JPH0420551B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image transmission device, such as a facsimile, which compresses, transmits, and reproduces an image signal.

2. Description of the Related Art Conventionally, as a method for transmitting image signals as quickly and efficiently as possible, data compression transmission is known in which the hole length of the signal is removed.
In data compression transmission, the number of compression codes generated per scanning line is significantly dependent on the image, so speed smoothing is essential when sending data to a constant speed transmission path. For this purpose, a transmission buffer memory is provided in the transmitter/receiver to temporarily store data. Conventionally, the receiving device notifies the transmitting device that the image recording device is ready for recording. After receiving the notification of completion of recording preparation, the transmitting device starts transmitting the compressed code and stores it in the receiving device transmission buffer memory.
After the accumulation amount reaches a certain value, recording of the image is started.

A conventional image transmission device will be described below with reference to FIG.

In FIG. 2, 20 is a transmitting device, 21 is a receiving device, 22 is an image information transmission path, and 23 is a response information transmission path. In the transmitting device 20, the image signal 32 read by the image reading device 24 is compressed and encoded by the compression device 25, and the compressed code 33 is temporarily stored in the transmission buffer memory 27. Then, after the transmitting device 20 is notified via the response information transmission path 23 that the recording preparation (preparation to start printing) of the receiving device 21 has been completed and the state is ready for recording, the transmitting device 20 transfers the data to the transmission buffer memory 27. The compressed code is read out from the transmission controller 26 and sent to the image information transmission path 22 via the transmission control device 26. The reception control device 28 writes the compressed code sent through the image information transmission line 22 into the transmission buffer memory 31. Then, when a certain amount of compressed codes have been accumulated in the transmission buffer memory 31, the restoring device 29 reads out the compressed codes and decodes them to obtain an image signal 35. The image signal 35 is sent to the image recording device 30, and a recorded image can be obtained.

Problems to be Solved by the Invention However, in the above configuration, a line separate from the image information transmission line 22 is required to notify the completion of preparation of the image recording device 30. This image recording device 30
The preparation time until recording becomes possible includes, for example, the time required to wind the paper/the time from the activation of the rotary drum until the rotation speed becomes stable, and takes 30 to 40 seconds. Therefore, the image recording device 30
If the compressed code is transmitted after becoming ready for recording, the time required to prepare for recording and the time to accumulate in the transmission buffer memory 31 will be added, so it will take a considerable amount of time to perform the recording operation, and the transmission will be delayed. The problem was that it was inefficient. The reason why this is done is that analog facsimile, or digital facsimile without compression,
Therefore, it is thought that the concept of a system that does not use buffer memory is also applied to a transmission system that performs compression.

The present invention solves the above-mentioned problems of the prior art, and is intended to shorten the time from the start of information transmission for one page to the completion of printing by effectively utilizing buffer memory. That is, by using the transmission buffer memory, which was used only for the purpose of absorbing variations in the number of codes generated per line, the compressed codes are postponed during the recording preparation time of the image recording device and stored in the transmission buffer memory.
The purpose is to shorten transmission time.

Means for Solving the Problems The present invention provides a transmitting device with a data compression means for compressing image data, and a transmission control means for controlling transmission of the compressed image data compressed by the data compression means, and also includes: A receiving device is provided with a receiving control means for controlling the reception of compressed image data, and a data restoring means for restoring the compressed image data and reproducing the image data by the image recording means. A reception buffer memory is provided to temporarily hold compressed image data that is deferred and transmitted from the transmitting device until the image recording device is able to start recording, and the transmission control device in the transmitting device is configured to control the transmission of the image data. a time calculation means for calculating the recording start time required by the recording means; a code number calculation means for calculating the number of codes stored in the reception buffer memory for temporarily holding compressed image data in the receiving device; and the time calculation means. and a control means for giving a recording start instruction signal to the image recording means based on the calculation result of the code number calculation means.

Effects With the above configuration, the present invention allows the transmitting device to calculate the recording start of the receiving device from the required time for preparing the receiving device, thereby making it possible to know the recording start of the receiving device without using response information. Transmission time can be shortened by postponing compression codes during recording preparation time.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an image transmission device according to an embodiment of the present invention. In Figure 1, 1
0 is a transmitting device, 12 is an image information transmission path, and 11 is a receiving device. In the transmitting device 10 , upon start-up, the image signal 14 generated in the image reading device 1 is compressed and encoded in the compression device 2 , and the compressed code 15 is stored in the single-transmission buffer memory 6 . On the other hand, the transmission control device 3 notifies the reception device 11 of an activation start command. The receiving control device 7, which has received the activation start command, instructs the image recording device 9 to start preparation. Furthermore, the transmission control device 3 sets the required preparation time in a timer (not shown) of the calculation section 5, and starts the timer. The transmission control unit 4 transmits the compressed code stored in the transmission buffer memory 6 to the receiving device 11 via the image information transmission path 12.
At the same time, the transmission control section 4 notifies the calculation section 5 of the number of transmitted codes. The calculation unit 5 calculates the number of transmitted codes and stores the number in the transmission buffer memory 1 of the reception control device 7.
Calculate the number of codes stored in 3.

The reception control device 7 transmits the compressed code sent through the image information transmission path 12 to the transmission buffer memory 1.
Write to 3.

The transmission control unit 4 of the transmission control device 3
While transmitting the compressed code stored in the transmission buffer memory 6 to the reception control device 7, the timer of the calculation section 5 is monitored. When the timer in the calculation unit 5 indicates the recording preparation time, it is considered that the preparation of the image recording device 9 is completed. (The receiving device has completed recording preparations.) Furthermore, when the number of transmitted codes exceeds a certain number, recording is started. That is, (1) the timer of the calculation unit 5 reaches the recording preparation completion time.

(2) T _COD ≧K However, T _COD : Number of transmitted codes K: Constant When the above conditions (1) and (2) are satisfied, the transmission control unit 4
sends a recording start command to the reception control device 7. In response to the recording start command, the restoration device 8 reads out the compressed code 16 stored in the transmission buffer memory 13 and decodes it to obtain an image signal 17. The image signal 17 is sent to the image recording device 9 to obtain a recorded image.

As described above, according to this embodiment, since response information notifying the state of the receiving device 11 is not required, control becomes simple even if a plurality of receiving devices exist. Also,
Since the recording start command is transmitted from the transmitting device 10 to the receiving device 11 to start recording, a plurality of receiving stations start recording at the same time, so that all the receiving stations operate in unison. Furthermore, since the compression code is postponed during the preparation time of the image recording device 9, the transmission time is shortened.

Effects of the Invention As described above, the present invention calculates the preparation time of the receiving device in the transmitting device, further calculates the number of transmitted codes, and transmits a recording start command based on the calculation result. By postponing the compression code during recording start and preparation, the image transmission time can be shortened.

[Brief explanation of drawings]

FIG. 1 is a block wiring diagram of an image transmission apparatus according to an embodiment of the present invention, and FIG. 2 is a block wiring diagram of a conventional image transmission apparatus. 1... Image reading device, 2... Compression device, 3...
Transmission control device, 4...Transmission control unit, 5...Calculation unit, 6...Transmission buffer memory, 7...Reception control device, 8...Restoration device, 9...Image recording device, 1
0... Transmitting device, 11... Receiving device, 12... Image information transmission path, 13... Transmission buffer memory.

Claims (1)

[Scope of Claims] 1. A transmitting device is provided with a data compression means for compressing image data, and a transmission control means for controlling transmission of the compressed image data compressed by the data compression means, and a method for receiving the compressed image data. The receiving device is provided with a reception control means for performing control, and a data restoration means for restoring the compressed image data and reproducing the image data by the image recording means. A reception buffer memory is provided to temporarily hold compressed image data that is postponed and transmitted from the transmitting device until it is possible to start, and the transmission control means in the transmitting device is configured to perform the recording required by the image recording means. a time calculation means for calculating a start time; a code number calculation means for calculating the number of codes stored in the reception buffer memory for temporarily holding compressed image data in the receiving device; the time calculation means and the code number; An image transmission device comprising: control means for providing a recording start instruction signal to the image recording means based on the calculation result of the calculation means.