JPS60199267A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To improve quickly disturbance of a picture by providing a means selecting automatically a one-dimensional data compressing means in receiving a negative response at the establishment of a protocol in the equipment where the compression means of a one-dimensional data and a compression means of two-dimensional data are provided. CONSTITUTION:A control section 1 identifies a function of a station to be called by a DIS signal from the station to be called, and as a result, when the station to be called has the function receiving coded unified information through the two-dimensional compressing means, a data compression means selection signal (a) brings the mode of the data compression section 2 into the two-dimensional compression mode having an excellent transmission efficiency and a transmission speed selection signal (b) sets a MODEM 4 to a high speed MODEM rate and after a DCS signal is transmitted, a test data is transmitted so as to check the data transmission error rate. When the data transmission error rate is higher than the specified value and the response signal from the station to be called is a negative response, the mode is set again. That is, the mode of the data compression section 2 is brought into the one-dimensional compression mode and the MODEM rate of the MODEM 4 is brought into the MODEM rate lower than the preceding rate, and after a DCS signal is transmitted, the test data is transmitted again.

Description

TECHNICAL FIELD The present invention relates to a facsimile machine, and more particularly to a facsimile machine having one-dimensional data compression means and two-dimensional data compression means.

Prior Art When performing facsimile communication, test data is generally sent using a high-speed modem before image information is sent. When a negative response comes back to this test data,
If the modem rate (transmission rate) continues, the modem rate is sequentially reduced until a positive response is returned. In this way, transmission of image information is started at the modem rate at which the positive response was received.

On the other hand, there are two types of compression methods (encoding methods) for one-picture information: a one-dimensional compression method and a two-dimensional compression method. 1
The dimensional compression method is a method for compressing data based only on information from the currently scanned scan line, and the two-dimensional compression method is a method for compressing data by also taking in information from the previous scan line. Compared to two-dimensional compression methods, one-dimensional compression methods have disadvantages in that they have a lower data compression rate and lower transmission efficiency, but they have the advantage that even if an error occurs on the receiving side, the error spread is small.

There are facsimile machines that use these two types of data compression methods. In this device, when test data is sent at a certain modem rate and a negative response is returned due to a high data transmission error rate on the line, conventionally the data compression method is simply converted to a lower modem rate. Not converted.

In other words, at the time of shipment, a bit switch is used to give priority to the two-dimensional compression method with better transmission efficiency, and if there are many errors in the image information, service personnel switch to the one-dimensional compression method, which causes less image distortion, so that the image distortion can be quickly corrected. cannot be improved.

Purpose The purpose of the present invention is to provide a facsimile machine configured to solve the problems of the prior art as described above, automatically select an appropriate data compression method according to the condition of a single line, and quickly improve image distortion. The goal is to provide equipment.

composition Hereinafter, the configuration of the present invention will be explained using one example.

FIG. 1 is a block diagram showing a schematic configuration of a facsimile machine according to an embodiment of the present invention.

In FIG. 1, l is a control unit that controls protocol establishment, etc., 2 is a data compression unit that has one-dimensional compression means and two-dimensional compression means, 3 is a reading unit that reads image information, and 4 is a plurality of modem rates. modem with
55 is a network control unit (NCU) that controls the communication line network.

Next, control for establishing a protocol for transmitting image information by the facsimile machine shown in FIG. 1 will be explained with reference to the flowchart shown in FIG.

First, the operator makes a call to the other station (not shown), confirms that the called station is the desired called station by the CED signal from the called station, and then presses the send button. is switched from the telephone side to the facsimile machine side (201, 202).

The control unit 1 identifies the function of the called station based on the DIS signal from the called station, and as a result, if the called station has the function of receiving image information encoded by the two-dimensional compression means, ,
First, the data compression unit 2
The mode is set to a two-dimensional compression mode with good transmission efficiency, and the modem 4 is set to a high modem rate by a transmission rate selection signal, and a DC5 signal of a mode setting command is sent to the called station (204 and 205).

Next, test data is sent at a fixed modem rate and the data transmission error rate is checked (206).

If the data transmission error rate is lower than the specified value and the response signal from the called station is a false response, the image information from the reading unit 3 is
The encoded image information is encoded by the dimension compression means, and the encoded image information is sent to the network control device i! according to the modem rate. 5 (207.208.209). If the data transmission error rate is higher than the specified value and the response signal from the called station is a negative response, the mode is reset. That is, data compression section 2
The mode is set to one-dimensional compression mode, the modem rate of modem 4 is set to a modem rate slower than the previous modem rate, and after transmitting the DO3 signal (207, 208, 21D), test data is transmitted again.

When the control unit 1 finishes transmitting one page of image information, it determines whether or not there are multiple pages of image information to be transmitted, and if there are multiple pages, it transmits an MPS signal indicating that (211.216 ),
If there are not multiple pages, an EOP signal indicating the end of communication is sent, and after receiving the response, a DCN signal indicating call release is sent and the line is disconnected (212.213.214.
215).

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If I-Sf++11er4 771, continue to send image information in the same mode (216, 217, 21
8,209). If the response signal to the MPS signal is a negative response, change the transmission mode from the next page, send the test data in the same manner as above, and select the mode appropriate for one line (218.210, 206), that is, if the previous data compression mode was the two-dimensional compression mode, the mode is changed to the one-dimensional compression mode, and the modem rate is also set to a slower rate. If the previous data compression mode is one-dimensional compression mode.

Leave the data compression mode unchanged and reduce only the modem rate. Note that if the DIS signal indicates that image information encoded by two-dimensional compression cannot be received, the data compression means is fixed to the one-dimensional compression means and only the modem rate is changed, and no acknowledgment is received. Image information is transmitted at the obtained modem rate (204, 219, 222).

In this way, on a line where the data transmission error rate is high and a negative response is returned, automatic control is performed to select a one-dimensional compression method with a small error spread, rather than a two-dimensional compression method with a large error spread. By doing so, image disturbance can be quickly improved.

FIG. 3 is a transmission control signal time chart when a negative response is received after sending the test data when transmitting two pages worth of image information.

First, the operator calls the other party's station by telephone. The receiving side R that receives the call sends the called station identification signal (CED signal) of 21001-1z indicating that the called station (receiving side R) is a non-voice terminal, and the DIS signal indicating its own function. Send it back. After checking the DIS signal, if transmission using the two-dimensional compression method is possible, the sending side S sends a mode setting command DC3 signal to notify that the image information VD2 encoded by the two-dimensional compression means will be transmitted at a modem rate of 9600 bps. Subsequently, test data TRD is transmitted. If a negative response FTT signal is returned in response to the test data TRD, the sending side S changes the mode and transmits the image information VDI encoded by the one-dimensional compression means using the mode setting command DC8 signal at a modem rate of 720 ubps. After informing the test data TRD that it will be transmitted, the test data TRD is transmitted again. In response, when a CFR signal indicating an affirmative response is returned, the transmitting side S transmits the image information vD1 in the corresponding mode. When the sending of one page is completed, the sending side S sends an MPS signal to send the next page.

When the MCF signal indicating a positive response to the MPS signal is returned, the image information VDI is sent in the same transmission mode as the previous page.
Send. When the transmission of the image information on the second page is completed, the sending side S sends an EOP signal indicating the end of communication, and when an MCF signal indicating an acknowledgment is returned, a DCN signal indicating call cancellation and line disconnection are sent. A Disc signal indicating this is transmitted.

FIG. 4 is a transmission control signal time chart when a negative response is received after transmitting image information when transmitting image information for two pages.

In this case, an affirmative response CFR is returned to the first test data TRD after informing that the image information encoded by the two-dimensional compression means will be transmitted at a transmission rate of 9600 bps, and the first page is The image information VD2 encoded by the dimension compression means is transmitted at a transmission rate of 9600 bps. The response to the MPS signal indicating the presence of the next page is the RTN signal indicating a negative response. Therefore, it is notified that the image information encoded by the one-dimensional compression means will be transmitted at a transmission rate of 7200 bps, and the test data TDR is sent back. Since a positive response CFR is returned to this test data TRD, the second page is the image information V encoded by the one-dimensional compression means.
DI is transmitted at a transmission rate of 7200 bps.

Effects As explained above, the facsimile machine of the present invention
In many cases, it is possible to automatically select an appropriate data compression method depending on the line condition and quickly improve image distortion.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing a facsimile device according to an embodiment of the present invention, FIG. 2 is an operation flowchart of FIG. 1, and FIG. 3 is a transmission control signal time when a negative response signal is received after transmitting test data. FIG. 4 is a transmission control signal time chart when a negative response signal is received after image information is transmitted. ■=control unit, 2: data compression unit, 3: reading unit, 4: modem, 5: network control device. Figure 1 Figure 6 Figure 6 Company 4 Figure 2

Claims (1)

[Claims] H) A facsimile apparatus having an i-dimensional data compression means and a two-dimensional data compression means, characterized in that the facsimile apparatus is provided with means for automatically selecting the one-dimensional data compression means when a negative response is received at the time of protocol establishment. facsimile machine.