JPH0746403A - Original picture reader - Google Patents

Abstract

PURPOSE:To improve the read precision of an original by always setting shading correction data of a same level. CONSTITUTION:The reader is provided with an original close contact read device 1, an original carrier roller 2 pressing an original P onto the original close contact read device 1, an arithmetic operation circuit 11 applying shading correction to read picture information to provide an output, and a memory 10 from which shading correction data are fed to the arithmetic operation circuit 11, and also with an original identification circuit 12 to identify a white reference correction sheet 13 with correction data described thereon. The original identification circuit 12 is provided with a correction data rewrite control function rewriting shading correction data in the memory 10 based on the shading correction read by the original close contact read device 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manuscript image reading device, and more particularly to a manuscript image reading device which is used in an image information processing device such as a facsimile or an image scanner and which reads the image information of a manuscript by photoelectric conversion. It is a thing.

[0002]

2. Description of the Related Art FIGS. 5 to 6 show a schematic structure of a conventional document image reading apparatus. Among these, FIG. 5 shows a sectional view of a mechanical portion of an apparatus in a conventional example, and FIG. 6 shows a configuration example of an image data input circuit by a conventional shading correction method.

In FIG. 5, reference numeral 51 denotes a document contact type reading device. This document contact type reading device 51
Has a function of reading an image of a document and performing photoelectric conversion. Further, reference numeral 57 indicates an automatic paper feeding unit. The automatic paper feeding unit 57 includes a document separating piece 54 and a document feeding roller 53, and separates and feeds documents one by one toward the document contact type reading device 51. Further, reference numeral 52 indicates a white original feeding roller. The original document feeding roller 52 pushes the fed original document to the reading position A of the original document contact type reading device 51 and conveys the original document while closely adhering the original document, and the original data for the white reference determination of the original document described above. It has a function of being read by the contact type reading device 51.

The reference data for the white reference determination and the image data of the original read by the original contact type reading device 51 are subjected to shading correction calculation through an analog / digital conversion element 59 as shown in FIG. 6, for example. It is sent to the arithmetic circuit 61. Reference numeral 60 represents a memory for storing the shading data for at least one line which stores the reference data for the white reference determination described above.

[0005]

However, in the above-mentioned conventional example, when the white reference data read by each sensor element and the shading data stored in the memory are subjected to shading correction in the arithmetic circuit,
Partial deterioration of each sensor element in the original contact type reading device caused by extraneous light and deterioration with time of an LED, which is a light source for reading an original image, cause a large partial decrease in output of the data, resulting in a decrease in original image information. There was an inconvenience that the reading became inaccurate.

Further, in a document image reading apparatus or the like in which the white reference setting of a document is performed by a white document conveying roller, the document conveying roller is contaminated by the passage of a document, and the shading correction data of the contaminated part is output. As a result, there is a problem that reading of the document image information becomes inaccurate as in the above case.

[0007]

An object of the present invention is to improve the inconvenience of the conventional example, and in particular, it is possible to always set the same level of data for the shading correction data, thereby improving the reading accuracy of the document image information. It is an object of the present invention to provide a document image reading apparatus which aims at the above.

[0008]

According to the present invention, an original reading device for reading shading correction data and original information by an optical method, and an original for constantly bringing an original P fed into the original reading device into contact with the original reading device. The transport roller, an arithmetic circuit that performs shading correction of the image information read by the document reading device, and outputs the shading correction data, and a memory that sends shading correction data to the arithmetic circuit.

A document detecting sensor is provided on the upstream side of the document conveying roller. An original discriminating circuit for discriminating whether the original P sent to the original reading device is an original for reading information or a white reference correction sheet having correction data based on the output signals of the original detection sensor and the original reading device, It is installed in the output stage of the above-mentioned document reading device.

The document identifying circuit has a correction data rewriting control function for rewriting the shading correction data in the memory based on the shading correction data read by the document reading device. This aims to achieve the above-mentioned object.

[0011]

[Operation] When the white reference correction sheet 13 is set, the original detection sensor first determines that it is the white reference correction sheet 13, and the information is input to the original identification circuit 12 in FIG. Next, when the white reference correction sheet 13 is fed to the document reading device, the white reading portion 13B of the white reference correction sheet 13 is started to be read by the document reading device. Then, the white part data of the white reference correction sheet 13 that has been read is rewritten with the data for shading correction in the memory 10. Then, the white reference correction sheet 13 is ejected by the document feeding roller 2, and the rewriting of the data in the memory 10 is completed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment shown in FIGS. 1 to 4, a document contact type reading device 1 as a document reading device for reading shading correction data and document information by an optical method, and a document P sent to the document contact type reading device 1. A document feeding roller 2 that is always in contact with the document reading device 1, an arithmetic circuit 11 that performs shading correction of image information read by the document contact type reading device 1, and outputs the shading correction data. And a memory 10.

A paper guide 6 is provided on the upstream side of the document conveying roller 2, and a document detection sensor 5 is provided at the paper guide 6 portion. A document feeding roller 3 and a document separating piece 4 are provided between the document detecting sensor 5 and the document contact type reading device 1 described above.

Further, based on the output signals of the document detection sensor 5 and the document contact type reading device 1, the document P sent to the document contact type reading device 1 is an information reading document or a white reference carrying correction data. A document identification circuit 12 for identifying whether the correction sheet 13 (see FIG. 3) is provided at the output stage of the document contact type reading device 1 described above.

The document identifying circuit 12 has a correction data rewriting control function for rewriting the shading correction data in the memory 10 based on the shading correction data read by the document contact type reading device 1.

The white reference correction sheet 13 is a sheet having a width equal to or larger than the maximum effective reading width of the document close contact type reading device 1 and a length equal to or larger than a document transportable length.
B (constant color) has a length of at least 1 [mm] or more and exists over the entire width of the original contact type reading device 1 in the reading width direction, and the white reference correction sheet 13 is an identification hole 13A for identifying the other sheet. Is provided.

The white reference correction sheet 13 has a white band 13B having a predetermined width in a direction orthogonal to the sheet conveying direction. The white band 13B of the white reference correction sheet 13 is coated with a transparent resin, which has the advantage that the white portion 13B of the white reference correction sheet 13 is resistant to stains and prevents deterioration of the sheet material.

More specifically, the original contact type reading device 1 has a function of reading an image of the original P and performing photoelectric conversion. Reference numeral 7 indicates an automatic paper feeding section, which is composed of a document separating piece 4 and a document feeding roller 3 and has a function of separating and feeding the documents P one by one toward the document contact type reading device 1. There is.

Further, the document feeding roller 2 has a document feeding function of pushing the document P fed as described above to the reading position A of the document contact type reading device 1 and bringing them into close contact with each other to convey the document P. .

FIG. 2 is a block diagram showing the relationship between the original contact type reading device 1 and the arithmetic circuit 11 for correcting the shading of the data read by the original contact type reading device 1.

In FIG. 2, the document identifying circuit 12 is
It is determined whether the original image data read by the original close contact type reading device 1 is the data of a general original or the white data of the white reference correction sheet 13 (see FIG. 3). In the case of the data of an ordinary original, an analog / digital conversion element ( A / D conversion element)
9 and the white data of the white reference correction sheet 13 is input to the memory 10.
Further, the memory 10 can store at least one line of shading data. Then, as described above, the arithmetic circuit 11 has a function of performing a shading correction operation on the original image data read by the original contact type reading device 1.

Next, the operation of this embodiment will be described.

When the white reference correction sheet 13 shown in FIG. 3 is set in the apparatus, as shown in FIG.
The leading edge of the white reference correction sheet 13 is detected by the white reference correction sheet 13, and the white reference correction sheet 13 is conveyed while being conveyed to the reading position A of the original contact type reading device 1 by the original feeding roller 3.
Since the identification hole 13A is provided so as to pass above the document detecting sensor 5, at the moment when the identification hole 13A passes the document detecting sensor 5, the document detecting sensor 5 is moved to the position shown in FIG.
As shown in (B), the state is once undetected. When the identification hole 13A of the white reference correction sheet 13 has finished passing, the document detection sensor 5 is in the detection state again as shown in FIG. 4 (C).

This information is input to the document identifying circuit 12 in FIG. 2 and it is determined that the white reference correction sheet 13 is set in the apparatus, so that the shading data in the memory 10 in FIG. The reference correction sheet 13 is automatically conveyed. The timing of conveyance from the end position of the identification hole 13A inside the white reference correction sheet 13 to the white portion 13B is softly controlled by the step angle of the stepping motor that drives the document conveyance roller 2. When the white part 13B of the white reference correction sheet 13 reaches the reading position A of the original contact reading device 1, the reading of the white part 13B of the white reference correction sheet 13 is started.

The white reference correction sheet 13 that has been read
The white part data of is rewritten with the data for shading correction in the memory 10. The white reference correction sheet 13 is ejected by the document feeding roller 2, and the rewriting of the data in the memory 10 is completed.

[0026]

Since the present invention is constructed and functions as described above, according to the present invention, the white reference correction sheet is set in the apparatus in the same manner as a general original and is read by the original close contact type reading device. The original shading data can be rewritten, and the partial output reduction of the shading correction data due to sensor or LED deterioration can be prevented, which enables accurate reading of the manuscript image information, which is an unprecedented excellent manuscript image reading. A device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an example for executing shading correction on information read by the original contact type reading device in FIG.

FIG. 3 is an explanatory diagram showing an example of a white reference correction sheet used in FIG.

FIG. 4 is an explanatory diagram showing the operation of FIG. 1, and FIG. 4 (A) shows a state immediately after a white reference correction sheet is input;
4B shows a state in which the white reference correction sheet has been detected, and FIG. 4A shows a state immediately after the white reference correction sheet has separated from the detection sensor.

FIG. 5 is a schematic configuration diagram showing a conventional example.

FIG. 6 is a block diagram showing an example for executing shading correction in FIG.

[Explanation of symbols]

 1 Document close contact type reading device as a document reading device 2 Document feeding roller (white) 3 Document feeding roller 10 Memory 11 Calculation circuit 12 Document identification circuit 13 White reference correction sheet

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[Procedure amendment]

[Submission date] January 12, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

FIG. 4 is an explanatory diagram showing the operation of FIG. 1, and FIG. 4 (A) shows a state immediately after a white reference correction sheet is input;
(B) shows a state in which the white reference correction sheet is detected .
4 (C) denotes a state immediately after the white reference correction sheet has left the detection sensor.

Claims (3)

[Claims] 1. A document reading device for reading shading correction data and document information by an optical method, a document feeding roller for constantly bringing a document fed into the document reading device into contact with the document reading device, and the document reading device. In a document image reading apparatus including an arithmetic circuit for performing shading correction of read image information and outputting the shading correction data, and a memory for sending shading correction data to the arithmetic circuit, a document detection sensor is provided upstream of the document conveying roller. At the same time, an original discriminating circuit which discriminates whether the original sent to the original reading device is an information reading original or a white reference correction sheet having correction data based on the output signals of the original detection sensor and the original reading device. On the output stage of the original reading device, Document identification circuit, the document reading based on the shading correction data read by the device rewrites shading correction data in the memory the correction data rewrite control function original image reading apparatus characterized by comprising a. 2. The original image reading apparatus according to claim 1, wherein the white reference correction sheet includes a white band having a predetermined width in a direction orthogonal to the sheet conveying direction. 3. The white band portion of the white reference correction sheet,
3. A transparent resin coating is applied.
The document image reading apparatus described.