JPH08125869A - Method and device for image communication - Google Patents

Abstract

PURPOSE: To prevent the occurrence of deterioration of character image of the transmitted information by the use of a simple structure in transmitting images by multivalue encoding (JPEG). CONSTITUTION: When a JPEG encoding part 107 encodes the multivalue encoding data at the transmission, a control part 112 generates the transmitted information as binary image data, and an MMR encoding part 113 makes it the binary encoding data. The control part 112 adds the prescribed marker codes or the like to the binary encoding data and composites them into the multivalue encoding data at the transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image communication apparatus and method, for example, an image communication apparatus and method for communicating binary image data and multi-valued image data.

[0002]

2. Description of the Related Art Conventionally, an image communication apparatus typified by a facsimile apparatus has greatly developed due to international standardization of communication related to ITU. From the early international standards called group 1 and group 2 to group 3 (hereinafter referred to as G3), facsimile has become widespread worldwide. In particular, the most popular G3 facsimile is the ITU-T (formerly CCITT) recommended T.70. 4, T.I. Three
0, T. 5, T.S. It is defined by the standard No. 6 and new functions will be standardized in the future.

Through such a process, the ITU-T is currently studying the recommendation T.S. JP defined by 81
This is the introduction of the EG coding system into the G3 standard. The JPEG encoding method has been developed to efficiently compress halftone image data in which one pixel is expressed in a multi-valued (for example, 8-bit) level. In a general baseline process, conventional lossless encoding is performed. Unlike the MMR coding system and the like, it is known to be a lossy coding system. This is J
This is because the PEG baseline process performs compression after the approximate processing of the original image data.

[0004]

However, when the above-mentioned JPEG encoding is introduced into the G3 facsimile, there are the following problems.

(1) Normally, in a G3 facsimile, transmission information is added to each page of an image on the transmitting side and the image is transmitted to a receiver. This transmission information includes character information such as the dial number of the transmission side terminal, the name data of the transmission side, the date and time information at the time of transmission, the page number of the transmission page, and may be transmitted as image data loaded on each page. Are known. In the conventional G3 facsimile, the lossless coding method MH, M
Since the R, MMR encoding method is used, the transmission information of each page can be read well without deterioration even when received. However, JP which is an additional inverse encoding method
It has been known that if the transmission information is electronically transmitted as a part of an image page by using the EG encoding method, complicated characters such as Chinese characters are significantly deteriorated and become unreadable. (2) Further, when introducing the JPEG encoding system to the G3 facsimile, the transmission information added to the page is transmitted as a character code to the receiving side without being transmitted as an image,
A method is also known in which the receiving side terminal develops and adds to an image when recording a page. However, in this method, if the receiving terminal does not have font data, the transmitting information cannot be recorded on the receiving side, and the MH,
The character font of the transmission information used in the MR and MMR encoding methods cannot be selected. Further, in the case of binary image communication, the transmission information is included in the image information and transmitted as in the conventional method.
Since the character code information is transmitted at the time of PEG coding, there is a problem that the control and the device configuration become complicated.

Further, a method of changing the quantization table so as not to drop the high frequency component of the image is conceivable, but this method greatly reduces the image compression rate. The problems as described above have been a hindrance to the introduction of the JPEG encoding system to particularly inexpensive G3 facsimiles.

The present invention has been made to solve the above problems, and in order to solve the above problems, J
It is an object of the present invention to provide an image communication device and a method that do not cause deterioration in a character image of transmission information with a simple configuration in image transmission by PEG encoding.

[0008]

In order to achieve the above-mentioned object, the present invention comprises the following constitutions.

That is, multi-valued encoding means for obtaining multi-valued encoded data by encoding image data as a multi-valued image, and transmission information relating to the image data is encoded as a binary image to obtain binary encoded data. It has a binary encoding means, a synthesizing means for synthesizing the multilevel encoded data and the binary encoded data, and a transmitting means for transmitting the multilevel encoded data synthesized by the synthesizing means. Is characterized by.

For example, the multilevel encoding means is characterized by performing JPEG encoding.

For example, the binary coding means is characterized by performing MMR coding.

For example, the synthesizing means synthesizes the multi-level coded data for one page by adding the binary coded data to the multi-level coded data.

For example, the synthesizing means measures the data length of the binary coded data and adds it to the multilevel coded data together with the binary coded data.

For example, the synthesizing means adds a predetermined marker code immediately before the binary coded data and synthesizes the multilevel coded data.

For example, the transmitting means performs ECM communication, and the synthesizing means allocates a predetermined frame of a plurality of image frames in one page to the binary coded data,
It is characterized in that other frames are combined by being assigned to the multi-level encoded data.

For example, the transmitting means is characterized by performing G3 communication.

For example, the transmitting means encodes the image data by the binary encoding means and transmits the image data when the destination does not have a function of decoding the multi-level encoded data. To do.

[0018]

With the above configuration, it is possible to add transmission information binary-coded by the MMR coding method, for example, to an arbitrary location in the image data multi-value coded by the JPEG coding method and transmit the image data. It is possible to obtain the unique action and effect.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings.

<First Embodiment> FIG. 1 shows a block configuration of an image communication apparatus to which the present embodiment is applied. This device is
It is a G3 facsimile apparatus that operates based on the G3 standard of the TU-T recommendation, has a JPEG encoding function, and is capable of transmitting multi-valued images.

Reference numeral 112 in FIG. 1 denotes a control unit of this apparatus, which is C
It is composed of a PU, a ROM, a RAM, a timing circuit, and the like. Reference numeral 105 denotes a scanner unit that reflects the original 103 on the original table glass 104 by the light source 102, optically reads it by the contact sensor 101, and outputs it to the raw image buffer 106 as multi-valued image data of 1 pixel 8 bits, and 107 is a raw image. By inputting multi-valued image data from the buffer 106, a known J
A JPEG encoding unit that performs a PEG baseline encoding process and sequentially transfers it to the control unit 112. A 113 inputs binary image data from the bus 111, performs known MMR encoding, and sequentially transfers it to the control unit 112. MMR encoder, 10
Reference numeral 8 denotes two communication buffer memories having a capacity of 64 KB, which is a known partial page memory for ECM (Error Correction Mode) communication. Further, 109 is a modem, and 110 is an NCU which is an interface for connecting to a line.

Next, the format of the JPEG encoded data output from the JPEG encoding unit 107 shown in FIG. 1 will be described with reference to FIG.

The JPEG encoded data has a three-step format of image / frame / scan for each page. The image on page 1 is an SOI (start of image) marker that indicates the start of data and an EOI that indicates the end.
(end of image) Represented by a frame sandwiched between markers. Although not shown in FIG. 2, an SOF (start of frame) indicating the start of a frame is displayed following the SOI marker.
e) There is a marker and header information called a frame header, and then SOS (start of sc) indicating the start of scanning.
an) A marker is placed, and subsequently, actual encoded image data is started. In Figure 2, EOB (end of bl
ock) indicates an encoding delimiter for one block of an image.

In the JPEG encoding method, as shown in FIG. 3, the original image to be encoded is divided into 8 × 8 pixel blocks (64 pixels), and the main scanning method is performed while encoding in block units. Will be done. At this time, 1
EOB is added every time encoding of a block is completed.
For example, an A4 size document of 200 ppi (pixel / inch) contains 216 blocks of data in the main scanning direction and 297 blocks of data in the sub scanning direction.

When one page of the image is completely encoded, a DNL (define number of lines) marker is added if necessary, and an EOI marker is added at the end to complete the creation of JPEG encoded data. Note that the Huffman coding method is used for coding the image block, but in order to identify the marker code (SOI, SOF, SOS, etc.), all the markers have "FFh" at the beginning, and It is considered that the code "FFh" does not appear in the encoded data of.

FIG. 4 shows a process of compressing and coding an image block in the JPEG baseline system. The pixel matrix of one block is first input to the DCT processing unit 41 and D
After CT (descrete cosign transfer) processing is performed, the quantization processing section 42 performs quantization processing, and the Huffman coding section 43 compresses by Huffman coding which is entropy coding, and outputs as JPEG coded data. To be done. Among these processes, by the quantization process which is a pre-process for image compression in the quantization processing unit 42,
It is generally known that high frequency components of an image are removed. When the high frequency components of the image are removed, the reproducibility of fine characters and sharp edge portions in the original image is markedly reduced, making it difficult to read the moji or the like.

Here, FIG. 5 shows an example in which by removing the high frequency component, the character part added as transmission information to the image page becomes difficult to read on the receiving side. The left image of Fig. 5 is the transmitted original image, which is transmitted after JPEG processing,
The right figure shows an example of decoding the received image. In both figures, the character information located at the top is the transmission information, which includes the dial number of the sender, the date and time information of the transmission, and the page number, so it is important information for the recipient of the image. Regardless, it turns out that it becomes difficult to read after JPEG.

Next, FIG. 6 shows the format of the coded data by the binary coding (MMR coding) processing of the transmission information by the apparatus of this embodiment, and will be described.

In FIG. 6, 61 is the transmission information shown in the upper part of FIG. The transmission information 61 is created as character code information by the control unit 112 before the image is transmitted, and is converted into binary image data by the font table of the ROM in the control unit 112. That is,
Binary imaging of transmission information is performed. This binary image is MM
It is encoded by the R encoding unit 113 and stored in the RAM in the control unit 112. Then, after adding dummy bits called pad bits to the encoded data string stored in the RAM so that the entire data string becomes a byte boundary, the byte length of the data string is counted. Then, the count value is added to the data string as the data length to generate the MMR data string shown in FIG.
The generated MMR data string is stored again in the RAM.

Next, the MMR data string shown in FIG.
A method of adding (inserting) to the JPEG data string shown in will be described with reference to FIGS. 7 and 8.

In this embodiment, the RA in the controller 112 is
A 4-byte marker is added to the MMR data string read from M and inserted into the JPEG data string. Hereinafter, this marker will be referred to as a transmission information marker, and will be referred to as “FF80
h ”is assigned. If the data string to be inserted into the JPEG data string is an MR data string by MR encoding, "F
"F81h", and "FF82h" is assigned if the MH data string is MH encoded.

FIG. 7 shows an example of inserting the MMR transmission information data sequence immediately before the start of an image block in the JPEG data sequence, and FIG. 8 shows the MMR transmission information data sequence in the middle of consecutive image blocks in the JPEG data sequence. Here is an example of inserting.

The purpose of adding the transmission information marker to the MMR data string is to make it possible to separate the MMR data string by extracting the transmission information marker from the JPEG image data. Here, as shown in FIG. 7, if it is decided in advance to arrange the MMR data sequence immediately after the SOS marker,
It is not always necessary to add the transmission information marker to the inserted MMR data string. However, when the transmission information marker is not added, the transmission information is recorded only at the top of the page unless the receiving side has a temporary storage memory for storing the received MMR data sequence. Therefore, if the MMR data string is inserted at an arbitrary position of the JPEG data string by the transmission information marker as shown in FIG.
It becomes possible for the receiving side to record the transmission information at an arbitrary position on the page.

Next, a case where JPEG image communication is performed according to the G3 procedure of the ITU-T recommendation will be described with reference to FIG. FIG. 9 shows a communication procedure in that case.

At the calling side, CFR (confirmation to
image data sent after receiving
UT Recommendation T.T. 4, T.I. Sent according to 30 ECM flow control. Communication buffers A and B shown in FIG. 1 are used as partial page memories for this ECM flow control.

FIG. 10 shows a flowchart of the transmission process in the control unit 112. Of course, the transmission process follows the communication procedure shown in FIG. 9 described above.

First, in step S1001, dialing is performed on the transmission destination to connect the line. Next, in step S1002, a CNG signal is transmitted, and in step S100
NSF (non-standard facilities) / DI
When the reception of the S (digital identification signal) signal is confirmed, the process proceeds to step S1004. Step S100
In No. 4, if the declaration of the JPEG function of the partner terminal cannot be detected from the received NSF / DIS signal, step S
In step 1005, normal binary image communication is executed.

On the other hand, when the declaration of the JPEG function of the partner terminal is detected in step S1004, step S10
In step 06, in order to command reception of multi-valued image data encoded by the JPEG encoding method, NSS (non-st
andard setup) / DCS (digital command signal) signal is transmitted. When the CFR is received as a positive response in step S1007, step S100
Proceed to 8. In step S1008, as the page transmission information, the information including the own telephone number, the date and time information, the page number, etc. shown in FIG. 5 is created, and the MMR encoding unit 113 generates the MMR data string shown in FIG. Then, in step S1009, the multi-valued image data read by the scanner unit 105 is sequentially encoded in the JPEG encoding unit 107, and in step S1010, step S10.
A transmission information marker is added to the MMR data string generated in 08 and inserted into the JPEG data string page by page.

In step S1011, the JPEG-encoded data string in which the MMR data string has been inserted by the above processing is sequentially transferred to the communication buffer 108 and sent out on the line via the modem 109 and NCU110.

As described above, according to the present embodiment, since the transmission information to be added to the page can be transmitted not by the JPEG code but by the binary image compression code, the characters of the transmission information recorded on the receiving side can be transmitted. The image is not deteriorated and legibility is improved.

Further, since the transmission information is transmitted as binary image data of the font on the transmitting side, it can be reproduced even if the receiving side does not have font data.

Further, since the transmission information can be inserted at an arbitrary position on the page, the transmission information can be output at an arbitrary position on the page even for a receiver having no special memory.

<Second Embodiment> The second embodiment according to the present invention will be described below. Since the configuration of the image communication apparatus in the second embodiment is similar to that of the first embodiment described above,
Description is omitted.

In the second embodiment, the transmission information is transmitted by using the image frame by the ECM without inserting the MMR transmission information into the JPEG encoded data string.

FIG. 11 shows an image format transmitted in the second embodiment. In FIG. 11, each frame is followed by a flag field (F), an address field (A), a control field (C), a facsimile control field (FCD), a frame number, and an information field. When the information field ends, a frame check sequence (FCS). ), 1 with flag field (F)
Let it be a frame.

As shown in FIG. 11, in the second embodiment, the MMR data string shown in FIG. 6 in the first embodiment is transferred to the first two frames (equivalent to 512 bytes) of the partial page, From the third frame (frame 2) to the 256th frame (frame 255), J
Transfer the PEG image data. As a result, one partial page of JPEG encoded data including MMR transmission information is formed.

On the receiving side, the top 2
Since it is known in advance that the frame portion is the MMR data string, even if the data shown in FIG. 11 is received, it is possible to reliably decode and record the transmission information.

Further, in each frame data shown in FIG. 11, it is possible to set a plurality of types of FCD information for the MMR data sequence and the JPEG data sequence. By doing so, the receiving side can identify which frame is the MMR data string, so that the transmitting side can insert the MMR transmission information at an arbitrary position on the page.

The operation of the second embodiment described above is as follows.
It is controlled by the control unit 112 as in the first embodiment, that is, the operation program in the control unit 112 is different.

The flow chart of the transmission process of the control unit 112 in the second embodiment will be described below with reference to FIG.

First, in step S1201, dialing is performed on the transmission destination to connect the line. Next, in step S1202, a CNG signal is transmitted, and in step S120
When the reception of the NSF / DIS signal is confirmed in step 3, the process proceeds to step S1204. In step S1204, the JPE of the partner terminal is determined from the received NSF / DIS signal.
If the declaration of the G function cannot be detected, the process advances to step S1205 to execute normal binary image communication.

On the other hand, when the declaration of the JPEG function of the partner terminal is detected in step S1204, step S12
Proceed to 06, in order to command reception of multi-valued image data encoded by the JPEG encoding method, NSS / DCS
Send a signal. When the CFR is received as the affirmative response in step S1207, step S12
Go to 08. In step S1208, the transmission information as shown in FIG. 5 is transmitted as the page transmission information by the MMR encoding unit 1.
At 13, the head 2 frames (frame 0 and frame 1) of the ECM in the communication buffer 108 are created using the MMR data sequence shown in FIG. And step S1209
In, the multi-valued image data read by the scanner unit 105 is sequentially encoded by the JPEG encoding unit 107, and a JPEG data string is created after the third frame (frame 2) in step S1210.

Then, in step S1211, the ECM frames created by the above processing are sequentially transmitted to the line via the modem 109 and NCU110.

As described above, according to the second embodiment,
By dividing the ECM image frame in the communication buffer into the transmission information and the JPEG image data and transmitting them as one partial page, it is possible to obtain the same effect as that of the first embodiment described above.

In the first and second embodiments described above, the MM is used as a method for binary-coding the transmission information.
Although the example using the R encoding method has been described, the present invention is not limited to this example, and any method suitable for encoding a binary image such as MR or MH can be used. Encoding may be performed using any method.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0057]

As described above, according to the present invention,
The transmission information to be added to the page is a multilevel encoding method (JPE
Since it can be transmitted as a code according to the binary coding method (MMR) instead of the code according to G), the multi-valued (JPEG) coding process can be received without any special change and without complicating the device configuration. The character image of the transmission information recorded on the side is not deteriorated and the legibility is improved.

Further, since the character information of the transmission information is formed by the font of the transmission side, it is not necessary to have font data on the reception side, and further, the transmission information can be inserted at an arbitrary position on the page. The transmission information can be printed at an arbitrary position on the page even for a receiver that does not have.

[0059]

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image communication apparatus to which an embodiment according to the present invention is applied.

FIG. 2 is a diagram showing a JPEG encoded data format in the present embodiment.

FIG. 3 is a diagram for explaining JPEG encoding in this embodiment.

FIG. 4 is a diagram for explaining JPEG encoding in this embodiment.

FIG. 5 is a diagram illustrating an example of image deterioration due to JPEG encoding.

FIG. 6 is a diagram showing an encoded data format of transmission information in the present embodiment.

FIG. 7 is a diagram showing an example of inserting transmission information into JPEG encoded data according to the present embodiment.

FIG. 8 is a diagram showing an example of inserting transmission information into JPEG encoded data in the present embodiment.

FIG. 9 is a diagram showing a communication procedure in the present embodiment.

FIG. 10 is a flowchart of a transmission process in this embodiment.

FIG. 11 is a diagram showing an ECM transmission format in a second embodiment according to the present invention.

FIG. 12 is a flowchart of a transmission process in the second embodiment.

[Explanation of symbols]

 105 Scanner Unit 106 Raw Image Buffer 107 JPEG Encoding Unit 108 Communication Buffer 109 Modem 110 NCU 111 Bus 112 Control Unit 113 MMR Encoding Unit

Claims (18)

[Claims] 1. A multi-valued encoding means for obtaining multi-valued encoded data by encoding image data as a multi-valued image, and transmission information relating to the image data is encoded as a binary image to obtain binary encoded data. It has a binary encoding means, a synthesizing means for synthesizing the multilevel encoded data and the binary encoded data, and a transmitting means for transmitting the multilevel encoded data synthesized by the synthesizing means. An image communication device characterized by. 2. The image communication apparatus according to claim 1, wherein the multi-level encoding means performs JPEG encoding. 3. The image communication apparatus according to claim 1, wherein the binary encoding means performs MMR encoding. 4. The synthesizing means synthesizes the multi-level coded data for one page by adding the binary coded data to the multi-level coded data. Image communication device. 5. The synthesizing means measures the data length of the binary coded data and adds it to the multilevel coded data together with the binary coded data.
An image communication device according to claim 1. 6. The image communication apparatus according to claim 5, wherein the synthesizing unit adds a predetermined marker code immediately before the binary coded data and synthesizes the multilevel coded data. 7. The transmitting means performs ECM communication, the synthesizing means allocates a predetermined frame of a plurality of image frames in one page to the binary coded data, and the other frames to the multilevel coded data. The image communication device according to claim 1, wherein the image communication device is synthesized by allocating to the. 8. The image communication apparatus according to claim 1, wherein the transmission means performs communication according to the G3 procedure. 9. The transmitting means encodes the image data by the binary encoding means and transmits the image data when the transmission destination does not have a function of decoding the multi-level encoded data. The image communication device according to claim 1. 10. A multi-valued encoding process for obtaining multi-valued encoded data by encoding image data as a multi-valued image, and transmitting information related to the image data as a binary image to obtain binary encoded data. A binary coding step; a synthesizing step of synthesizing the multilevel encoded data and the binary coded data; and a transmitting step of transmitting the multilevel encoded data synthesized by the synthesizing means. An image communication method characterized by. 11. The image communication method according to claim 10, wherein the multi-value encoding step is JPEG encoding. 12. The image communication method according to claim 10, wherein the binary encoding step is MMR encoding. 13. The synthesizing step synthesizes the multi-level coded data for one page by adding the binary coded data to the multi-level coded data. Image communication method. 14. The image according to claim 13, wherein in the combining step, the data length of the binary coded data is measured and added to the multilevel coded data together with the binary coded data. Communication method. 15. The image communication method according to claim 14, wherein in the synthesizing step, a predetermined marker code is added immediately before the binary coded data to synthesize the multilevel coded data. 16. The ECM communication is performed in the transmitting step, and a predetermined frame of a plurality of image frames in one page is assigned to the binary coded data in the combining step, and the other frames are assigned to the multilevel coded data. 11. The image communication method according to claim 10, wherein the image communication method is performed by allocating to each other. 17. The image communication method according to claim 10, wherein the transmitting step performs communication according to a G3 procedure. 18. The transmitting step is characterized in that the image data is encoded by the binary encoding step and transmitted when the transmission destination does not have a function of decoding the multi-level encoded data. The image communication method according to claim 10.