JP2942283B2 - Image data retransmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A multi-valued data reading unit that reads an original image as multi-valued data is transmitted to a receiving side while binarized image data of the multi-valued data is transmitted to the receiving side. Regarding the image data retransmission method of the image transmission / reception device capable of retransmitting the data in response to the transmission request, a threshold value used for binarization is applied to the received image so that a clear image can be obtained on the receiving side. The purpose of the present invention is to provide an image data retransmission method capable of retransmitting clear image data without any trouble on the transmission side by making it possible to change to an appropriate value. A multi-valued data storage unit for storing the multi-valued data read for a certain period of time, a read instruction unit for reading out the multi-valued data from the storage unit in response to a retransmission request from the receiving side, and setting the multi-valued data to a variable threshold. It is configured to include a binarization unit that performs binarization based on the threshold value, and a threshold value change unit that changes the threshold value according to a density change command from the receiving side.

[Industrial applications]

The present invention relates to a data retransmission method of an image transmitting / receiving device,
In particular, it has a multi-valued data reading unit that reads an image as multi-valued data, transmits image data obtained by binarizing the multi-valued data to a receiving side, and retransmits the data in response to a retransmission request from the receiving side. The present invention relates to an image data retransmission method of an image transmission / reception device capable of performing image data transmission.

[Conventional technology]

 Conventionally, there has been an image transmitting / receiving apparatus as shown in FIG.

The apparatus includes a main control unit 50 that performs various controls, an image sensor 51 that reads an original image as multi-valued image data (hereinafter, referred to as “multi-valued data”), and performs binarization of the multi-valued data. A binarizing unit 53 for performing various image processing such as compression on the binarized image data;
And a line control unit 561 for controlling a line, and a telephone number, binarized image data for retransmission and a telephone number for retransmission are stored in a telephone number storage area 52a and a binarized data storage area 5 respectively.
2b, a recording unit 59 for recording received data, and a timer for measuring a fixed time to hold binarized image data as the retransmission data in the memory 52. 61, and an operation panel 60 such as a keyboard for performing various instructions such as input of a telephone number by an operator.

Further, the binarizing section 53 is a slice level generating section for generating a fixed slice level for binarizing the multi-value data read by the image sensor 51.
53b, the slice level and the image sensor 5
Comparison unit 53a that compares the levels of the multi-value data read in step 1
And

Further, the main control unit 50 includes a read instruction unit 55 that instructs to read the binary data stored in the memory 52 when a retransmission request is received from the receiving side through the line. is there.

 This example operates as follows.

The multi-valued data read by the image sensor 51 is obtained by being compared by the comparison unit 53a with a preset fixed slice level generated by the slice level generation unit 53b of the binarization unit 53. The obtained binarized image data is transferred to the image processing unit 562 and the memory 52.

The binarized data transferred to the image processing unit 562 is subjected to image processing such as compression, transferred to the line control unit 561, and transmitted to the receiving side via the line.

The binarized data binarized by the binarization unit 53 is stored in the memory 52 for a certain period of time. The binarized data is deleted when the fixed time measured by the timer 61 has elapsed, but when the retransmission request is received from the destination within the time, the main control unit The read-out instruction unit 55 reads out the binary data, and transmits the data again from the line control unit 561 to the other party through the line based on the stored telephone number.

[Problems to be solved by the invention]

By the way, as described above, the device according to the conventional example,
If a request for retransmission is received from the receiver,
It simply transmitted the binarized data stored in 52 again.

Therefore, if the cause of the unclear image data received on the receiving side is due to the darkness or lightness of the multi-valued data,
Simply retransmitting the binarized data temporarily stored in the memory 52 does not solve any blurring.

Accordingly, the present invention provides an image which can retransmit clear image data to the receiving side as much as possible in response to a retransmission request from the receiving side when the received image data is too dark or too dark to be unclear. The purpose of the present invention is to provide a data retransmission method.

[Means for solving the problem]

In order to solve the above technical problems, the present invention has a multi-value data reading unit 1 for reading an original image as multi-value data as shown in FIG. 1 and receives image data obtained by binarizing the multi-value data. A multi-value data storage unit 2 for storing multi-value data read by the reading unit 1 for a certain period of time in an image transmitting / receiving apparatus capable of transmitting the data to a receiver and re-transmitting the data in response to a re-transmission request from a receiver. A read instructing unit 5 for reading multi-valued data from the storage unit 2 in response to a retransmission request from the receiving side, a binarizing unit 3 for binarizing the multi-valued data based on a variable threshold, And a threshold value changing unit 4 for changing the threshold value according to a density change command from the side.

[Action]

Transmission and retransmission of image data according to the retransmission method according to the present invention are performed as follows.

As shown in FIGS. 1 and 2, the transmitting side calls the receiving side in step S1, and the transmitting side reads the contents of the image to be transmitted in step S2 as multi-valued data by the multi-valued data reading section 1, The data is stored in the multi-value data storage unit 2 for a certain time.

In step S3, the binarization unit 3 binarizes the multi-value data based on a threshold, and transmits the binarized data to the receiving side in step S4.

If the receiving side receives unclear image data and desires retransmission, the transmitting side is called (polling) in step S5, and an image density change command and a retransmission request are notified to the transmitting side in step S6. Become.

In step S7, when the threshold change unit 4 on the transmission side receives the notification, the threshold change unit 4 changes the threshold of the binarization unit 3.

That is, if the received density is too dark, the threshold level is increased to make it difficult to be black, and if the received density is too low, the threshold level is lowered to make it easy to become black. good.

In step S8, the read instruction unit 5 reads again the multi-value data stored in the multi-value data storage unit 2,
In step S9, the binarizing unit 3 newly creates binarized data based on the changed threshold value, and transmits the data to the receiving side in step S10.

〔Example〕

 Next, examples of the present invention will be described.

A transmitting / receiving apparatus according to the data retransmission method according to the present embodiment is as shown in FIG.

As shown in the figure, the present apparatus has a main control unit 10 capable of performing various controls of the apparatus, an image sensor 11 as a multi-value data reading unit 1 that reads contents from an original image as multi-value data, Memory 12 for storing various data
A binarizing unit 13 for binarizing the multi-valued data, an image processing unit 162 for performing image processing such as image compression, a line control unit 161 for controlling line connection, and time measurement. A timer 21 for performing an operation, an operation panel 20 for an operator to input data such as a telephone number, and a recording unit 19 for recording received data.

Further, in the memory 12, a telephone number storage area 12a for storing a telephone number of a destination, a binarized data storage area 12b for storing binarized data, and a multi-level storage for storing multi-level data. A value data storage area 12c is provided.
The binarization unit 13 includes a slice level generation unit 13b that generates a slice level as a variable threshold, a comparator that compares the multilevel data with the slice level to generate binary data, and the like. And a comparison unit 13a.

Further, based on a request from the receiving side, the main control unit 10 sets a threshold value of the binarizing unit 13, that is, a threshold value changing unit 14 that changes a slice level, and in response to a request from the other party. A read instruction unit 15 for instructing the memory 12 to read multi-value data. The image processing unit 162 includes a buffer memory 162b for temporarily storing the binary data and a processing unit 162a for performing processing such as compression on the stored data. The recording unit 19 is used for recording received data on a recording sheet.

Subsequently, the operation of the retransmission method according to the present embodiment will be described.

When transmitting the contents of the original image, a call is made to the receiving side of the destination in step SJ1 through the line based on the telephone number of the destination specified by the operator through the operation panel 20.

When there is a call, in step SJ2, the receiving side sends a response signal (CED, NSF, CSI, DIS signal) to the transmitting side in response to the calling.

Here, the CED signal indicates a called station confirmation signal, is a network control signal in facsimile communication, and is a signal indicating that the receiving side (called side) is a facsimile terminal apparatus (no voice control). It is output when it can be received.

The NSF (Non-Standard-Facilities) signal is a CCIT
In the transmission control procedure of T.30, this is a control signal indicating a specific request that exceeds the range of the recommendation in the T.series. CSI (Called Station Identification) is a called station identification signal, and the telephone number of the own station is notified to the transmitting side as identifying the calling station.

Further, DIS (Digital Identification Signal) is a signal indicating whether or not the device on the receiving side is different from the standard protocol of the CCITT recommendation.

When these response signals are notified from the receiving side to the transmitting side and the facsimile communication procedure is enabled, in step SJ3, the transmitting side sends a training signal (TCF) to the receiving side. Here, the “training signal” refers to a signal of a predetermined format that is sent to the receiving side on a trial basis to check the signal transmission state of the line.

The receiving side confirms whether or not the signal has been received without error. If the signal has been received without error, a CFR (Comfirm) signal indicating to the transmitting side that the confirmation is positive is transmitted to the transmitting side in step SJ4. You will be notified.

When the transmitting side receives the signal, in step SJ5, the receiving side stores the multi-valued data read by the image sensor 11 in the multi-valued data storage area 12c of the memory 12, and the binarizing section 13 And slice level generator
The threshold value set by 13b is compared by the comparing unit 13a, and the binarized image data (PIX) is transmitted to the receiving side through the line by the line control unit 161.

If the image received on the receiving side is too dark or too faint and unclear, the receiving side operator polls the transmitting side (by calling the transmitting side facsimile apparatus from the receiving side facsimile apparatus). An operation of receiving a previously set original is performed.

That is, in step SJ6, the receiving side outputs a call signal to the transmitting side, and in step SJ7, when the above-described response signal (CED, NSF, CSI, DIS) is transmitted from the transmitting side to the receiving side, With SJ8, the receiving side sends an NSC signal and DT to the transmitting side.
By transmitting the C signal, the transmitting side is requested to transmit an image signal.

Here, NCS (Non-Standard Facilities Command)
The signal is a mode setting command of a polling operation in which the dialing facsimile apparatus requests the facsimile apparatus that has received the dialing to transmit an image signal.
The C (Digital Transmit Comand) signal is a digital transmission command and has the same meaning as the NSC signal.

When the transmission side receives the signal, the threshold change unit 14 of the main control unit 10 sets the slice level generation unit 13b of the binarization unit 13.
Is instructed to change the slice level (threshold). That is, if the image received on the receiving side is too dark, the slice level of the density is increased so as not to be too dark, and if the received image is too light, the slice level of the density is lowered and is not too thin. Set as follows.
Further, the read instruction section 15 of the main control section 10 causes the multi-level data storage section 12c of the memory section 12 to read the multi-level data stored in the multi-level data storage section 12c before being converted into the binary data transmitted to the receiving side and transmitted to the receiving side. The binarization unit 13 performs binarization based on the changed slice level.

In step SJ9, the transmitting side receives an NSS (Non-Standard Fa
cilities Set-Up) signal is sent to the receiving side to set standard equipment.

Here, the NSS signal is a response signal to the DIS signal, and indicates an attribute of an image signal to be transmitted from now on.

In step SJ10, the transmitting side sends a training signal to the receiving side.

When the receiving side receives the training signal in step SJ11, the receiving side sends a CFR signal to the transmitting side indicating that the result of receiving the training signal is positive to the transmitting side.

If there is a CFR signal, the transmitting side retransmits the image in step SJ12.

If the predetermined time has elapsed in step SJ13, the contents stored in the multi-value data storage unit 12c of the memory 12 will be deleted.

〔The invention's effect〕

As described above, in the present invention, when retransmission is performed because image data received on the receiving side is too dark or too thin to be unclear, a threshold value used for binarizing multi-valued data is set as a threshold value. It can be changed according to the command of the receiving side.

Therefore, a clear image can be retransmitted by the changed threshold value without bothering the transmitting side according to the degree of the density of the image received by the receiving side.

[Brief description of the drawings]

1 is a block diagram showing the principle of the present invention, FIG. 2 is a flowchart showing a retransmission method according to the present invention, FIG. 3 is a block diagram according to the embodiment, FIG. 4 is a flowchart according to the embodiment, and FIG. Is a block diagram according to a conventional example. 1 (11): Multi-value data reading unit (image sensor) 2 (12c): Multi-value data storage unit (multi-value data storage area) 3, 13: Binarization unit 4, 14: Threshold value change Part 5,15 …… Readout instruction part

Claims (1)

(57) [Claims] A multi-valued data reading section (1) for reading an original image as multi-valued data, the image data obtained by binarizing the multi-valued data is transmitted to a receiving side, and a re-transmission request from the receiving side is provided. A multi-level data storage unit (2) for storing multi-level data read by the reading unit (1) for a certain period of time; and a re-transmission request from a receiving side. A read instruction unit (5) for reading multi-valued data from the storage unit (2), a binarization unit (3) for binarizing the multi-valued data based on a variable threshold value, An image data retransmission method, comprising: a threshold value changing unit (4) for changing a threshold value according to a density change command.