JPS628984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image signal processing device that processes an image signal (hereinafter referred to as a scanning line signal) obtained by scanning an original, such as a facsimile signal.

In a facsimile machine that employs a band compression method, the linear density is usually switched depending on the information density of the transmitted document in order to reduce transmission time. That is, a plurality of scanning line signals depending on the information density are collectively converted into a single scanning line signal. Depending on the information density of the sent document, set the linear density (resolution) to, for example, 7.7 lines/mm or 3.85 lines/mm.
mm, 2.57 lines/mm (that is, 1:1/2:1/3) and transmits. When the information density of the original is high, the signal is set at 7.7 lines/mm for each scanning line, when the information density is intermediate, the signal is set at 3.85 lines/mm, and one scanning line signal is sent every 2 scans, and when the information density is low, is 2.57 lines/mm
One scanning line signal is transmitted every three scans. On the other hand, when the receiving side receives one scanning line signal,
In each of the above cases, the cooperation coefficients are matched by repeating one scan, two scans, and three scans.

Conventionally, in such cases, one scanning line signal out of a plurality of scanning line signals has been processed as a signal and transmitted. This conventional processing method can be used to obtain one scanning line signal every three scans.
This will be explained using FIG. 1 as an example. scan line 1
Reference numerals 1, 12, and 13 indicate three scanning line signals to be processed at once. Conventionally, one scanning line signal among these three scanning line signals, for example, scanning line signal 11
, and the remaining scanning line signals 12 and 13 were not transmitted and were discarded. Therefore, the transmitted signal is
As shown in figure a, the black part 2 of the sent document will be displayed.
1 is transmitted, but portions that are not recognized as black on the scanning line signal 11, such as the black portions 22 and 23, are omitted. Therefore, the image recorded on the receiving side becomes as shown in FIG. 2b, and the information in the black portions is significantly lost, which is a cause of deterioration in image quality.

An image signal processing method that eliminates these drawbacks, maintains the advantages of band compression, minimizes the loss of information in the transmitted document, and can obtain recorded images of good image quality is disclosed in Japanese Patent Application Laid-Open No. 51-51216, for example. It is stated in the No. In other words, in this method, multiple scanning line signals obtained by scanning an image are processed all at once, the number of which corresponds to the information density of the image, into a single scanning line signal. A logical sum signal of a plurality of scanning line signals is generated, and this logical sum signal is used to collectively process a single scanning line signal.

Japanese Unexamined Patent Publication No. 51-51216 describes a device equipped with a one-line memory and an OR gate as an apparatus for carrying out such an image processing method. It is not possible to input a new scanning line signal to this memory. Therefore, two sets of one-line memories and OR gates are provided, and when one set outputs an OR signal, the other set is alternately switched to generate an OR signal. Therefore, two 1-line memories and two OR gates are required, and switching circuits are also required on the input side and the output side, respectively, making the configuration considerably complicated and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and to provide an image signal processing device that can generate an OR signal of a plurality of scanning line signals with an extremely simple and inexpensive configuration.

The present invention provides an apparatus for obtaining a single scanning line signal by collectively processing a plurality of scanning line signals obtained by scanning an image in a number corresponding to the information density of the image.
a shift register having a number of bits equal to the number of pixels included in one scanning line signal; an OR gate having one input terminal connected to the scanning line signal input terminal and an output terminal connected to the input terminal of the shift register;
an AND gate in which one input terminal is connected to the output terminal of the shift register and the output terminal is connected to the other input terminal of the OR gate, and the first scanning line signal among the plurality of scanning line signals to be processed at once. a control circuit that supplies a signal to the other input terminal of the AND gate to turn off the AND gate during the period and turn on the other bases; , a logical sum signal of a plurality of scanning line signals that are supplied immediately before the scanning line signal to be processed at once is supplied as a single scanning line signal that is processed at once. .

The present invention will be described in detail below with reference to the drawings.

In the present invention, when processing a scanning line signal prior to transmission, if there is even one black at a corresponding pixel position of a plurality of scanning line signals to be processed at once, the processed single scanning line is processed. The pixel corresponding to the signal is made black. In other words, when processing three scanning line signals 11, 12, and 13 as shown in Fig. 1, if there is black in even one of the pixels corresponding to the top and bottom, that is, the pixel position with the same number, the corresponding position of the transmission signal is detected. The pixels in the image are black. The transmitted signal processed in this way is shown in Figure 3a, and the image recorded on the receiving side is as shown in Figure 3b, where not only the black part 21 but also the black parts 22 and 23 are shown. There are no omissions, and recorded images with good image quality can be obtained.

FIG. 4 is a block diagram showing the configuration of an example of an image signal processing device according to the present invention. An input scan line signal to be processed is received at an input terminal 41, and a strobe signal corresponding to each pixel of the input scan line signal is received at a strobe signal input terminal 42. A signal obtained by collectively processing a plurality of scanning line signals is output from the output terminal 43. The strobe signal input terminal 42 is connected to a pixel counter 44 via a conductive wire 401, and the number of pixels for one scanning line is counted using the strobe signal. The output terminal of this pixel counter 44 is connected to a scanning line counter 45 via a conductive wire 402,
Count the number of scanning lines to be processed at once. The output terminal of the scanning line counter 45 is scanned through the conductor 403.
It is connected to a scan line discriminator 46 to discriminate between the first scan line and the other scan lines among the scan lines to be collectively processed. The output terminal of this scanning line discriminator 46 is connected to the conductor 4
04 to one input terminal of the AND gate 47. The output terminal of this AND gate 47 is connected via a conductor 405, the input terminal 41 is connected to the input terminal of an OR gate 48 via a conductor 406, and the output terminal of this OR gate is connected to the input terminal of a shift register 49 via a conductor 407. The number of bits in this shift register 49 corresponds exactly to the number of pixels for one scanning line signal, and a strobe signal is supplied as a shift clock. The output of this shift register 49 is connected to the output terminal 43 via a conducting wire 409 and to the other input terminal of the AND gate 47 via a conducting wire 410.

Next, the operation of this example device will be explained. It is assumed that both the pixel counter 44 and the scanning line counter 45 are initially cleared. Scan line discriminator 4
6 receives the output of the scanning line counter 45 via a conducting wire 403, discriminates whether the content of the scanning line counter 45 is O or not, and supplies this discrimination output. The output of this scanning line discriminator 46 is connected to open and close an AND gate 47 via a conductor 404, and when the content of the scanning line counter is O, the AND gate 47
Close 7 and open it when it is not O. Therefore, the output of the AND gate 47 is initially no signal, and the scanning line signal is sent from the input terminal 41 to the conductor 406.
The signal passes through the OR gate 48 and is led to the serial input terminal of the shift register 49 via a conductive wire 407. A strobe signal generated corresponding to each pixel of the scanning line signal supplied to the input terminal 41 is counted by the pixel counter 44 from the input terminal 42 via the conductor 401, and at the same time is counted by the pixel counter 44 via the conductor 408 to the shift clock terminal of the shift register 49. The scanning line signal supplied to the serial input terminal is read. In this way, the scanning line signals together with the strobe signals are read into the shift register 49 and stored one after another. When exactly one scanning line worth of signals is stored, the first pixel of the first scanning line signal appears at the output terminal of the shift register 49. On the other hand, the pixel counter counted the number of pixels for one scanning line, so it turned O again.
Then, a carry signal is sent to the scanning line counter 45 via the conductor 402, and the scanning line counter 45 counts this to indicate that reading for one scanning line has been completed. The content of the scan line counter 45 is discriminated as not O by a scan line discriminator 46 via a conductor 403, and this output is supplied to an AND gate 47 via a conductor 404, which opens the AND gate 47. Therefore, when the second and subsequent scanning line signals are input, the AND gate 47 is open, so the output of the shift register 49 passes through conductors 409 and 410, passes through the AND gate 47, and passes through the conductor 405. It is supplied to one input terminal of OR gate 48. The other input terminal of the OR gate 48 is supplied with a scanning line signal from the input terminal 41 via a conductor 406. Since the output of the OR gate 48 is connected to the serial input terminal of the shift register 49 via the conductor 407, the first pixel of the second scan line signal is the first pixel already stored in the shift register 49. is logically summed with the first pixel of the scanning line signal and shifted in from the serial input terminal of the shift register 49.
The second pixel of the first scanning line signal appears at the serial output terminal of the first scanning line signal. Of course, this shift is effected by the incoming strobe signal corresponding to the pixel, and the number of read pixels is subsequently counted by the pixel counter 44. Generally, the nth pixel of the second scanning line signal is logically ORed with the nth pixel of the first scanning line signal already stored in the shift register 49, and
It is shifted in from the serial input terminal No. 9. Therefore, after all the second scanning line signals arrive, the contents of the shift register 49 are the logical sum of each pixel corresponding to the first scanning line signal and the second scanning line signal. It has become a new scanning line signal. Thereafter, by the same operation, the third and subsequent scanning line signals are further added as a logical sum, and the contents of the shift register 49 become a sequence of signals given by the logical sum of each pixel in the corresponding order of the plurality of scanning lines. Become. This sequence of signals is used as a transmission signal as shown in FIG. 3a. In other words, if even one pixel is black at the corresponding position of a plurality of scanning line signals to be processed at once, the pixel at the corresponding position of the transmitted scanning line signal can be made black.

FIG. 5 shows an example in which the image signal processing apparatus of the present invention shown in the block diagram in FIG. 4 is constructed using an IC. In FIG. 5, the same parts as those shown in FIG. 4 are designated by the same reference numerals. Pixel counter〓〓〓〓
The Ta 44 is made by Texas Instruments.
It is constructed by connecting three SN7493 type ICs in series, and the scanning line counter 45 is constructed using an SN74107 type IC manufactured by Texas Instruments, which counts four scanning lines in this example. In addition, the shift register 49 uses two 2533 type ICs manufactured by Fairchild.
Configure by arranging them in series.

In the image signal processing device of the present invention described above, a logical sum signal of a plurality of scanning line signals is created by a combination of a shift register for one scanning line, one OR gate, and one AND gate, and this is Since the new scanning line signal can be output while being processed, the configuration is extremely simple and inexpensive.

The present invention is not limited only to the examples described above, but can be modified and modified in many ways. For example, in the above example, the logical sum is calculated for black pixels, but it is also possible to perform the logical sum for white pixels.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing multiple scanning line signals to be processed at once; FIGS. 2a and b are diagrams showing scanning line signals and recorded images obtained by a conventional processing method; FIGS. 3a and b 4 is a block diagram showing the configuration of an example of the signal processing device of the present invention, and FIG. 5 is a diagram showing the specific configuration of the signal processing device of the present invention. It is a circuit diagram. 41...Scanning line signal input terminal, 42...Strobe signal input terminal, 43...Processing scanning line signal output terminal, 48...OR gate, 49...Shift register, 44...Pixel counter, 46...Scanning line discrimination Vessel, 47...and gate. 〓〓〓〓

Claims (1)

[Claims] 1. In an apparatus for obtaining a single scanning line signal by collectively processing a plurality of scanning line signals obtained by scanning an image in a number corresponding to the information density of the image, A shift register having a number of bits equal to the number of pixels included, an OR gate having one input terminal connected to the scanning line signal input terminal and an output terminal connected to the input terminal of the shift register, and one input terminal connected to the output terminal of the shift register. and an AND gate whose input terminal is connected to the other input terminal of the OR gate and whose output terminal is connected to the other input terminal of the OR gate. a control circuit that supplies a signal that can be turned off and turned on during other periods to the other input terminal of the AND gate; An image signal processing device characterized in that a logical sum signal of a plurality of supplied scanning line signals to be processed at once is obtained as a single scanning line signal processed at once. 2. The device according to claim 1, further comprising an input terminal for receiving a strobe signal corresponding to a pixel, the strobe signal controlling writing and reading of the shift register, and counting the strobe signal. a scanning line counter that counts the output of the pixel counter; and a scanning line discrimination circuit that determines whether the counted value of the scanning line counter reaches the number of scanning line signals to be combined. , an image signal processing device characterized in that the AND gate is controlled by the output of the scanning line discrimination circuit.