JPH02277657A - Image signal processing method - Google Patents

Abstract

PURPOSE:To enable an image of a required magnification to be effected by a method wherein an analog image signal is converted to a digital image signal, and is stored and held for a while, and the stored digital image signal is joined by the held same digital image signal to be stored. CONSTITUTION:When a trigger signal DIN for read is supplied to an image sensor 21, an analog image signal V1 is obtained. This signal V1 is converted to a digital image signal V2 with an A/D converter 22. When recording of 1 to 1 is performed, a selector 23 is switched to a contact (a) side and after ending shift operation of 1 to 1 with a register 24, is switched from the contact (a) to a contact (b). Consequently the register 24 performs shift operation again, and supplies its output to a memory circuit 25. Therefore, one pixel content analog image signal V1 is digitalized, is multiplied also two times, and that digital image signal is stored in the memory circuit 25. Therefore, by dividing a thermal head by reading that, magnified recording can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Fields of Application] The present invention is directed to reading paper wound into a roll, or The present invention relates to an image signal processing method suitable for use when recording the above-mentioned characters, figures, images, etc. on sheet-like paper.

[Prior Art] Copying machines are generally known as devices that read and record images. Some image recording apparatuses of this type are configured so that image reading is performed by a photoelectric conversion element such as a CCD, and image recording is performed by a recording means such as a thermal head.

Since the output signal of the COD, in other words, the image signal, is an analog signal, the image signal is converted into a digital signal and stored for each scan, and then sequentially read out to drive the thermal head to record the image. ing.

On the other hand, there are known devices that can not only record a read image at a ratio of 1:1, but also enlarge or reduce it by N times.

[Problem to be solved by the invention] In conventional enlarged recording, when obtaining an image signal from an image sensor such as a CCD, a clock signal is frequency-divided by 1/H and digitized using this frequency-divided clock signal. The digital image signal is multiplied by N times, that is, an integral number, by driving a register that temporarily holds the image signal and a memory circuit.

However, when using a copying machine, there are cases where it is necessary to make an enlarged copy by a factor other than an integral number, such as 1.4 times, and a copying machine that can make enlarged copies at any magnification has been proposed.

However, in the method of dividing the clock signal described above,
It was difficult to set a magnification other than an integer multiple.

On the other hand, as a means for arbitrarily setting the magnification, it is possible to use a zoom lens or the like, but this method is not preferable because the mechanical structure becomes complicated. Furthermore, enlarged recording using software requires time for signal processing, and there is a limit to speeding up reading and recording.

Therefore, the image signal of one pixel (-cell) is digitized and digitally multiplied by N times. That is, the level of each pixel of the read image signal is sampled and digitized. and,
In order to increase the image signal N times, the clock signal is frequency-divided by 1/H, and the frequency-divided digital image signal is added.

However, since the image signal is an analog signal, if the level at the sampling position is not held, the sampling level will fluctuate, and as a result, multiple levels (for example, binary) will have to be digitized. It is not possible to record an image that is faithful to the image. For example, a capacitor can be used as a level hold circuit, but in this case, a large number of capacitors must be provided corresponding to the number of pixels, and since some kind of impedance is connected to the capacitor, there is no risk of damage due to discharge. Level fluctuations cannot be completely reduced to zero.

The present invention has been made to solve the above-mentioned problems, and its object is to provide an image signal processing method that can perform enlarged recording of an image at a desired magnification regardless of level fluctuations of an analog image signal.

[Means and effects for solving the problem] The object of the present invention is to convert an analog image signal into a digital image signal, store it and temporarily hold it, and add the stored digital image signal to the stored digital image signal. This is achieved by an image signal processing method in which a digital image signal is additionally stored, and the digital image signal after the additional storage is read out as one image signal.

In other words, the same digital image signal stored at - time is added to the digital image signal that has been digitized and stored based on one sampling position of the analog image signal, so the level fluctuation of the analog image signal after sampling is not affected. A plurality of identical digital image signals corresponding to one analog image signal can be obtained without being affected, and an image signal with a desired magnification can be obtained.

Furthermore, the above object of the present invention is to multiply a digitalized image signal by an integer, and to compare a count value set in advance to a desired value with a preset count value for the digital image signal multiplied by an integer. The output is thinned out by
This is achieved by an image signal processing method that obtains a digital image signal with a different magnification from the digital image signal multiplied by an integer.

That is, an analog image signal is converted into a digital image signal and multiplied by an integer, and a count value in which the thinning cycle of the other digital image is set to a desired value in advance using a counter, for example, and the digital image signal multiplied by an integer are The decimation number is compared with a preset count value using, for example, a digital comparator, and by the decimation output obtained by the comparison, it is possible to obtain a digital image signal with a different magnification from the digital image signal multiplied by an integer. .

In other words, by comparing the count value set to the desired value and the count value of the digital image signal multiplied by an integer, if the count values match, the image signal is thinned out, and the multiplication factor other than the integer multiple is thinned out by the thinning number. Can be set to .

[Embodiment] Hereinafter, a first embodiment of the image signal processing method according to the present invention will be described based on the accompanying drawings.

The feature of this embodiment is the signal processing method when performing N-fold enlargement recording based on the image signal read from the original, but for convenience of explanation, we will explain the structure of the copying machine to which the present invention is applied sequentially. explain.

FIG. 1 is a perspective view of an enlarged copying machine to which the present invention is applied;
For example, it is configured to be able to enlarge and copy an A4 size original to AI size, and also to copy at a magnification of 1:1.

This enlarged copying machine includes a document reading device 1 and a recording device 2. The reading device 1 is equipped with an image sensor for scanning the document in the width direction and reading the image. When the document 4 is supplied to the reading device 1 from the document insertion slot 3, the document 4 is scanned by the image sensor. The document is conveyed to the original document outlet 5 and is discharged from the document discharge port 5.

The recording device 2 has a width of 594 m wound in a roll shape, for example.
The printer is equipped with three thermal heads that accommodate m of thermal paper 6 and print and scan the thermal paper 6 in the width direction. The three thermal heads have 64 dots within the effective main scanning width, are arranged at equal intervals on the same sub-scanning line, and each thermal head scans the thermal paper 6 at the same distance at the same time, thereby scanning one line across the width direction. is printed. Thermal paper 6 on which predetermined printing has been performed
is discharged from the discharge port 12.

FIG. 2 is a schematic configuration diagram of the recording apparatus 2, in which a roll of thermal paper 6 is loaded so as to be sandwiched between conveyor rollers made of silicone rubber, polyacetal, or the like. The thermal head 9 is fixed to a base 10 and scans in contact with the thermal paper 6 supported by a platen 11 to perform printing. When one scan across the entire width of the thermal paper 6 is completed, the print signal supplied to the thermal head 9 is cut off.
Returns to the original position and prepares for the next printing.

Next, an image signal processing method will be explained with reference to FIGS. 3 to 6.

FIG. 3 shows a signal processing system that enables N-fold enlarged recording (copying) and 1:1 recording.

The image sensor 21 reads the original 4, and since the image signal V1 generated by reading, that is, the read signal is an analog signal, it is converted by the A/D converter 22 into, for example, an 8-bit digital image signal V2. Ru.

The selector 23 is a so-called switch circuit, and has 1:
When recording 1, the contact is switched to the a side, and when recording is enlarged by N times, the contacts a and b are switched.

First, the signal processing operation when switching to the contact a side will be explained. The digital image signal V2 is supplied to the register 24 via the contact a of the selector 23.

The register 24 is, for example, a serial input type and parallel output type shift register, and supplies the digital image signal V3 temporarily held in a state in which the digital image signal V2 is shifted by one pixel to the memory circuit 25. The operations from reading to storing described above are performed sequentially for one scanning period of the image sensor 21.

FIG. 4 shows a waveform diagram during the 1:1 image recording, in which a trigger signal DIN for reading from the system controller (not shown) to the image sensor 21 is shown.
, an analog image signal V1 is obtained in synchronization with the clock signal CLK. Note that the analog image signal V1
Each number attached to indicates one pixel.

Since the analog image signal V1 is digitized as described above and then temporarily held, the memory circuit 2
5, they are sequentially stored in a state shifted by one pixel as shown as WR.

Therefore, when recording an image, 1:1 image recording is performed by sequentially reading out the stored digital image signals and driving the thermal head 9 as described above.

Next, a signal processing method for enlarged recording will be explained with reference to FIGS. 3 and 5.

In this case, after the 1:1 shift operation by the register 24 is completed, the selector 23 is switched from contact a to contact in synchronization with the falling edge of, for example, the final bit of the register output. Each switching operation is automatically performed by a system controller (not shown).

Since the output level of the register 24 maintains the same level after the 1:1 shift, it is sequentially supplied to the register 24 via the contacts of the selector 23, for example, starting from the most significant digit. As a result, the register 24 receives the clock signal c.
The shift operation is performed again in synchronization with lk, and the output thereof is supplied to the memory circuit 25. Therefore, the analog image signal v1 for one pixel is digitized, and as shown in FIG.
As shown in 1-1), (1-2), (2-1>, and (2-2), the digital image signal is doubled. The doubled digital image signal is stored in the memory circuit 25. Therefore, by reading this and driving the thermal head 9, it is possible to perform twice enlarged recording.

What should be noted in the signal processing operation is that the analog image signal V1 may be sampled at only one position as shown in FIG. That is, sif the first time) (1-1)
The resulting digital image signal V2 is converted into an analog image signal V
For example, the X position of 1 is sampled and digitally converted. Since the digital image signal (1-2) is obtained by shifting the digital image signal (1-1) as described above, there is no need for sampling.

If the digital image signal (1-2) is to be converted by sampling, sampling will be performed based on the level of the X position, for example, where the level has changed. ) is (1-
1) is changed from the value of 1). However, according to the image signal processing method shown in this embodiment, the digital image signals (1-1) and (1-2) for multiplying one pixel by N are
can be set to the same value, and accurate N-times recording, in this case, double-times recording, can be performed on the document.

Next, a second embodiment will be described with reference to FIG. Note that this embodiment uses two registers to multiply the digital image signal by N times, and the image sensor 21
, A/D converter 22, and memory circuit 25 have the same functions as described above.

When recording an image with a magnification of 1:1, selector 23
Connect to contact a. In this case, the digital image signal shifted by one pixel by the register 24 is supplied to the memory circuit 25 via the contact a. That is, in the embodiment described above, the same image signal processing as when switching to contact a is performed.

On the other hand, when performing enlarged recording, the selector 23 is switched to the contact point "S". In this case, the digital image signal shifted by one pixel by the register 24 is supplied to the register 24a connected in series. As a result, from the register 24a, (1-1), (1-2) ・
. . . A digital image signal shown in the figure is obtained and supplied to the memory circuit 25 in the same manner as described above.

Therefore, also in the image signal processing method shown in this embodiment, enlarged recording can be performed without being affected by level fluctuations of the analog image signal v1.

Note that the enlarged recordings described above are all 2x magnification, but by increasing the number of registers installed in Figure 6, the magnification of 4x, 8x, etc. can be achieved in Figure 3 without increasing the number of registers. It is also possible to do this.

However, all of the above magnifications are integral multiples, and in actual use, a magnification of 140%, for example, may be necessary.

Such magnification is achieved by performing image signal processing as described below.

Next, as a third embodiment of the present invention, an image signal processing method for achieving a magnification other than an integer multiple will be described.

FIG. 7 is an explanatory diagram showing the basic concept of this embodiment. The analog image signal v1 corresponding to one pixel in the main scanning direction shown in FIG. 2
) are respectively stored in memory as shown in FIG. 7(B). Next, as shown in FIG. 7(C), the light is supplied to the heating elements constituting the thermal head, but at this stage it is thinned out and transferred.

As a result, the thermal head shown in FIG. 7(C) has four
One of the pieces will be thinned out and output,
The magnification is determined by this thinning number.

Next, the signal processing will be explained in more detail with reference to FIGS. 8 and 9.

The image signal processing system shown in FIG. 8 is provided between the memory circuit shown in FIG. 7(B) and the thermal head shown in FIG. 7(C), and includes output ports, B1, B2. ,
...Bn has (1-1n, (1-2), (2-1)
, (2-2) are sequentially supplied. The CLK generator A1 is provided with a counter 31 that counts the clock signal and outputs a count value every desired cycle, and the output ports B1, B2, . . . Comparators 41, 42, . . . , 4n are provided for comparing the values. Note that a programmable down counter or the like may be applied to the counter 31.

When the count value set by the counter 31 and the count value set by the comparators 41 to 4n are equal,
A signal is output from each comparator 41 to 4n.

The output of each comparator is connected to NAN via the ○R circuit 51.
The signal is supplied to the D circuit 52, and the memory write timing signal is thinned out to become a memory write signal.

Now, suppose that the set value of the counter 31 is set to "10", and the comparators 41, 42, and 43 provided in the paths of the output ports (Bl, B2, and B3) are set to "3" and "6", respectively.
Set to "10". As a result, the memory write signal W
R is thinned out at the timing of "3", "6", and "10", and as shown in Figure 9, (21) (3-1) (5 -2) is thinned out to become the memory person data. That is, image sensor-2
When compared with the analog image signal V1 obtained from 1, 5
This means that the number of pixels has increased to 7 pixels, and the 140% enlarged recording can now be performed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above, and various modifications are possible.

For example, by selecting the set value of the counter and the set value of each comparator, it is possible to set a magnification other than the above-mentioned 140%.

[Effects of the Invention] According to the image signal processing method of the present invention, an analog image signal is converted into a digital image signal, stored and temporarily held, and the same held digital image signal is added to the stored digital image signal. By storing the same digital image signal, a plurality of the same digital image signals can be obtained.

Therefore, N based on the digital image signal digitized corresponding to one sampling position of the analog image signal is not affected by the level fluctuation of the analog image signal.
It can be doubled.

Further, according to the image signal processing method of the present invention, an analog image signal is converted into a digital image signal and multiplied by an integer, and a count value for setting a thinning period of the digital image signal and a digital image signal multiplied by an integer are obtained. By comparing the count value for setting the number of thinnings, it is possible to obtain a digital image signal with a different magnification from the digital image signal multiplied by an integer, and perform enlarged recording other than the integer.

Therefore, the magnification at which enlarged recording is performed can be arbitrarily changed by setting the plurality of count values, and image recording can be performed at various magnifications.

[Brief explanation of drawings]

1 to 5 show a first embodiment of the present invention, in which FIG. 1 is a perspective view of an enlarged copying machine, FIG. 2 is a schematic configuration diagram of a recording device, and FIG. 3 is an image signal A circuit diagram of the processing system, Fig. 4 is a waveform diagram explaining the image signal processing method, Fig. 5 is a waveform diagram showing the relationship between the integer magnification of the image signal and sampling, and Fig. 6 explains the second embodiment. FIG. 7 is an explanatory diagram showing the thinning operation of a digital image signal, FIG. 8 is a circuit diagram explaining the thinning operation, and FIG. 9 is a waveform diagram showing thinning and magnification. Reference numeral 1 in the figure: Reading device 2/Recording device 6 Thermal paper 9-Thermal head 21 Image sensor 22, ..., A/D converter 23 Selector 24
Register 25...-Memory circuit 31--Counter 41-4n--Comparator Vl Analog image signal V2 Digital image signal (A) No. (B) Fig. (C) Fig.

Claims (2)

[Claims] (1) Convert an analog image signal into a digital image signal, store it and temporarily hold it, add and store the held digital image signal to the stored digital image signal, and store the digital image signal after the additional storage. An image signal processing method that reads out a single image signal. (2) The digitized image signal is multiplied by an integer, and the digital image signal multiplied by the integer is compared with a preset desired count value and the preset count value is thinned out and output. An image signal processing method for obtaining a digital image signal with a different magnification from a digital image signal multiplied by an integer.