JPH0435154A - Picture reader - Google Patents

Abstract

PURPOSE:To correct a picture signal by giving a reflected light from an original to a 1st photoelectric conversion element so as to generate a regular picture signal and giving a reflected light from a standard white board to a 2nd photoelectric conversion element with less element number than that of the 1st photoelectric conversion element thereby obtaining shading distortion information therefrom. CONSTITUTION:A light radiating from a light source 4 radiates an original 3 on an original platen 2 and a standard white board 5. A reflected light from the white board 5 having intensity distribution information of a light from the light source 4 is reflected in a reflecting mirror 15. When a rotary mirror 12 is set to a position shown in dotted lines, the light reflected in the rotary mirror 12 is formed to a photoelectric conversion element 14 by a lens 13. A signal representing the intensity distribution of the light from the light source 4 is sent to an output terminal 18. The signal is stored in a memory in a signal processing circuit and used for correcting the shading distortion of the picture signal. When the rotary mirror 12 is selected to a position shown in solid lines, the reflected light from the original 3 is made incident in a translucent mirror 9 through an optical path of reflecting mirror 6 reflecting mirror 7 reflecting mirror 8. The light transmitted through the mirror 9 is formed to the photoelectric conversion element 11 by a lens 10 and a picture signal with high resolution representing picture information of the original 3 is sent to an output terminal 17.

Description

[Detailed description of the invention]

[Industrial application field] The present invention relates to an image reading device.

[Conventional Technique #11] Various configurations have been proposed for image reading devices that use photoelectric conversion elements to photoelectrically convert light from a subject into electrical signals for each pixel. This is well known. [Problems to be Solved by the Invention] By the way, in an image reading device, if there is unevenness in the intensity distribution of the light source used to illuminate the original when reading the original, the intensity distribution of the light from the light source will be distorted in the read image signal. Since shading distortion occurs in response to unevenness in the image, image reading devices are often equipped with a circuit for correcting shading distortion. Various types of contour emphasizing circuits that add contour signals to images have been proposed. Conventionally, the above-mentioned shading distortion correction circuit and contour enhancement circuit were configured separately, resulting in a complicated configuration of the reading device. [Means for Solving Problem 1] The present invention provides a first method including a translucent mirror, which reflects light reflected from a document irradiated by light emitted from a light source.
A first element having a number of pixels capable of generating a regular image signal by the first light transmitted through the semi-transparent mirror among the light reflected from the original document. a means for obtaining a regular image signal from a photoelectric conversion element; and a means for obtaining a regular image signal from a photoelectric conversion element;
The light is transmitted through a rotating mirror in a second imaging optical system including a rotating mirror to a second photoelectric conversion element having a smaller number of pixels than the first photoelectric conversion element. a standard white plate provided at a position where light from the light source is always applied;
The third light generated by the light from the light source being reflected by the standard white plate can be applied to the second photoelectric conversion element through the rotary mirror in the second imaging optical system. and a rotating position of the rotating mirror provided in the second imaging optical system described above to a first rotating position such that the second light is applied to the second photoelectric conversion element. and means for switching to a second rotational position such that the third light is applied to the second photoelectric conversion element; A rotating mirror receives the reflected light from the original and the reflected light from a standard white plate provided at a position where the light from the light source is always applied, and the reflected light from the rotating mirror enters the mirror. means for forming an image of the transmitted light of the semi-transparent mirror on a first photoelectric conversion element having an element having a number of pixels capable of generating a regular image signal;
means for forming an image of the reflected light from the semi-transparent mirror on a second photoelectric conversion element having an element having a smaller number of pixels than the photoelectric conversion element; The rotating mirror is placed at a first rotating position where the light reflected by the standard white plate is incident on the semi-transparent mirror via the rotating mirror. Provided is an image reading device comprising switching means. [Operation] The reflected light from the document irradiated by the light emitted from the light source is applied to the first photoelectric conversion element, which has an element with a number of pixels capable of generating a regular image signal, to generate a regular image signal. let Further, the reflected light from a standard white plate provided at a position where light from a light source is always applied is applied to a second photoelectric conversion element having a smaller number of elements than the number of elements in the first photoelectric conversion element, An image signal having shading distortion information is generated. Further, when reading the original, reflected light from the original is also applied to the second photoelectric conversion element described above, so that a narrow band image signal can be obtained from the second photoelectric conversion element.

【Example】

Hereinafter, specific details of the image reading device of the present invention will be explained in detail. FIGS. 1 and 2 are block diagrams of different embodiments of the image reading apparatus of the present invention. In Figures 1 and 2, 1 is the body of the reading device, 2 is the document table, 3 is the original, 4 is the light source, 5 is the standard white plate, 6 to 8
, 15.19 are reflective mirrors, 10 and 13 are lenses, 9 is a semi-transparent mirror, 11 is a first photoelectric conversion element, 12.16 is a rotating mirror, 14 is a second photoelectric conversion element, and 17 is a first photoelectric conversion element. 18 is the output terminal of the second photoelectric conversion element. For example, a COD line sensor (CCD line image sensor) is used as the first photoelectric conversion element 11 and the second photoelectric conversion element described above. As the first photoelectric conversion element 11, one configured with a large number of elements capable of generating high-resolution image signals is used, and as the second photoelectric conversion element 14, the above-mentioned first photoelectric conversion element 14 is used. A structure having fewer elements than the photoelectric conversion elements 11 is used. The optical system shown in FIGS. 1 and 2 is moved to a predetermined position in the space below the document table 2 by a transport mechanism (not shown) during the reading operation of the document 3 placed on the document table 2. It is designed to move at a speed of . The standard white plate 5 is provided at a position where it is constantly irradiated with light from the light source 4, and the reflected light from this standard white plate 5 contains information indicating the intensity distribution of the light from the light source. First, in the image reading device shown in FIG.
The light emitted from the light source 4 illuminates the standard white plate 5 as well as the document 3 on the document table 2. Light source 4 mentioned above
The reflected light from the standard white plate 5 having information on the light intensity distribution is reflected by the reflecting mirror 15 toward the rotating mirror 12. When the rotating mirror 12 described above is set at the rotating position shown by the dotted line in FIG. 14, and a signal indicating the intensity distribution of the light from the light source 4 is sent from the second photoelectric conversion element 14 to the output terminal 18. The signal sent to the output terminal 18 described above is stored in a memory provided in the signal processing circuit following the output terminal 18 described above, and is converted into the image signal outputted from the first photoelectric conversion element 11. Used to correct shading distortion. The rotating mirror 12 described above is switched to the rotating position indicated by the dotted line in FIG. 1 before the image reading device starts the reading operation for the original 3.
Information on the intensity distribution of light from the light source 4 is stored at this rotating position of the rotating mirror 12. Next, with the above-described rotating mirror 12 switched to the rotating position shown by the solid line in FIG.
When a reading operation is performed, the light emitted from the light source 4 illuminates the original 3 through the original platen 2, and the reflected light generated on the original 3 follows the optical path of reflection fjA6→reflector 7→reflector 8→ The light is incident on the semi-transparent mirror 9. Of the light incident on the semi-transparent mirror 9 described above, the light that has passed through the semi-transparent mirror 9 is transferred to the first photoelectric conversion element 11 by the lens 10.
imaged from the first photoelectric conversion element 11 to the output terminal 17
A high-resolution image signal indicating image information of the document 3 is sent to. Further, among the light incident on the semi-transparent mirror 9 described above, the light reflected by the semi-transparent mirror 9 is reflected by the reflecting mirror 19 and then transferred to the rotating mirror 12.
incident on . When the rotating mirror 12 is in the state shown by the solid line in FIG. 1, the reflected light from the rotating mirror 12 is imaged by the lens 13 on the second photoelectric conversion element 14.
A low-resolution image signal representing image information of the document 3 is sent from the second photoelectric conversion element 14 to the output terminal 18 . Next, in the image reading device shown in FIG.
The light emitted from the light source 4 illuminates the standard white plate 5 as well as the document 3 on the document table 2. Light source 4 mentioned above
The reflected light from the standard white plate 5 having information on the light intensity distribution and the reflected light from the document 3 on the document table 2 are
It will be reflected towards the direction where 6 is present. When the rotating mirror 16 described above is set at the rotating position shown by the dotted line in FIG. If the light is reflected by the rotating mirror 16 and enters the reflecting mirror 7, and if the rotating mirror 16 is set at the rotating position shown by the solid line in FIG. Of the light incident on the rotary mirror 16, the reflected light from the original 3 on the document table 2'' is reflected by the rotary mirror 16 and enters the reflecting mirror 7. If the rotating mirror 16 is switched to the rotating position shown by the dotted line in FIG. 2 before the image reading device starts reading the original 3, the rotating mirror 16 will move from the reflecting mirror as described above. The reflected light from the standard white plate 5 which is incident on 7 is reflected by a reflecting mirror 8 and is incident on a semi-transparent mirror 9. The light reflected by the semi-transparent mirror 9 is imaged by the lens 13 onto the second photoelectric conversion element 14, and a signal indicating the intensity distribution of the light from the light source 4 is sent from the second photoelectric conversion element 14 to the output terminal 18. Sent out. The signal sent to the output terminal 18 described above is stored in a memory provided in the signal processing circuit following the output terminal 18 described above, and is converted into the image signal outputted from the first photoelectric conversion element 11. Used to correct shading distortion. As described above, when the rotating mirror 16 is set at the rotating position shown by the dotted line in FIG. The image signal output from the first photoelectric conversion element 11 based on the imaged light is unnecessary. Next, with the above-described rotating mirror 16 switched to the rotating position shown by the solid line in FIG.
When a reading operation is performed, the light emitted from the light source 4 irradiates the original 3 through the original platen 2, and the reflected light generated on the original 3 is reflected from the rotating mirror 16→reflecting mirror 7→reflecting mirror 8→ The light is incident on the semi-transparent mirror 9 through the optical path. Of the light incident on the semi-transparent mirror 9 described above, the light that has passed through the semi-transparent mirror 9 is transferred to the first photoelectric conversion element 11 by the lens 10.
A high-resolution image signal representing image information of the document 3 is transmitted from the first photoelectric conversion element 1] 11 to the output terminal 17. In addition, among the light incident on the semi-transparent mirror 9 described above, the light reflected by the semi-transparent mirror 9 is imaged by the lens 13 on the second photoelectric conversion element 14, and is output from the second photoelectric conversion element 14 to the output terminal. A low-resolution image signal indicating image information of the original 3 is sent to 18. In the image reading apparatus shown in FIG. 1 and FIG. What is a low-resolution image signal that represents image information?
It is used in the subsequent signal processing circuit to generate a contour signal obtained as a difference signal between both signals, and the signal processing circuit corrects the shading distortion of the light from the light source and outputs a high-resolution signal with contour emphasis. image signals are output.

【Effect of the invention】

As is clear from the detailed explanation above, the image reading device of the present invention includes an element having a number of pixels capable of generating a regular image signal from the light emitted from the light source and reflected from the document irradiated with the light. The light reflected from the standard white plate provided at a position where the light from the light source is always applied is transmitted to the first photoelectric conversion element provided to generate a regular image signal. is applied to the second photoelectric conversion element having a smaller number of elements than the number of elements in the original to generate an image signal having shading distortion information. Since light is applied so that a narrow band image signal can be obtained from the second photoelectric conversion element, in the image reading device of the present invention, the image signal generated by the second photoelectric conversion element is generated by the reflected light from the standard white plate. It is possible to eliminate shading distortion due to non-uniformity of the light intensity distribution of the light source using the narrowband image signal generated by the image signal, and also to eliminate the shading distortion caused by the non-uniformity of the light intensity distribution of the light source. Since the image signal can be processed using the signal as an unsharp signal, it is possible to provide a high-performance image reading device with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are block diagrams of different embodiments of an image reading device of the present invention. 1... Main body of reading device, 2... Original table, 3...
Original, 4... Light source, 5... Standard white plate, 6-8, 1
5.19...Reflector, 10.13...Lens, 9.
... Semi-transparent mirror, 11... First photoelectric conversion element, 12,
16... Rotation value, 14... Second photoelectric conversion element, 1
7... Output terminal of the first photoelectric conversion element, 18... 'Output terminal of the second photoelectric conversion element Patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Scope of Claims] 1. Applying the reflected light from the document irradiated by the light emitted from the light source to a first imaging optical system including a semi-transparent mirror, means for obtaining a regular image signal from a first photoelectric conversion element comprising an element with a number of pixels capable of generating a regular image signal by the first light that has passed through the semi-transparent mirror; Of the reflected light from the original document, the second light reflected by the semi-transparent mirror described above is transmitted through the rotating mirror in the second imaging optical system including the rotating mirror. a standard white plate provided at a position where the light from the light source is always applied; Then, the third light generated by the light from the light source being reflected by the standard white plate can be applied to the second photoelectric conversion element through the rotary mirror in the second imaging optical system. and means for adjusting the rotating position of the rotating mirror provided in the second imaging optical system so that the second light is applied to the second photoelectric conversion element. An image reading device 2 comprising means for switching between a rotating position and a second rotating position such that the third light is applied to the second photoelectric conversion element; a rotating mirror into which the reflected light from the original document and the reflected light from the standard white plate provided at the position where the light from the light source is always applied; and the reflected light from the rotating mirror. means for forming an image of the transmitted light of the semi-transparent mirror on a first photoelectric conversion element having an element having a number of pixels capable of generating a regular image signal; means for forming an image of the reflected light from the semi-transparent mirror on a second photoelectric conversion element having an element having a smaller number of pixels than the first photoelectric conversion element; The rotating mirror has a first rotational position where the light is incident on the semi-transparent mirror through the rotating mirror, and a second rotational position where the light reflected by the standard white plate is incident on the semi-transparent mirror via the rotating mirror. An image reading device comprising: means for switching between