JPS61261960A - Image reader - Google Patents

Abstract

PURPOSE:To eliminate the generation of an omission and doubling of an image, and to improve the picture quality by preparing plural driving pulse clocks of a phtoelectric converting element, and executing a reduction and magnification of the image by switching its driving pulse clock in accordance with a variable power request. CONSTITUTION:In accordance with a variable power command, a discriminating signal of one of reduction, unmagnification and magnification is applied to a switch SW1 from a controller 6, it is connected to a reduction oscillating circuit 7, when the discriminating signal is of reduction, and a synchronizing signal of an output frequency f1 from the circuit 7 is sent out to a clock generator 5 and a sample holding circuit 2. Subsequently, a CCD 1 is driven by the frequency f1, an image data is sampled in a shorter time than a standard (unmagnification) by the sample holding circuit 2, and thereafter, binary-coded by a binary-coding circuit 3, and also, when it is processed by a fixed sample rate in an image processing circuit 4, when it has been brought to a print output by a recording means, a reduced reproducing image is obtained. In the same way, unmagnification and magnification images are processed.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention has a variable magnification function of enlarging and reducing, and converts reflected light or transmitted light from a document, microfilm, etc. into a CCV (charge-coupled device) or the like. The present invention relates to image reading devices such as facsimile machines and copying machines that read various information such as characters and drawings by forming an image on a photoelectric conversion element.

[Summary of Disclosure] This specification and drawings have a magnification function of enlarging and reducing.
In image reading devices such as facsimile machines and copying machines that read various information such as characters and drawings by imaging reflected or transmitted light from originals, microfilm, etc. on a photoelectric conversion element such as a CCD (charge-coupled device), By preparing multiple drive pulse clocks for photoelectric conversion elements such as CCDs and switching the drive pulse clocks according to the request for magnification,
The present invention discloses a technique for improving image quality without causing image deletion or duplication.

Note that this summary is provided solely for the purpose of quickly accessing the technical content of the present invention, and does not have any influence on the technical scope of the present invention or the interpretation of rights.

[Prior art 1] Conventionally, this type of image reading device generally uses an oscillation circuit that outputs a fixed oscillation frequency as a CCD drive pulse.
Read the data on the CD and read the sample hold data 2
After converting it into a value, the process of enlarging or reducing it was performed. This expansion or reduction is 1. For example, bit thinning in the main scanning direction,
This has been done by overlapping bits, by thinning out lines in the sub-scanning direction, by overlapping lines, or by varying the print scanning speed on the printer side. Also, devices have been proposed that use optical systems such as lenses, such as zoom lenses, to perform magnification and reduction.

[Problems to be Solved by the Invention] However, the conventional enlargement/reduction mechanism with such a configuration has the disadvantage that image quality deteriorates due to missing or duplicated images, or causes an increase in manufacturing costs. was there. In addition, the conventional apparatus had a serious drawback in that it was not possible to use a matrix configuration when reproducing halftones using a dither method or the like, which was a limitation in the image reading configuration due to enlargement and reduction.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device that eliminates the above-mentioned drawbacks and enables image reading that involves image enlargement and reduction with a relatively simple configuration without degrading image quality. .

[Means for Solving Problems] In order to achieve the present object, the present invention provides a photoelectric conversion element that converts light from an image to be read into an electrical signal, and outputs a clock speed of a drive pulse that drives the photoelectric conversion element. The apparatus is characterized in that it includes variable drive pulse supply means that is variable in accordance with an instruction to change the size of the image, and that the output image is enlarged or reduced in size by varying the clock speed.

[Function] Since the present invention has the above-described configuration, it is possible to read an image that involves enlarging or reducing the image with a relatively simple configuration without degrading the image quality.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the basic configuration of an apparatus according to an embodiment of the present invention.

Here, a is a photoelectric conversion element such as a COD, which converts reflected light from an original or transmitted light from a microfilm into an electrical signal and outputs the electrical signal. b is variable drive pulse supply means;
The clock speed of the drive pulse for driving the photoelectric conversion element a is changed and outputted in accordance with a magnification instruction (command signal) of the output image. By changing the clock speed by 1 degree, the video synchronization of the output signal of the photoelectric conversion element a changes, and it is possible to enlarge, reduce, and change the magnification of one image to the same size.

FIG. 2 shows the circuit configuration of the image reading device of the present invention. Here, 1 is a CC port (charge-coupled device) as a photoelectric conversion element in which a plurality of light-receiving elements are arranged in a line. The reflected light from the original or the transmitted light from the microfilm is formed into an image, and this formed optical image is photoelectrically converted into an electrical signal as an image signal. 2 is a sample and hold circuit that samples and holds the output of the CCD 1, and is synchronized with a variable CCD drive pulse (synchronization signal) to be described later. 3 is a binarization circuit, which converts the sample rate of the data sampled and held by the sample and hold circuit 2 and converts it into a Z value. 4 is an image processing circuit which uses a fixed synchronization signal of standard oscillation frequency fo generated by standard oscillation circuit 8 in order to match the video interface with an external device.

Further, 5 is a clock generator for drive control of the CGDI, and mainly sends a transfer lock (CCD drive pulse) of the CCD 1 and a line synchronization signal to the CGDI. 6 is a controller as a control means, standard,
Three types of synchronizing signals whose oscillation frequencies are changed according to reduction and enlargement are selected by switching the switch S-1. COD mentioned above
The selected synchronization signal is used for the transfer lock.

Further, the above-mentioned line synchronization signal is a signal that defines the movement in the sub-scanning direction and the accumulation time of CCI), and a fixed clock input from the controller ε is used (see FIG. 3 (I)). Oscillation circuits 7 to 9 output synchronizing signals of oscillation frequencies fo, f, f2 for reduction, standardization, and expansion, respectively. It is assumed that the oscillation frequency f1 for reduction is higher than the standard oscillation frequency f0, and the oscillation frequency f2 for expansion is lower than the standard oscillation frequency f0.

In the above configuration, an example of the operation of the apparatus of the present invention will be described with reference to the flowchart of FIG.

First, either by manual selection or automatic selection, reduce 9
Instructions for same size and enlargement are given (step 5t-94);
i.e. external scan button (not shown) or automatic (
For example, in response to a variable magnification command selected by firmware), an identification signal for either reduction (1-1 magnification) or enlargement is sent from the controller 6 to the switch SWI, and the switch S%1 is sent to the switch SWI.
11, 3 types of oscillation frequencies fo + fl + f by choosing the winner
The second synchronization signal is selected (steps S5 to S7). As this switch SWI, for example, an electrical contact, a relay, a multiplexer IC (integrated circuit), a data selector IC, a sub CPU (central control unit), etc. are used. For example, when the identification signal is a reduction signal, it is connected to the reduction oscillation circuit 7, and a synchronization signal of frequency f outputted from the circuit 7 is sent to the clock generator 5 and the sample hold circuit 2.

Next, the CCD 1 starts reading the image (
Step S8), at this time, the clock generator 5:
In synchronization with the line synchronization signal from the controller 6, the oscillation frequencies fo, f! are selected by the switch SWI. Or drive ccot with f2. The image data A sampled and held by the sample and hold circuit 2 in synchronization with the output of the CCl 11 is standard and reduced.

Depending on the enlargement, the waveforms are shown in FIGS. 3(A) to 3(C).

The image data shown in FIGS. 3(A) to 3(C) is analog video data output from the sample and hold circuit when, for example, a document image as shown in FIG. 4 is input to ccot. That is, the image data in FIG. 3(A) is video data of a standard same-size image. The image data in Figure (B) is video data of a reduced image, and the reduction oscillation frequency f is larger than the standard oscillation frequency fo.
The video period becomes shorter. In addition, the image data in the same figure (C) is video data of an enlarged image, and the oscillation number f for enlargement is
2 is smaller than the standard oscillation frequency fo, so its video period becomes longer.

As is clear from FIGS. 3(A) to (C), when reducing 5 images, the sample and hold circuit 2 synchronizes with the synchronizing signal of the oscillation frequency f for reduction, so that the same image as the standard (same size) image is used. Information is sampled in a short time, and for image enlargement, the same image information is sampled for a longer time than in the standard case using the sample hold circuit 2 in synchronization with a synchronizing signal of the enlargement oscillation frequency f2.

Next, in step S9, the output video data A of the sample and hold circuit 2 is binarized by the binarization circuit 3, and further processed at a fixed sample rate by the image processing circuit 4. When you print out the image, you can get a reproduced image at the same size, reduced size, or enlarged size.

In this embodiment described above, three types of oscillation circuits 7 to 9 are used: reduced, standard, and enlarged. However, two types of oscillation circuits, enlarged and standard, or reduced and standard, may be used. In the circuit, a fixed oscillation circuit is used for a fixed reduction or enlargement ratio, and a variable frequency oscillation circuit such as a VCO (voltage controlled oscillator) is used for a variable reduction or enlargement ratio. Furthermore, by making the above-mentioned line synchronization signal variable, it is possible to enlarge or reduce the sub-scanning direction as well. Furthermore, by controlling the switching timing of the switch SWI with the controller 6, it becomes possible to partially reduce or partially enlarge the image.

[Effects of the Invention] As explained above, according to the present invention, a simple configuration is provided in which a plurality of drive pulse clocks for photoelectric conversion elements such as CODs are prepared and the drive pulse clocks are switched according to a request for zooming. Since I reduced or enlarged the image by
Image quality can be improved at a low cost without the occurrence of image deletion or duplication.

Further, according to the present invention, image processing such as dither halftone reproduction processing can be performed on data that has been compressed or reduced in a subsequent image processing circuit, so that it is possible to perform image processing such as dithering halftone reproduction processing on data that has been subjected to contraction or reduction processing, so that it is possible to perform image processing such as dithering halftone reproduction processing on data that has been subjected to compression or reduction processing, so that it is possible to perform image processing such as dithering halftone reproduction processing on data that has been subjected to compression or reduction processing, so that it is possible to perform image processing such as dithering halftone reproduction processing on data that has been subjected to compression or reduction processing, so that it is possible to perform image processing such as dithering halftone reproduction processing on data that has been subjected to contraction or reduction processing. No problems arise.

Furthermore, according to the present invention, since the drive pulse clock for driving the photoelectric conversion element described above is switched, it is possible to perform partial reduction of an image, which was previously difficult, by simply controlling the timing of this switching. The effect is that partial enlargement can be easily performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the basic configuration of the device of the present invention, Fig. 2 is a block diagram showing an example of the circuit configuration of the device of the present invention, and Figs. 3 (A) to (C) are the sample and hold circuits of Fig. 2. 3(D) is a waveform diagram showing the output timing of the line synchronization signal. FIG. 4 is a waveform diagram showing an example of the waveform of the output signal A of FIG. 3 is a plan view showing an example of a document image. FIG. 5 is a flowchart showing an example of the operation of the apparatus of the present invention shown in FIG. DESCRIPTION OF SYMBOLS 1... COD, 2... Sample hold circuit, 3... Binarization circuit, 4... Image processing circuit, 5... Clock generator, 6... Controller, 7... - Reduction oscillation circuit, 8... Standard oscillation circuit, 9... Enlargement oscillation circuit. The basic configuration of the device of the present invention is shown in 4 rows. Figure 1: Akira Kimi IL/1 time, 1 person, Il. Mouth figure 3

Claims (1)

[Scope of Claims] a) A photoelectric conversion element that converts light from an image to be read into an electrical signal; and b) A clock speed of a drive pulse that drives the photoelectric conversion element is variable in accordance with an instruction to change the magnification of an output image. c) variable drive pulse supply means for supplying a variable drive pulse, and c) enlarging/reducing the output image by varying the clock speed.