JPS6134788Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile signal reproducing device, and particularly to a device for recording change points in the sub-scanning direction in halftones.

Conventionally, in order to increase the reproduction speed of facsimile signals, an apparatus has been developed that simultaneously reproduces one line of pixels in the main scanning direction, as shown in FIG. Such a device includes a number of recording elements 94 corresponding to the number of pixels for one line in the main scanning direction;
It consists of a shift register 92 with the same number of flip-flops 93 as 4, and an AND gate 95 connected to the output side of each flip-flop 93 to send the stored contents to the corresponding recording element 94. After storing the image signal 82 for one line in the main scanning direction, AND
By applying a control signal 96 to one input terminal of the gate 95, images can be reproduced one main scanning line at a time.

However, in the above device, the received image signal 8
When a jitter occurs in 2, as shown in ₃ in FIG. 3d, the jitter is reproduced as is, as shown in ₃ in FIG. 3f, and the quality of the reproduced image is significantly impaired.

The present invention is based on the fact that the reproduced image has a correlation in the sub-scanning direction, and that when the changing points of the reproduced image are reproduced in halftones, for example, when the reproduced image is text information, the intelligibility increases by 15 to 20%. is equipped with a storage unit that simultaneously stores at least two lines in the sub-scanning direction, detects the presence or absence of an image signal in each pixel of an adjacent line, and when there is an image signal on both lines. The object of the present invention is to provide a facsimile signal reproducing device that can improve the clarity of the reproduced image by reproducing the image signal in black, or in halftone if there is an image signal in only one of them.

The present invention will be specifically described below based on embodiments shown in the drawings.

The facsimile signal reproducing device according to the present invention includes:
As shown in FIGS. 1 and 2, in the sampling circuit 1, the received image signal 80 is sampled and quantized using the clock signal 81, and then the main scanning signal 80 is quantized.
The shift registers 3 and 3a that store the quantized image signal 82 are changed for each line by the gate circuit 2.

The gate circuit 2 includes four sets of AND gates 21, 2
Consisting of 2, 23, 24, 1st and 2nd AND
The output signal 82 of the sampling circuit 1 is input to one input terminal of the gates 21 and 22, and the switching signals 83 and 84 output from the switching signal generation circuit 6 are input to the other input terminal. Switching signal generation circuit 6
is one in which signals are output alternately to both output terminals each time the phase signal 85 is inputted once, and therefore 1
For each main scan, the image signal 82 is the first or second AND
The signals are output alternately from either gate 21 or 22. The switching signals 83 and 84 are simultaneously input to the third and fourth gates 23 and 24, respectively, and the clock signal 81 input to the other end is input to both gates 23 and 2.
4 to 1 scanning line alternately.

The number of shift registers storing the image signal 82 is 2.
Each register 3, 3a has a number of flip-flops 3 corresponding to the number n of reproduced pixels in the main scanning direction.
Consists of 1.

The first shift register 3 includes a first AND gate 2
1 and the third AND gate 23
The image signal output from the second gate 22 and the clock signal output from the fourth gate 24 are respectively input to the second shift register 3a. The signals are alternately switched and stored in the first and second shift registers 3, 3a. 1st and 2nd
The outputs from the flip-flops 31 and 31 at the same location in the shift registers 3 and 3a are simultaneously applied to the control circuit 4, and two types of control signals 86 and 87, long and short, are applied to the recording element 5 depending on the presence or absence of a significant signal. It is possible.

Each control circuit 4 has the same configuration, and the second
As shown in the figure, the image signals output from the first shift register 3 and the second shift register 3a are input to an AND gate 41 and an exclusive OR gate 42 whose input sides are connected in parallel. If both signals are stored in the same bit in 3a, the signal is output from the AND gate 41, and if only one is input, it is an exclusive signal.
A signal is output from the OR gate 42. Further, the output signal from the AND gate 41 is combined with a pulse signal 86 having a long pulse width corresponding to black reproduction of the recording element 5.
Apply to AND gate 43, exclusive OR
The output of the gate 42 is combined with a short pulse signal 87 having a pulse width corresponding to halftone reproduction of the recording element 5.
applied to AND gate 44. Both AND gate 4
In addition to the additional OR gate 45, the outputs of 3 and 44 are
By connecting the recording element 5 to the output side of the OR gate 45, one of the long and short pulses 86 and 87 is applied to the recording element 5 during the phase period, thereby making it possible to reproduce not only black but also a half-black state.

However, when the transmitting side sequentially scans each line ₁ , ₂ , etc. of the original 90 as shown in Fig. 3a, the lines correspond to the white and black parts of the original 90 as shown in Fig. 3b. The image signal 80 is transmitted.

On the receiving side, on the other hand, by quantizing the image signal in the sampling circuit 1 using the clock signal 81 as shown in FIG. 3c, the recording element 5 as shown in FIG.
A quantized image signal 82 having a shape corresponding to the number of is obtained.
This image signal 82 is processed by the gate circuit 2, for example.
The image signal _{No. 1} is stored in the first shift register 3, the image signal No. ₂ is stored in the second shift register 3a, and so on, while changing the storage register for each main scanning line.

Here, since _{the first} and _second image signals 82 and 82 have the same waveform with the three bits h, i, and j in the "high" state, the h, i, and jth control circuits 4 use the long pulse 86 as the recording signal. In Fig. 3e,
₂ , the recording element 5 prints in black for 3 bits.

Next, when jitter occurs in the transmission line, as shown in ₃ in FIG.
The image signal 82a stored in the shift register 3 is
Significant signals exist only at the j, k-th bits. The signals _{No. 2} and _{No. 3} are compared bit by bit in the control circuit 4. That is, since h, i, k and bits only have a significant signal of either ₂ or ₃ , the control circuit 4 outputs a short pulse 8.
7 is selected and displayed in an intermediate tone as shown in ₃ in FIG. 3e, and the j-th bit is displayed in black since both lines have significant signals. Therefore, in conventional equipment,
As shown in ₃ in FIG. 3F, the reproduced portions that are missing or protrude are displayed in halftones, and defects during reproduction due to jitter, noise, quantization errors, etc. become less noticeable.

In the above embodiment, the time for applying the signal to the recording element 5 is changed to reproduce the halftone.
Depending on the type of recording element, the voltage or current value can be changed as appropriate.

In addition, the number of shift registers 3 is increased to 3 or more, and 1
If there is a significant signal only on the line, the first gradation,
It goes without saying that the above embodiment can be extended to perform reproduction at three or more gradations, such as a second gradation when there is a signal on two lines.

As mentioned above, the present invention is equipped with a plurality of shift registers 3 that store image signals for one line, and
In addition to changing the register 3 stored each time, the contents of each register are compared bit by bit and reproduced in multiple gradations from black to white depending on the presence or absence of a significant signal, so jitter, etc. This has an excellent effect of reducing the influence of the image and improving the quality of the reproduced image.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an outline of the device according to the present invention, Fig. 2 is an electric circuit diagram showing details of the signal selection circuit in Fig. 1, and Figs. 3 a to f are reproductions from scanning of a transmitted original. Explanatory diagram showing the situation up to 4th
The figure is a block diagram showing a conventional example. 2... Gate circuit, 3, 3a... Shift register, 4... Control circuit, 5... Recording element, 6... Switching signal generation circuit.

Claims (1)

[Claims for Utility Model Registration] Image signals for one line of main scanning are serially input into a storage unit and stored digitally, and then the stored contents of each bit are retrieved in parallel to generate image signals for one line. In an apparatus for simultaneous reproduction, a plurality of sets of memory sections are provided, and the input side of each memory section is provided with a gate circuit 2 for switching the memory section for each main scanning line, and the output side of each memory section is provided with a gate circuit 2 for switching the memory section for each main scanning line. A control unit is provided that outputs a control signal that compares the memory contents at the same address in the storage unit and determines the print density depending on the presence or absence of a significant signal. A recording element 5 is provided for each bit in the storage section, and the control section prints the recording element 5 darker when there are many storage sections storing significant signals at the same location. Further, a facsimile signal reproducing device is characterized in that when there is a small number of storage units storing significant signals, a control signal is outputted to make printing lighter. The playback device according to claim 1, wherein the storage unit is a shift register.