JPH0515102B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an image processing apparatus that reads an original image line by line and outputs an image signal for image reproduction.

(Prior art) In a conventional image processing device of this type, that is, a so-called copying machine, for example, when copying an A4 size document image of 297 mm in width at a pixel density of 16 pel/mm, a 4752-bit solid-state image sensor is used. using columns,
Assuming 1 bit is 9 microns, the width of the original image is 297
mm is optically reduced to 42.768 mm, which is read and converted into an image signal for each pixel column, and the image signal is supplied to the recording section. In the recording section, the image signal is recorded using a laser beam printer, for example, which is set to record an image at a pixel density of 16 pel/mm, that is, 1 dot is 62.5 microns, and the document image is printed in A4 size. Visualize.

Generally, in this type of image processing device, main scanning of the original image is performed electrically by sequentially switching the solid-state image sensor array, and sub-scanning is performed by mechanical parallel movement of the pixel array imaging optical system. conduct. Therefore, when performing variable-magnification copying, that is, copying that is enlarged or reduced to a size different from the original image, the speed of the mechanical scanning of the sub-scanning is made different from that for full-size copying, and the speed of the enlarged copying is changed. In the case of enlarged copying, the sub-scanning speed is reduced, and in the case of reduced copying, the sub-scanning speed is increased. Interpolation between pixels is applied to the data, and pixel thinning is performed in the case of reduced copying.

Therefore, in the case of enlarged copying, there is no difference in the amount of image information read and reproduced and recorded compared to that of full-size copying, and there is no change in the definition of the reproduced recorded image, but in the case of reduced copying, Conventional image processing of this type has the drawback that the amount of image information to be read, reproduced and recorded is smaller than in the case of full-scale copying, and the definition of the reproduced and recorded image is reduced, such as missing thin lines, resulting in a significant deterioration of image quality. There was a problem with the device.

(Objective) An object of the present invention is to provide an image processing device that eliminates the above-mentioned conventional drawbacks and can perform reduced reproduction without causing image quality deterioration such as missing fine lines in reproduced recorded images. , a light source that illuminates the original image; a solid-state image sensor array that generates image signals of N pixels per line by reading the original image illuminated by the light source; In the 1x mode, the image signal is interpolated and output at predetermined intervals as an image signal for 1x image reproduction of M pixels larger than N pixels, and in the N/M reduction mode, it is output as an N/M reduced image of N pixels as it is. The present invention provides an image processing apparatus having an output means for outputting an image signal for reproduction at the predetermined intervals.

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

The image processing apparatus of the present invention not only does not perform pixel thinning of the image signal read by electrical scanning of the solid-state image sensing element array when reducing copying, but also
The image quality of the reproduced recorded image is maintained by performing interpolation processing between the pixel columns of the image signal read by mechanically moving the pixel column imaging optical system.

FIG. 1 shows an example of the basic configuration of a reading section in an image processing apparatus of the present invention. In the illustrated configuration,
A moving document 1 is illuminated by an illumination lamp 2,
The image on the original 1 is projected onto a solid-state image sensor array (CCD) 4 by a lens 3 and photoelectrically converted to form an image signal, and the image signal (IVDO) 6 is extracted via an amplifier 5.

Next, FIG. 2 shows an example of the basic configuration of a laser beam printer as a recording section in the image processing apparatus of the present invention. In the illustrated configuration, the image signal (IVDO) 6 from the reading section described above is guided to a semiconductor laser 9 via a DC controller 7 and a laser driver 8, and the laser light is modulated. On the other hand, the polyhedral mirror 13 is rotated by the scanner motor 11 driven by the scanner driver 10 in response to a drive signal synchronized with the image signal from the DC controller 7 . It is fed back to the driver 10 and controlled in synchronization with the image signal. The photosensitive drum 1 is charged and rotated by the laser beam deflected by the polyhedral mirror 13 through the lens 14.
5 is scanned to record an electrostatic latent image on the drum surface, and the reflected laser beam from the fixed mirror 16 is
The light is received by a photodiode 18 through a slit 17 to drive a horizontal synchronizing circuit 19, and a scanner driver 10 is synchronously controlled via a DC controller 7. Note that the electrostatic latent image on the photosensitive drum 15 is
After being visualized using an electrophotographic processing device (not shown), the image is transferred and taken out.

Next, FIG. 3 shows an example of the circuit configuration of the reading section in the image processing apparatus of the present invention. In the illustrated circuit configuration, a solid-state image sensor array (CCD) _{23 is driven by a clock pulse φ 1} obtained by dividing the original clock signal from a clock generator 20 by a frequency divider ( ) 21, as described above with reference to FIG. The image signal read in this way is sent to an amplifier 24 and an A/D converter 25.
are sequentially written into the memory () 26. The clock pulse φ ₂ that controls writing of the image signal to the memory ( ) 26 is generated by the clock generator 20.
The frequency of the original clock signal is variably divided by a frequency divider (22), and the frequency division ratio is variably set according to the magnification information of the reproduction/recording. memory()
The image signal written in 26 is first transferred to a separately provided memory () 27, and then clock pulse φ ₃ is generated from a separately provided clock generator 28.
is driven and sequentially read out. This clock pulse _φ3 is synchronized with the write control clock in the recording section, and the image signal read from the memory ( ) 27 is transferred to the recording section, where it is reproduced and recorded as described above.

FIG. 4 shows a time chart showing the time relationship between the image signal and the clock pulse φ ₂ for driving the image signal writing to the memory ( ) 26 in the circuit configuration of the reading section described above. In the illustrated time chart, a solid-state image sensor array (CCD) 23
When the driving clock pulse φ ₁ and the memory ( ) 26 write driving clock pulse φ ₂ have the same clock period, and φ ₂ = φ ₁ , the pixel density is the same at 1:1 with respect to the pixel density of the image signal. If the clock period of the writing drive clock pulse φ ₂ is twice the clock period of the CCD driving clock pulse φ ₁ (φ ₂ = 2φ ₁₎ , the pixel density of the image signal The image signal is written into the memory ( ) 26 at a pixel density twice that of 2:1, and the clock period of the write driving clock pulse φ ₂ is set to 1/2 of the clock period of the CCD driving clock pulse φ ₁ . φ ₂ = φ ₁ /
2, the pixel density of the image signal is 1:
Memory of image signals at 1/2 times the pixel density of 2 ()
Write to 26. Therefore, as before, φ ₂
If = φ ₁ , we assume that the same size copy is to be made.
When φ ₂ =2φ ₁ , the copy is enlarged by 200%, and when φ ₂ =φ ₁ /2, the copy is reduced by 50%.

As you can see from the time chart above, when making a reduced copy, the pixels of the image signal are thinned out, resulting in a significant deterioration in image quality, but when making an enlarged copy, the pixels of the image signal are divided and interpolated, so the enlarged copy Even if you do this, there will be no deterioration in image quality. In the image processing apparatus to which the present invention is applied, by utilizing the relationship between deterioration and maintenance of image quality, the memory write drive clock pulse φ ₂ and the CCD are adjusted so that φ ₂ >φ ₁ even during full-size copying. A clock cycle with a driving clock pulse φ ₁ is set, and the original image is reduced and projected onto a solid-state image sensor array at a reduction ratio corresponding to the clock cycle, and reduced copying is performed.
Furthermore, when copying at the same size, pixels of the image signal are interpolated and enlarged so that the same size image can be reproduced and recorded.

For example, as shown in FIG. 5, which is a combination of FIG. 1 and FIG.
In the reading section, which is moved by a motor 36 driven by a motor driver 35 under feedback control by an encoder 37 and illuminated by a light source 33 driven by a dimming circuit 31 and a lighting circuit 32, a clock pulse for driving memory writing is used. _φ2 and
The clock period with the CCD driving clock pulse φ ₁ is set to φ ₂ =1.33φ ₁ , and the document 34 with a width of 297 mm is reduced and projected onto the solid-state image sensor array 39 with a 3564-bit configuration.
Driven by clock pulse φ ₁ to increase pixel density
Read at 12pel/mm. Further, the speed of sub-scanning by moving the original 34 is set to a speed suitable for full-size copying, and the pixel density is set to 16 pel/mm. Furthermore, when the read image signal is driven by clock pulse φ ₂ and written to memory ( ) 43, φ ₂ =1.33φ ₁ , so interpolation between pixels is performed and memory ( ) 43 is written.
43, the number of bits in one line is 4752 bits, and the pixel density is 16 pel/mm. The image signal is transferred to a memory ( ) 45, driven and read out by a clock pulse _φ3 having the same clock cycle as the write clock of the printer, and supplied to a printer (not shown) for enlarged copying.

On the other hand, in order to obtain a reduced image, it is sufficient to reduce the clock cycle of clock pulse φ ₂ for memory write drive and increase the speed of sub-scanning due to the movement of the original. Since the image is obtained by interpolation, a reduced image can be obtained by reducing the number of interpolated pixels without thinning out pixels until φ ₂ =φ ₁ . In the above example, when φ ₂ =φ ₁ , a 75% reduced image is obtained. As described above, since the pixels of this reduced image are not thinned out, the amount of read image information does not decrease, resulting in a high-quality reduced image.

In the example described above, the copy magnification in the sub-scanning direction was set to the desired magnification by changing the sub-scanning speed. Similarly, the copy magnification in the sub-scanning direction can be changed by interpolating or thinning out pixels by signal processing of image signals.

(Effect) As explained above, according to the present invention, N/M
In the reduction mode (N<M), the image signals generated by the solid-state image sensor array are output as they are, so
Even in the N/M reduction mode, omission of original image information such as thin lines does not occur due to thinning, and high-quality reduced image reproduction is possible. Therefore,
The present invention is particularly effective when applied to, for example, a case where an A2 size reader is combined with an A3 size printer to make a reduced copy of an original image.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the basic structure of the reading section in the image processing apparatus of the present invention, and FIG. 2 is a block diagram showing an example of the basic structure of the recording section.
FIG. 3 is a block diagram showing an example of the circuit configuration of the reading section, FIG. 4 is a time chart showing an example of the operation of each part in the circuit configuration of the reading section, and FIG. 5 is the entire reading section. FIG. 3 is a block diagram showing an example of the configuration. 1, 34... Original, 2, 33... Illumination lamp (light source), 3, 14, 38... Lens, 4, 23,
39... Solid-state image sensor array (CCD), 5, 24, 4
1... Amplifier, 6, 29, 47... Image signal, 7
...DC controller, 8...laser driver,
9...Semiconductor laser, 10...Scanner driver, 11, 36...Motor, 12...Tachometer generator, 13...Polyhedral mirror, 15...Photosensitive drum, 16...Fixed mirror, 17...Slit,
18...Photodiode, 19...Horizontal synchronization generation circuit, 20, 28, 40, 44, 46...Clock generator, 21, 22...Frequency divider, 25, 42...
...A/D converter, 26, 27, 43, 45...
...Memory, 30...Control unit (CPU), 31
...Dimmer circuit, 32...Lighting circuit, 35...Motor driver, 37...Encoder.

Claims (1)

[Scope of Claims] 1. A light source that illuminates a document image; a solid-state image sensor array that generates an image signal of N pixels per line by reading the document image illuminated by the light source; and a solid-state image sensor array that generates an image signal of N pixels per line. In the 1x mode, the generated image signal of N pixels is interpolated and outputted at a predetermined interval as an image signal for 1x image reproduction of M pixels larger than N pixels, and in the N/M reduction mode, the image signal of N pixels is output as is. An image processing apparatus comprising an output means for outputting at the predetermined intervals as an image signal for reproducing an N/M reduced image.