JPH0923326A - Communication method for facsimile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit picture data i0 accordance With the idle capacity of a reception memory. SOLUTION: Before transmission of picture data, the data volume is preliminarily recognized on the transmission side. The idle capacity of the reception memory is included in a capability declare statement on the reception side. The reception side compares the idle capacity of the reception memory with the data volume of picture data to be transmitted to discriminate whether this data can be transmitted as it is or not. If it can be transmitted, data is normally transmitted; but if it cannot be transmitted, picture data is compressed again at a high compression rate. If it cannot be transmitted regardless of this compression, transmission is stopped, and a call is originated again after a while.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile communication method for performing transmission using this receiving memory when the receiving side facsimile has a receiving memory for storing received image data. Regarding

[0002]

2. Description of the Related Art In the case of transmitting image data using a facsimile, there is a facsimile on the receiving side provided with a receiving memory in order to shorten the transmission / reception time and to cover printing paper run-out on the receiving side. This receiving memory has a function of accumulating a certain amount of received image data, and then reading the content and printing it. In such devices, as long as the receiving memory capacity allows,
The image data can be normally received and processed regardless of the printing speed or the presence or absence of printing paper on the receiving side.

[0003]

The conventional facsimile communication method as described above has the following problems to be solved. When the receiving memory as described above is provided in the receiving side facsimile, the image data received in the receiving memory has not been printed yet,
Alternatively, the reception memory may become full by receiving a large amount of image data at one time. In such a case, reception is interrupted on the way and facsimile communication is interrupted. At this time, the same image data must be transmitted from the beginning again from the transmitting side. In particular, in the case of the gradation mode that faithfully reproduces the light and shade of photographs, a large amount of image data is transmitted. A sufficient free space is required to receive this and store it in the receiving memory. In this case,
If the receiving memory has a large capacity, the cost of the device increases. However, if the transmission is frequently interrupted, the convenience of the user is impaired by requiring the user to carry out retransmission and the like.

[0004]

The present invention adopts the following constitution in order to solve the above problems. According to the method of the present invention, when transmitting image data by facsimile, the transmitting side prepares the image data to be transmitted in advance, and inquires the free space of the receiving memory on the receiving side after the line connection and before starting the transmission. If the amount of image data to be transmitted exceeds the free space of the receiving memory, the transmission of the image data is stopped and the line is disconnected before the transmission is started. It should be noted that after the transmission is stopped and the line is disconnected, when the preset waiting time elapses, the receiving side may call again.

According to another method, after the line is connected and before the transmission is started, the free space of the receiving memory on the receiving side is inquired, and the amount of image data to be transmitted exceeds the free space of the receiving memory. In this case, the image data prepared in advance is recompressed, the amount of image data to be transmitted is reduced, and it is determined whether the amount of image data to be transmitted again exceeds the free space of the receiving memory. You can also

[0006]

On the transmitting side, the amount of data is recognized in advance before the image data is transmitted. Then, the free capacity of the receiving memory is included in the capability declaration statement on the receiving side. On the transmission side, the free space in the receiving memory is compared with the amount of image data to be sent,
Determine if it can be sent as is. If the transmission is possible, the normal transmission is performed, and if the transmission is not possible, the image data is recompressed at a higher compression rate. If the transmission is still not possible, stop the transmission and wait for a while to call again.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is an explanatory diagram showing an embodiment of a facsimile communication method according to the present invention. Prior to this description, first, the configuration of a facsimile terminal suitable for implementing the present invention will be described. FIG. 2 is a specific block diagram of the facsimile terminal. The device shown in the figure is controlled by a processor (CPU) 1, and the following devices are connected to the processor 1 via a bus line 2. That is, here, the read image processing unit 3 and the encoding / decoding device (ENC / DE
C) 4, read only memory (ROM), random access memory (RAM) 6, RTC 7, print image processing unit 8, mechanical interface 9, speaker (SP) 1
0, an operation unit (OPE) 11, a modem 12, and a communication control unit (NCU) 13 are connected.

The read image processing section 3 is a section for processing an image for transmission read by the scanner 15 to obtain image data. The print image processing unit 8 is a unit that performs control for sending the contents to the printer 16 for printing based on the received image data. The communication control unit 13 is a unit that controls a facsimile transmission / reception protocol through the line 19. These block configurations are the same as those of conventional facsimile machines. Here, in order to carry out the method of the present invention, the following functional blocks are included in the processor 1 and the ROM 5 storing the operation program thereof.

FIG. 3 is a functional block diagram for implementing the present invention. First, on the transmitting side, the read image processing unit 3 that receives the output of the scanner 15 is provided with, for example, an A / D converter (A / D) 21 and an encoding / decoding device 4. The encoding / decoding device 4 is a part that compresses and encodes the read image data in a fixed procedure. Although there are several well-known compression processes used in facsimile machines, a function that can be used to select and compress any of these types when the method of the present invention is carried out. Shall have.

The transmission image data 23 is temporarily stored in the RAM 6. This is data after compression processing by any method. Further, in order to detect the amount of the transmitted image data 23, an image data amount detection unit 24 is provided.
Further, an image data amount storage unit 25 is provided to store the detection result. On the other hand, the receiving side is provided with a free space detecting section 28 for checking the free space of the receiving memory 29. The receiving memory 29 stores image data received in the past. Therefore, the free capacity of the receiving memory 29 itself changes from moment to moment depending on the operating state of the facsimile on the receiving side. This is the free space detector 28
Detects and sends the result to the sender by the procedure described later. The data corresponding to the free space is stored in the free space storage unit 26 on the transmitting side. Then, the comparison unit 27 compares the image data amount stored in the image data amount storage unit 25 with the free space stored in the free space storage unit 26, determines which is larger, and outputs the result. Has become. According to the result, the procedure described later is executed.

The present invention is realized by a device having a function of reading a document on the transmitting side in advance, accumulating it in a storage device, and transmitting it. Here, the reading operation of the document by the apparatus of FIG. 2 will be described. First, a document is placed on the scanner 15 and the operation unit OPE11 is operated to set the reading mode. At this time, if you specify the telephone number of the receiving side and press the transmission start button (not shown),
The reading of the document by the scanner 15 is started. The document is read line by line and converted into image data by the read image processing unit 3. In this case, there is either a binary mode in which each pixel is converted into binary data of white or black, or a gradation mode in which each pixel is expressed in multiple gradations including its shade.

The image data compression mode is determined by the capability of the receiving side. If the capability of the receiving side is known in advance, adjust to the highest level of that capability. If you are unsure, usually
Compress to the lowest known MH code adopted. In addition to the well-known MR,
Method, MMR method, etc. exist and each compresses data at a higher compression rate. This processing is performed by the encoding / decoding device 4. And the result is RAM
6 is stored. In this way, the transmission image data stored in the RAM 6 has its data amount detected by the image data amount detection unit 24 in FIG. 3, and the result is the image data amount storage unit 2
Stored in 5. Note that this processing is executed by the processor 1 in FIG. 2 according to the program stored in the ROM 5. The result is stored in an area provided in a part of the RAM 6.

The line connection and transmission processing executed thereafter will be described with reference to FIG. In step S1 of FIG.
The transmission image data described above is read and compressed. The procedure by the transmitting side facsimile terminal F1 shown on the left side and the procedure by the receiving side facsimile terminal F2 shown on the right side are alternately repeated to transmit the image data. In step S2, the communication control unit 13 shown in FIG. 2 makes a call operation to the line. Next, a well-known predetermined protocol for facsimile transmission / reception in steps S2 to S8 is executed. A CNG signal indicating that the calling station is a non-voice terminal is transmitted from the transmitting facsimile terminal F1 (step S2).

The receiving facsimile terminal F2 outputs a CED tone indicating that the called station is a non-voice terminal (step S3). Further, the reception side facsimile terminal F2 thereafter transmits NSF, CSI, DIS signals and the like in order to convey the capability of the reception side device to the transmission side (step S4). At this time, according to the present invention, the free space of the receiving memory is notified from the receiving side at the same time. This is due to the processing of the free space detection unit 28 in FIG. On the sending side, according to such notification from the receiving side,
A signal for determining the transmission mode is output. In addition,
At this stage, the comparison unit 27 shown in FIG. 3 compares the transmission image data amount with the free space of the reception memory (step S
5).

Then, if the free space is sufficient, it is decided to transmit. When it is determined that the data can be transmitted by compressing the data, that is determined and the transmission is continued. That is, in step S6, training for checking the line status is performed,
When the preparation for reception is confirmed in step S7, training is performed in step S8, and subsequently, transmission image data is transmitted in step S9. This step S
In the ninth embodiment, the transmission image data, which has been compressed by any compression method up to now, is recompressed by another method having a higher compression rate so as to match the free space of the reception memory. As a method of this recompression, there is a method in which once compressed data is restored to the original uncompressed image data, and then compressed again using another compression method. By transmitting the image data in this manner, it is possible to prevent the reception side from stopping the reception due to the lack of free space.

The comparison between the amount of image data to be transmitted and the free space of the receiving memory and the operation according to the result will be described more specifically. 4 and 5 are flowcharts of the communication method operation of the invention. First, in step S1, as described above, the original is set and read, and when the completion is detected in step S2, the amount of image data to be transmitted is stored in step S3. When the call is started in step S4 and the capability declaration of the receiving side is received in step S5, the free capacity of the receiving memory is stored in step S6. Here, in step S7, it is determined whether or not the free space is satisfactory as compared with the transmission data amount.

In this case, the line density and the compression mode are checked to determine whether the line density and the compression mode of the read document are within the capability of the receiving side. If it is determined that the free space of the receiving memory is satisfactory, the transmission mode is set in step S8, and N is set in step S9.
SS and DCS are transmitted, and transmission of image data is started in step S10 as usual. On the other hand, when it is determined that the free space of the receiving memory is insufficient, the process proceeds to step S11. Then, if the image data prepared up to now is recompressed by another method, it is predicted whether or not the image data will be sufficient for the free space of the receiving memory. In this case, the amount of image data according to the compression mode is arithmetically processed by the empirical value to roughly estimate the amount, and the amount of image data is compared with the free space.

In this case, the prepared image data may be uncompressed or may be stored in the state of the lowest compression rate. In some cases, it is prepared by being compressed at a relatively high compression rate. In each case, the image data is once restored to a non-compressed state, the data amount when compressed by another compression method is calculated, and the determination in step S11 is performed. If it is determined that the image data can be compressed, the process proceeds to step S12, the image data compression method is changed, and the amount of compressed image data is stored in step S13. Specifically, for example, by converting the gradation mode to the binary mode and changing the line density and the like, the compression rate changes as shown below, and the free space of the memory required for storage changes.

<Example of Changing Line Density> Before compression After compression 15.4 (1 / mm) → 7.7 (1 / mm) 7.7 (1 / mm) → 3.85 (1 / mm) gradation (Photo) mode → Binary mode <Reference compressed data (required memory capacity for receiving in MMR mode)> Photo original Binary original gradation: 15.4 (1 / mm) 800 KByte → (200 KByte) binary; 15. 4 (1 / mm) 140 → 150 2 values; 7.7 (1 / mm) 100 → 125 2 values; 3.85 (1 / mm) 50 → 100

In step S14, the amount of data after compression is compared with the free space in the memory on the receiving side to determine whether or not the condition is satisfied. If the conditions are met, step S
8, the image data transmission process is performed. On the other hand, if it is determined in step S11 that even if it is compressed, it cannot be stored in the free space of the memory on the receiving side, the DCN signal is transmitted in step S15, and the line is disconnected in step S16. . That is, even if the image data is transmitted in such a state, it is clear that the transmission is interrupted, and if it is necessary to retransmit, it is better not to perform the transmission procedure from the beginning. Therefore, the line is disconnected here.

In this case, generally, the free space of the receiving memory increases after the printing output is completed. Therefore, if the call is called again after some time, there is a high possibility that the free space of the receiving memory has returned to a sufficient value at that time. Therefore, in this embodiment, in step S17, the preset waiting time is measured and the call is reissued.
In this case, the image data once read is retained as it is, for example. Then, after that, in step S5, the free space of the receiving side memory is inquired again. Here, the processes after step S6 are performed again. If you repeat these steps,
The image data can be transmitted when the call is retried several times.

The present invention is not limited to the above embodiments. The configuration of the facsimile, the transmission procedure of the facsimile, the selection of the compression mode and the contents thereof may be freely changed according to the configuration of the system. In addition, the recognition of the amount of image data to be transmitted, the free space of the reception memory on the receiving side, the hardware for inquiry and recognition, and the procedure thereof can be freely changed without departing from the above-mentioned gist. It is possible.

[0023]

According to the facsimile communication method of the present invention described above, the image data to be transmitted is prepared in advance, the amount of the image data is compared with the free space in the receiving memory on the receiving side, and the image data for receiving is received. If the available memory capacity is exceeded, image data transmission will be stopped before the start of transmission, so it is possible to prevent waste due to the transmission being interrupted after the start of transmission due to insufficient free space in the receiving memory on the receiving side and starting over. It Further, even if the transmission is once stopped, communication may be possible if the call is reissued after the set waiting time has elapsed. The automation reduces the burden on the operator. Further, by changing the compression method of the image data to be transmitted according to the free space of the receiving memory, it is possible to reduce the transmission data amount, which has been conventionally interrupted, but to reduce the transmission data amount.

In consideration of this lack of free space in the memory, compression of a high compression rate in advance deteriorates the transmitted image. However, the free space in the memory on the receiving side is recognized to determine the optimum compression rate. If adopted, higher quality image transmission becomes possible.

[Brief description of drawings]

FIG. 1 is an explanatory view of a facsimile communication method according to the present invention.

FIG. 2 is a block diagram of a facsimile terminal.

FIG. 3 is a functional block diagram for implementing the present invention.

FIG. 4 is an operation flowchart (No. 1) of the communication method of the present invention.

FIG. 5 is a flowchart (No. 2) of operation of the communication method of the present invention.

[Explanation of symbols]

 F1 sending side facsimile terminal F2 receiving side facsimile terminal S1 to S9 processing steps

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 1/21 H04N 1/21

Claims (3)

[Claims] 1. When transmitting image data by facsimile, the transmitting side prepares image data to be transmitted in advance, and inquires about the free space in the receiving memory on the receiving side after the line connection and before starting transmission, When the amount of image data to be transmitted exceeds the free space of the receiving memory, the transmission of the image data is stopped before the transmission is started, and the line is disconnected. Method. 2. The facsimile communication method according to claim 1, wherein when the preset waiting time elapses after the transmission is stopped and the line is disconnected, the receiving side is called again. 3. After the line connection and before the start of transmission, the free space of the receiving memory on the receiving side is inquired, and when the amount of image data to be transmitted exceeds the free space of the receiving memory, Re-compress the image data prepared in advance to reduce the amount of image data to be transmitted, and again to determine whether the amount of image data to be transmitted exceeds the free space of the receiving memory. 3. The facsimile communication method according to claim 1 or 2.