication procedure of a conventional facsimile machine.

As shown in the figure, when a transmitter places a call to communicate with a receiver, the receiver seizes the telephone line, and the non-standard procedural signal NSF, the called station. The identification signal CSI and the digital identification signal DIS are transmitted to the transmitter. Subsequently, in the transmitter, of the non-standard procedure signal NSF, called station identification signal CSI, and digital identification signal DIS, first transmitted from the receiver,
The 20 bytes set in the called station identification signal CSI is compared with a telephone number registered in advance as a telephone number for closed communication, and it is determined whether the 20 bytes match the telephone number. I do.

When the 20 bytes match the telephone number (CIS check OK), the transmitter transmits the transmitting terminal identification signal TSI and the digital command signal DCS to the receiver. Subsequently, the transmitter transmits the training check Tr to the receiver. On the other hand, if the 20 bytes do not match the telephone number, the transmitter transmits a disconnection command signal DCN to the receiver to disconnect the telephone line.

[0007] Further, the receiver operates as a transmitting terminal identification signal TSI.
Is compared with a telephone number registered in advance as a telephone number for closed-area communication, and it is determined whether or not the 20 bytes match the telephone number. If the 20 bytes and the telephone number match (TIS check OK), the receiver normally receives the training check Tr, and then sends a reception preparation confirmation signal CFR to the transmitter as shown in FIG. Send.
On the other hand, if the 20 bytes do not match the phone number,
The receiver receives the disconnection command signal DCN as shown in FIG.
To the transmitter to disconnect the telephone line.

[0008] Upon receiving the reception preparation confirmation signal CFR, the transmitter encodes the binary data using the Huffman table, transmits the modulated data to the receiver, and continues the subsequent communication. In the receiver, 20 bytes set in the transmission terminal identification signal TSI of the transmission terminal identification signal TSI and the digital command signal DCS first transmitted from the transmitter and the telephone for closed area communication By comparing a telephone number registered in advance as a number, it is also possible to determine whether or not the 20 bytes match the telephone number.

[0009]

However, in the above-mentioned conventional facsimile apparatus, a communication partner in closed area communication is specified by a telephone number, so that a telephone number registered in advance is set in a user mode or a service mode. By making the change, a third party can enter the closed area communication relatively easily.

In addition, since a procedure signal for notifying a communication partner of a telephone number for closed-area communication can be easily analyzed, communication security in closed-area communication is low and reliability is reduced. And since the Huffman table is created assuming a general document image,
If the image is different from that of a general document, the compression ratio of the binary data will be low. In that case, the communication time cannot be shortened.

The present invention solves the above-mentioned problems of the conventional facsimile apparatus, thereby improving the security of communication in closed communication, increasing the compression ratio of binary data, and shortening the communication time. It is an object of the present invention to provide a facsimile apparatus capable of performing the following.

[0012]

For this purpose, in a facsimile apparatus of the present invention, a plurality of Huffman tables and a Huffman table selecting means for selecting an arbitrary Huffman table among the plurality of Huffman tables upon transmission. And encoding / decoding means for compressing binary data and restoring encoded data with reference to the selected Huffman table.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a facsimile apparatus according to a first embodiment of the present invention, FIG. 4 is a diagram showing correspondence between run lengths and code data according to the first embodiment of the present invention, and FIG. FIG. 6 is a diagram showing a part of the contents of a table, FIG. 6 is a first diagram showing a part of the contents of a Huffman table for closed area communication according to the first embodiment of the present invention, and FIG.
FIG. 21 is a second diagram showing a part of the contents of the Huffman table for closed range communication in the embodiment.

In FIG. 1, reference numeral 11 denotes an operation interface unit serving as a Huffman table selecting means;
Denotes a CPU having an arithmetic unit (not shown), a direct memory access control circuit, an interrupt control circuit, and the like. 13 is connected to a scanner (not shown) and converts image data of an image of a document read by the scanner into binary data. ,
An image processing unit 14 for processing the restored binary data; encoding / decoding means 14 for encoding the binary data to generate code data or decoding the code data to generate binary data Encoding / decoding unit as 15;
The T.U. 4 is a Huffman table defined in FIG.

Hi (i = 1, 2,..., N) is a Huffman table for closed area communication created independently, and 17 is a CPU.
12 is a ROM for storing control programs, 18 is a RAM for temporarily storing various data, and 19 is an ITU
T. in the T Recommendation. A communication control unit for performing communication control according to a communication procedure defined by 30 or the like; a modem for modulating code data to analog modulation data; and a demodulator for demodulating the modulation data to digital code data;
Is a line control unit for controlling connection to a telephone line network, and 22 is a print control unit connected to a printer (not shown) for controlling printing.

The operation interface unit 11
Is connected to the CPU 12 and includes an input device, a display device, and the like (not shown). The operator performs operations such as input, registration, and confirmation of a telephone number, an ID number, and the like. CPU1
Reference numeral 2 generally performs system control of the entire facsimile apparatus, management of image data, communication control, print control, and the like. Said C
The PU 12 is connected to the image processing unit 13, the encoding / decoding unit 14, the Huffman table 15, the Huffman table Hi for closed area communication, the ROM 17, the RAM 18, the communication control unit 19, the modem 20, and the print control unit 22 via the bus B. Connected.

The RAM 18 stores not only data such as telephone numbers and ID numbers input to the operation interface unit 11 but also binary data generated by the image processing unit 13, a coding / decoding unit 14. , Temporarily stores code data and binary data obtained by encoding or decoding, data before modulation transmitted or received by the modem 20, and the like. That is, the RA
M18 is also used as a buffer memory for various data in the entire facsimile machine.

In the facsimile apparatus having the above-described configuration, when an image of a document is read line by line by a scanner, and image data corresponding to the image is generated, the image data is sent to an image processing unit 13, and the image data is sent to the image processing unit 13. Processing unit 13
Is converted into binary data composed of white data and black data for each pixel, and then sent to the encoding / decoding unit 14 where it is encoded to generate encoded data.

At this time, the encoding / decoding unit 14 detects the length of continuous white pixels and black pixels, that is, the run lengths of white and black. For example, if the pixels of the image of the document read line by line are white-white-black-white black-black-black-white-black-white-black-black-black, the white and black run lengths are white 3 black 5 white 2 black 4.

Next, the encoding / decoding section 14 refers to the Huffman table 15 in FIG. 5 to generate encoded data corresponding to the run length. The Huffman table 15
, The code data corresponding to run-length white 3 is 1
000, the code data corresponding to the run-length black 5 is 0011, the code data corresponding to the run-length black 2 is 0111, and the code data corresponding to the run-length black 4 is 011. The code data corresponding to white 3 black 5 white 2 black 4 is 10000011
0111011.

By the way, the Huffman table Hi for closed area communication is created independently, and stored independently in a memory (not shown). And, for example, in FIGS.
Huffman table H for closed range communication as shown in
1, the code data corresponding to the run length in H2 is set differently from the code data corresponding to the run length in the Huffman table 15 in FIG. Therefore, the encoding / decoding unit 14 can also generate encoded data corresponding to the run length by referring to the Huffman table Hi for closed area communication.

For example, when referring to the Huffman table H1 for closed area communication, as shown in FIG. 6, the code data corresponding to the run-length white 3 is 1111 and the code data corresponding to the run-length black 5 is 0010, and the code data corresponding to run-length white 2 is 1110
The code data corresponding to run-length black 4 is 00
11, the code data corresponding to the run-length white 3 black 5 white 2 black 4 is 11110010111000.
It becomes 11.

Referring to the Huffman table H2 for closed range communication, as shown in FIG. 7, the code data corresponding to the run-length white 3 is 1011 and the code data corresponding to the run-length black 5 is 011, the code data corresponding to run-length white 2 is 1100, and the code data corresponding to run-length black 4 is 10, so the code data corresponding to the run-length white 3 black 5 white 2 black 4 is , 1011011110010.

Next, the facsimile apparatus having the above-described configuration
The operation of registering a number and the operation of selecting the Huffman table Hi for closed area communication will be described. In performing the closed area communication, the operator operates the operation interface unit 11 in advance to store an ID number common to all the facsimile apparatuses performing the closed area communication in the RAM 18.
Register by storing in. In this embodiment, in order to send an ID number from a transmitter to a receiver, an IT
The T.U. Since the password signal defined in 30 is used, an ID number of up to 20 digits (digits) can be used. In order to send the ID number from the transmitter to the receiver, a telephone number or the like can be used instead of the password signal.

Next, the operator operates the operation interface unit 11 to select an arbitrary closed-area communication Huffman table Hi common to each facsimile machine in correspondence with the registered ID number, and register it in the RAM 18. I do. In this case, another Huffman table Hi for closed area communication is selected for each ID number. However, when the number of registered ID numbers is larger than the number n of Huffman tables Hi for closed area communication, one closed area communication A plurality of ID numbers can be assigned to the Huffman table Hi for use.

Next, a communication procedure in the facsimile apparatus having the above configuration will be described. FIG. 8 is a diagram showing a communication procedure of the facsimile apparatus according to the first embodiment of the present invention. The operator sets a document (not shown) on the scanner and operates the operation interface unit 11 (FIG. 1) to input the ID number and the telephone number of the receiver.

The CPU 12 determines whether the input ID number matches any of the ID numbers registered in advance. If the input ID number matches one of the ID numbers registered in advance, one Huffman table Hi for closed-area communication corresponding to the ID number is selected. The fact that the ID number does not match any of the ID numbers registered in advance is displayed on a display device (not shown) of the operation interface unit 11.

On the other hand, the image data of the original image read line by line by the scanner is converted into the binary data by the image
4 The encoding / decoding unit 14 first detects a run length. For example, as described above, if the pixels of the image of the document read line by line are white-white-black-white-black-black-black-white-black-white-black-black-black, the run length is white 3 black 5 white 2 black 4. .

Subsequently, as shown in the figure, when the transmitter calls for communication with the receiver, the receiver seizes the telephone line, and receives the non-standard procedure signal NSF, the called station. The identification signal CSI and the digital identification signal DIS are transmitted to the transmitter. The digital identification signal DIS includes a bit declaring that a password can be received.

The transmitter transmits the digital identification signal DI of the non-standard procedure signal NSF, called station identification signal CSI, and digital identification signal DIS first transmitted from the receiver.
It is determined whether or not there is a bit in S that declares that the password can be received (check the password receiving ability). If there is a bit declaring that the password can be received, the transmitter transmits the password frame PWD, the transmitting terminal identification signal TSI, and the digital command signal DCS to the receiver. The password frame PWD conforms to the T.30 standard in the ITU-T recommendation. Has the format of the password signal defined in 30;
Since the input ID number is included as the password, the Huffman table Hi for closed area communication corresponding to the ID number is indicated by the password frame PWD. Further, the transmitter transmits the training check Tr to the receiver.

On the other hand, if there is no bit declaring that the password can be received, the transmitter transmits a disconnection command signal DCN (not shown) to the receiver to disconnect the telephone line. The receiver sets the received password frame PW
It is checked whether the ID number included in D matches any of the ID numbers registered in advance for closed-area communication. If the ID number included in the received password frame PWD matches any of the ID numbers registered in advance for the closed area communication,
A Huffman table Hi for closed area communication registered corresponding to the D number is selected. The Huffman table Hi for closed area communication selected by the receiver is the same as the Huffman table Hi for closed area communication specified by the transmitter. Then, the receiver performs the training check Tr
Is normally received, a reception preparation confirmation signal CFR is transmitted to the transmitter.

On the other hand, the received password frame PWD
Does not match any of the ID numbers registered in advance for closed-area communication, the receiver transmits the disconnection command signal DCN to the transmitter to disconnect the telephone line. The transmitter transmits a reception preparation confirmation signal CFR
Is received, the encoding / decoding unit 14 encodes the binary data with reference to the selected Huffman table Hi for closed area communication, and generates encoded data corresponding to white and black run lengths.

Huffman table Hi for closed area communication
Is, for example, a Huffman table H1 for closed area communication, the code data corresponding to run-length white 3 is 111
1 and the code data corresponding to run-length black 5 is 0
010, the code data corresponding to run-length white 2 is 1110, and the code data corresponding to run-length black 4 is 0011.
The code data corresponding to white 2 black 4 is 1111001011100011.

Next, the transmitter modulates the code data by the modem 20 into modulated data, transmits the modulated data to the receiver via the line control unit 21, and continues the subsequent communication. On the other hand, when receiving the modulated data, the receiver demodulates the modulated data into code data.
Subsequently, the encoding / decoding unit 14 decodes the encoded data with reference to the selected Huffman table Hi for closed-area communication to generate binary data.

For example, if the code data generated by the transmitter with reference to the Huffman table H1 for closed area communication is 1111001011100011, the coding / decoding unit 14 of the receiver refers to the Huffman table H1 for closed area communication and performs the above-described processing. When the code data is decoded, the pixels of the image of the document read line by line become white-white-black-white-black-black-black-white-black-white-black-black-black.

When all the modulated data has been transmitted to the receiver, the transmitter transmits a procedure end signal EOP indicating that the transmission of the modulated data has been completed to the receiver. Next, the receiver normally receives the modulated data, and
When the procedure end signal EOP is received, a message confirmation signal MCF is transmitted to the transmitter. When receiving the message confirmation signal MCF, the transmitter receives the disconnection command signal DCN.
To the receiver to disconnect the telephone line.

In the receiver, the binary data is processed by the image processing unit 13 and transferred to the printer via the print control unit 22 as print data. The printer prints an image on a recording medium (not shown) according to the print data. As described above, in the present embodiment, one Huffman table Hi for closed communication corresponding to the ID number is selected by the receiver from the plurality of Huffman tables Hi for closed communication uniquely created,
A transmitter generates code data with reference to the Huffman table Hi for closed-area communication, and a receiver decodes the code data with reference to the Huffman table Hi for closed-area communication. Therefore, even if the ID number is changed in the user mode or the service mode,
Even if the password frame PWD for notifying the number can be analyzed, a third party cannot enter the closed area communication unless the Huffman table Hi for the closed area communication corresponding to the ID number is provided. Can not.

Therefore, the security of the communication in the closed area communication can be enhanced, and the reliability can be improved. Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

FIG. 9 is a diagram showing a relationship between a Huffman table for closed area communication and a RAM according to the second embodiment of the present invention, and FIG. 10 is a flowchart showing an encoding process according to the second embodiment of the present invention. FIG. 11 is a diagram showing a communication procedure of the facsimile apparatus according to the second embodiment of the present invention. In this case, the RAM 18 stores the code data Di (i = 1, i) corresponding to the Huffman table Hi for each closed area communication.
2,..., N), and a pointer for detecting and storing the length of the code data Di stored in the area.

Next, the operation of selecting a Huffman table Hi for closed area communication and performing communication in the facsimile apparatus according to the present embodiment will be described. The operator
An original (not shown) is set on the scanner, and the operation interface unit 11 (FIG. 1) as a Huffman table selecting means is operated to input an ID number, a telephone number of the receiver, and the like. And 1 by scanner
The image data of the document image read line by line is converted into binary data consisting of white data and black data for each pixel in the image processing unit 13 and then sent to a coding / decoding unit 14 as coding / decoding means. Can be

The encoding / decoding unit 14 first detects each of the white and black run lengths. For example, as described above, if the pixels of the image of the document read line by line are white-white-black-white-black-black-black-white-black-white-black-black-black, the run length is white 3 black 5 white 2 black 4. .

Next, the encoding / decoding section 14 generates code data Di corresponding to the run length by sequentially referring to the Huffman tables Hi for each closed area communication, and generates the code data Di.
Is stored in each area in the RAM 18. At this time, the encoding / decoding unit 14 sequentially moves the pointer of the RAM 18, detects the length of each code data Di stored in each area by the pointer, and stores the length in the pointer. That is, the encoding / decoding unit 14 first selects the Huffman table H1 for closed area communication,
The pointer of M18 is moved to the area assigned in correspondence with the Huffman table H1 for closed area communication.
As shown in FIG. 6, in the Huffman table H1 for the closed area communication, the code data Di corresponding to the run length white 3 is 1111, the code data Di corresponding to the run length black 5 is 0010, and the run length is 0010. White 2
Is 1110, and the code data Di corresponding to run-length black 4 is 0011, so that the code data D1 corresponding to the run-length white 3 black 5 white 2 black 4 is 1111001011100011.

Therefore, the encoding / decoding unit 14 is provided with a RAM
The code data D1 is stored in an area assigned to correspond to the Huffman table H1 for closed area communication in the area 18. The length of the stored code data D1 is detected by a pointer and stored in the pointer. Next, the encoding / decoding unit 14 selects the Huffman table H2 for closed area communication, and moves the pointer of the RAM 18 to an area assigned in correspondence with the Huffman table H2 for closed area communication. As shown in FIG. 7, in the Huffman table H2 for closed-area communication, the code data Di corresponding to the run-length black 3 is 1011 and the code data Di corresponding to the run-length black 5 is 011.
Code data Di corresponding to run-length white 2 is 1100
Since the code data Di corresponding to the run-length black 4 is 10, the code data D2 corresponding to the run-length white 3, black 5, white 2, and black 4 is 1011011110010.

Therefore, the encoding / decoding unit 14 is
The code data D2 is stored in an area assigned to correspond to the Huffman table H2 for closed area communication in the area 18. The length of the stored code data D2 is detected by a pointer and stored in the pointer. As described above, for one line of image data, the code data Di is generated with reference to the Huffman table Hi for each closed area communication, and when the code data Di is stored in all the areas in the RAM 18, the following is performed. With respect to the image data of the line, the code data Di is generated with reference to the Huffman table Hi for each closed area communication, and the code data Di is stored in all the areas in the RAM 18.

Subsequently, the coding / decoding unit 14 detects the length of the code data Di stored in each area by using a pointer, and detects the length of the code data D of the previous line already stored.
Add to the length of i. When all the binary data is encoded for the image data of the image of one page of the original and each code data Di is stored in each area in the RAM 18, the code / decoding unit 14 Are compared with each other, and the code data Di having the shortest total length is selected.
Also, only the code data Di having the shortest total length is
Stored together with a number Ni (i = 1, 2,..., N) representing the corresponding Huffman table Hi for closed area communication,
8, all the code data Di stored in other areas are erased.

The code data Di having the shortest total length is stored in the Huffman table H for closed area communication, for example.
2, the code data D2 corresponding to run-length white 3 black 5 white 2 black 4 is 1011011110010.

Next, a communication procedure performed by the facsimile apparatus having the above configuration will be described. As shown in FIG.
When a transmitter places a call to communicate with a receiver, the receiver seizes the telephone line and sends a non-standard procedural signal N
SF, called station identification signal CSI and digital identification signal D
Send IS to transmitter. The non-standard procedure signal NSF includes a bit declaring that a plurality of Huffman tables Hi for closed area communication are provided, and a bit indicating the number Ni of the Huffman table Hi for each closed area communication.

The transmitter includes, in the non-standard procedure signal NSF among the non-standard procedure signal NSF, called station identification signal CSI and digital identification signal DIS first transmitted from the receiver, each of the closed-area communication signals. It is determined whether a bit declaring the presence of the Huffman table Hi and a bit indicating the number Ni of the Huffman table Hi for each closed area communication are included.

When the above-mentioned bits are included in the non-standard procedure signal NSF, the transmitter confirms that the receiver has the same Huffman table Hi for closed-area communication as the Huffman table Hi for closed-area communication of the receiver. Then, the digital command signal DCS and the non-standard function setting signal NSS are transmitted to the receiver. At this time, the number Ni of the Huffman table Hi for closed-area communication corresponding to the code data Di having the shortest total length, which is selected by the code / decoding unit 14 of the transmitter and stored in the RAM 18, is set to the non-standard value. The function setting signal NSS is set. Further, the transmitter transmits the training check Tr to the receiver.

On the other hand, when the bit is not included,
The transmitter transmits a disconnection command signal DCN to the receiver to disconnect the telephone line. The receiver uses the non-standard function setting signal NSS
The number Ni of the Huffman table Hi for closed area communication set therein is confirmed. If the number Ni can be confirmed, the encoding / decoding unit 14 selects the Huffman table Hi for closed area communication corresponding to the number Ni. The Huffman table Hi for closed area communication selected by the receiver is the same as the Huffman table Hi for closed area communication selected by the transmitter. Then, when the receiver receives the training check Tr normally,
The reception preparation confirmation signal CFR is transmitted to the transmitter.

If the number Ni cannot be confirmed, the receiver transmits a disconnection command signal DCN to the transmitter to disconnect the telephone line. Then, when receiving the reception preparation confirmation signal CFR, the transmitter transmits the code data Di having the shortest total length as modulation data to the receiver, and continues the subsequent communication.

On the other hand, in the receiver, the code data D
When i is received, the encoding / decoding unit 14 decodes the code data Di with reference to the selected Huffman table Hi for closed area communication. For example, if the code data D2 generated by the transmitter with reference to the Huffman table H2 for closed area communication is 1011011110010, the coding / decoding unit 14 of the receiver refers to the Huffman table H2 for closed area communication to generate the code data D2. Are decoded, the pixels of the image of the document read line by line become white-white black-white black black black white black-white black black black.

When all the modulated data has been transmitted to the receiver, the transmitter transmits a procedure end signal EOP indicating that the transmission of the modulated data has been completed to the receiver. next,
When the receiver receives the modulation data normally and receives the procedure end signal EOP, the receiver confirms the message confirmation signal MC.
Send F to the transmitter. When receiving the message confirmation signal MCF, the transmitter transmits a disconnection command signal DCN to the receiver to disconnect the telephone line.

In the receiver, the binary data is processed by the image processing unit 13 and the print control unit 22
Is transferred to the printer as print data via the printer. The printer prints an image on a recording medium (not shown) according to the print data. Note that, in addition to the independently created Huffman table Hi for closed area communication, the T.U. Huffman table 15 defined in 4
May be selected.

As described above, in the present embodiment, the transmitter calculates the sum of the lengths from the code data Di generated by referring to the Huffman table Hi for each closed area communication created independently. The shortest code data Di is selected, and the receiver sets the same Huffman table H for closed area communication as the transmitter.
i is selected, and the code data Di is decoded with reference to the Huffman table Hi for closed-area communication.

Therefore, the security of the communication in the closed area communication can be enhanced, and the reliability can be improved. Further, the compression rate of the binary data can be increased, and the communication time can be shortened.
Then, in addition to the Huffman table Hi for each closed area communication created independently, T.H. in the ITU-T recommendation. If the Huffman table 15 defined in 4 can be selected, it is more likely that code data Di having a shorter total length will be obtained, so that the compression ratio of binary data is further increased. And the communication time can be further shortened.

Next, the flowchart will be described. Step S1: One line of image is read. Step S2: A run length is detected. Step S3: Select the Huffman table H1 for closed area communication. Step S4: The code data D1 corresponding to the run length is generated with reference to the Huffman table H1 for closed area communication. Step S5: The code data D1 is assigned to the RA assigned to the Huffman table H1 for closed area communication.
It is stored in the area in M18. Step S6: The length of the code data D1 stored in the area is detected by the pointer and stored in the pointer. Step S7: It is determined whether all the Huffman tables Hi for closed area communication have been selected. If all Huffman tables Hi for closed area communication have been selected, step S
The process proceeds to step S8, and if not selected, returns to step S3. Step S8: It is determined whether the processing for one line is completed. When the processing for one line is completed, the process proceeds to step S9, and when not completed, the process returns to step S2. Step S9: To judge whether the processing for one page is completed. When the process for one page is completed, the process proceeds to step S10, and when not completed, the process returns to step S1. Step S10 The code data Di having the shortest total length is selected from the stored code data Di. Step S11: Delete the other code data Di.

The present invention is not limited to the above embodiment, but can be variously modified based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0059]

As described above in detail, according to the present invention, in a facsimile apparatus, a plurality of Huffman tables and an arbitrary Huffman table among the plurality of Huffman tables are selected upon transmission. It has a Huffman table selecting means and an encoding / decoding means for compressing binary data and restoring encoded data with reference to the selected Huffman table.

In this case, the Huffman table is selected in the transmitter, and when the binary data is encoded with reference to the Huffman table, unless the receiver has the selected Huffman table, a third party is required. Cannot enter the closed area communication. Therefore, communication security in closed area communication can be enhanced, and reliability can be improved.

Further, since a Huffman table that generates the shortest code data can be selected from each Huffman table, not only can the compression ratio of binary data be increased, but also the communication time can be shortened. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus according to a first embodiment of the present invention.

FIG. 2 is a first diagram showing a communication procedure of a conventional facsimile machine.
FIG.

FIG. 3 is a second diagram showing a communication procedure of the conventional facsimile machine.
FIG.

FIG. 4 is a diagram showing correspondence between run lengths and code data according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a part of the contents of a standard Huffman table.

FIG. 6 is a first diagram showing a part of the contents of a Huffman table for closed area communication according to the first embodiment of the present invention.

FIG. 7 is a second diagram showing a part of the contents of the Huffman table for closed area communication according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a communication procedure of the facsimile apparatus according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between a Huffman table for closed area communication and a RAM according to the second embodiment of the present invention.

FIG. 10 is a flowchart illustrating an encoding process according to the second embodiment of the present invention.

FIG. 11 is a diagram showing a communication procedure of the facsimile apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 operation interface unit 14 encoding / decoding unit 15 Huffman table Di encoded data Hi Huffman table for closed area communication

Claims (4)

[Claims] (A) a plurality of Huffman tables;
(B) a Huffman table selecting means for selecting an arbitrary Huffman table from the plurality of Huffman tables upon transmission; and (c) compressing binary data and encoding code data with reference to the selected Huffman table. A facsimile apparatus comprising encoding / decoding means for performing restoration. 2. Each of the Huffman tables is a Huffman table for closed area communication, and (b) the Huffman table selecting means selects a Huffman table for closed area communication in correspondence with an ID number registered in advance. The facsimile apparatus according to claim 1, wherein 3. The facsimile apparatus according to claim 2, wherein the ID number and the Huffman table for the closed area communication are shared between a transmitter and a receiver. 4. The facsimile apparatus according to claim 1, wherein said Huffman table selecting means selects a Huffman table having the shortest code data.