JP2003283769A - Image reader and image read method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct a gap in data between line sensors even in the case of magnification/reduction modes or the like. <P>SOLUTION: The image reader is provided with: a CCD sensor 1 wherein a plurality of line sensors 1r, 1g, 1b are arranged nearly in parallel at a prescribed interval; a turning section 2 for turning the CCD sensor 1 nearly in parallel with a plane wherein a plurality of the line sensors 1r, 1g, 1b are arranged, an angle control section 3 for controlling a turning angle of the CCD sensor 1 by the turning section 2 in response to a read mode o the original by the CCD sensor 1; and a position correction section 4 for associating the read signal and the position of the original when the original is read while the turning section 2 turns the CCD sensor 1. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus and an image reading method for reading a document by an optical reading unit in which a plurality of line sensors are arranged in parallel at a predetermined interval.

[0002]

2. Description of the Related Art In order to read a color original, an R
Optical scanning is performed by scanning an original reading position using an optical reading unit in which a plurality of line sensors corresponding to respective colors (red), G (green), B (blue), and the like are arranged in parallel at a predetermined interval. The signal of each color is taken in by the reading means.

Since a plurality of line sensors corresponding to the respective colors are arranged in parallel at a predetermined interval,
The document reading position of each line sensor is displaced.
Therefore, it is necessary to prevent the color shift due to this shift by performing so-called gap correction by matching the shift of the document reading position in each line sensor.

Regarding gap correction, Japanese Patent Publication No. 4-1565
Japanese Unexamined Patent Publication No. 9 discloses a technique of using a delay circuit to absorb the deviation of the document reading position in each line sensor. Further, Japanese Patent Application Laid-Open No. 11-98351 discloses a technique for linearly interpolating a read signal between two pixels when a gap correction cannot be performed by an integral multiple, such as when enlarging / reducing a document reading.

[0005]

However, in the gap correction in the case of performing enlargement / reduction in reading an original, the technique of linearly interpolating the read signal between two pixels does not actually scan. Since the image is treated as being scanned, perfect gap correction cannot be performed, which causes color misregistration. The occurrence of the color misregistration causes an erroneous detection of color / monochrome automatic discrimination of a document, and causes a problem that color processing is erroneously performed even for a monochrome document.

[0006]

The present invention has been made to solve the above problems. That is, the present invention provides an optical reading unit in which a plurality of line sensors are arranged substantially parallel to each other at a predetermined interval, a rotating unit that rotates the optical reading unit substantially parallel to a surface in which the plurality of line sensors are arranged, and an optical reading unit. An angle control means for controlling the rotation angle of the optical reading means by the rotating means according to the reading mode of the original by the reading means, and a reading operation when the original is read while the optical reading means is rotated by the rotating means. The image reading apparatus is provided with a position correcting unit that associates the signal with the position of the document.

Further, according to the present invention, a step of rotating the optical reading means substantially in parallel with a surface on which a plurality of line sensors are arranged according to a reading mode of the original and a step of rotating the optical reading means with the original read It is also an image reading method including a step of associating the read signal with the position of the document.

In the present invention as described above, since the optical reading means is rotated according to the reading mode of the original,
The intervals between the plurality of line sensors can be freely changed along the sub-scanning direction of the document, and the gap correction can be accurately performed without performing signal interpolation between two pixels.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating an image processing apparatus according to this embodiment. That is, this image processing apparatus is an apparatus for reading a document in color,
A CCD sensor 1 in which a plurality of line sensors 1r, 1g, and 1b corresponding to each color of (red), G (green), and B (blue) are arranged substantially in parallel at a predetermined interval, and the CCD sensor 1 is the line sensor 1
A rotation unit 2 that rotates substantially parallel to the surfaces where r, 1g, and 1b are lined up, and an angle control unit 3 that controls the rotation angle of the CCD sensor 1 according to the reading mode of the document selected by the mode selection unit 5. A position correction unit 4 that corrects a read signal of a document read while the CCD sensor 1 is rotated.

Each of the line sensors 1r, 1g, 1b of the CCD sensor 1 which is an optical reading means has thousands of pixels arranged in a line, and is formed or mounted on a predetermined substrate. The CCD sensor 1 according to the present embodiment is provided with a rotating unit 2 for rotating the line sensors 1r, 1g, and 1b substantially in parallel with each other, and an angle setting signal from the angle control unit 3 is used. It can be rotated at an accurate angle.

The rotating portion 2 is capable of rotating the CCD sensor 1 at a set angle with high precision by, for example, a stepping motor. The rotation angle of the CCD sensor 1 is set by an instruction from the angle control unit 3, and when the normal image reading mode is selected by the mode selection unit 5, the original document is directly changed by the rotation angle 0 ° (not rotated). Scanning will be performed. On the other hand, when the reduction / enlargement reading mode or the high resolution mode is selected by the mode selection unit 5, the rotation angle is set according to the magnification and the resolution.

The position correction section 4 corrects the deviation between the read signal and the position of the document, which occurs when the document is read while the CCD sensor 1 is rotated. The position correction unit 4 also performs gap correction when the document is read in the normal reading mode.

Now, the gap correction will be described.
2A and 2B are schematic diagrams for explaining the gap correction. FIG. 2A shows an example of the gap correction with an integral multiple, and FIG. 2B shows an example of the gap correction by interpolation.

First, as shown in FIG. 2A, in the normal document reading mode, the read data at the same point K of the document is read at intervals of the line sensors 1r, 1g, 1b (here, n).
R data, G data, and B data are read in this order with a delay of (line interval).

Therefore, the transfer of R data is performed for 2n lines,
By delaying the transfer of G data by n lines, the transfer of each RGB data for the same point K is synchronized. This makes it possible to correct the data transfer deviation with respect to the same point K that occurs at the line intervals of the line sensors 1r, 1g, 1b.

Next, when the enlargement / reduction reading of the document is performed, the sub-scanning speed is changed according to the enlargement / reduction magnification. For example, when performing X% enlargement / reduction reading, the sub-scanning speed is set to 100 / X times. Therefore, it is possible to read n with the same size (100%) image reading.
In a device that performs a gap correction that delays the data transfer for a line, when performing X% enlargement / reduction reading,
A data transfer delay corresponding to n × (X / 100) lines is performed.

In this case, n × (X / 100) may not be an integer. Therefore, one of RGB data is obtained by linear interpolation between two points as shown in FIG. That is, in order to generate the red data and the green data in accordance with the blue data B1 read at the position K1 of the document, the red data R1 and the green data G1 when the blue data B1 is read, Linear interpolation is performed using the red data R2 and the green data G2 when the blue data B2 is read corresponding to the next K2.

As a result, although the red data and the green data are not actually read at the position of K1,
It is assumed that red data and green data corresponding thereto are generated and read at the same point K1.

However, in such a linear interpolation between two points, since the red data and the green data are not actually read at the position of K1, errors in the interpolation are included. This causes color misregistration, which leads to erroneous detection of automatic color / black and white selection of a document.

Therefore, in the present embodiment, when reading the enlargement / reduction of the document, the CCD sensor 1 is rotated by the rotating unit 2 described above, so that the plurality of line sensors 1r, 1g, 1b are rotated. The gap along the sub-scanning direction is changed so that accurate gap correction can be realized only by an integer multiple line delay without performing interpolation between two points.

FIG. 3 is a schematic diagram for explaining the relationship between the rotation of the CCD sensor and the line spacing. That is, FIG.
As shown in FIG. 3A, the line spacing along the sub-scanning direction when the CCD sensor 1 is rotated by the angle θ is shown in FIG.
As shown in, when the actual line spacing is n, it is expressed by the following equation.

N ′ = n × (X / 100) / cos θ Here, n ′ represents a line interval along the sub-scanning direction after rotation, and X represents a reading magnification for enlargement / reduction.

The rotation control unit 3 sets the rotation angle θ of the CCD sensor 1 so that n'is an integer. As a result, even when performing enlarging / reducing reading, accurate gap correction can be performed only by an integral multiple line delay.

Next, the image reading method of this embodiment will be described. First, when the reading mode of enlargement / reduction is selected by the mode selection unit 5 shown in FIG. 1, the reading mode is passed to the angle control unit 3. In the angle control unit 3, C is calculated based on the above-described calculation formula according to the enlargement / reduction ratio.
The rotation angle θ of the CD sensor 1 is set, and the rotation angle θ is passed to the rotation unit 2.

The rotation unit 2 rotates the CCD sensor 1 based on the rotation angle θ passed from the angle control unit 3. Figure 4
(A) shows a state in which the CCD sensor 1 is rotated by an angle θ.

Next, the document is scanned while the CCD sensor 1 is rotated. That is, by moving in the sub-scanning direction to the optical relative position between the CCD sensor 1 and the document, CC
The document is read while the D sensor 1 is rotated.

FIG. 4B is a schematic diagram showing an image read while the CCD sensor 1 is rotated. By rotating the CCD sensor 1, the number of read pixels along the main scanning direction increases and the read image 10 of each color is read.
r, 10g, and 10b are CCD sensors 1 with respect to the position of the document.
It becomes oblique according to the rotation angle θ. The read images 10r, 10g, and 10b of each color are passed to the position correction unit 4 shown in FIG.

Next, the position correction unit 4 reads the read image 10
Correction is performed to align the reading position of r, 10g, and 10b with the position of the document. First, read image 1 for each color
Gap correction is performed to align the positions of 0r, 10g, and 10b in the sub-scanning direction. FIG. 5A shows the read images 10r ', 10g', and 10b 'of each color after the positions are aligned. This gap correction can be realized only by the data delay of an integral multiple between the lines described above, without using the interpolation of two pixels.

Thereafter, the read images 10r 'of each color, 1
0g 'and 10b' are enlarged / reduced along the main scanning direction (processing according to the magnification), and inclination correction (positioning) is performed along the sub-scanning direction. As a result, as shown in FIG. 5B, the read image 1 of each color obtained by accurately enlarging / reducing the original is provided.
0r ″, 10g ″, and 10b ″ can be generated and output from the position correction unit 4.

In the present embodiment, the CCD sensor 1 can be rotated to increase the number of pixels read by the line sensors 1r, 1g, 1b for each color in the main scanning direction. That is, when the high resolution mode is selected by the mode selection unit 5, the rotation angle θ of the CCD sensor 1 is set by the angle control unit 3 according to the resolution. CCD sensor 1
By rotating, the number of read pixels along the main scanning direction increases, and high-resolution reading can be performed.

Even in this case, if the rotation angle θ of the CCD sensor 1 is set so that the delay interval of the data transfer of each line sensor 1r, 1g, 1b is an integral multiple of the read pixel interval of each line sensor 1r. The gap correction of the data read by 1g and 1b can be accurately corrected only by the delay process of data transfer, and the occurrence of color misregistration can be suppressed.

[0032]

As described above, the present invention has the following effects. That is, when performing the gap correction in the line sensor of each color, even in the mode such as the enlargement / reduction mode, the correction can be accurately performed only by the data delay process of an integral multiple between the lines, and the color shift of the read signal is prevented. It becomes possible to do. As a result, the color / monochrome automatic determination of the read image can be accurately performed, and it is possible to prevent erroneous color processing of the monochrome original.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an image processing apparatus according to this embodiment.

FIG. 2 is a schematic diagram illustrating gap correction.

FIG. 3 is a schematic diagram illustrating the relationship between the rotation of the CCD sensor and the line spacing.

FIG. 4 is a schematic diagram (No. 1) for explaining the image reading method of the present embodiment.

FIG. 5 is a schematic diagram (No. 2) for explaining the image reading method of the present embodiment.

[Explanation of symbols]

1 ... CCD sensor, 2 ... rotation part, 3 ... angle control part, 4 ...
Position correction unit, 5 ... Mode selection unit

Claims (4)

[Claims] 1. An optical reading unit in which a plurality of line sensors are arranged substantially parallel to each other at a predetermined interval, and a rotating unit that rotates the optical reading unit in substantially parallel to a surface in which the plurality of line sensors are arranged, Angle control means for controlling the rotation angle of the optical reading means by the rotating means according to the reading mode of the original by the optical reading means, and reading of the original with the optical reading means being rotated by the rotating means. In this case, the image reading apparatus is provided with a position correction unit that makes the read signal correspond to the position of the document. 2. The rotation angle of the optical reading unit is set by the rotation control unit so that a reading delay interval along the sub-scanning direction of the plurality of line sensors is set to a sub-scanning direction of each of the plurality of line sensors. The image reading apparatus according to claim 1, wherein the angle is an integral multiple of the reading interval along the line. 3. A method for reading an original by an optical reading means in which a plurality of line sensors are arranged substantially parallel to each other at a predetermined interval, wherein the plurality of line sensors are arranged in the optical reading means according to a reading mode of the original. An image reading method comprising: a step of rotating substantially parallel to a surface; and a step of associating a signal obtained by reading an original with the optical reading means rotated with a position of the original. 4. The rotation angle of the optical reading means is set such that the reading delay interval of the plurality of line sensors in the sub-scanning direction is equal to the reading delay interval of each of the plurality of line sensors in the sub-scanning direction. The image reading method according to claim 3, wherein the angle is an integral multiple of.