JP3163304B2 - Encoding / decoding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding / decoding system, and more particularly, to improving the signal processing performance of a host control unit by simplifying the transfer of commands between the host control unit and the encoding and decoding units. The present invention relates to an encoding / decoding system suitable for use in a facsimile apparatus.

[0002]

2. Description of the Related Art In a facsimile, CCITT is used to improve transmission efficiency when transmitting image data.
(International Telegraph and Telephone Advisory Committee),
The transmission of the image data is performed using the MH, MR, and MMR coding schemes. This encoding method is
This is a method of transmitting black and white change points in image data corresponding to codes, and when encoding the same number of data bits, when the number of black and white change points per unit length is large, the data is correspondingly increased. Has the property that the processing amount of the data increases and the encoding speed of the data decreases as the processing amount of the data increases. Also,
The same applies to the decoding of encoded data. If there are many black and white change points per unit length in the original data,
When the same code bit number is decoded, the number of bits of decoded data is very small.

For this reason, in recent facsimile apparatuses, even when processing such data having many black and white changing points, encoding and decoding can be performed at high speed. Means have begun to be developed, one example of which is disclosed in JP-A-60-194670 or JP-A-62-35780.

However, when the entire facsimile system is viewed in addition to the encoding and decoding units, the host control unit, the memory unit, the reading unit, the recording unit, the encoding unit and the decoding unit in the system are respectively Since the operation is closely related, it is clear that an efficient facsimile system cannot be constructed by ignoring the transmission and reception of control signals between these peripheral devices and the state of the data bus load.

[0005] It should be noted that this type of facsimile system 1
For example, pp64-72 of Electronic Technology, April 1988,
And an electronic technology disclosed in August 1990, pp. 67 to 71, but in this facsimile system, nothing is mentioned about improving the efficiency of the encoding and decoding units.

[0006]

The above-mentioned conventional high-speed encoding / decoding means only discloses means for reducing the number of parts by converting a facsimile system into a gate array. How to send and receive control signals between the three parts, ie, the conversion unit, the host control unit, and the reading unit, and
Attention is paid to improving the way of transmitting and receiving control signals among the three components of the decoding unit, the host control unit, and the recording unit, and performing high-speed processing with a small number of components as a whole facsimile system. Not something.

For this reason, when the above-mentioned high-speed encoding / decoding means is incorporated in a facsimile system, the control load of the encoding / decoding means on the host control section becomes excessive, and the host control section If a processor having a high processing capability is used or a means for increasing the number of processors is not added, the high-speed processing performance of the encoding and decoding means cannot be sufficiently exhibited. . In this case, when a conventional processor is used as the host control unit, the processing load on the host control unit becomes excessive in order to improve the user application service of the facsimile system as a whole. However, there was a problem that it was not possible to respond to satisfaction.

Also, in the facsimile which shows the prior art of the present invention, since the host control unit manages the timing of starting and completing the operation of each unit, the data processing speed in the encoding and decoding unit is reduced. When trying to increase it, the processing load of the host control unit becomes excessive, and there is a problem that a satisfactory data processing speed cannot be obtained.

In order to increase the speed of the encoding and decoding means and to improve user application services, a processor having a high processing capability is used or the number of processors is increased. If this is the case, there is a problem that the cost increases accordingly.

The present invention has been devised to solve the above-mentioned various problems at once, and one object of the present invention is to simplify command transmission and reception between a host control unit and an encoding unit and a decoding unit. Accordingly, it is possible to provide an encoding / decoding system capable of processing information of the entire system by using a small number of components and achieving high throughput by using a low-cost host control unit. It is in.

It is another object of the present invention to provide an encoding / decoding system which does not need to transmit / receive a command in real time from a host control unit.

[0012]

In order to achieve the above two objects, an encoding / decoding system according to the present invention comprises at least a reading section for scanning and reading an original, and a reading section for reading by the reading section.
A coding and decoding unit for encoding took data, the information processing
And a host control unit that performs overall control on the document . When the host control unit receives a document reading request from the reading unit , the host control unit sets the encoding / decoding unit to the encoding mode.
Supplies an encoding preparation command to the encoding / decoding unit,
Thereafter, the encoding decoding portion, in the absence intervention of the host controller receives the start request read from the reading unit
And performing an encoding process on the data.
The encryption / decryption unit, without the intervention of the host control unit,
When a page end request is received from the reading unit, the data
And the host control unit is coded.
The host control unit supplies the encoding end signal.
Upon receiving the end signal, the reading unit is instructed to perform an encoding end command.
The first means for supplying

Further, in order to achieve the above two objects,
The encoding / decoding system according to the present invention includes at least a receiving unit
Or encoded data input from the encoded data storage unit
An encoding / decoding unit for decoding
A recording unit that records encoded data , and a host control unit that performs overall control on information processing, wherein the host control unit reads a document from the reception unit or the encoded data storage unit.
Upon receiving a recording request, the encoding / decoding unit decodes and records
Mode , and a decoding command is supplied to the encoding / decoding unit . After that, the encoding / decoding unit , without the intervention of the host control unit, the reception unit or the
When a recording start request is received from the encoded data storage unit , the data is decoded, and
The receiving unit is configured to receive the data without the intervention of the host control unit.
Page end request from the communication unit or the encoded data storage unit
Receiving the data, terminates the data decryption process and
Supplying decoded completion signal to the host controller, the host controller receives the decoded end signal, the recording
Second means for supplying a decoding end command to the unit.

[0014]

In addition, in the course of the encoding and decoding performed by the second means and the third means, the encoding unit and the decoding unit use a line memory unit having a storage capacity of three lines. The line memory unit has a function of preventing encoding of a line on which input of read data has not been completed, and a function of preventing recording of data on a line on which decoded data has not been input. And a fourth means having a function of preventing writing of restored data again on restored image data which has not been recorded and output.

[0016]

[0017]

SUMMARY OF] According to the first means, when performing encoding, before the reading unit starts the encoding process the data obtained by reading an original in coding and decoding unit, host control parts are coding the coded commands required for the encoding process
To the encoding / decoding unit, and prepares the encoding / decoding unit for encoding processing. Thereafter, the encoding / decoding unit determines the timing for starting the encoding process independently without the intervention of the host control unit, and then converts the data obtained from the original into a page unit without using an external memory. To encode. Further, the encoding / decoding unit independently determines the timing for terminating the encoding process without interposing the host control unit as before, thereby terminating the encoding process and controlling the encoding end signal by the host control. Supply to the department. At this point, the host control unit determines the end signal from the encoding / decoding unit, and instructs the next control operation.

According to the second means, when performing the decoding process, the decoding process is started by the encoding / decoding unit for the encoded data input from the receiving unit or the encoded data storage unit. Beforehand, the host control unit supplies a command necessary for the decoding process to the host control unit, and makes the encoding / decoding unit prepare for the decoding process. Thereafter, the encoding / decoding unit determines the timing for starting the decoding process independently without the intervention of the host control unit, and then converts the input encoded data in page units without using an external memory. Decrypt. Further, the encoding / decoding unit independently determines the timing for ending the decoding process without the intervention of the host control unit as before, thereby ending the decoding process and sending a recording end signal to the host. Supply to the control unit. At this point, the host control unit determines the end signal from the encoding / decoding unit, and instructs the next control operation.

According to the above-described operations, the host control unit does not need to perform real-time control on these processes during the encoding and / or decoding processes, and the load on the host control unit is greatly reduced. Become. Furthermore, since the time required for the real-time control can be used for processing other information, the encoding and / or decoding processing executed by the host control unit can be speeded up.

Further, even if the encoding / decoding process is speeded up as described above, the host control unit manages the start and end timings of the encoding / decoding process, and Compared with the prior art method in which the host control unit controls the encoding unit and the decoding unit in real time, the processing load on the host control unit is rather reduced, so that a high-performance processor capable of high-speed processing is provided. use,
And the need for the use of multiprocessors is completely eliminated.

In addition to the above, according to the fourth means, at the time of encoding read data of an original or at the time of recording data after decoding, the data is stored in a line memory unit having a storage capacity of three lines. Is temporarily stored,
Speed up in pipeline processing. Also, it prevents the encoding of the data for the line to which the data has not yet been input, prevents the output of the data for the line to which the data after the decoding has not been input to the recording unit, and the recording of the data which has not yet been input. Since it has a function of preventing restoration data from being written again on restoration image data that has not been output, a control device for properly managing the flow of codes and image data is not required.

The line memory section includes A3
Even if a paper of a size is read at 400 dpi, it is sufficient to use a memory having a memory capacity of about 2 kbytes for three lines. In order to manage the line memory unit at a high speed, it is more economical in terms of hardware to incorporate the line memory unit in the encoding unit and the decoding unit than to use a unique processor. It can be simplified.

By adopting each of the above means, the host control unit only intervenes in the encoding unit and the decoding unit for each page of the original, so that the host controller reads data from the encoding unit and transmits data to the decoding unit. It is possible to realize high-speed recording with high cost performance.

[0024]

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

FIG. 1 is a block diagram showing a facsimile apparatus to which the encoding / decoding system according to the present invention is applied.

In the figure, 1 is an encoding unit, 2 is a decoding unit, 3 is an encoding processing unit, 4 is a line memory unit, 5 is a decoding processing unit, 6 is a line memory unit, and 7 is a host control unit. A microprocessor unit (hereinafter referred to as a host MPU), 8 is a reading unit, 9 is a recording unit, 10 is a communication control unit, 11 is a code data memory unit, 12 to 21 are control buses, and 22 to 29 are data Line. Also,
The encoding unit 1 and the decoding unit 2 constitute an encoding / decoding unit 40, and the reading unit 8, the recording unit 9, the communication control unit 10, the code data memory unit 11 and the like constitute a data input / output unit 41. I have.

The encoding section 1 comprises an encoding section 3 and a line memory section 4, and the decoding section 2 comprises a decoding section 5 and a line memory section 6. The reading unit 8 scans and reads a document, and supplies the read image data to the line memory unit 4 of the encoding unit 1 via the data line 22. The line memory unit 4 is a memory having a storage capacity for three lines of the document and capable of reading at a constant speed of 10 Mb / s or more, and temporarily stores the read image data. Next, the data is read out for encoding and supplied to the encoding processing unit 3 via the data line 23. The line memory unit 6 also has a storage capacity for three lines of the original and is capable of reading at a constant speed of 10 Mb / s or more, and temporarily stores the image data decoded by the decoding processing unit 5. , And then read out for recording, supplied to the recording unit 9 via the data line 27 and recorded there. The reading unit 8, the recording unit 9, and the encoding unit 1 and the decoding unit 2 are connected to the host MPU 7 via control buses 12 to 17, respectively, and are connected between the reading unit 8 and the line memory unit 4, the line memory unit 4 And encoding processing unit 3
The control buses 18 to 21 and the data lines 22, 23, 26, and 27 are connected to each other, between the decoding processing unit 5 and the line memory unit 6, and between the line memory unit 6 and the recording unit 9, respectively. Further, the encoding processing unit 3, the decoding processing unit 5,
The communication control unit 10 and the code data memory unit 11 communicate with the host MP via data lines 24, 25, 28 and 29, respectively.
Connected to U7.

In this case, the communication control unit 10 and the code data memory unit 11 are not indispensable in the encoding / decoding system according to the present invention. For example, in a filing device or the like, a device connected to a file device or the like is used. It is.

Here, regarding the operation of the facsimile apparatus shown in FIG. 1, a processing flow performed by the host MPU shown in FIG.
The description will be made with reference to FIG. 3 and a diagram showing the time history of the processing among the three units of the system, the host MPU, and the encoding unit shown in FIG.

However, in the following description, the term "page" in the present invention means, in addition to a page representing a physical break in a normal meaning, a mark or a shape characteristic of paper in advance. Pages including the breaks determined by the above. The page serving as a unit when scanning and reading an original and printing image data is determined by the amount of movement of the image in the vertical direction (sub-scanning direction). It means the size of the image determined by the paper feed amount (feed amount). By the way, as shown in FIG. 9, even if an image is formed only of characters, a photograph is inserted between characters, or a case where characters, photos, and pictures are mixed, for example, The movement amounts m ₁ , m ₂ , and m ₃ in each case are counted in the same manner.

In FIG. 3, first, a document to be read is set on the reading unit 8 and a document reading request signal 50 from the reading unit 8 is supplied to the host MPU 7 via the control bus 14. The encoding mode setting command 5 is transmitted to the encoding processing unit 3 of the encoding unit 1 via the control bus 17.
Supply 1 At this time, the encoding unit 1 transmits the command 5
1 enters an encoding preparation state, and waits for a reading start request signal 52 from the reading unit 8. Next, when the reading start request signal 52 is directly input to the encoding unit 1 through the control bus 18 without passing through the host MPU 7, the encoding unit 1 enters the encoding processing state immediately after receiving the reading start request signal 52. The image data obtained by reading a document supplied from the reading unit 8 via the data line 22 is encoded. This encoding processing state is continued until the page end request signal 53 is input from the reading unit 8 to the encoding unit 1 via the control bus 18 directly without passing through the host MPU 7. When the encoding unit 1 receives the page end request signal 53, the encoding unit 1 enters an idle state, and at the same time, supplies an encoding end signal 54 to the host MPU 7 via the control bus 16. Upon receiving the encoding end signal 54, the host MPU 7 confirms the end of encoding, and at the same time,
A command 55 is supplied to the system to perform control required by the system. Here, the necessary control includes checking whether there is a paper jam that hinders normal execution of the facsimile operation, and a reading mode for transferring the next original to a predetermined position when there is the next original. This corresponds to the control of data. Then, when there is a next original, the reading unit 8 supplies the next original reading request signal 56 to the host MPU 7, and thereafter the above-described processing is executed again. If not, the above process is continuously executed until reading of all originals and encoding of the read data are completed.

If a page is marked in advance or a break determined by the shape characteristics of paper is used as the page, the reading section or the mark or the feature separately from the reading section is used. If the mark and the feature are detected by a newly provided processing unit for detecting the position, the location where the detection is performed is logically recognized as a page break. The same processing can be continued.

FIG. 2 shows that the host M
The processing flow executed by the PU 7 is shown.

Normally, the host MPU 7 performs not only facsimile overall control for a facsimile, that is, control for reading a document or recording image data,
It also controls image data transmitted via a communication system, processes information in a man-machine I / F unit, and the like. First, when the host MPU 7 is in a standby state, the host MPU 7 When there is any control request from the system, the whole system control process is started and executed (step 30). At this time, in the overall system control processing, in order to perform an appropriate processing according to a request from each system, a request from the system is determined as shown in FIG. (Step 3
0 '). In this request determination, processing relating to document reading and image data recording is performed individually, and other processing is collectively determined as other system request determination processing.

During the above-mentioned determination, the reading of the original and the decision to execute or stop the encoding of the read data are made as follows. First, it is determined whether or not there is a document in the reading unit 8 (step 31). If the determination is YES, a coding mode setting process is performed according to the supply of the document reading request signal 50 (step 32). At the same time, an encoding mode setting command 51 is supplied to the encoding unit 1 via the control bus 17 to return to the first standby state. If the determination is NO, the control immediately returns to the first standby state. After the output of the command 51, it is determined whether or not one page of the document has been read by the reading unit 8 (step 33). If the determination is YES, the encoding completion confirmation and the system are required. The control is performed (step 34) to return to the first standby state. If the determination is NO, the control immediately returns to the first standby state.

FIG. 5 is a system diagram showing transmission paths and transmission orders of various signals during the above-described series of operations. In the drawings, the order of transmission of the signals is shown.

In FIG. 3, when a document is set on the reading unit 8 and a document reading request signal 50 is output from the reading unit 8 via the control bus 14 to the host MPU 7, the host MP
U7 detects the document reading request signal 50. When the detection is performed, the host MPU 7 supplies the encoding mode setting command 51 to the encoding unit 1 via the control bus 17. The encoding unit 1 enters a state of waiting for a reading start request signal 52, and when the reading start request signal 52 is supplied from the reading unit 8 via the control bus 18, the original supplied via the data line 22 The encoding process of the image data obtained by reading is started. After the start of the encoding process, the encoding unit 1 continues the encoding process in the set encoding mode until the page end request signal 53 is input. When reading of one page of the document is completed and a page end request signal 53 is supplied from the reading unit 8 to the encoding unit 1 via the control bus 18, the encoding unit 1 stops the encoding process. At this time, the encoding unit 1
Outputs an encoding end signal 54 to the host MPU 7 via the control bus 16 and enters an idle state. Thereafter, the operation returns to the initial state, and when there is still a document to be read, the above operation is repeatedly performed in the above order.

As described above, the host MPU 7 monitors the application of the original reading request signal 50 supplied from the reading unit 8 when reading the original and encoding the read image data. Read request signal 50
Is supplied to the encoding unit 1 as long as the encoding mode setting command 51 for encoding preparation is supplied to the reading unit 8 without the intervention of the host MPU 7. The reading of the document and the coding of the read image data are performed independently only between the image processing unit and the encoding unit 1, and the real-time control of the host MPU 7 is not required during this period. Also, at the end of the encoding process of the read image data, the host MPU 7
Similarly, application of the encoding end signal 54 supplied from the reading unit 8 is monitored for each page of the document, and after the reception of the encoding end signal 54 is detected, control of other information processing can be appropriately executed. Things.

Next, the operation of decoding coded data and recording the decoded image data will be described with reference to FIGS. 1, 2 and 4.

First, when there is encoded data of a document to be recorded by the recording unit 9 in the communication control unit 10 or the code data memory unit 11, the document is transmitted from the communication control unit 10 or the code data memory unit 11. The recording request signal 60 is transmitted from the host MPU 7
The host MPU 7 supplies the recording mode setting command 67 to the recording unit 9 via the control bus 13 and decodes the recording mode setting command 67 via the control bus 17 to the decoding processing unit 5 of the decoding unit 2. The mode setting command 61 is supplied. At this time, the recording unit 9 enters a recording preparation state by the supply of the command 67, and the decoding unit 2
1 and enters a decoding preparation state, and then enters a state of waiting for a recording start request signal 62 supplied from the recording unit 9. At this time, the recording start request signal 62
When the data is directly input from the recording unit 9 to the decoding unit 2 via the control bus 21 without passing through the U7, the decoding unit 2 enters the decoding processing state immediately after receiving the recording start request signal 62,
Data is transmitted from the communication control unit 10 or the code data memory unit 11.
The decoding of the encoded data supplied via the data line 25 is performed. This decoding processing state is continued until the page end request signal 63 is input from the communication control unit 10 or the code data memory unit 11 to the decoding unit 3 via the host MPU 7. When the decoding section 2 receives the page end request signal 63, the decoding section 2 enters an idle state and supplies a decoding end signal 64 to the host MPU 7 via the control bus 16. Upon receiving the decoding end signal 64, the host MPU 7 confirms the end of decoding, and supplies a command 65 to the system to perform control required by the system.

In this case, the necessary control includes checking whether there is a paper jam which may hinder the normal execution of the facsimile operation, and when there is encoded data of a document to be further recorded next, the recording of the encoded data is performed. This corresponds to control of a recording motor or the like for preparation. When there is encoded data of the original to be recorded next, a next original recording request signal 66 is supplied from the communication control unit 10 or the encoded data memory unit 11 to the host MPU 7, and thereafter, the above-described processing is performed. Is executed again. At this time, if there is no instruction to interrupt the processing in the middle, the above-described processing is continuously executed until the encoded data of all the originals to be recorded is exhausted.

FIG. 2 also shows a processing flow executed by the host MPU 7 in the above processing.

This processing flow is almost the same as the processing flow for reading a document and encoding read data. First, when the host MPU 7 is in a standby state, the host MPU 7 If there is any control request to the system, the whole system control process is started and executed (step 30), and then a request from the system is determined (step 30 '). In this case, the decoding of the encoded data and the decision whether to execute or stop the recording of the decoded data are made as follows. First, it is determined whether or not there is encoded data to be recorded (step 3).
5) If the determination is YES, a decoding mode setting process is performed in accordance with the supply of the document recording request signal 60 (step 36), and the decoding mode is sent to the decoding unit 3 via the control bus 17. The control returns to the initial standby state by supplying the command setting command 61, and immediately returns to the initial standby state when the result of the determination is NO. After the output of the command 61, it is determined in the recording unit 9 whether or not the recording of one page of the document has been completed (step 37). If the determination is YES, a decoding completion confirmation and a system are necessary. (Step 38), and returns to the initial standby state. If the determination is NO, the control immediately returns to the initial standby state.

FIG. 6 is a system diagram showing transmission paths and transmission orders of various signals during the above-described series of operations. In the drawings, the order of transmission of the signals is shown.

In FIG. 6, encoded data of an original to be recorded in the communication control unit 10 or the encoded data memory unit 11 is shown.
When a document recording request signal 60 is output from the communication control unit 10 or the code data memory unit 11 to the host MPU 7, the host MPU 7 outputs the document recording request signal 60.
Is detected. When the detection is performed, the host MPU 7
Supplies a decoding mode setting command 61 to the decoding unit 2 via the control bus 17 and simultaneously supplies a recording mode setting command 67 to the recording unit 9 via the control bus 13.
The decoding unit 2 enters a state of waiting for the recording start request signal 62, and when the recording start request signal 62 is supplied from the recording unit 9 via the control bus 21, it is supplied via the data line 25. The decoding process of the encoded data is started. After the start of the decoding process, the decoding unit 2 continues the decoding process in the set decoding mode until the page end request signal 63 is input. Then, the transmission of the encoded data for one page of the original is completed, and a page end request signal 63 from the communication control unit 10 or the encoded data memory unit 11 is sent.
Is supplied to the host MPU 7 and further from the host MPU to the decoding unit 2 via the control bus 17, the decoding unit 2
Stops the decoding process. At this time, the decoding unit 2 outputs a decoding end signal 64 to the host MPU 7 and the recording unit 9 via the control bus 16, and enters an idle state. Thereafter, the operation returns to the initial state, and when there is still encoded data of the original to be recorded, the above operation is repeated in the above order.

As described above, regarding the decoding of the encoded data and the recording of the decoded data, the host MPU 7 supplies the original supplied from the communication control unit 10 or the encoded data memory unit 11 to the original. The application of the recording request signal 60 is monitored, and when the document recording request signal 60 is supplied, the decoding mode setting command 61 and the recording for the decoding unit 2 and the recording unit 9 for preparation for decoding are recorded. As long as the supply of the recording mode setting command 67 for the preparation of the data is performed, the encoded data is independently transmitted only between the decoding unit 2 and the recording unit 9 without the intervention of the host MPU 7. The decoding of the data and the recording of the decoded data are performed, and during this time, the real-time control of the host MPU 7 is not required. Also, when the decoding of the encoded data and the recording of the decoded data are completed, the host MP
U7 monitors the application of the decoding end signal 64 supplied for each page of the document from the communication control unit 10 or the code data memory unit 11 as before, and monitors the application of the decoding end signal 64. After the reception is detected, control of other information processing can be appropriately executed.

Next, a method of transmitting and receiving control signals between the encoding unit 1 and the reading unit 8 and between the line memory 4 and the encoding processing unit 3 will be described with reference to FIG.

In the figure, reference numeral 100 denotes a data bus interface.
Face (I / F), 101 is 3-line address control I
/ F and 102 are read control I / Fs and 103 is an encoding operation unit, which are connected in a chain to form an encoding processing unit 3
Is composed.

The read control I / F 102 has a function of detecting a page start signal and a page end signal among the control signals transmitted and received via the control bus 18, and the page control is performed by the function. Detect page start signal and page end signal,
The read start and read end timing of each page of the document is interposed with the reading unit 8 without any other control, and the data input / output incorporated in the read control I / F 102 is performed. A timing signal is controlled to read a document and encode the read data. Also,
3-line address control I / F 101 and data bus I / F
F100 controls the transfer of image data between the line memory unit 4 and the encoding processing unit 3 as described below.

In general, when encoding image data, the greater the number of black and white pixel change points per unit length in the image data, the more time is required for encoding the image data. It costs. Usually, when reading the image data, the image data is read at a constant speed. However, when the image data is read at a constant speed, the image data is read.
If no memory means is arranged between the reading unit 8 and the encoding unit 1, the reading data must be encoded in synchronization with the reading of the image data at a constant speed. On the other hand, when encoding image data at a constant speed, in order to prevent the generation of an unencoded image data signal when the encoding is delayed, usually, in consideration of its security. The input speed of image data input to the encoding unit 1 is suppressed.

By the way, even when the memory means is arranged between the reading unit 8 and the encoding unit 1, if the encoding speed of the image data is set to be relatively high, the image is still not obtained. Since there is a risk that encoding may be performed up to a line where data reading has not been completed, a function that prevents the line being encoded from overtaking the image data input line of the memory means. Need to be added.

In this case, in order to encode the image data at a high speed, the image data is stored in the RAM in units of pages of the original.
If the encoding is executed after the completion of the storage, it is not necessary to perform the setting in consideration of the safety with respect to the encoding time, and high speed can be expected. However, a huge bit map page memory is required. In addition, the memory management function becomes large, which is extremely uneconomical.

The present invention employs a configuration capable of coping with such a case. By incorporating the above functions in the encoding processing unit 4, the processing load of an external control element can be increased. Instead, it can be implemented with a simplified configuration.

That is, according to the present invention, a three-line address control I / F 101 having a function of preventing overtaking of a line for which image data has not been set is arranged in the encoding processing unit 4.
The line memory 4 for three lines is arranged in the encoding unit 2. The overtaking prevention function of the image data unset line includes, for example, a method of providing an image data setting completion flag for each line unit, setting of a line address in advance based on the paper size and reading density, and A method of controlling so as to always have the set address difference between the image data input line and the image data input line, or providing a counter so as to always generate a difference greater than a certain value between the image data input line and the encoding line. It can be sufficiently realized by using a general method such as a setting method as described above. In this case, the image data supplied from the reading unit 8 is supplied to the line memory 4 under the control of the 3-line address control I / F 101.
And stored temporarily, and then the data bus I
The data is sent to the coding operation unit 103 via / F100, where the coding is executed, and then output as coded data.

As described above, if the above arrangement is adopted, only a new memory management function for three lines is added to the encoding processing unit 4, and no additional large memory management function is required. Thus, the hardware can be sufficiently simplified.

Here, the reason why the speed of data processing can be improved only by the line memory 4 having a capacity of three lines will be described. In MR and MMR encoding, the line immediately before the line to be encoded is used. Since two-dimensional encoding is performed with reference to a reference line, two lines of line memory are required. However, if a line memory management function having a capacity of three lines is provided, the encoding process is being executed. And the remaining one
Since the lines can be used for inputting image data in a pipeline manner, the speed of the data processing can be increased. Normally, a document used in a facsimile or an office has a maximum size of about A3.
Even if a high-resolution reading of 00 dpi is performed, a control of at most about 2 kbytes is sufficient, and it is uneconomical to use a processor for such control.

As described above, according to the present invention, the line memory 4 for three lines and the three-line address control I / F 1
By simply adding 01 or the like, economical pipeline processing can be performed and data processing can be speeded up. Therefore, the load on each control bus is reduced, a document reading speed of 10 Mb / s can be achieved, and the line density in the sub-scanning direction used in the G3 facsimile is 7.7 lines / m.
Even in the case of m, an A4-size original is read in about one second, and the read data can be encoded. By the way, this speed is more than 10 times that of normal G3 facsimile communication.
If communication is performed after storage in a memory or the like, it is possible to reduce the waiting time for reading a document by a sender with high cost performance.

Next, with reference to FIG. 8, a method of transmitting and receiving control signals between the decoding unit 2 and the recording unit 9 and between the line memory 6 and the decoding processing unit 5 will be described.

In the figure, reference numeral 110 denotes a data bus interface.
Face (I / F), 111 is 3-line address control I
/ F, 112 is a recording control I / F, 113 is a decoding operation unit, and these are combined in a chain to form a decoding processing unit 5.
Is composed.

The recording control I / F 112 has a function of detecting a recording page start signal among the control signals transmitted and received via the control bus 21 and a function of outputting a recording page end signal. With this function, the recording page start signal is detected and the recording page end signal is output, and the recording start and end of recording for each page unit of the document are performed without any other control. The timing is taken between the recording unit 9 and
By controlling the data input / output timing signal built in the recording control I / F 112, decoding of the encoded data and recording of the decoded data are executed. Also, a 3-line address control I / F 111 and a data bus I / F 1
Numeral 10 controls the transfer of image data described below between the line memory unit 6 and the decoding processing unit 5.

Here, as in the case of encoding, when decoding encoded data, the larger the number of black and white pixel change points per unit length in the encoded data, the larger the number of change points. The rate at which encoded data is decoded per unit time is reduced. In general, when the decoded image data is recorded, the image data is recorded at a constant speed. However, when the image data is recorded at a constant speed, the image data is recorded. If no memory means is arranged between the recording unit 9 and the decoding unit 2, the recording of the image data is performed at a constant speed synchronized with the decoding speed of the encoded data. I have to. On the other hand, when the image data is recorded at a constant speed, in order to prevent the undecoded data from being recorded when the decoding is delayed, the image data is usually considered in consideration of its security. Data recording speed.

Further, even when the memory means is arranged between the decoding unit 2 and the recording unit 9, if the decoding speed of the encoded data is set to be relatively high, it is still not possible. Since there is a risk of rewriting the restored image data on a line where the image data has not been output to the recording unit 9, that is, so-called overwriting, decoding is performed. There is a need to add a function that prevents the line being overtaken from the recording line of the image data of the memory means.

Even in this case, in order to decode the encoded data at a high speed, the decoded image data is stored in a memory such as a RAM for each page, and after the storage is completed, By executing the recording, it is not necessary to perform the setting in consideration of the security for the decoding time, and high speed can be expected. However, in this case, a huge bitmap page memory is required, and the memory management function is required. And become extremely uneconomical.

The present invention employs a configuration capable of coping with such a case. By incorporating the above functions in the decoding processing unit 5, it is possible to increase the processing load on an external control element. Instead, it can be implemented with a simplified configuration.

That is, according to the present invention, the three-line address control I / F 111 having the overtaking prevention function for preventing the recording of the decoded data from overtaking the decoding line in the decoding processing unit 5. , And a line memory 6 for three lines is arranged in the decoding unit 2. The overtaking prevention function can be sufficiently realized by using the same general method as the above-mentioned overtaking prevention function used in encoding. Also in this case, the encoded data is decoded by the decoding operation unit 113, and the decoded image data is transmitted to the 3-line address control I / F 111.
Is input to the line memory unit 6 via the data bus I / F 110 and temporarily stored, then read out and supplied to the recording unit 9 where it is recorded.

As described above, if the above arrangement is adopted, only a new memory management function for three lines is added to the decoding processing unit 5, and no additional large memory management function is required. Thus, the hardware can be sufficiently simplified.

Here, the reason why the speed of the data processing can be improved only by the line memory unit 6 having the capacity of three lines will be described. The MR and MMR decoding is performed immediately before the decoded line. Is used as a reference line to perform two-dimensional decoding, a line memory for two lines is required. However, if a line memory management function having a capacity for three lines is provided, the decoding During execution, the remaining one line can be used for outputting decoded data to be recorded in a pipeline manner, so that the data processing can be speeded up. Also in this case, a document used in a facsimile or an office is usually up to about A3 size and 400 dpi.
Even if such high-definition reading is performed, since control of at most about 2 kbytes only needs to be performed, it is uneconomical to use a processor for such control, as in the case described above.

As described above, the present invention is applicable to the decoding of encoded data and the recording of the decoded data.
By simply adding the line memory unit 6 for three lines and the three-line address control I / F 111, economical pipeline processing can be performed and data processing can be speeded up. . For this reason, the load on each control bus is reduced, a speed of 10 Mb / s can be achieved as a decoding speed of coded data, and a linear density of 7.7 lines / mm in the sub-scanning direction used in G3 facsimile. In this case, the encoded data of an A4 size document can be decoded in about one second, and the decoded data can be recorded. By the way, this speed is
It is 10 times or more that of normal G3 facsimile communication. If the received coded data is compressed once and stored in a memory or the like and output collectively after completion of the communication, The recording waiting time can be shortened, and the recording service which is considered comfortable for the operator can be realized with high cost performance.

The above description has been made on the assumption that the encoding and the decoding can operate independently. In this case, the reading of the original and the decoding of the decoded data are performed. A multi-operation enabling simultaneous operation with recording can be realized, which greatly contributes to improvement of service.
When this multi-operation is executed, the use of time sharing or the like requires complicated control and may cause a delay in the execution time, but has a very large effect that the hard cost can be reduced. Things.

On the other hand, when the multi-operation is not performed, the configurations of the encoding unit 1 and the decoding unit 2 are simplified, for example, the line memories 4 and 6 are shared, and the data bus I / F 100, 110 can be changed to a bidirectional bus I / F. Further, a 3-line address control I / F 101, 111, a read control I / F 10
2 and the data input / output timing signal of the recording control I / F 112 can be shared, so that a more simplified configuration can be obtained.

The above description has been made on the case where the encoding / decoding system according to the present invention is applied to a facsimile apparatus. However, the applicable model of the encoding / decoding system according to the present invention is not limited to a facsimile apparatus. It is applicable to other models.

In the above description, the encoding unit 1, the decoding unit 2, the host MPU 7, the reading unit 8, the recording unit 9, the communication control unit 10, the code data memory unit 11, and the like are individually configured. However, the present invention is not limited to such an individual configuration, and if the configuration includes the function of each configuration, the configuration is appropriately combined with the configuration. be able to.

In particular, when the encoding unit 1 and the decoding unit 2 are configured, the encoding unit 1 and the decoding unit 2 are combined into one large-scale integrated circuit (LSI) as in the conventional case. Incorporation, the connection between the LSI and the external circuit is made by pins derived from the LSI, or the encoding unit 1 and the decoding unit 2 are incorporated into one board, and the connection between the board and the external circuit is established. The connection may be made by a pin led out to the board. However, when such an LSI or board configuration is adopted, in addition to the conventionally derived pins,
It is necessary to newly provide a pin for inputting and outputting a page end signal.

In addition, as a medium for reading an original performed by the reading unit 8 and / or recording data performed by the recording unit 9, the medium is not limited to paper. Instead, a medium such as a magnetic device or an optical file may be appropriately used.

Further, at least the decoding unit 2 and the recording unit 9
Can be integrated into an integrated device, and they can be configured in the form of a printer.

[0076]

As described above, in the encoding / decoding system according to the present invention, the command required by the host control unit before the start of the encoding / decoding processing is determined for each page unit of the document. Only after supplying the data to the device, and then the encoding unit or the decoding unit is operated in a state where the host control unit is not interposed.
That is, without using a large-capacity external memory ,
Reading and reading data of the document - the encoding of data, as well as code cade - data decoding and decoded de - since the data recorded in to run respectively, manage the entire period the host controller to control The load is greatly reduced as compared with the conventional method.

The encoding / decoding system according to the present invention does not require the real-time transmission and reception of control signals by the host control unit 7 during the encoding process or the decoding process. The processing itself is also faster than the conventional one, and has a remarkable effect that the input / output processing of the document can be performed at a speed higher than or equal to 10 times the input / output speed of the document in a normal G3 facsimile.

The encoding / decoding method according to the present invention is as follows.
Since the bitmap page memory, which has been conventionally required, is not used, the signal processing of the relevant portion is simplified, and the speed of other signal processing can be increased correspondingly. Further, by adopting the simplified signal processing, the load on the host control unit 7 is greatly reduced, so that the use of a processor having high processing performance or the use of a multiprocessor is improved despite the improved control function. No longer required, more advanced services
Screws can be realized at low cost.

As a result, there is an excellent effect that a service in which the waiting time of the operator is greatly reduced and a service in which the man-machine property is improved can be provided with high cost performance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a facsimile apparatus to which an encoding / decoding method according to the present invention is applied.

FIG. 2 is a flowchart illustrating a flow of a process executed by a host MPU.

FIG. 3 is an explanatory diagram showing the time history of processing among a system, a host control unit, and an encoding unit during encoding.

FIG. 4 is an explanatory diagram showing the time history of processing among a system, a host control unit, and a decoding unit at the time of decoding.

FIG. 5 is a hardware image diagram showing the time history of the processing of FIG. 3 by the flow of a control signal.

FIG. 6 is a hardware image diagram showing the time history of the processing in FIG. 4 by the flow of a control signal.

FIG. 7 is a system diagram showing a configuration of an encoding unit and a flow of a control signal.

FIG. 8 is a system diagram showing a configuration of a decoding unit and a flow of a control signal.

FIG. 9 is an explanatory diagram showing the amount of movement of an image in the sub-scanning direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Encoding part 2 Decoding part 3 Encoding processing part 4, 6 Line memory part 5 Decoding processing part 7 Host MPU (Host control part) 8 Reading part 9 Recording part 10 Communication control part 11 Code data memory part 12, 13 , 14,15,16,17,18,19,2
0, 21 control bus 22, 23, 24, 25, 26, 27, 28, 29 data line 40 encoding / decoding section 41 data input / output section 100, 110 data bus interface (I /
F) 101, 111 3 line address control I / F 102 read control I / F 103 encoding operation unit 112 recording control I / F 113 decoding operation unit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Kojima 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (56) References JP-A-2-58977 (JP, A) JP-A-56-85176 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/41 -1/419 H03M 7/30

Claims (5)

(57) [Claims] At least a reading for scanning and reading a document.
And isolation portion includes a coding and decoding unit for encoding the data read by the reading unit, and a host control unit that performs overall control to the information processing, the host controller from the reading unit
When a document reading request is received, the encoding / decoding unit is encoded.
Mode and the encoding / decoding unit
Supply command, after which the encoding and decoding unit,
In the absence intervention of the host controller, from the reading unit
Upon receiving the reading start request, the data encoding process is performed.
Further, the encoding / decoding unit includes the host control unit.
A page end request from the reading unit without any intervention
Upon receiving the data, the data encoding process is terminated and
Supplying an encoding end signal to the host control unit;
When the control unit receives the encoding end signal, the reading unit
An encoding / decoding method characterized in that an encoding end command is supplied to the encoding device. 2. At least a receiving unit or encoded data
Encoding decoding for decoding encoded data input from the storage unit
Recording the data decoded by the encoding unit and the encoding / decoding unit.
And a host control unit that performs overall control on information processing, wherein the host control unit includes the reception unit or
Upon receiving a document recording request from the encoded data storage unit , sets the encoding and decoding unit to a decoding recording mode and supplies a decoding command to the encoding and decoding unit ,
Thereafter, the encoding / decoding unit , without the intervention of the host control unit, the receiving unit or the encoded data recording.
When a recording start request is received from the storage unit, the data is decrypted.
Processing, and the encoding / decoding unit further performs
The receiving unit or the code
When a page end request is received from the encoded data storage unit,
The host controller terminates the data decryption process.
And supplies a decoding end signal to the host control unit.
Upon receiving the decryption completion signal, coding and decoding scheme and supplying the decoded ends co <br/> command to the recording unit. Wherein the coding and decoding unit includes a line memory unit having a storage capacity of three lines, according to claim 1, characterized in that temporarily stores the read data or
Coding and decoding scheme of the other two described. 4. The encoding / decoding section includes means for preventing an address of pixel data read from a line memory section from overtaking an address of pixel data input to the line memory section. Claim 3
Encoding / decoding method. 5. An encoding / decoding section according to claim 1, wherein said encoding / decoding section comprises one large-scale collection.
An integrated circuit (LSI) or a single board,
A page end request is received by the LSI or the single board.
Wherein each pin for transmitting and transmitting is provided.
3. The encoding / decoding method according to 1 or 2 .