JP2004153725A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader capable of correcting read positional deviation (inclination, read starting position) from read data of a CCD sensor provided in an apparatus itself. <P>SOLUTION: In the image reader for reading an original C which is placed on original platen glass 2 via a lens 3 with a charge coupled device sensor 4, the apparatus has a correction operating part 17 for operating a correction value in order to correct the read position deviation, and a correction processing part 18 for performing correcting processing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus that reads a document placed on a platen glass with a CCD (Charge Coupled Device) sensor through a lens and converts the document into image data.
[0002]
[Prior art]
Conventional image reading devices are adjusted and inspected at the time of product shipment, and their performance is guaranteed. However, image reading position shifts due to installation conditions (installation surface is not horizontal or inclined), resulting in poor image quality. was there.
[0003]
As described above, conventionally, a black reference is set in the main scanning direction (two places) and the sub-scanning direction outside the original reading area on the original platen glass, and the reading is performed. However, a correction error may occur depending on the installation accuracy of the black reference and the assembling accuracy of the parts on which the black reference is installed. The cost is increased due to the necessity of a component based on black (for example, see Patent Document 1).
[0004]
There has also been a technique for determining a correction value from the average of the previous position detection value and the latest position detection value of the black reference. It depends on the cost of parts (see, for example, Patent Document 2).
[0005]
In addition, there is a description of a technique for correcting a reading position shift, but since a geometric shape pattern is provided on the platen glass, pattern setting accuracy is required as in the above two techniques. Regardless of whether the pattern component is raised or printed, accuracy and cost are required (for example, see Patent Document 3).
[0006]
The reading position deviation (inclination, reading start position) correction by this technique uses a reference color pattern or shape pattern on the platen glass, and a pattern similar to the platen glass or two-color printing on the document scale. / Printing / sticking cost is required, and pattern position accuracy is required.
[0007]
Furthermore, there is a method in which a document edge is read at several places to calculate a tilt correction value. However, when a document is transparent like OHP paper, reliable edge detection cannot be performed (for example, see Patent Document 4).
[0008]
[Patent Document 1]
JP 2001-257844 A [Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-101277 [Patent Document 3]
JP-A-8-184774 [Patent Document 4]
JP-A-11-252351
[Problems to be solved by the invention]
In the above-described conventional technology, it is necessary to add a means for correcting the image reading position deviation, and its installation accuracy and cost become new problems, and a correction value is calculated at a position distant from the position where the document is actually read. Therefore, there is a problem that an error is easily generated by the distance.
[0010]
Accordingly, an object of the present invention is to provide an image reading apparatus that corrects a reading position deviation (inclination, reading start position) from data read by a CCD sensor included in the apparatus itself in order to solve the above problems. It is in.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, according to the first aspect of the present invention, in an image reading apparatus that reads an original placed on an original platen glass via a lens with a charge-coupled device sensor, the reading position is corrected. The most important feature is an image reading apparatus having a correction operation unit for calculating a correction value and a correction processing unit for performing a correction process.
[0012]
According to the second aspect of the present invention, there is provided the image reading apparatus according to the first aspect, further comprising a non-image processing unit that performs image processing on a non-image area in order to read a shape of a document scale placed on the platen glass. Main features.
[0013]
According to a third aspect of the present invention, there is provided an image reading apparatus according to the first aspect, wherein the correction calculation unit and the correction processing unit are used for converting scale shape read data into tilt correction data.
[0014]
According to a fourth aspect of the present invention, there is provided an image reading apparatus according to the first aspect, wherein the correction calculation unit and the correction processing unit are used to use scale shape read data as read start position correction data.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of an image reading apparatus according to the present invention. As shown in FIG. 1, the image reading apparatus includes a housing 1, a document table glass 2, a lens 3, a CCD sensor 4, document scales 5, 6, and carriages 7, 8. When the carriages 7 and 8 move, image data is sent to the CCD sensor 4 to obtain read data.
[0016]
FIG. 2 is a flowchart showing a flow from reading the document scale shape to applying correction to the read document image. The carriages 7 and 8 are started (S1), and the edges of the original scales 5 and 6 are read at both ends of the original width (S2). A reading start position shift is calculated from the read data (S3), and a reading start correction value is determined (S4).
[0017]
As for the amount of inclination, the amount of inclination is calculated from the data read in S2 (S5), and the inclination correction value is determined (S6). Thereafter, the read image is subjected to the correction determined in S4 and S6 (S7).
[0018]
FIG. 3 is a block diagram showing an embodiment of a mechanism for correcting a reading start position and a tilt used in the image reading apparatus according to the present invention. When the operation unit 10 is operated in the scanner A, the main body control unit 13 operates. The reflected light from the document surface incident on the CCD sensor 4 is converted by the A / D conversion block 11.
[0019]
The output converted by the A / D conversion block 11 is sent to the image processing unit 14 and the non-image processing unit 15 of the image processing unit (IPU) B. The output sent to the non-image processing unit 15 is calculated by a tilt / read start position correction calculation unit 17 to calculate a tilt / read start position, processed by a tilt / read start position correction processing unit 18, and is plotted by a plotter unit (optical writing) 19. Sent to
[0020]
The output of the APS sensor 12 of the scanner A is sent to the document size determination unit 16 of the image processing unit B, and thereafter, the inclination / reading start position is calculated by the inclination / reading start position correction calculation unit 17, and the inclination / reading start position is calculated. The data is processed by the position correction processing unit 18 and sent to the plotter unit (optical writing) 19.
[0021]
FIG. 4 is an enlarged view showing a portion where the original platen glass and the left original scale are joined. In the figure, the document table glass 2 and the left document scale 5 are schematically shown. The figure shows output data of the shape of the left original scale 5 at a certain position read by the CCD sensor 4 when the carriages 7 and 8 move downward. The output of the CCD sensor 4 changes depending on the shape of the original scale 5 (change in brightness due to unevenness).
[0022]
FIG. 5 is an enlarged view showing a portion where the platen glass and the back side document scale are joined. In the figure, the document table glass 2 and the back document scale 6 are schematically shown. FIG. 9 shows output data of the shape of the rear document scale 6 at a certain position read by the CCD sensor 4 when the carriages 7 and 8 move downward. The output of the CCD sensor 4 changes depending on the shape of the rear document scale 6 (change in brightness due to unevenness).
[0023]
FIG. 6 is a schematic diagram showing a document scale edge reading position defined as a left-back document scale intersection and a document size end. In the figure, the document scale edge reading position is set to the intersection 20 of the left document scale 5 and the back document scale 6 and the document size ends (A4, DLT, etc.) 21 and 22 of the documents C and D.
[0024]
By cooperating with the APS sensor 12, it is also possible to perform correction on the spot according to the set document. Further, if the left document scale 5 is attached at an angle, the document also becomes the left scale 5 and a part that must be read cannot be read. However, the tilt correction value and the APS sensor 12, it is possible to read the entire original.
[0025]
By setting the document scale edge reading position at the intersection 20 between the left and back document scales 5 and 6 and the document size end (A4, DLT, etc.), appropriate correction is applied to the document size even if the document scale is warped. It becomes possible.
[0026]
FIG. 7 is a schematic view showing a document placed on a platen glass at an angle. On the document table glass 2 surrounded by the left document scale 5 and the back document scale 6, a document E placed at a correct position is shown by a dotted line, and a document F inclined is shown by a solid line. In this state, there are a portion 23 where the document is not read and a portion 24 where the document is read even though there is no document.
[0027]
【The invention's effect】
As described above, according to the first aspect, the reading position deviation (inclination, reading start position) is corrected from the reading data of the CCD sensor included in the apparatus itself, so that an expensive and complicated apparatus (jig) is required. It is possible to perform the correction without selecting the installation location of the image reading device.
[0028]
According to the second aspect, the correction of the reading position shift of the image reading device is performed based on the original scale shape read by the CCD sensor, so that it is possible to perform the correction without the need for additional components or positional accuracy accompanying the components. Further, by calculating a correction value from data of a document scale edge serving as a reference of a document set, it is possible to absorb variations in assembling components and variations in component replacement and perform correction.
[0029]
According to the third aspect, by setting the document scale edge reading position to the intersection of the left and the rear document scales and the document size end, it is possible to appropriately correct the document size even if the scale is warped. Become.
[0030]
According to the fourth aspect, by setting the scale edge reading position at the intersection of the left-back document scale and the document size end, it is possible to perform appropriate correction according to the document size even if the scale is warped. .
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of an image reading apparatus according to the present invention.
FIG. 2 is a flowchart showing a flow from reading a document scale shape to applying correction to a read document image.
FIG. 3 is a block diagram showing an embodiment of a mechanism for correcting a reading start position and a tilt used in the image reading apparatus according to the present invention.
FIG. 4 is an enlarged view showing a portion where a document table glass and a left document scale are joined;
FIG. 5 is an enlarged view showing a portion where a platen glass and a back side document scale are joined;
FIG. 6 is a schematic diagram showing a document scale edge reading position which is a left-back depth document scale intersection and a document size end;
FIG. 7 is a schematic diagram showing a document placed on a document table glass at an angle.
[Explanation of symbols]
2 platen glass 3 lens 4 CCD sensor (charge coupled device sensor)
5 Document scale 6 Document scale 15 Non-image processing unit 17 Correction calculation unit 18 Correction processing unit A Scanner C Document

Claims (4)

In an image reading apparatus that reads a document placed on a platen glass via a lens with a charge-coupled device sensor, a correction calculation unit that calculates a correction value to correct a reading position shift, and a correction processing unit that performs a correction process An image reading device comprising: The image reading apparatus according to claim 1, further comprising a non-image processing unit that performs image processing on a non-image area in order to read a shape of a document scale placed on the platen glass. 2. The image reading apparatus according to claim 1, wherein the correction calculation unit and the correction processing unit are used to convert the original scale shape read data into tilt correction data. 2. The image reading apparatus according to claim 1, wherein the correction calculation unit and the correction processing unit are used to use scale shape read data as read start position correction data.

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