JPS6233793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile signal encoding method intended to improve transmission efficiency by removing redundancy of facsimile signals.

Conventionally, facsimile signals are encoded by encoding image signals every one or two lines, but in general, facsimile signals have a high correlation between signals between adjacent lines, especially between the lines of a document. In the all-white section or all-black section, the same code is repeatedly transmitted, making the signal redundant.
This hindered the improvement of transmission efficiency.

The present invention has been made in view of the above-mentioned circumstances, and in order to eliminate the above-mentioned drawbacks, the signal in the all-white or all-black section is encoded in several lines at once, thereby eliminating the generation of repetitive codes in the conventional system and improving the facsimile signal. The object of the present invention is to provide a facsimile signal encoding method that removes redundancy from facsimile signals and performs efficient transmission by obtaining an efficient signal sequence.

Hereinafter, the present invention will be described based on examples with reference to the drawings.

FIG. 1 shows an embodiment of a facsimile transmitting device applied to the method of the present invention, FIG. 2 (a) and (b) show a signal transmission format for image information, and FIG. 3 shows an example of a transmitted original.

First, referring to FIG. 1, an image signal a read by a reading section 1 and converted into black and white binarized is stored in a memory in a 1 or 2 line encoding circuit 2.

At the same time, this image signal a is also introduced to the all-white/all-black detection circuit 3 according to the present invention, and this circuit verifies whether it is all white, all black, or something else.

If the test result is (i) other than all white and all black, the 1 or 2 line encoding circuit 2 encodes every 1 or 2 lines of the image signal a, and adds a synchronization code and After adding an image information code and arranging it into the format shown in FIG. 2B, it is transferred to the buffer memory 6 as a signal f.

(ii) Next, if it is all white or all black, 1 or 2
The line encoding circuit 2 is made to stop encoding by the signal b issued from the all-white and all-black detection circuit 3, and at the same time, the all-white or all-black section encoding circuit 4 assigns a specific code to all-white or all-black, respectively. and count the number of consecutive all-white or all-black lines. When the all-white or all-black section ends, the frame check sequence shown in Fig. 2A consists of a synchronization code, an all-white or all-black code, the number of lines in the all-white or all-black section, and a check bit (same as a general frame check sequence CRC). This signal g is transferred to the buffer memory 6 several times in succession. At the same time, 1 or 2 line encoding circuit 2
A signal c indicating the end of the all-white or all-black section is sent to the circuit 2, and the encoding in the circuit 2 is restarted.

If the all-white or all-black section is long and the buffer memory 6 becomes empty during the counting period, a signal i indicating that the buffer memory 6 is empty causes the dummy signal generation circuit 5 to output the signal g. is operated to send out a dummy signal h to the buffer memory 6.

In addition, when a code with the same pattern as a control code such as a synchronization code is generated in the code created in the all-white or all-black section encoding circuit 4, a zero is inserted into the generated code to distinguish it from the control signal. d activates the dummy signal generator 5 to add a dummy signal (for example, if the output code is made into a byte structure, add 7 bits of the dummy signal after inserting zero)
This is done to prevent the same pattern from appearing.

Furthermore, recording the all-white or all-black section on the receiving side that receives the transmission signal j requires a time of (recording time for one line) x (number of lines in the all-white or all-black section). Alternatively, if the all-black section is long, there is a risk that the buffer memory on the receiving side will overflow. For this reason, the receiving side is equipped with a buffer memory with a capacity corresponding to the longest frame of the encoded signal of image information, and the transmission time of one frame of image information sent next to the all-white or all-black signal is If the transmission time of one frame of image information is shorter than the recording time required for the black section, the signal e is used to add a dummy signal corresponding to the time difference. The signal generating circuit 5 is controlled to send out necessary dummy signals.

As described above, in the method of the present invention, by effectively utilizing the dummy signal generation circuit, efficient transmission is possible for all-white or all-black sections of any length using a buffer memory of a certain capacity. Become.

As described above, the present invention detects an image signal obtained by scanning reading every one line or every two lines,
Since it counts consecutive all-white or all-black lines and encodes the result, it eliminates the generation of repeated codes and reduces transmission time, making it an efficient means of transmitting facsimile signals. Therefore, the intended purpose of the invention can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a facsimile transmission device applied to the method of the present invention, FIG. FIG. 1...Reading unit, 2...1 or 2 line encoding circuit,
3... All white/all black detection circuit, 4... All white or all black section encoding circuit, 5... Dummy signal generation circuit, 6... Buffer memory.

Claims (1)

[Scope of Claims] 1. A reading unit that reads and scans a transmitted original and outputs a black-and-white binary image signal, and encodes the image signal from this reading unit every line or two lines, and adds a synchronization code and Outputs a coded image signal with an image information code attached, and if the transmission time of one frame of the coded image signal is shorter than the recording time required on the receiving side, a dummy signal corresponding to the time difference is added. an encoding circuit that outputs a control signal instructing the reader to read the image; Or, in the case of all black, an all-white all-black detection circuit that outputs an all-white or all-black verification signal and stops the encoding operation of the encoding circuit; Or input an all-black test signal, count and encode the number of consecutive lines, output an all-white or all-black line signal with a synchronization code, an all-white or all-black code, and a check bit, and Alternatively, an all-black interval end signal is output to the encoding circuit to restart the encoding operation, and if a code having the same pattern as a control code such as a synchronization code is generated, a dummy signal is attached to the generated code. an all-white or all-black section encoding circuit that outputs a control signal instructing the encoding circuit to perform an all-white or all-black section; an encoded image signal of the encoding circuit, an all-white or all-black line signal of the all-white or all-black section encoding circuit; While inputting the output signal of the dummy signal generation circuit and outputting the transmission signal, the memory becomes empty while the all-white or all-black section encoding circuit is counting the number of consecutive all-white or all-black lines. In this case, a buffer memory outputs a control signal indicating that the memory is empty, and the all-white or all-black section encoding circuit inputs the control signal from this buffer memory and converts the all-white or all-black line signal into the all-white or all-black line signal. The dummy signal continues to be output to the buffer memory until the dummy signal is output to the buffer memory, and the dummy signal is output to the buffer memory by the time difference according to the control signal corresponding to the time difference from the encoding circuit. A facsimile signal encoding method comprising: a dummy signal generation circuit that outputs a dummy signal to the buffer memory to distinguish it from the control signal for generating the same pattern code when inputted from the all-black interval encoding circuit. .