JPH0646757B2 - Image transmitter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image transmitting apparatus that compresses and encodes an image signal and transmits the image signal.

<Prior Art> As a compression encoding method for such a device, there are one-dimensional compression such as MH encoding and two-dimensional sequential encoding such as MR encoding. Two-dimensional compression has a higher compression rate than one-dimensional compression,
Once an error occurs, it also affects successive lines. Especially in the case of fine characters, it is difficult to discriminate. In recent years, a facsimile machine transmits information about the transmission time and the transmission source as image data on the transmission side so that the reception time and the transmission source can be recognized on the reception side.

However, it is preferable that these pieces of information are sufficiently smaller than the characters in the manuscript so that useless space is not used, but since the characters are small, it is impossible to determine when an error occurs in transmission by MR.

<Purpose> In view of the above-mentioned drawbacks of the prior art, the present invention is an image transmitting apparatus capable of recognizing the above information even if an error occurs by transmitting the information regarding the transmission source or the transmission time as one-dimensional encoded data. The purpose is to provide.

<Correspondence with Claims> (See FIG. 7A) The two-dimensional encoding means for two-dimensionally encoding the image signals of a plurality of lines representing the read image by using the correlation with the preceding line is the present embodiment. The example corresponds to the MR encoding of ENC 23-1.

The character generator that generates information about the originator or the time of origination as image information corresponds to the character generator CG25.

The one-dimensional encoding means for encoding the image information line by line corresponds to the conversion from the run length RL of ENC23-1 to the MH code.

Also, the transmission means for sequentially transmitting the image information encoded by the one-dimensional encoding means and the image signal encoded by the two-dimensional encoding means corresponds to the modem 19.

<Embodiment> An embodiment of a facsimile apparatus for realizing the present invention will be described in detail below.

(Mechanical System) FIG. 1 shows a sectional view of a facsimile apparatus. In the figure
41 is a CCD solid line image sensor, 42 is an imaging lens, 4
3 is a mirror, 44 is an original illumination lamp, 45 is an original feeding roller, 46 is an original discharging roller, 47 is an original feeding tray, 31 is an original detection sensor for detecting the presence or absence of an original on the original tray. .

Further, 34 is a roll paper storage cover, 35 is roll paper, 36 is an original and recording paper discharge tray, 37 is a cutter, 38 is a roll paper discharging roller, 39 is a roll paper conveying roller, 40 is a recording head, and 33 is a recording head. A roll paper cover sensor that detects opening / closing of the cover 34.

In the figure, at the time of reading the original, the original on the original feeding tray 47 is conveyed by rollers 45 and 46. The original is illuminated by the lamp 44 at the reading position P, and the reflected light is reflected by the mirror 43 and the lens 42.
An image is formed on the image sensor 41 via the, and the image sensor 41 converts the image into an electric signal.

On the other hand, at the time of recording, the roll paper 35 is nipped by the roller 39 and the head 40 and conveyed, and at the same time, the head 40 is placed on the heat-sensitive roll paper 35.
An image is formed by. When the recording for one page is completed, the roll paper 35 is cut by the cutter 37 and is discharged onto the paper discharge tray 36 by the rollers 38.

(Basic Block) FIG. 2A is a basic control block diagram of the facsimile apparatus of this embodiment. In the figure, 1 is a reading unit for reading a document image and converting it into an electric image signal, 3, 5, 7 are one of its modes, a random access memory (hereinafter referred to as RAM) functioning as a buffer for temporarily storing the image signal, and 9 is First-in first-out RAM (FIFORAM), which functions as an image memory that stores image signals for several pages, 11
A read-only memory (hereinafter ROM) that stores the operation program of the MPU23, 13 is a RAM that stores the flags and data that are necessary for the operation of the MPU, 15 is an operation unit that has an input key, a display, etc., and 17 is a thermal paper. A recording unit for recording copy images, received images and management data, 19 a modem for modulating transmission data and demodulating the received data, 20 a telephone, 21 a communication line 22 for controlling connection of the modem 19 or the telephone 20. The network control unit (hereinafter NCU), 25 is a character generator that stores character fonts for transmitting the transmission time and the name of the transmission source as image data in addition to the original image and recording communication management data. The device (hereinafter referred to as CG) 23 is an MPU that controls the entire system. In this embodiment, as the MPU 23, a 16-bit data bus 24 and an Intel 8086 capable of directly accessing a memory space of up to 4 megabytes are used.

The merit of using this MPU is that it has a 16-bit data bus, which makes it easy to handle encoded image data. For example, run length code 2048
12bit data is required to handle bit data, 8b
If you use it's MPU, you have to access it twice, but if it is 16 bits, you only need to access it once.

In addition, since a large capacity memory space can be directly accessed, it is possible to use the system memory as an image memory and provide a broadcasting function. In the conventional device, an external memory unit or a memory that the MPU cannot access directly via the bus even within the device was used to have a broadcast function as an image memory, but the circuit became complicated,
There was a problem such as enlargement of the device.

(Function of MPU) There are six types of basic functions of the MPU 23 as shown in Fig. 2 (B). The encoding function of each function will be described below.

Encoding function (Run length → MH, MR code conversion, etc.) a) Run length → MH code conversion When performing encoding, first, a 1-line reading command is issued to the reading unit 1. Then, the reading unit 1 converts the read image data of one line into a run length code and writes the run length code in the RAM3, and the MPU23 reads the run length code from the RAM3 and uses it to read the code conversion table in the ROM11. To convert to MH code. Conversion table is RO
The MH code data, which is expanded on M11 and corresponds to the run indicated by the address, is written with the run length code as the address. The structure of the MH code data is shown in FIG.

In FIG. 3 (A), the MH code is entered in the upper 12 bits on the left. Since the MH code is a variable length code, the code length of the MH code is inserted in the lower 4 bits to recognize the code length. Although the MH code is assigned to the upper 12 bits, the longest 13-bit code exists in the MH code table. To deal with that, the code length is 13
Looking at the bit codes, it can be seen that the beginning (MSB) of all codes starts with "0". Therefore, in the data in the conversion table, 12 bits excluding the leading "0" are used as the MH code, and the information of the data length "13" is added. Then, when the data tone is "13" by drawing the conversion table, the MPU adds "0" to the beginning of the code.

Thus all MH codes and their code lengths are all
Since it fits in 16bit, it can be easily processed by a 16bit MPU (micro processing unit) and the MH code can be searched at high speed.

b) Run length → MR code conversion The conversion to MR code is performed by MPU23 with reference to the basic flow shown in CCITT's T4 recommendation. The most frequent and important item in the basic flow is There is "white / black inversion detection of pixel". Therefore, the data written by the reading unit to RAM3 is run-length coded so that the detection can be performed easily.

A program flow for converting the MR code by the run length code is shown in FIG. 3 (B), and a subroutine for determining the parameter b1 is shown in FIG. 3 (C).

In FIG. 3 (B), parameters a0 and b1 are first initialized to 0, and the run length code next to the target line is read to determine a1, and b1 is determined by the routine in FIG. 3 (C). After that, b2 is called with the RL code next to the reference line to decide. Then, the MR code is determined by the ME encoding routine recommended by T4, and at the same time, the next value of the parameter a0 is determined.

In FIG. 3 (C), the parameter b1 is determined in accordance with the definition of the recommendation that the a0 is the first color change point where the color (white, black) is different from a0 in the target line on the right side of a0.

As described above, since the conversion to the MR code is performed from the run length code, it can be performed extremely quickly and easily as compared with the conversion from the raw image data.

C) CG code to MH code conversion This device has a function of converting information such as characters in addition to the image data read by the reading unit into an MH code and transmitting it as image data. , First, with CG code, fetch the raw data corresponding to CG code from CG25, convert it to run length code, and then MH
It is converted into a code and sent. The conversion table output is not the run length code but the raw data. The number of codes increases when the table is created with the run length.
This is because a large CG table is required, so that the raw data can be used to reduce the capacity of the CG25. Also, by using the raw data, decoding is required when transmitting in an uncompressed mode such as G2 mode. There is also the merit of disappearing.

As shown in the table below, the operation modes relating to the transmission / reception and transfer of image data in this embodiment have a great many modes. The data flow and code form in each mode will be described below with reference to the drawings.

First, FIGS. 4 (a) to 4 (c) are flowcharts of the judgment algorithm of the MPU 23 used when the present apparatus determines the above-mentioned 14 operation modes M1 to M14.

In this embodiment, the start key 51, the one-touch dial key 54, and the speed dial key 5 on the operation panel 50 shown in FIG. 5 are used.
3. Start up with the memory key 52.

Further, judgment / branching is performed based on the outputs of the sensor 31 for detecting the presence or absence of the document in FIG. 1, the sensor 32 for detecting the ON / OFF state of the telephone hook, and the roll paper cover sensor 33.

Furthermore, the mode of the partner machine is set to G3 by the communication of the pre-procedure signal prior to the message (image data) communication of the facsimile communication.
You can know the mode or G2 mode. At the same time, it is possible to know whether the partner machine has the MR coding function or only the MH coding function.

Further, it is possible to determine whether or not the FIFORAM 9 can be used at the time of message communication based on the usage state of the image memory of the own device.
If the memory is stored in the RAM 9, the RAM 9 cannot be used, and if the memory is not stored, the RAM 9 can be used.

The 14 operation modes determined by this flow are added with item numbers M1 to M14.

First, when the start key is pressed, it is checked whether the handset is off-hook or on-hook as shown in FIG. 4 (a). If it is on-hook, the original copy mode M14 is entered if the original is at the transmission position. If there is no original and the roll paper cover is closed, the roll paper cutter operates, and if the cover is open, the roll paper is fed by a predetermined amount.

On the other hand, in the case of off-hook, if there is a document, the transmission mode is set, and M1, M
Move to 2, M3, M6. On the other hand, if there is no document on the off-hook, the routine proceeds to the distribution routine of the reception mode shown in FIG. In FIG. 4 (b), M7 to M11 are selected according to the partner key mode and the availability of RAM9.

FIG. 4C shows a mode allocation routine when the memory key 52 is pressed.

When the memory key 52 is pressed, the software timer starts, and when the document is placed on the reading unit 1 during this timer,
The memory mode M12 is entered, and the image data of the original is stored in the RAM 9.

If the start key 51 is pressed when the document is not placed on the reading unit 1, if the hook is on-hook at this time, the memory copy mode M13 in which the image data in the RAM 9 is recorded in the recording unit 17 is entered.

If it is off-hook at this time, the memory transmission mode is entered. When the one-touch key 54 or the speed dial key 53 is pressed, the memory transmission mode is entered regardless of the state of the hook. The memory transmission mode is divided into a G3 memory transmission mode M4 or a G2 memory transmission mode M5 depending on whether the partner machine is a G2 or G3 machine.

When the memory key is pressed and the document is not placed on the reading section and there is no other key operation, the display 55 (Fig. 5) is displayed.
Displays the amount of image data stored in RAM9, waits for the software timer to expire, and returns to standby mode.

The flow of image data for the two modes M1 and M2 among the modes M1 to M14 will be described below.

(Mode M1) G3 Original Transmission, MH, RAM9 Available The flow of image data in mode M1 will be described with reference to FIG.

The reading unit 1 converts the image data for one line into a run length code RL and writes the run length code RL in the RAM 3 according to a read command from the MPU 23. Then, the MPU 23 transfers the data in the RAM 3 to the two line buffers RAM5 and RAM7 as they are, alternately by one line, and encodes the run length code RL read from the two line buffers into the MH code and writes the MH code in the FIFORAM9. . Then, the MPU 23 transfers the MH code from the FIFORAM 9 byte by byte to the modem in response to the data request interrupt from the modem 19. At this time, the minimum transfer time is calculated for each line and the fill bit is inserted.

Character information such as the originator and origination time added to the beginning of the image is transferred to the FIFORAM 9 using the conversion function of the raw image data 25 output from the CG 25 to the raw data → MH code.

Except for the case of the reading unit 1 → RAM 3 and the modem 19 → NCU 21 in the figure, all other data transfers are performed via the bus 24 of the MPU 23.

In the data request interrupt from the modem 19, the interrupt interval changes depending on the transmission rate. Since data transfer is done in byte units, 8/9600 = 9600bps
An interrupt occurs every 0.83 × 10 ^-3 sec.

Further, when the data transfer from RAM3 to RAM5, RAM7 is completed, the MPU 23 outputs a read command to the reading unit. While the MPU 23 is performing the encoding process ENC and the interrupt process, the reading unit 1 reads the document and converts the raw data to the run length data.

(Mode M2) G3 original transmission, MR, RAM9 can be used. Fig. 7 (A) shows the flow of image data. The data flow is almost the same as in mode M1. The difference is ENC23-
The code after 1 is to become the MR code. However, the data from CG25 is output from ENC23-1 in MH code. For example, when a character of 24 × 16 dots is added to the beginning, data for 24 lines is transmitted by MH code.

CG data in MH and image data in MR are shown in FIG. 7 (B).
The program for storing in RAM9 is shown. First, the number of lines L of CG data is initialized, the data of each line is called from the beginning, raw data is converted to run length RL code, RL code is converted to MH code, and stored in RAM 9 for each line.

When 24 lines are completed, the image data of RL code is read from RAM5 or 7 this time, and M of FIG. 3 (B) and (C) is read.
According to the R encoding routine, each line is converted into MR code and stored in RAM9.

<Effect> As described above, the image transmitting apparatus of the present invention is configured to transmit the information about the originator or the time in the form of a one-dimensional compression code when the image is two-dimensionally sequentially encoded and transmitted. Even if an error occurs during the transmission of the above, it does not affect other lines, so that the above information can be surely recognized on the receiving side. Further, since the letters, numbers and the like representing the above information can be made as small as possible, the space used for other than the image can be minimized.

In this embodiment, the MH code is shown as an example of one-dimensional coding, but simple Huffman coding may be used.
Also, the READ method, the MMR method, or the like may be used as the two-dimensional sequential encoding.

[Brief description of drawings]

FIG. 1 is a sectional view of the facsimile apparatus of this embodiment, FIG. 2 (A) is a basic control block diagram of the facsimile apparatus of this embodiment, and FIG. 2 (B) is the basics of the MPU 23 of FIG. 2 (A). FIG. 3 (A) shows the function, and M in the ROM 11 of FIG. 2 (A).
Fig. 3 is a diagram showing the structure of H code data, Fig. 3 (B) and (C) are flow chart diagrams for converting run length code to MR code, and Figs. 4 (a), (b) and (c) are MPU23 14 FIG. 5 is a flow chart for determining the normal operation mode, FIG. 5 is a plan view of the operation unit 50, and FIG. 6 is a view showing a flow of image data in mode M1,
FIG. 7A is a diagram showing the flow of image data in mode M2,
FIG. 7 (B) shows MH code for CG data and M for image data.
It is a flowchart figure for storing in RAM9 by R code. In the figure, 1 is a reading unit, 3, 5 and 7 are RAMs, 9 is a FIFORAM used as an image memory, 23 is an MPU, and 25 is a CG.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Motoaki Yoshino 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasuhide Ueno 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Nobuhiro Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yosei Oto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ken Ono 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigeo Miura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

[Claims] 1. A two-dimensional encoding means (23-1) for two-dimensionally encoding an image signal of a plurality of lines representing a read image using a correlation with a preceding line, and an image of information about a transmission source or a transmission time. Character generating means (25) for generating information, one-dimensional encoding means (23-1) for encoding the image information in line units, and the image information and the image information encoded by the one-dimensional encoding means An image transmitting apparatus comprising: a transmitting means (19) for sequentially transmitting the image signals encoded by the two-dimensional encoding means.