JPH05308531A - Facsimile equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide a facsimile apparatus capable of performing appropriate encoding by effectively utilizing the characteristics of various encoding methods. By performing encoding using a different encoding method that is predetermined according to the operation mode of the facsimile apparatus, a communication image such as a memory transmission image can be encoded by an MR encoding method that has little influence on errors. Accumulation,
Immediate images such as memory copy images are stored using the MMR coding method, which has a higher compression efficiency than the MR coding method. In addition, the remaining memory amount is detected, and when the remaining amount is small, the MMR encoding method with good compression efficiency is selected. further,
Allow the user to select the optimal coding scheme.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile machine having an image memory.

[0002]

2. Description of the Related Art Conventionally, in this type of facsimile apparatus, when image data is stored in an image memory for memory transmission or memory copying, the same encoding method is always used for encoding. For example, for both the memory transmission image and the memory copy image, the MR coding method (parameter K =
8) Encoding and storage are performed.

[0003]

However, in general, MMR is used.
The encoding method has a better data compression rate than the MR encoding method, but has a great influence on an error due to a bit defect of the image memory.

Therefore, the accumulation of only the MR coding system has little effect on errors due to bit defects and the like,
When the image memory has a small capacity from the beginning, or when the image memory is used due to a memory transmission reservation and the available image memory has a small remaining capacity, there is a drawback that the memory is easily overrun.

On the other hand, in the storage of only the MMR coding system,
Although the possibility of memory over is lower than that of the MR encoding method, it is less reliable as a method of accumulating memory transmission images, etc., due to the large influence of errors when bit defects etc. occur due to long-term use. There was a drawback.

For this reason, conventionally, when the image data is stored in the image memory, the same encoding method is always used for encoding. Therefore, there is a problem that the encoding becomes improper depending on the operation mode. ..

It is an object of the present invention to provide a facsimile apparatus capable of performing proper encoding by effectively utilizing the characteristics of each encoding method.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a communication image such as a memory transmission image is transmitted by performing encoding using a different encoding method determined in advance according to an operation mode of a facsimile apparatus. Accumulation is performed by the MR encoding method that has less influence on errors, and an immediate image such as a memory copy image is accumulated by the MMR encoding method having a higher compression efficiency than the MR encoding method.

Further, according to the present invention, when the image data is stored in the image memory, the MR coding system is selected by comparing the unused capacity of the image memory with the coding switching capacity, for example, if the unused capacity is larger. If the unused capacity is smaller, the MMR coding method is selected.

Furthermore, the present invention enables the user to select the optimum coding method by using the coding method set by the storage coding setting means.

[0011]

1 is a block diagram showing a first embodiment of a facsimile apparatus of the present invention.

The main controller 1 is composed of a microprocessor, a ROM for program memory, a RAM for work area, etc., and controls the operation of the entire apparatus.

The image memory 2 is composed of a D-RAM or the like, and is for accumulating the image data coded by the coding processing section 8a.

The control data storage memory 3 is composed of an S-RAM or the like, and is for storing the set values registered by the operator, the management data of the apparatus, and the like.

The communication control unit 4 is composed of a modem, an NCU (network control unit) and the like, and exchanges image information and the like with a partner communication unit through a line.

The operation unit 5 is composed of a keyboard or the like, and is used by the operator to make various inputs.

The display section 6 is composed of an LCD or the like and performs various displays.

The reading unit 7 is composed of a CCD image sensor, a document feeding mechanism, an image processing device, etc., and optically reads a document, converts it into electrical image data, and further corrects it to obtain a high-definition image. It outputs data.

The encoding processing unit 8a is for encoding (MH, MR, MMR, etc.) raw image data.

The decoding processing section 8b restores the encoded image data to raw image data.

The recording control unit 9 is composed of a thermal printer, a laser printer or the like, and outputs image information and the like on recording paper.

Here, as the encoding method performed by the encoding processing unit 8a, (A) CCITT Recommendation T. MH coding method described as a one-dimensional coding method in (4) CCITT Recommendation T.4. MR coding method described as a two-dimensional coding method in (C) CCITT Recommendation T.4. 4 as an extended two-dimensional encoding method, and CCITT recommendation T.264. The MMR encoding method described as the basic facsimile encoding method in 6 is cited.

For a detailed description of these encodings, see
Since it is described in the above CCITT recommendation, it will be briefly described.

First, in the MH encoding system, each scan line of image data is run-length, and the run-length data is converted into an MH code. This is a coding method in which this processing is performed over all scanning lines.

Next, the MR encoding method is a method of comparing a black-and-white change pixel with a corresponding reference pixel of a previous scanning line (reference line) and encoding the shift. Since this coding method always advances the coding while comparing it with the previous scanning line, the compression rate is better than that of the MH coding method. However, if there is an error line, the subsequent scanning line is affected by it. There is a drawback that it ends up. In order to compensate for this drawback, a parameter "K" is set. For example, when the parameter K = 4, the leading scanning line is MH encoded and the following three scanning lines are MR encoded. After that, by repeating this for every four lines, the part affected by the error is limited.

The MMR encoding method is an encoding method in which a white line is virtually assumed as a reference line for the first scanning line in a page and thereafter MR encoding is performed over all scanning lines. Therefore, with this method, the compression rate is better than with the MR encoding method, but if there is an error line, the scanning lines after that cannot be restored at all.

As described above, the compression ratio of data is improved in the order of MH, MR, and MMR, but on the other hand, if an error occurs, the influence on the subsequent line becomes large.

2 and 3 are schematic diagrams for explaining the method of managing the image memory in this embodiment.

The image management record and page management record shown in FIG. 2 and the block management table shown in FIG. 3 are management information necessary for accumulating image data in the image memory 2, and are the control data storage memory 3 It is stored in.

One image management record is generated each time image data is stored in the image memory 2 by transmission, copying, etc., and is held until the image data is deleted. File attributes (send, receive, etc.) in the image management record
And a pointer to the page management record of the first page.

The page management record is generated each time one page is stored, and manages one page of image data in the image memory 2. The page management record includes a mode (encoding method, main scanning width, sub-scanning direction density, etc.), page number, a pointer to the page management record of the next page, first memory block information, and the like. An end code (NULL) is set in the pointer portion of the page management record of the last page. Here, the memory block is one in which the image memory 2 is divided into blocks of a certain fixed size.

The block management table has an area of one-to-one with respect to the memory block and manages the image data in the image memory 2. A pointer to the area of the block in which the next image data is stored is stored in each area, and the end code (NULL) is set in the area of the last block of the page. Moreover, an unused memory block in the image memory 2 can be obtained by searching a free area from the beginning of the block management table.

When reading the image data in the image memory 2, first, a pointer to the page management record of the first page is obtained from the image management record. Then, the first memory block information is obtained from the page management record, and the pointer is sequentially followed until the end code (NULL) is found from the area of the block in the block management table. Next, the pointer to the next page management record is obtained from the previous page management record, and the same processing is performed until the pointer part of the page management record ends (NULL).

FIG. 4 is a flow chart for explaining the processing at the time of memory transmission in this embodiment. The processing at the time of this memory transmission is executed under the following five controls. (A1) First, the reading control unit 7 reads a document and outputs raw image data. (A2, A3) Next, the raw image data is encoded by the encoding processing unit 8
It is encoded by the MR encoding method by a and stored in the image memory 2 by the management method described above. (A4) Then, when the memory storage of at least one page is completed, the MR-coded image data stored in the image memory 2 is sequentially restored to the raw image data by the decoding processing unit 8b. Further, the restored image data is encoded by the encoding processing unit 8a by an encoding method (MH, MR, MMR, etc.) adapted to the receiver of the other party. (A5) The last encoded image data is sent to the line by the communication control unit 4.

The encoding processing units 8a used in the above (A2) and (A4) may be different from each other.

FIG. 5 is a flow chart for explaining the processing at the time of memory copy in this embodiment. The processing at the time of this memory copy is executed under the following four controls. (B1) First, the reading control unit 7 reads a document and outputs raw image data. (B2, B3) Next, the raw image data is encoded by the encoding processing unit 8a.
Is encoded by the MMR encoding method and stored in the image memory 2 by the above management method. (B4) Then, when the memory storage of at least one page is completed, the MMR encoded image data stored in the image memory 2 is sequentially restored to the raw image data by the decoding processing unit 8b. (B5) The recording control unit 9 records the finally restored image data on the recording paper.

As described above, in the first embodiment, the memory transmission image is the MR coding system and the memory copy image is the MMR coding system at the time of accumulating in the image memory 2 of the above (A2) and (B2). By performing encoding using different encoding methods, an MR image encoding method that is less affected by an error is used for the memory transmission image to maintain reliability, and an immediate image such as a memory copy image is obtained. In order to improve the efficiency of memory usage, the MMR coding method with a high compression rate is used.

In the first embodiment, the memory transmission image / memory copy image is MR coding system / M, respectively.
MR coding system is used, but MH coding system / MR
Coding system, MH coding system / MMR coding system, etc.
Other combinations may be used depending on the actual conditions of processing.

Further, both of them use the MR coding method,
Only the parameters may be switched, such as the parameter K = 4 for the memory transmission image and the parameter K = 8 for the memory copy image. That is, such a change of only the parameters is included in the different encoding methods of the present invention.

Further, in the first embodiment, the encoding method predetermined according to each operation (transmission, copy, etc.) is
Although each is fixed, the operator may be allowed to set the encoding method in advance by the operation unit 5.

Next, a second embodiment of the present invention will be described. In the second embodiment, when the image data is stored in the image memory 2, a coding method is used to determine whether the memory is likely to run out by comparing the unused capacity of the image memory 2 with a predetermined coding switching capacity. This is selected and encoded.

FIG. 6 is a flow chart showing the memory accumulation operation of image data in the second embodiment. The configuration and control other than the operation of selecting the encoding system are the same as those in the first embodiment (FIGS. 1 to 5).

In FIG. 6, when the storage in the image memory 2 is started, first, an unused image management record is acquired,
And each setting is performed (S1), then an unused page management record is acquired, and each setting is performed (S2). In addition,
If these management records cannot be obtained, an error will occur due to memory overflow.

When the management record is acquired and set as described above, the unused capacity of the image memory 2 is calculated (S3). This unused capacity can be easily calculated, for example, by searching a free area in the block management table.

Next, the coding switching capacity set in this facsimile is compared with the unused capacity calculated in S3 (S4). If the unused capacity is larger, the MR coding system is selected. If the unused capacity is smaller (S5), the MMR encoding method is selected (S6),
Set in the page management record acquired earlier. Note that the encoding switching capacity is based on the large amount of unused capacity and
The reference value indicates a reference value for determining which encoding method should be selected, and is stored in the control data storage memory 3 in advance.

Next, an unused block management table is acquired and set (S7), encoded by the encoding processing unit 8a using the previously selected encoding method, and accumulated in the corresponding memory block ( S8). In this way, the accumulation is repeated until the original for one page is completed (S10), but if the corresponding memory block becomes full in the middle, the process returns to S7 (S9).

If an unused block management table cannot be acquired in S7, an error end (memory overflow) occurs.

Further, in S10, when the original for one page is completed, it is judged whether or not there is a next page (S1).
1) If there is a next page, the process returns to S2, and if there is no next page, the accumulation in the image memory 2 ends.

In this way, it is judged whether or not the unused area of the image memory 2 is large with reference to a constant coding switching capacity. For example, the storage is performed by MMR encoding with high compression efficiency.

Although the MR coding system and the MMR coding system are used in the second embodiment, the processing such as the MH coding system and the MR coding system or the MH coding system and the MMR coding system is performed. Other combinations may be used depending on the actual situation.

Further, both of them use the MR coding method,
When the unused capacity is large, the parameter K = 4, and when the unused capacity is small, the parameter K = 8.
You may make it switch only a parameter. That is, such a change of only the parameters is included in the different encoding methods of the present invention.

In the second embodiment, the encoding switching capacity is fixed by the facsimile machine, but it may be set by the operator using the operation unit 5.

In the second embodiment, the unused capacity and the coding switching capacity are compared every time one page is stored, but the comparison is made only at the beginning of one communication (or one copy), and the page is compared. The encoding method may not be changed even when the value of the symbol changes. This can be achieved by performing the operations of S3 to S6 only in the first page in FIG.

Next, a third embodiment of the present invention will be described. In the third embodiment, the user can select the optimum coding method by using the coding method set by the storage coding setting means.

FIG. 7 is a flow chart showing the memory accumulation operation of image data in the third embodiment. The configuration and control other than the operation of selecting the encoding system are the same as those in the first embodiment (FIGS. 1 to 5).

In FIG. 6, when the storage in the image memory 2 is started, first, an unused image management record is acquired,
And each setting is performed (S21), then an unused page management record is acquired, and each setting is performed (S22). If these management records cannot be acquired, the process ends in error due to memory overflow.

When the management record is acquired and set as described above, the coding method selected by the storage coding setting means is set in the page management record acquired in S22 (S23). Here, the storage coding setting means is
For example, each time the key on the operation unit 5 is pressed, the encoding is switched, and the LED corresponding to each encoding on the display unit 6 is turned on to notify the operator of the currently selected encoding.

Next, an unused block management table is acquired and set (S24), encoded by the encoding processing unit 8a using the previously set encoding method, and stored in the corresponding memory block ( S25). In this way, the accumulation is repeated until the original for one page is completed (S2
7) If the memory block is full during the process, the process returns to S24 (S26).

If an unused block management table cannot be acquired in S24, an error end (memory overflow) occurs.

In S27, when the original for one page is completed, it is determined whether there is a next page (S2
8) If there is a next page, the process returns to S22, and if there is no next page, the storage in the image memory 2 ends.

In this way, the image can be stored in the image memory 2 by being encoded by the encoding method selected by the operator.

In the third embodiment, the storage coding setting means is selected by turning on the LED, but it may be selected by the LCD display on the display section 6.

In the third embodiment, the coding system to be selected is not specifically described, but the above-mentioned MH, MR, MMR coding systems and other coding systems are selected. Alternatively, the parameter K of the MR coding method may be selected. That is, such a change of only the parameters is included in the different encoding methods of the present invention.

In the third embodiment, the coding method is changed every time one page is stored. However, the coding method is selected only at the beginning of one communication (or one copy), and the coding is performed even if the page is changed. The method may not be changed. this is,
In FIG. 7, the operation of S23 may be performed only on the first page.

In each of the above embodiments, the image memory 2
Although the memory transmission image and the memory copy image are used as the image data to be stored in, the same can be applied to the memory reception image.

Also, when outputting various reports such as a communication management report, the same applies to a report image in which one page is entirely encoded and stored in the image memory 2 and then printed while being decoded. can do.

[0067]

As described above, according to the present invention,
For example, image data such as a memory transmission image is stored by a coding method that has little influence on errors, and immediate images such as a memory copy image are stored by a coding method with higher compression efficiency. By performing different encoding depending on the operation mode, it is possible to improve the usage efficiency of the image memory while maintaining the reliability of the communication image.

Further, according to the present invention, when the image data is stored in the image memory, different encoding is performed according to the result of comparison between the unused capacity of the image memory and the encoding switching capacity, so that the memory overflow occurs. The optimum encoding method can be selected according to the risk of.

Further, according to the present invention, the user can select the optimum coding method by the storage coding setting means.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a method of managing an image memory in the above embodiment.

FIG. 3 is a schematic diagram illustrating a method of managing an image memory in the above embodiment.

FIG. 4 is a flowchart illustrating a process at the time of memory transmission in the above embodiment.

FIG. 5 is a flowchart illustrating a process at the time of memory copy in the above embodiment.

FIG. 6 is a flowchart showing the operation of the second embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main control part, 2 ... Image memory, 3 ... Control data storage memory, 4 ... Communication control part, 5 ... Operation part, 6 ... Display part, 7 ... Reading part, 8a ... Encoding process part, 8b ... Decoding Processing unit, 9 ... Recording control unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Otani 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masao Kiguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (4)

[Claims] 1. A facsimile apparatus having an encoding processing unit for encoding image data and an image memory for accumulating the encoded data, wherein the encoding processing unit has a plurality of encoding systems, In encoding, a facsimile apparatus is characterized in that encoding is performed by using different encoding methods which are predetermined according to an operation mode of the facsimile apparatus. 2. A facsimile apparatus having an encoding processing unit for encoding image data and an image memory for accumulating the encoded data, wherein the encoding processing unit has a plurality of encoding systems and A calculation unit for calculating the unused capacity of the image memory and a comparison unit for comparing the unused capacity of the image memory with the encoding switching capacity are provided, and different encoding methods are used based on the comparison result by the comparison unit. A facsimile machine characterized by performing encoding by means of. 3. A facsimile apparatus according to claim 2, further comprising means for setting the encoding switching capacity. 4. A facsimile apparatus having an encoding processing unit for encoding image data and an image memory for accumulating the encoded data, comprising storage encoding setting means, and a code set by this setting means. A facsimile apparatus characterized in that image data is encoded by using an encoding method and stored in an image memory.