JPH0773328B2 - Image transmitter - Google Patents

Description

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

<Prior Art> Conventionally, a technique has been known in which a document image is read, an image signal is encoded, and then the image signal is transmitted to shorten a transmission time. Also, due to recent advances in communication technology, it is possible to send a large amount of information in a short transmission time, for example, 9600 bits / sec can be transmitted by a general public telephone line.

Therefore, a situation in which the reading and encoding speeds are not in time for the transmission speed actually occurs.

For example, using the facsimile machine as an example, the information amount when one line encodes all white lines is 31 bits including the EOL signal in the case of the MH code, and 15 bits including the EOL signal in the case of the MR code. It's a bit. Therefore, this is 9600 bits / sec
, The time required for transmission is 3.2 msec for MH and 1.
It is 5 msec.

On the other hand, the time required to read and encode one line is 2.7 msec for the storage (reading) time, 2.2 msec for the data transfer time, and the encoding processing time when a charge storage type image sensor such as CCD is used. Is 0.1msec, which is 5.0msec in total. That is MH
A free time of 1.8 msec occurs in the case of the code and 3.5 msec in the case of the MR code. Conventionally, a dummy signal called a file bit was transmitted during this idle time and waited for the end of encoding. This is a problem particularly in a region where the amount of encoded signals is small, for example, in the margin of the leading edge of the document, and the amount of dummy signals is very large at the leading edge of the document, resulting in a long transmission time.

<Purpose> In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide an image transmitting apparatus that reduces the amount of dummy signals regardless of the amount of encoded signals and shortens the transmission time.

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

(Mechanical System) FIG. 1 shows a sectional view of the facsimile machine. 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, and 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 put 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 discharged onto the paper discharge tray 36 by the roller 38.

(Basic Block) FIG. 2 (A) is a basic control block diagram of the facsimile machine of this embodiment. In the figure, reference numeral 1 is a reading unit for reading an original image and converting it into an electric image signal, 3, 5 and 7 are random access memories (hereinafter referred to as RAM) functioning as a buffer for temporarily storing the image signal, and 9 is a code. First-in first-out RAM that stores the converted image signal
(Hereinafter FIFORAM), 11 is a read-only memory (hereinafter ROM) that stores the MPU23 operation program, 13 is RAM that stores the flags and data necessary for MPU operation, and 15 is an operation that has input keys, a display, etc. 17 is a recording unit for recording a copy image, a received image and management data on a thermal paper, 19 is a modem for modulating transmission data and demodulating the reception data, 20 is a telephone, 21 is a communication circuit 22 and modem 19 is Alternatively, a network control unit (hereinafter referred to as NCU) 23 that controls connection to the telephone 20 and 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.

There are six basic functions of the MPU23 as shown in FIG. 2 (B). Hereinafter, each function will be described in the flow of image data.

(Communication Operation) The flow of image data during the transmission operation will be described with reference to FIG. In this example, an MH code transmission example is shown.

The reading unit 1 converts the image data for one line into a run length code RL by a reading command from the MPU 23 and transfers the data in the RAM3 as it is to the two line buffers RAM5 and RAM7 alternately, one line at a time. The run length code RL read from the line buffer of the book is encoded into the MH code and written in the FIFORAM9. Then, in response to the data request interrupt from the modem 19, the MPU 23 transfers the MH code from the FIFORAM 9 to the modem one by one. At this time, the minimum transfer time is calculated for each line and the file bit is inserted. The 1-byte data transferred from the FIFORAM 9 to the modem 19 is transmitted to the receiving side via the telephone line via the NCU 21.

Here, except for the case of the reading unit 1 → RAM3 and the modem 19 → NCU21 in the figure, all other data transfer is performed via the bus 24 of the MPU23.

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.

(Regarding Start Timing of Encoding and Reading) Next, the timing of starting the flow chart and reading in FIG. 4 will be described.

Perform the previous steps in step SP1. The pre-procedure includes making a call to the receiver and sending various digital control signals to the receiver. When the receiving side is ready to receive, it receives the CFR indicating it, and the transmitting side sends the modem 19 in SP3 to SP5.
Sends a training signal and instructs continuous transmission of "1", and simultaneously sets the timer. Further, at this time T1, the reading and encoding of the original is instructed. The timer is for setting the time to stop the continuous transmission of "1". Until the timer times out, continue sending "1" and set the receiving side to the receiving state. During this time, reading and encoding are also executed, and the encoded image data of the leading portion of the original is stored in the FIFORAM 9. And when the timer times out T2
Then, the transmission of "1" data from the MPU 23 to the modem 19 is stopped, the interrupt from the modem 19 to the RAM 9 is enabled, and the image data stored in the RAM 9 can be read. Therefore, from time T2, image data PI
X is sent to the receiver. At the time point T2, the image data is already stored in the RAM 9 to some extent, so that even if there is a margin in the leading portion of the document, the situation in which the reading and encoding are not in time for the transmission speed does not occur.

When the transmission of one page is completed at SP8, the presence or absence of the next page is determined at SP9. If the next page is present, the process returns to SP3 and the same operation is performed. On the other hand, if there is no next page, the transmission operation ends.

As described above, since the image is read and encoded during transmission of the training signal and "1" and the encoded image data is stored in the memory, the image data is encoded at the beginning of the image data transmission start. It is possible to reduce the total transmission time by reducing the amount of dummy bits, which are dummy signals, to be transmitted.

In this embodiment, reading and encoding are started after CFR detection. An error often occurs before the CFR is detected, and the read information is wasted. Therefore, it is preferable that the CFR is detected.

<Effect> As described in detail above, according to the present invention, since the reading and encoding are not in time for the transmission of the image data in the initial stage of the transmission of the image data, the transmission amount of the dummy signal is reduced, and the entire transmission of the image is performed. The time can be shortened.

Further, since the reading and encoding are started after the reception completion signal is received, the read information is not wasted, and if an error occurs before the reception completion signal is received, the retransmission operation is performed. It can be done smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view of the facsimile machine of this embodiment, FIG. 2 (A) is a control block diagram of the device of FIG. 1, and FIG. 2 (B).
Is a functional block diagram of the MPU 23, FIG. 3 is a block diagram showing the flow of image data during transmission, FIG. 4 is a control flow chart, and FIG. 5 is a timing chart.

Front page continuation (72) Inventor Yasuhide Ueno 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. (72) Insei Yoshio 3-30-3 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Person Masahisa Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-54-43410 (JP, A)

Claims (1)

[Claims] 1. A reading unit for reading an original image and converting it into an image signal, an encoding unit for compression-encoding the image signal, a storage unit for temporarily storing the encoded image signal encoded by the encoding unit, Transmitting means for transmitting the encoded image signal in the storage means, receiving means for receiving a completion signal indicating that reception preparation is completed from a partner receiver, after receiving the completion signal and before transmitting the encoded image signal Training signal sending means for sending a training signal to the receiver of the other party, and, after the receiving means receives the completion signal, causes the reading means and the encoding means to start operating, and during the sending of the training signal, the storage An image transmitting apparatus, characterized in that the means has a control means for storing the encoded image signal.