JP2000287048A - Image input device and storage medium for storing image input control procedure of the image input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of reproducibility of the colors of an image because of the overlap of the color components of the image obtained through color separation. SOLUTION: In a preparation stage of image input, a CPU 14 receives image data from each of line sensors 11r, 11g, 11b, 11ir, while sequentially selecting and lighting light sources 12r, 12g, 12b, 12ir via a signal processing circuit 13 and obtains correction data to correct an overlap signal, caused by the overlap between the light emission wavelength band of the light sources and the wavelength band of the spectral sensitivity distribution of the line sensors. At main scanning, the CPU 14 causes the light sources 12r, 12g, 12b, 12ir to light up simultaneously. The CPU 14 in this case corrects the image data outputted from the line sensors 11r, 11g, 11b, 11ir via the signal processing circuit 13, on the basis of the correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device, and more particularly, to an image input device such as a digital camera or a scanner for color separation of an image of a subject and inputting the image, and an image input control procedure of the image input device. It relates to a storage medium.

[0002]

2. Description of the Related Art There is known an image input device which reads an image of a sheet-shaped document or a developed photographic film and outputs a digital image signal. The image input device has a line sensor that reads an image of a document linearly. When reading an image, the image input device outputs an image signal output from the line sensor while relatively moving the original and the line sensor along a direction perpendicular to the direction in which the line sensor extends.

When an image of a color original is input by the above-described image input device, for example, image input by a monochrome line sensor is repeated three times at the same original reading position, and light sources of R, G, and B colors are used at that time. Some are switched sequentially. That is, by switching the wavelength of the light source, the image of the entire original is read line-sequentially while performing color separation. By performing color separation as described above, an image signal including three color components of red (R), green (G), and blue (B) can be obtained.

[0004]

However, the color components of the image signal obtained by color separation as described above have overlapping areas as described below. Then, due to the presence of the overlapping area, when an image is reproduced based on an image signal composed of R, G, and B color components,
The fidelity of the reproduced color was sometimes reduced. Less than,
This problem will be described.

In color separation, it has been described that image input by a monochrome line sensor is repeated three times while switching light sources of R, G, and B at the same document reading position. The spectral composition (intensity distribution for each wavelength of the light source) of each of the R, G, and B light sources is a ridge-shaped distribution curve that is broadened when the light wavelength is plotted on the horizontal axis and the intensity is plotted on the vertical axis. . When the distribution curves of these three light sources are drawn on the same graph, they are separated in the vicinity of the peaks of the respective curves, but overlap each other at the tails.

Now, consider a case where the light source of B color is turned on, and the image of the document is subjected to color separation to input an image. In the above-described case, the image signal output from the line sensor mainly includes color information of a component in the B wavelength band. However, since the spectral composition of the light source has a bulging distribution as described above, the image signal output from the line sensor in the above-described case has an adjacent wavelength band, that is, the color of the component of the G color band. Contains information.

Similarly, when the light source of G color is turned on and the image of the original is color-separated and an image is input, the color information of the B and R band components is included in the image signal output from the line sensor. Contains. Further, when the light source of R color is turned on and the image of the document is color-separated and the image input is performed, the image signal output from the line sensor includes the color information of the component of the band of G color.

[0008] The R, G,
The color of the image reproduced by superimposing the images of B color may not always be able to faithfully reproduce the color of the document due to the overlap of the color components described above.

SUMMARY OF THE INVENTION An object of the present invention is to suppress a decrease in color reproducibility of an image due to overlapping color components of an image obtained by color separation.

[0010]

FIG. 1 shows an embodiment of the present invention.
The following invention will be described in association with. (1) The image input device according to the first aspect of the present invention,
An image of a subject is converted to a first image having color information in a first wavelength band.
A first color separation means 24r for separating the image of the subject into a second image; and a second color for separating the image of the subject into a second image having color information in a second wavelength band that partially overlaps the first wavelength band. A first photoelectric conversion unit 11r for reading a first image and outputting a first image signal; a second photoelectric conversion unit for reading a second image and outputting a second image signal 11g; correction means 14 for correcting an overlapping portion of a color component of an image obtained by combining the first and second image signals.
And the above-mentioned object is achieved. (2) The image input device according to the invention described in claim 2 is:
The first color separation means 24r is arranged between the subject and the first photoelectric conversion means 11r, and the second color separation means 24g
Is disposed between the subject and the second photoelectric conversion unit 11g. (3) The image input device according to the invention described in claim 3 is:
A first light source 12r having a first emission wavelength band overlapping at least a part of the second wavelength band;
correction amount calculating means 14 for obtaining a correction amount when correcting an overlapping portion of color components based on the second image signal output from the second photoelectric conversion means 11g in a state where r is lit. is there. (4) The image input device according to the invention described in claim 4 is:
The image processing apparatus further includes a second light source 12g having a second emission wavelength band and capable of emitting light simultaneously with or independently of the first light source 12r; And correcting the second image signal output from the second photoelectric conversion unit 11g based on the correction amount obtained by the correction amount calculation unit 14 with both the second light sources 12r and 12g turned on. It is. (5) According to the invention described in claim 5, the image of the subject is converted to the first image.
A first color separation unit 24r that separates a first image having color information of components within the first wavelength band; and color information within a second wavelength band that partially overlaps the image of the subject with the first wavelength band. Color separation means 24 for separating into a second image having
g; first photoelectric conversion means 11r for reading the first image and outputting the first image signal; and second photoelectric conversion means 11 for reading the second image and outputting the second image signal
g and is applied to a storage medium for storing an image input control procedure of the image input device having g. Then, a correction procedure for correcting an overlapping portion of a color component of an image obtained by combining the first and second image signals is stored.

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easier to understand. However, the present invention is not limited to this.

[0012]

FIG. 1 shows a schematic configuration of a scanner as an example of an image input apparatus according to an embodiment of the present invention. The scanner 1 repeats an operation of linearly inputting an image of a document to be image-inputted by an image sensor having a plurality of line sensors in which photoelectric conversion elements (pixels) are linearly arranged. At this time, the scanner 1
Each time the image sensor inputs a document image linearly, the image sensor and the document are relatively moved gradually in a direction substantially perpendicular to the extending direction of the image sensor in a plane facing the document. The scanner 1 inputs a two-dimensional image of a document by repeating the above operation. In the following description, the pixel array direction of the line sensor is referred to as a main scanning direction, and a direction parallel to the document surface to be read and orthogonal to the main scanning direction is referred to as a sub-scanning direction.

In FIG. 1, an illumination light source 12 connected to a signal processing circuit 13 via a driver 18 includes a red (R) color, a green (G) color, a blue (B) color, and an infrared (IR) color.
Illumination light sources 12r, 12g and 12b and 12i for colors
r. These four color light sources 12r, 12g, 12
The control of turning on / off of b and 12ir is controlled by the signal processing circuit 13. The signal processing circuit 13 outputs an arbitrary one of the four light sources 12r, 12g, 12b, and 12ir.
Light sources of one or more colors can be turned on, or all four colors can be turned on.

The image sensor 11 connected to the signal processing circuit 13 has four line sensors 11r, 11g, and 1 having spectral sensitivity to R, G, B, and IR colors.
1b and 11ir. These line sensors 1
1r, 11g, 11b and 11ir will be described. On the light receiving surface of the line sensor 11r for the R color, an R color on-chip filter 24r having an increased spectral transmittance for the R color is formed. Similarly, the light receiving surface of the line sensor 11g for G color has a line sensor 1 for G color and a line sensor 1 for B color.
The line sensor 11 for the B color and the IR color is provided on the light receiving surface 1b.
On the light receiving surface of ir, on-chip filters 24g, 24b, and 24ir of G, B, and IR colors whose spectral transmittances are increased for each color are formed for the IR color. As described above, the on-chip filters 24r, 24b, 24
g and 24ir via each of the line sensors 11
r, 11b, 11g and 11ir are subjected to color separation by inputting an image of a document. That is, the product of the spectral transmittance of each of the on-chip filters 24r, 24g, 24b, and 24ir and the spectral sensitivity of the line sensor in the absence of these on-chip filters indicates the spectral power of each of the line sensors 11r, 11g, 11b, and 11ir. Sensitivity is determined.

In addition, instead of forming the on-chip filters on the light receiving surfaces of the line sensors 11r, 11b, 11g and 11ir, the following may be performed. That is, each light separated using a known dichroic mirror or the like may be guided to each of the four rows of monochrome line sensors. Alternatively, the image sensor may be configured by a single line of monochrome line sensors. In this case, color separation is performed by repeating image input with a single line of monochrome line sensors while sequentially switching filters with increased spectral transmittance for each of R, G, B, and IR colors. Further, on-chip filters having high spectral transmittance for the R, G, B, and IR colors may be sequentially arranged on the light receiving surfaces of the pixels constituting one line sensor. In short, the above-described filter or dichroic mirror for performing color separation may be provided in the optical path between the original, that is, the subject and the line sensor.

The line sensor 11 configured as described above
Each of r, 11g, 11b and 11ir outputs an analog image signal to the signal processing circuit 13. The signal processing circuit 13 A / D converts the analog image signal. The signal processing circuit 13 corrects a digital image signal obtained by A / D conversion, that is, image data, which will be described later in detail.

Referring now to FIG. 2, light sources 12r, 12r
g, 12b, and 12ir, ie, the intensity distribution of each light source for each wavelength, and the line sensor 11r,
The spectral sensitivities of 11g, 11b and 11ir will be described.

FIG. 2A shows light sources 12r, 12g, and 12g.
In this figure, the intensity distribution for each of the wavelengths b and 12ir is plotted on a single graph, with the horizontal axis representing the wavelength λ and the vertical axis representing the relative intensity I. In FIG. 2 (a), the curve labeled B is the light source 12b, the curve labeled G is the light source 12g, and the curve labeled R is the light source 12r.
, Respectively, indicate the spectral composition of the light source 12ir. As is clear from these curves, the intensity distribution curves of the respective light sources overlap each other at the base.

FIG. 2B shows the line sensors 11r and 11r.
The spectral sensitivity characteristics of g, 11b and 11ir are overlaid on one graph, and the horizontal axis represents the wavelength λ and the vertical axis represents the relative sensitivity S. In FIG. 2 (b), the curve labeled B is the line sensor 11b, the curve labeled G is the line sensor 11g, the curve labeled R is the line sensor 11r, and the curve labeled IR is the IR sensor. Curved lines indicate the spectral sensitivity of the line sensor 11ir. Similar to those shown in FIG. 2 (a), these curves also have overlapping spectral sensitivity curves of the respective line sensors. FIG. 2C will be described later.

Referring again to FIG. 1, the configuration of the scanner 1 will be described. The correction data storage device 16 connected to the signal processing circuit 13 stores R color correction data Rc, G color correction data Gc, B color correction data Bc, and IR color correction data IRc, which will be described in detail later. The signal processing circuit 13 stores these correction data in the correction data storage device 16.
, Or can be read from the correction data storage device 16.

An image storage device 17 connected between the signal processing circuit 13 and the interface circuit 15 temporarily stores image data output from the signal processing circuit 13. The image data stored in the image storage device 17 is output to the host computer 2 connected to the scanner 1 via the interface circuit 15.

A motor 22 is connected via a driver 21 to a CPU 14 which is connected to the signal processing circuit 13 so that bidirectional data can be transmitted and received. The motor 22 drives a transport mechanism (not shown) to drive the original to be read and the image sensor 1.
This is a driving source for driving the relative position with respect to 1 in the sub-scanning direction.

ROM 19 connected to CPU 14, RA
The M20 and the flash memory 23 will be described.
The ROM 19 stores a program executed by the CPU 14 and the like. The RAM 20 is used as a stack area or a work area for programs executed by the CPU 14. The flash memory 23 stores adjustment parameters for obtaining the mechanical accuracy, electrical accuracy, and the like of the scanner 1. Instead of storing the program executed by the CPU 14 in the ROM 19, a program transferred from the host computer 2 described later may be stored in the RAM 20. Alternatively, a program transferred from the host computer 2 may be written in the flash memory 23 and converted into firmware. In these cases, the program is read from the hard disk drive 3, floppy disk drive 4, or CD-ROM drive 5 connected to the host computer 2.

The host computer 2 temporarily stores the image data transferred from the scanner 1 in the RAM 2a,
An image is displayed on a display device (not shown) connected to the host computer 2. The image data stored in the RAM 2a is output to the hard disk drive 3 or the floppy disk drive 4 as needed. Scanner 1
Is started in response to an image input command signal from the host computer 2 to the scanner 1.

When the main scanning operation, that is, the operation of inputting an image of a read original and outputting image data to the host computer 2 is performed by the scanner 1 configured as described above, the illumination light sources 12r, 12g, 12b, and 12ir
Are illuminated collectively in four colors. Regarding the image sensor 11 and the illumination light source 12, the emission wavelength bands of the illumination light sources 12r, 12g, 12b, and 12ir overlap as described above. Also, the line sensors 11r, 11
The wavelength bands of the color information of the images separated by g, 11b, and 11ir also overlap.

The spectral characteristics of the image sensor 11 and the light source 12
When attention is paid to the relationship with the spectral characteristics of, for example, the wavelength band of the sensitivity distribution of the B color line sensor 11b and the emission wavelength band of the illumination light source 12g of G color overlap. Due to this overlap, the image signal output from the B-color line sensor 11 includes a signal Bg generated by the wavelength component of the G-color illumination light source 12g, as indicated by the hatched area in FIG. 2C. . In the following, the line sensor 11
r, 11g, 11b, and 11ir, the sensitivity distribution wavelength bands and illumination light sources 12r, 12g, 12b, and 1
The above-mentioned signal generated by the overlap of the emission wavelength bands of the 2irs is called an overlap signal.

For example, as the overlap signal included in the image signal output from the B color line sensor 11b,
In addition to g, Br and Bir may exist. The overlap signal Br is
This occurs when the emission wavelength band of the R color illumination light source 12r and the wavelength band of the sensitivity distribution of the B color line sensor 11b overlap. The overlap signal Bir occurs when the emission wavelength band of the IR color illumination light source 12ir and the wavelength band of the sensitivity distribution of the B color line sensor 11b overlap. In the example shown in FIGS. 2A and 2B, the overlapping signals Br and Bi
r becomes zero. Similarly, the image signals output from the G color line sensor 11g can include the overlap signals Gb and G
r and Gir, which can be included in the image signal output from the R color line sensor 11r.
ir. The image signals output from the IR color line sensor 11ir may include the overlapping signals IRb and IRb.
Rg and IRr. The scanner 1 can reproduce an image with higher color reproducibility by performing a correction process on the image signal output from the image sensor 11 and removing the signal components of these overlapping signals as described later. It is.

The image input operation of the scanner 1 will be described. The operation of the scanner 1 is controlled by the CPU 14. The scanner 1 roughly performs the following operations. That is, the scanner 1 (1) detects the overlap signal, obtains a correction amount for reducing the overlap signal included in the image signal obtained at the time of the main scan performed later, (2) performs the prescan operation, 3) Perform a main scan and (1)
Based on the correction amount obtained in the above operation, a correction process is performed on the image signal obtained in the main scan, and output to the host computer. Hereinafter, the three operations will be described with reference to FIGS.

The flowchart shown in FIG. 3 shows an image input operation control procedure which is started by the CPU 14 in response to an image input command signal being issued from the host computer 2 to the scanner 1.

Upon receiving an image input command signal from the host computer 2, the CPU 14 initializes a document reading position in S101. When the scanner 1 is for reading a transparent original such as a photographic film, the original reading position is initialized so that there is no original to be read between the illumination light source 12 and the image sensor 11. When the scanner 1 reads a reflection document such as a printed document or a photograph printed on photographic paper, the following is performed when the document reading position is initialized. That is, the reading head unit in which the illumination light source 12 and the image sensor 11 are disposed
Move to a position facing the white or neutral gray reference plate.

In S102, the CPU 14 issues an R-color illumination lighting command signal to the signal processing circuit 13. The signal processing circuit 13 issues a control signal to the driver 18 to turn on the R color illumination light source 12r.

In S103, the CPU 14 issues an image input command signal to the signal processing circuit 13. Upon receiving this command signal, the signal processing circuit 13 sends the G color line sensor 11
The image signals output from the g and B color line sensors 11b and the IR color line sensor 11ir, that is, the overlap signals Gr, Br and IRr are input. These overlapping signals Gr, Br and IRr are A / D converted by the signal processing circuit 13 and output to the CPU 14. Duplicate signal G
Each of r, Br, and IRr has a data number corresponding to the number of pixels of the G color image sensor 11g. The CPU 14 controls the overlapping signals Gr, Br and IRr
Is stored in the RAM 20.

In S104, the CPU 14 issues a G color illumination lighting instruction signal to the signal processing circuit 13. The signal processing circuit 13 issues a control signal to the driver 18 to turn off the R color illumination light source 12r and turn on the G color illumination light source 12g.

In S105, the CPU 14 issues an image input command signal to the signal processing circuit 13. Upon receiving this command signal, the signal processing circuit 13 sends the R color line sensor 11
overlap signals Rg and Bg output from the r and B color line sensors 11b and the IR color line sensor 11ir, respectively.
And IRg. These overlapping signals Rg, Bg
And IRg are A / D converted by the signal processing circuit 13 and
Output to PU14. The CPU 14 outputs the overlap signal Rg,
Bg and IRg are stored in the RAM 20.

In S106, the CPU 14 issues a B-color illumination lighting instruction signal to the signal processing circuit 13. The signal processing circuit 13 issues a control signal to the driver 18 to turn off the G color illumination light source 12g and turn on the B color illumination light source 12b.

In S107, the CPU 14 issues an image input command signal to the signal processing circuit 13. Upon receiving this command signal, the signal processing circuit 13 sends the R color line sensor 11
overlap signals Rb, Gb output from r, G color line sensor 11g and IR color line sensor 11ir, respectively.
And IRb. These overlapping signals Rb, Gb
And IRb are A / D converted by the signal processing circuit 13 and
Output to PU14. The CPU 14 outputs the overlap signal Rb,
Gb and IRb are stored in the RAM 20.

In step S108, the CPU 14 issues an IR color lighting ON command signal to the signal processing circuit 13. The signal processing circuit 13 issues a control signal to the driver 18 to turn off the B color illumination light source 12b and turn on the IR color illumination light source 12ir.

In S109, the CPU 14 issues an image input command signal to the signal processing circuit 13. Upon receiving this command signal, the signal processing circuit 13 sends the R color line sensor 11
r, G color line sensor 11g and B color line sensor 1
1b, the overlap signals Rir, Gir output from each of
And Bir. These overlapping signals Rir, G
ir and Bir are A / D converted by the signal processing circuit 13 and output to the CPU 14. The CPU 14 sets the overlap signal R
ir, Gir, and Bir are stored in the RAM 20.

At S110, the CPU 14 proceeds to S10
3, the correction data Rc, Gc, and Bc are obtained from the respective duplicate signals stored in the RAM 20 in S105, S107, and S109.
And IRc. These correction data Rc, G
c, Bc and IRc are stored in the correction data storage device 16 via the signal processing circuit 13.

The correction data Rc, Gc, Bc and I
Rc is data output from the image sensor 11 at the time of the main scan and referred to when the CPU 14 corrects image data obtained by A / D conversion by the signal processing circuit 13. That is, it is correction data for removing components of each overlapping signal from the image data. The CPU 14
The correction data Rc, GcBc and IRc are calculated from the following equations. Rc = Rg + Rb + Rir Formula (1) Gc = Gr + Gb + Gir Formula (2) Bc = Br + Bg + Bir Formula (3) IRc = IRr + IRg + IRb Formula (4)

The correction data Rc is transmitted to the R color line sensor 11.
This is to eliminate an overlapping signal component caused by the overlap between the wavelength band of the spectral sensitivity r and the emission wavelength bands of the illumination light sources 12g, 12b, and 12ir.
The correction data Gc is for removing an overlapping signal component caused by the overlapping of the wavelength band of the spectral sensitivity of the G color line sensor 11g and the emission wavelength band of the illumination light sources 12r, 12b, and 12ir. The same applies to the correction data Bc and IRc, and a description thereof will be omitted. In the above, the line sensors 11r, 11b, 11g and 11i of each color
r and the illumination light sources 12r, 12g, 1
Although the processing is performed assuming that the emission wavelength bands of 2b and 12ir all overlap each other, the present invention is not limited to this example.

For example, a case will be described in which only the wavelength band of the spectral sensitivity of the G color line sensor 11g overlaps with the emission wavelength band of the R color illumination 12r. In this case, S
In 103, the CPU 14 may obtain the average value of only the overlap signal Gr. Then, in S110, the CPU 14 may determine the correction data Rc as shown by the following equation (5) instead of the equation (1). Rc = Rg Equation (5)

In the above example shown in equation (5), only the correction data Rc has been described.
The same applies to Bc and IRc.

S101 by the CPU 14 described above.
The operations from S110 to S110 correspond to a control procedure for detecting a duplicate signal and obtaining a correction amount from the detected duplicate signal. S1 above
01 to S110, for example, the scanner 1
May be performed when the illumination light source 12 is replaced or when the illumination light source 12 is replaced. In this case, the correction data Rc,
Gc, Bc and IRc are stored in the flash memory 23. For this reason, the line sensors 11r, 11g, 11
b and 11 ir spectral sensitivities and illumination light sources 12 r and 12 r
Variations that may exist in the spectral composition of g, 12b, and 12ir can be absorbed. Further, FIG.
Correction data Rc, Gc, Bc and IRc each time the document to be read is changed as shown in the flowchart of FIG.
Has the following effects. That is, the spectral composition of the illumination light sources 12r, 12g, 12b, and 12ir has some temperature dependence. Correction data Rc, Gc, Bc each time the document to be read is changed
If IRc is obtained, a stable image input result can be obtained regardless of the elapsed time after the power of the image reading apparatus 1 is turned on.

The CPU 14 executes S101 to S101 described above.
When the operation of S110 is completed, a prescan operation is performed in step S111. The prescan is a preliminary image input operation performed prior to the main scan, and is performed to set image input conditions for the main scan. That is, since the density, color balance, image reading range, and the like of the document to be read vary depending on the document, the scanner 1 roughly reads the document to be read in accordance with the default image input conditions. Based on the result of the rough reading, the conditions at the time of the main scan are set as follows.

In S111, the CPU 14 temporarily stores the image data output from the image sensor 11 and obtained by A / D conversion in the signal processing circuit 13 in the RAM 20. The CPU 14 also records the image data in the image storage device 17 via the signal processing circuit 13. CP
U14 sets the optimum image input condition at the time of the main scan based on the image data stored in the RAM 20. At this time, what is set by the CPU 14 includes the accumulation time of the image sensor 11, the gradation correction coefficient, and the like. The accumulation time of the image sensor 11 refers to the line sensor 11r,
It is the time related to the accumulation operation performed in each of 11g, 11b and 11ir. For example, when the image sensor 11 can individually control the start and stop of the accumulation operation for each of the line sensors 11r, 11b, 11g, and 11ir, the accumulation time is set by the CPU 14 corresponding to each line sensor. Is done. The gradation correction coefficient is set to maximize the gradation of an image reproduced by image data obtained by inputting an image. Since the details of the prescan are described in detail in Japanese Patent Application No. 11-10634 filed by the present applicant, a detailed description is omitted here.

While the conditions for the main scan are set by the CPU 14 as described above, the image data recorded in the image storage device 17 is output to the host computer 2 via the interface circuit 15. An image based on this image data is displayed on a display device (not shown). The operator sets an image reading range for the main scan based on the image displayed on the display device. The image reading range setting result is output from the host computer 2 to the CPU 14 via the interface circuit 15.

After ending the prescan operation control in S111, the CPU 14 performs main scan operation control in S112 to S116.

In S112, the CPU 14 issues an R, B, G, IR color illumination lighting command signal to the signal processing circuit 13. The signal processing circuit 13 issues a control signal to the driver 18 to turn on all of the illumination light sources 12r, 12g, 12b and 12ir at the same time.

In S113, the CPU 14 issues an image input command signal to the signal processing circuit 13. Upon receiving this command signal, the signal processing circuit 13 sends the signal to the line sensor 11r,
Image signals output from each of 11g, 11b and 11ir are input. The signal processing circuit 13 A / D converts these image signals and outputs them to the CPU 14. As described above, the signal processing circuit 13 controls the illumination light sources 12r and 12r.
Image signals are input from each of the line sensors 11r, 11g, 11b, and 11ir while g, 12b, and 12ir are simultaneously turned on. Therefore, the time required for image input can be reduced as compared with the case where the operation of inputting an image signal from the line sensor is repeated while sequentially switching the lighting color of the illumination light source.

In S114, the CPU 14 outputs the digital image data Rrg output from the signal processing circuit 13.
bir, Grgbir, Brgbir and IRrgb
A correction process is performed on each of the ir. Specifically, the processing represented by the following equations (6) to (9) is performed on all the data corresponding to each pixel constituting each of the line sensors 11r, 11g, 11b, and 11ir. R = Rrgbir-Rc Expression (6) G = Grgbir-Gc Expression (7) B = Brgbir-Bc Expression (8) IR = IRrgbir-IRc Expression (9) It should be noted that correction is made in the processing of S114 by the CPU 14. The data Rc, Gc, Bc and IRc are read from the correction data storage device 16 via the signal processing circuit 13 into the CPU 14 in advance.

The image data corrected as described above by the CPU 14 is recorded in the image storage device 17 via the signal processing circuit 13. The image data is sequentially output to the host computer 2 via the interface circuit 15.

In S115, the CPU 14 determines whether or not the image reading position of the document to be read has reached outside the reading range.
That is, it is determined whether the image input has been completed. S
If the determination at 115 is negative, the CPU 14 proceeds to S116, moves the relative position between the document to be read and the image sensor 11 by one reading pitch in the sub-scanning direction, and returns to S113. Until the main scan is completed, the CPU 14 executes S113,
The operations of S114, S115 and S116 are repeated.

If the determination in S115 is negative, the CPU 1
4 ends the image input operation.

According to the above control procedure by the CPU 14,
From the scanner 1 to the host computer 2, image data with enhanced color fidelity is output with the components of the overlap signal removed.

In the above description, the correction data Rc, Gc, Bc and IRc for removing the duplicate signal are CP
Although determined by U14, it may be determined by the signal processing circuit 13. Similarly, the correction of the image data at the time of the main scan may be performed by the signal processing circuit 13. In the scanner 1, the image sensor 11 and the illumination light source 12 are each of four colors. However, the present invention can be applied to a configuration in which each of them has two or more colors. Further, in the above description, R color, G color,
Line sensors 11r, 11g, 11 for B color and IR color
Although the example in which the image signals output from all of b and 11ir are corrected has been described, the present invention is not limited to this example. That is, for example, the G color line sensor 11g
The correction may be performed only on the image signal output from the. In this case, since the correction is performed on the image signal containing a large amount of green color component located near the peak wavelength of the relative luminous efficiency of the human eye, a large correction effect can be obtained for simple processing contents. . Alternatively, the color components of the read document may be determined, and correction may be performed on more color components.

The scanner 1 according to the above embodiment
Has a plurality of color light sources capable of emitting light individually or simultaneously, but the present invention is not limited to the above example. For example, the present invention can be applied to an image input device having a configuration including a white light source, a color separation device for three colors, that is, a switchable filter for three colors of R, G, and B, and a monochrome image sensor. In this case, S101 to S1 in FIG.
A procedure corresponding to the procedure shown in 10 is performed in an assembly process of the image input apparatus and the like. In this assembling process, light sources of three colors R, G, and B as adjustment tools are used instead of the white light source. Then, the correction data Rc, Gc and Bc are obtained through steps corresponding to S101 to S110 in FIG. 3 while sequentially turning on the light sources of the three colors.

Alternatively, by providing a switchable light source filter as described below between the light emitting portion of the white light source and the image sensor 11 of four lines, the original to be read can be read in the same manner as the procedure shown in FIG. Correction data can also be obtained each time it is changed. Light source filters are R, G,
It has a B3 color filter portion and a transparent portion. During the main scan, the light source filter has a transparent portion located between the light source and the image sensor 11. And
In the procedure for obtaining the correction data corresponding to S101 to S110 in FIG. 3, the light source filter is switched as follows. That is, when obtaining the overlap signals Gr and Br, the R color filter of the light source filter is positioned between the light source and the image sensor 11. In this state, the image sensor 1
The overlap signal Gr and Br can be obtained by inputting a signal from the image sensor 11 each time the filter for one is switched to G color and B color.

The present invention can be further applied to an image input device such as a digital video camera and a digital still camera (DSC) other than the scanner described above. Here, a case where the present invention is applied to a DSC will be described. The DSC records an image signal obtained by subjecting a subject image formed by a photographing lens to photoelectric conversion by an area sensor or the like. In this DSC, a single-plate type area sensor is often used. On a plurality of pixels arranged two-dimensionally in a single-plate area sensor, R, G,
B or yellow (Y), cyan (C), magenta (M), G
On-chip filters of each color are regularly arranged. That is, color separation is performed by a color filter provided between the subject and the area sensor. Take the wavelength on the horizontal axis,
If the spectral transmittance curves of these filters are plotted on one graph with transmittance plotted on the vertical axis, these curves overlap each other at the bottom. That is, the overlap signal described above exists in the DSC as well as in the scanner.

Therefore, in the DSC assembling process, correction data for suppressing the influence of the overlapping signal is obtained through the procedure described below. Note that the DSC described below
It is assumed that R, G and B on-chip filters are formed on the pixels of the area sensor.

In the DSC assembling process, R, G, B
R approximately equal to the spectral transmittance of the on-chip filter of
A white light source equipped with G and B color filters is used. Hereinafter, for convenience, the light source to which the R color filter is attached is referred to as an R color light source, and the light source to which the G color filter is attached is referred to as G light source.
The light source on which the color light source and the B color filter are mounted is referred to as a B color light source. As an example, a case will be described in which the overlap signals Rg and Rb included in the image signal output from the pixel on which the R-color on-chip filter is formed are obtained. In this case, the light receiving surface of the area sensor is illuminated with the G color light source, and subsequently with the B color light source. Each time these illumination light sources are switched, by inputting an image signal output from a pixel on which an R-color on-chip filter is formed, overlap signals Rg and Rb can be obtained. The overlap signals Rg, Rb, Gr, Gb, Br,
The correction data Rc, Bc and Gc are obtained based on Bg. The correction data Rc, Bc and Gc are recorded in an EEPROM or the like provided in the camera. When photographing is performed using the DSC, image data obtained by A / D conversion of an image signal output from the area sensor is corrected based on the correction data Rc, Bc, and Gc. By performing the correction on the image data as described above, an image with high color reproducibility can be obtained.

In the correspondence between the above-described embodiment and the claims, the R-color on-chip filter 24r controls the first color separation means, the G-color on-chip filter 24g controls the second color separation means, and the CPU 14 The processing of S114 in FIG. 3 is the correction means, the image sensor 11 is the first photoelectric conversion means and the second photoelectric conversion means, and the R color illumination light source 12r is the first photoelectric conversion means.
The processing of S110 in FIG. 3 by the CPU 14 is a correction amount calculating unit, the G color illumination light source 12g is a second light source,
The processing of S114 in FIG. 3 by the CPU 14 constitutes a correction procedure. The correspondence between the device having the R, G, and B color switchable filters and the monochrome image sensor and the claims is as follows. The three color switchable filters correspond to the first color separation means and the second color separation means. The monochrome image sensor corresponds to the first photoelectric conversion unit and the second photoelectric conversion unit.

[0063]

As described above, the present invention has the following effects. (1) According to the invention described in claim 1 or 5, the first
The image of the subject is separated by the color separation means and the second color separation means, and the first image and the second
An image obtained by inputting by obtaining first and second image signals based on the image and correcting an overlapping portion of color components of an image obtained by combining the first and second image signals. Color reproducibility can be improved. (2) According to the invention described in claim 3, the first light source having the first emission wavelength band overlapping at least a part of the second wavelength band included in the color information of the second image is turned on. In this state, by obtaining a correction amount for correcting the overlapping portion of the color components based on the signal of the second image output from the second photoelectric conversion means, the overlapping color components including the emission wavelength band characteristics of the light source are obtained. Can be corrected. (3) According to the invention described in claim 4, when inputting an image of a subject, a second image is obtained by the second color separation unit with both the first and second light sources turned on, By correcting the second image signal output from the second photoelectric conversion means based on the second image based on the correction amount obtained by the correction amount calculation means, the second photoelectric conversion is performed. The overlapping portion of the color component can be corrected from the second image signal output from the means.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a scanner that is an image input device according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams for explaining how color components of an image input after color separation are overlapped. FIG. 2A illustrates the spectral intensity of an illumination light source, FIG. 2B illustrates the spectral sensitivity of an image sensor, and FIG. c)
Is a diagram showing how image data color components overlap.

FIG. 3 is a flowchart illustrating an image input control procedure.

[Explanation of symbols]

 Reference Signs List 1 scanner 2 host computer 11 image sensor 11r R color line sensor 11g G color line sensor 11b B color line sensor 11ir IR color line sensor 12 illumination light source 12r R color illumination light source 12g G color illumination light source 12b B color illumination light source 12ir IR color illumination Light source 13 Signal processing circuit 14 CPU 16 Correction data storage device 24r R on-chip filter 24g G on-chip filter 24b B on-chip filter 24ir IR on-chip filter

Claims (5)

[Claims] A first color separation unit configured to separate an image of a subject into a first image having color information within a first wavelength band; and partially separating the image of the subject with the first wavelength band. A second color separation unit that separates into a second image having color information in the overlapping second wavelength band; a first photoelectric conversion unit that reads the first image and outputs a first image signal; A second photoelectric conversion unit that reads the second image and outputs a second image signal; and corrects an overlapping portion of a color component of an image obtained by combining the first and second image signals. An image input device comprising: a correction unit. 2. The image input device according to claim 1, wherein
The first color separation unit is disposed between the subject and the first photoelectric conversion unit, and the second color separation unit includes:
An image input device disposed between the subject and the second photoelectric conversion unit. 3. The image input device according to claim 1, wherein a first light source having a first emission wavelength band overlapping at least a part of the second wavelength band, and the first light source is turned on. And a correction amount calculating unit for obtaining a correction amount when correcting the overlapping portion of the color components based on the second image signal output from the second photoelectric conversion unit in the state where the correction is performed. Image input device. 4. The image input device according to claim 3, further comprising a second light source having a second emission wavelength band and capable of emitting light simultaneously with or independently of said first light source, When inputting an image of a subject, the correcting means may be configured to turn on the second light source while both the first and second light sources are turned on.
An image input device, wherein the second image signal output from the photoelectric conversion unit is corrected based on the correction amount obtained by the correction amount calculation unit. 5. A first color separation means for separating an image of a subject into a first image having color information within a first wavelength band, and a part of the image of the subject corresponding to the first wavelength band. A second color separation unit that separates into a second image having color information in the overlapping second wavelength band; a first photoelectric conversion unit that reads the first image and outputs a first image signal; And a second photoelectric conversion unit that reads the second image and outputs a second image signal. The storage medium stores an image input control procedure of an image input device, wherein the first and second A storage medium for storing an image input control procedure of an image input apparatus, which stores a correction procedure for correcting an overlapping portion of a color component of an image obtained by synthesizing an image signal.