JPS5926153B2 - Facsimile reception method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile receiving system that records by filling in gaps between scanning lines.

In facsimile receivers, the sub-scanning line density is coarse,
If the size of the recording pixel is smaller than that, blank areas will occur between each scanning line of the recorded and reproduced image, resulting in a so-called sagging phenomenon.

This blurring phenomenon degrades the image quality, making it difficult to read text, etc. In particular, in receiving devices that employ a multi-stylus method, in order to ensure isolation between each stylus, the stylus density is increased to improve resolution, but in this case, the image dot naturally becomes smaller, resulting in the sagging phenomenon described above. appears as an unavoidable problem.

In order to improve this sagging phenomenon, the received facsimile signal is stored for each scanning line, and the signals stored within the original scanning time are read out multiple times at high speed.
A method has been proposed in which information of the same content is recorded in the sub-scanning direction as many times as the number of times it is read. According to this method, it is possible to fill the gaps between scanning lines, increase the recording density, and prevent the occurrence of sagging phenomenon. However, since only one scanning line information is recorded between two scanning lines, it cannot be denied that the entire reproduced screen looks unnatural.

The present invention has been made with attention to the above-mentioned circumstances, and its purpose is to use information on two adjacent scanning lines to determine information to be recorded between the scanning lines, thereby reducing naturalness. To provide a facsimile receiving system that can prevent the sagging phenomenon without causing any sagging, does not require adding a special configuration to the recording means for recording between scanning lines, and has a simple configuration of the recording means. . Embodiments of the present invention will be described below with reference to the drawings.

In Figure 1, facsimile pixel signals displayed in black and white binary values are stored for each scanning line, and the logical product of the pixel signals that have the same timing in the main scanning direction between the preceding and succeeding scanning lines is taken. FIG. 2 is a block diagram showing the main parts of a facsimile receiving device that fills in the gaps between adjacent scanning lines. In the figure, A, B, and C are line memories that each store pixel signals for one scanning line.
B and C are connected to the nth and n
+1st and n+2nd scanning line information is written. Then, each line memory A, B, and C read out the written information at twice the writing speed while the other two line memories write the two scanning line information that is later read and switch. Writing is performed cyclically via devices 1, 2, and 3.

Therefore, one line memory performs a write operation for one scanning line information in a period T, and performs a read operation four times at twice the speed during a post-read period 2T.

Therefore, to each line memory A, B, C, switch 4, 5,
6 selectively output two clock signals CPl and C
P2 is supplied.

Here, the frequency of CP2 is set to be twice that of CPl. AND circuits 7, 8, and 9 operate on the two scanning line information stored in line memories A and B1 line memories B and C1 line memories C and A, respectively, so that they have the same timing in the main scanning direction. .

The selection circuit D selectively extracts the outputs of the line memories A, B, and C and the outputs of the AND circuits 7, 8, and 9 according to a predetermined time pattern, and supplies them to recording means (not shown). Control signals A, b, and c shown in FIG. 2A, b, and c are supplied to the switching devices 1, 2, and 3 and the switching devices 4, 5, and 6.

The operation of the apparatus configured as described above will be explained with reference to FIGS. 2, 3, and 3.

First, switchers 1 and 4 are switched in accordance with control signal a, and n-th (n is a natural number) scanning line information A1 is written into line memory A during period T using clock signal CP1.

During the continuing period 2T, the switches 1 and 4 are switched, and the information A1 is cyclically read out and written into the line memory A four times using the clock signal CP2. After this period ends, the contents are erased in preparation for the (n+3)th scanning line information to be stored next. During this period, that is, while the line memory A is circulating the memory contents during the period 2T, in the first half of the period 2T, the line memory B is stored with n+
The first scanning line information B1 is written in the second half of the period 2T, and the (n+2)th scanning line information C is written in the line memory C in accordance with the control signal c in the second half of the period 2T.

Similarly to line memory A, the information written in each line memory B and C is cycled four times by clock signal CP2. Therefore, as shown in FIG. 2, each line memory A, B,
The output of C is in the form of chronologically arranging information with the same content four times in T/2 cycles during the circulating period 2T. Therefore, for example, the contents of line memory A and the contents of line memory B are compared by the AND circuit 7 in the second half of the line memory A circulation period 2T, that is, in the first half of the line memory B circulation period 2T. Therefore, the selection circuit D sequentially extracts the signals in the order of the output of the line memory A, the output of the AND circuit 7, and the output of the line memory B at a period of T/2, and arranges them in time series as shown in Fig. 2d. and supplies it to the recording means. As a result, as shown in FIG. 3A, a signal Al be done.

The signal A, ×B1 recorded here takes into account not only one scanning line information A, but also the other scanning line information B1 that has a correlation with it, so the reproduced image will be natural. It is of good quality and maintains its properties without sagging. If the AND circuits 7, 8, and 9 in the above embodiment are used as OR circuits, it is possible to obtain signals A and +B from the two scanning line information A and B1, and based on this, two scanning line information A and B1 can be obtained. By filling in the gaps between lines, the recording density can be increased as shown in FIG. 3b.

Furthermore, in the above embodiment, the case where a signal based on a logical product or a logical sum is recorded once between two scanning lines is exemplified, but the frequency of the clock signal in the cycle period 2T is three times that of the clock signal in the write period. , 4 times, etc., the number of recording times can be increased to 2, 3, and so on. As described in detail above, the present invention sets the read speed of the three line memories capable of sequentially recording one line of scanning line information to an integral multiple of 2 or more of the write speed, and the first of the three line memories With scanning line information for the n-th (n is a natural number) and n+1-th consecutive lines written in the second line memory, the scanning line information for the subsequent n+2-th line is written in the remaining third line memory. After performing a recording operation based on the scanning line information read from the first line memory during the period in which scanning line information is written, the first and second line memories are written.
The recording operation is performed at least once based on the calculated value obtained by performing an AND or OR operation on the scanning line information for two consecutive lines read from the line memory of the main scanning direction for each pixel at the same timing. This allows recording to be performed in the gaps between the scanning lines.

Therefore, according to the present invention, it is possible to prevent the sagging phenomenon without impairing the naturalness, and there is no need to add a special configuration to the recording means for recording between scanning lines. The configuration can be simplified.

In addition, while writing scanning line information to one line memory, scanning line information is read from another line memory, so that writing to and reading from three line memories can be performed efficiently. Since it acts as a buffer memory for speed adjustment, it can support high-speed reception and recording with a small amount of line memory.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a facsimile receiver used to explain an embodiment of the present invention, FIG. 2 is a signal waveform diagram to explain the operation of the receiver, and FIG. FIG. 3 is a diagram showing an example of a reproduced image. A, B, C... Line memory, D...
Selection circuit, 1 to 6...Switcher, 7, 8, 9...
...AND circuit.

Claims (1)

[Claims] 1 Three line memories each capable of sequentially storing one line of scanning line information are provided, the read speed of these line memories is an integral multiple of 2 or more of the write speed, and the first of the three line memories is and the n-th (n is a natural number) and n+1-th successive 1s in the second line memory.
While scanning line information for one line has been written and scanning line information for the subsequent n+2 line is being written to the remaining third line memory, the first line memory is read. After performing a recording operation based on the scanning line information obtained through the operation, a reading operation is performed on the first and second line memories, and the obtained scanning line information for two successive lines is read as the main memory. A recording operation is performed at least once based on the calculated value obtained by performing an AND or OR operation for each pixel at the same timing in the scanning direction, and the recording operation is performed at least once for each pixel stored in the first and second line memories. A facsimile receiving system characterized in that recording based on the calculated value is performed at least once in a gap between recording scanning lines in which scanning line information is recorded.