JP3076689B2 - Color image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image input device used for a color scanner, a digital copying machine and the like.

[0002]

2. Description of the Related Art Conventionally, as a color image input device, as described in JP-A-2-154573,
A light source for illuminating the original, a dichroic filter for separating reflected light from the original into three primary colors of red, green and blue (hereinafter referred to as R, G and B), and R, G and B color separated by the dichroic filter And a photoelectric conversion element for receiving the reflected light through a lens and performing photoelectric conversion of the reflected light, and shading image information from the photoelectric conversion element using a white reference correction plate when inputting an original image. Some of them perform distortion correction and balance correction of document information of each color.

Here, the color image input apparatus performs photoelectric conversion even when the same density of the original is read due to unevenness in the light amount of the light source, a decrease in the light amount in the peripheral portion of the lens, and variation in each pixel of the photoelectric conversion element. Shading distortion that the image information from the elements does not become the same occurs, and when reading a color original through a dichroic filter, R,
Since the balance of G and B is lost, the shading distortion of the image information from the photoelectric conversion element and the loss of the balance of R, G and B are corrected by a white correction plate and an electrical method.

FIG. 9 shows an example of a conventional color image input device. The dichroic filter 1 is composed of R filters 1a, G
A filter 1b and a B filter 1c.
Any one of a, 1b, and 1c is arbitrarily selected by the operation panel. Before reading the document 3 on the platen 2, the filter selected by the operation panel of the dichroic filter 1 is set on the optical path, and then the scanning unit including the light source 5 and the mirrors 6 to 8 is turned white by the scanning unit driving unit. is installed in the reference correction plate 4 is moved to have a defined position. Then, the white reference correction plate 4 is illuminated by the light source 5, and the reflected light passes through mirrors 6 to 8, a selected filter of the dichroic filter 1, for example, an R filter 1 a and a lens 9, and a photoelectric conversion element 10 composed of a CCD. The photoelectric conversion is performed while the main scanning is performed. The output signal of the CCD 10 is stored in a line memory as correction data.

Next, the original 3 on the original platen 2 is read,
That is, the original 3 on the original table 2 is illuminated by the light source 5 and the reflected light passes through the mirrors 6 to 8, the selected filter 1 a of the dichroic filter 1, and the lens 9, and the CCD 10.
The photoelectric conversion is performed while the main scanning is performed. The correction data stored in the line memory is repeatedly read out in synchronization with the main scanning of the CCD 10 and applied to the reference voltage input terminal of the A / D converter. And at the same time, the shading distortion is corrected by the shading distortion correction data. The digital image signal from the A / D converter is processed by, for example, an image processing circuit and output to a printing machine, where three plates of yellow, magenta, and cyan (hereinafter, referred to as Y, M, and C) are printed.

[0006]

In the above color image input apparatus, before reading the original, the reflected light from the white reference correction plate 4 is photoelectrically converted by the CCD 10 through the selected filter 1a of the dichroic filter 1, and the correction data is read. Since this correction data is applied to the reference voltage input terminal of the A / D converter when reading the original and the analog image signal from the CCD 10 is converted into a digital image signal by the A / D converter, the shading distortion is corrected at the same time. The analog image signal voltage input from the CCD 10 to the A / D converter is too low with respect to the input voltage set by the white reference correction plate 4 and applied as correction data to the reference voltage input terminal of the A / D converter. A gap will occur.

For this reason, Y, which are complementary colors of R, G, and B,
Even if there is no density, M and C are recognized as being present with a certain density. As a result, when three plates of Y, M, and C are printed by the printing machine using the digital image signal from the A / D converter, the printed matter is printed in a high density portion, such as the background of the document, with extra ink. Will be added, and the overall image will be darker. This is mainly caused by unnecessary absorption of the ink used in the document and mismatching between the ink and the dichroic filter.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color image input apparatus which can solve the above-mentioned drawbacks and can accurately correct shading distortion of image information and imbalance of image information of each color.

[0009]

In order to achieve the above object, the invention according to claim 1 comprises a light source for illuminating a document, color separation means for separating reflected light from the document into three primary colors, Photoelectric conversion means for photoelectrically converting the reflected light color-separated by the separation means, a reference correction member used for shading distortion correction of image information and illuminated by the light source, and the photoelectric conversion means for reflected light from the reference correction member A correction means for correcting shading distortion of image information from the photoelectric conversion means with respect to reflected light from a document based on information from a document. 3. The reference correction member is selectively illuminated by the light source. The light source has correction areas of three different colors and is detachably provided.
The source is one of the three hue correction areas on the reference correction member.
A hue correction area corresponding to the separation color of the color separation means is illuminated.
And the correction means is configured to determine three of the correction areas for each color.
Corresponds to the separation color of the color separation means in the hue correction area of
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the document and the balance correction of the document information of each color are performed based on the information from the photoelectric conversion unit with respect to the reflected light from the hue correction area .

According to a second aspect of the present invention, there is provided a light source for illuminating a document, color separation means for separating light reflected from the document on the document table into three primary colors, and reflected light separated by the color separation means. In a color image input apparatus having photoelectric conversion means for performing photoelectric conversion and correction means for correcting shading distortion of image information from the photoelectric conversion means, the color image input device may be placed on the platen.
It is mounted interchangeably and has three different hue correction areas
Out of the three hue correction areas,
A reference chart is provided in which a correction region of a hue corresponding to a separation color is illuminated by the light source , and the correction unit performs a correction for each color.
On, the color of the correction region of the three colors of the correction region
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the document and the balance of the document information of each color with the information from the photoelectric conversion unit with respect to the reflected light from the correction region of the hue corresponding to the separation color of the separation unit. The correction is performed.

[0011]

According to the first aspect of the present invention, the color separation means of the color separation means among the three different hue correction areas of the reference correction member.
Is corrected by the light source , and the reflected light is photoelectrically converted by the photoelectric conversion unit via the color separation unit to become correction information. The original is illuminated by a light source, and the reflected light is color-separated by a color separation unit and photoelectrically converted by a photoelectric conversion unit. Correction means for each color
The color separation means of the three hue correction areas of the correction area.
The reflected light from the hue correction area corresponding to the separation color of
The reflected light from the original by the information from the photoelectric conversion means.
Of shading distortion of image information from photoelectric conversion means
The balance of the original information of each color is corrected.

According to the second aspect of the present invention, the color separation means of the three different hue correction areas on the reference chart is used.
Illuminated by the light source of the hue correction area corresponding to the separation color ,
The reflected light is photoelectrically converted by the photoelectric conversion unit via the color separation unit to become correction information. A document on the document table is illuminated by a light source, and the reflected light is color-separated by color separation means and photoelectrically converted by photoelectric conversion means. correction
The means may include, for each color, a correction area of three hues of the correction area.
From the hue correction area corresponding to the separation color of the color separation means
The original from the photoelectric conversion means for the reflected light
Of the image information from the photoelectric conversion means to the reflected light
Correction of loading distortion and balance of original information of each color
Do.

[0013]

FIG. 2 shows an optical system according to an embodiment of the present invention.
Reference numeral 1 denotes an electric circuit section of this embodiment. The color separation means 11 composed of a dichroic filter includes an R filter 11a, a G filter
A filter 11b and a B filter 11c are provided. The R filter 11a, the G filter 11b, and the B filter 11c are arbitrarily selected by a select switch on an operation panel, moved by a filter driving unit, and set in front of the lens 12. .

A reference correction plate 14 is detachably attached to the front of the document placing position on the document table 13. The reference correction plate 14 has an R area 14 a, a G area 14 b, a B area 14 c, as shown in FIG. 3. It has four hue correction areas called white areas (hereinafter referred to as W areas) 14d. R region 14a, G region 14b, B region 14 of reference correction plate 14
c is used when the original is read in the color mode, and R
Filter 11a, G filter 11b, B filter 11c
Corresponding to the selection, for example, the R region 14a → the G region 14b →
The selection is performed in the order of the B region 14c.

The R region 14a, the G region 14b, and the B region 14c may be selected in another order. When reading an original in the monochrome mode, the reference correction plate 14
Is used, and none of the dichroic filters 11 is set in front of the lens 12. When the original is read only in the color mode, the W area 14d of the reference correction plate 14 may be omitted.

Further, the peak hold circuits 22a, 22
b and 22c are provided corresponding to the R filter 11a, the G filter 11b, and the B filter 11c of the dichroic filter 11, and the selector 23 is connected to the peak hold circuit 22.
The input sides of a, 22b, and 22c are connected to the output side of the amplifier circuit 21 in accordance with the selection of the R filter 11a, the G filter 11b, and the B filter 11c, and the selector 24 outputs the output of the peak hold circuits 22a, 22b, and 22c. R on the side
Filter 11a, G filter 11b, B filter 11c
Is connected to the input side of the selector 25 in accordance with the selection.

The line memories 26a, 26b, 26
c is the R filter 11a of the dichroic filter 11,
The selector 27 is provided corresponding to the G filter 11b and the B filter 11c, and the selector 27 is connected to the line memories 26a, 26b, 26
The input side of c is R filter 11a, G filter 11b, B
Connected to the output side of the A / D converter 28 in accordance with the selection of the filter 11c, the selector 29
The output sides of 6a, 26b, 26c are connected to R filter 11a, G
D corresponding to the selection of the filter 11b and the B filter 11c
/ A converter 30 is connected to the input side.

Further, the selector 25 connects the output side of the selector 24 to the reference voltage (+ REF) input terminal of the A / D converter 28 and obtains the correction data prior to reading the original document. Is connected to the reference voltage (-REF) input terminal of the A / D converter 28 via the resistor 33, and the current / voltage conversion circuit 3
1 is connected to the + R of the A / D converter 28 via the resistor 32.
Connect to the EF input terminal, and connect the reference voltage (-REF) input terminal of the A / D converter 28 to the ground point. The D / A converter 30 has a reference voltage (VR +) input terminal connected to the output side of the selector 24 and a reference voltage (VR +).
-) The input terminal is connected to the output side of the selector 24 via the resistor 33.

Next, the operation of this embodiment will be described. When reading a document in the color mode, when the R filter 11a of the dichroic filter 11 is first selected by the select switch on the operation panel, the filter driving unit moves the R filter 11a and sets it in front of the lens 12. Next, prior to reading of the document, the scanning unit including the light source 15 and the mirrors 16 to 18 is moved by the scanning unit driving unit to a predetermined position where the R area 14a on the reference correction plate 14 is installed.

The R region 14a on the reference correction plate 14
Is illuminated by the white light source 15 and the reflected light is
6 to 18, an image is formed on a photoelectric conversion element 19 formed of a CCD by a lens 12 through an R filter 11a selected as a dichroic filter. CCD 19 is lens 1
The photoelectric conversion is performed while the main scanning is performed on the incident light image formed by step 2. A CCD reading circuit 20 constituted by using the CCD 19 outputs an output signal of the CCD 19 as a correction signal, and the correction signal is amplified by an amplifier circuit 21 and input to a peak hold circuit 22a by a selector 23.

The peak hold circuit 22a is connected to the amplifying circuit 21.
Is detected and held, and this maximum signal voltage value is input to the A / D converter 28 via the selectors 24 and 25 as a reference voltage. A / D converter 28
Represents the output signal of the amplifier circuit 21 as a peak hold circuit 22a.
A / D conversion based on the maximum signal voltage value from
The output data of the / D converter 28 is input to the line memory 26a by the selector 27 and stored as correction data.

Next, the reading of the document is started, and the document 34 on the document table 13 is illuminated by the light source 15 and its reflected light passes through mirrors 16 to 18 and the R filter 11a selected by the dichroic filter to form the lens 12. By CC
An image is formed on D19. At this time, the scanning units 15 to
Numeral 18 scans the original 34 on the original platen 13 by movement, and the CCD 19 repeatedly photoelectrically converts the incident light image formed by the lens 12 while performing main scanning.

The CCD reading circuit 20 outputs the output signal of the CCD 19 as an analog image signal. The analog image signal is amplified by the amplifier circuit 21 and input to the A / D converter 28 and the selector 23. The selector 23 inputs the analog image signal from the amplifier circuit 21 to the peak hold circuit 22a, and the peak hold circuit 22a detects and holds the maximum signal voltage value of the analog image signal.
The maximum signal voltage value of the analog image signal from the peak hold circuit 22a is given to the D / A converter 30 as a reference voltage.

On the other hand, the correction data in the line memory 26a is repeatedly read out in accordance with the main scanning of the CCD 19, and the correction data is input to the D / A converter 30 through the selector 29. The D / A converter 30 performs D / A conversion of the correction data from the line memory 26a based on the reference voltage from the peak hold circuit 22a, and the output signal of the D / A converter 30 is output by the current / voltage conversion circuit 31. The current / voltage conversion is performed, and the converted voltage is supplied to the A / D converter 28 through the selector 25 as a reference voltage.

The A / D converter 28 A / D converts the analog image signal from the amplifier circuit 21. At this time, the correction data from the line memory 26a is converted by the selector 29, the D / A converter 30, the current / voltage converter. By being supplied as a reference voltage to the A / D converter 28 via the circuit 31 and the selector 25, the A / D converter 28 performs A / D conversion of an analog image signal and performs shading distortion correction at the same time. The correction data is the R filter 11a of the dichroic filter 11.
Is obtained from the R region 14a on the reference correction plate 14 having a hue corresponding to the hue, the level difference between the analog image signal and the correction data can be reduced.

Next, when the G filter 11b of the dichroic filter 11 is selected by the select switch on the operation panel, the filter driving section moves the G filter 11b to set it in front of the lens 12. Then, prior to reading the document, correction data is obtained in the same manner as described above and stored in the line memory 26b. In this case, the G area 14b on the reference correction plate 14 is illuminated by the light source 15, and the reflected light is imaged on the CCD 19 by the lens 12 through the mirrors 16 to 18 and the G filter 11b selected by the dichroic filter. .

The output signal of the amplifier circuit 21 is input to the peak hold circuit 22b by the selector 23, and the peak hold circuit 22b detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value is input as a reference voltage to an A / D converter 28 through selectors 24 and 25, and the A / D converter 28 converts the output signal of the amplifier circuit 21 into an A / D converter based on the reference voltage. I do. A
The output data of the / D converter 28 is input to the line memory 26b by the selector 27 and stored as correction data.

Next, when reading the original, the original 34 on the original platen 13 is read in the same manner as described above. In this case, the output signal of the amplifier circuit 21 is input to the peak hold circuit 22b by the selector 23, and the peak hold circuit 22b detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value passes through the selector 24 and is
/ A converter 30 is provided as a reference voltage. The correction data in the line memory 26b is repeatedly read out in accordance with the main scanning of the CCD 19, and the correction data is supplied to the selector 29, the D / A converter 30, the current / voltage conversion circuit 3
1 and a selector 25 via an A / D converter 28 as a reference voltage.

Therefore, the A / D converter 28 performs the shading distortion correction simultaneously with the A / D conversion of the analog image signal, and the correction data is output from the dichroic filter 11.
Is obtained by the G area 14b on the reference correction plate 14 of the hue corresponding to the G filter 11b, the level difference between the analog image signal and the correction data becomes small.

Next, when the B filter 11c of the dichroic filter 11 is selected by the select switch on the operation panel, the filter driving section moves the B filter 11c to set it in front of the lens 12. Then, prior to reading the document, correction data is obtained in the same manner as described above and stored in the line memory 26c. In this case, the B region 14c on the reference correction plate 14 is illuminated by the light source 15, and the reflected light is imaged on the CCD 19 by the lens 12 through the mirrors 16 to 18 and the selected B filter 11c of the dichroic filter. .

The output signal of the amplifier circuit 21 is input to the peak hold circuit 22c by the selector 23, and the peak hold circuit 22c detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value is input as a reference voltage to an A / D converter 28 through selectors 24 and 25, and the A / D converter 28 converts the output signal of the amplifier circuit 21 into an A / D converter based on the reference voltage. I do. A
Output data of the / D converter 28 is input to the line memory 26c by the selector 27 and stored as correction data.

Next, when reading the original, the original 34 on the original platen 13 is read in the same manner as described above. In this case, the output signal of the amplifier circuit 21 is input to the peak hold circuit 22c by the selector 23, and the peak hold circuit 22c detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value passes through the selector 24 and is
/ A converter 30 is provided as a reference voltage. The correction data in the line memory 26c is repeatedly read out in accordance with the main scanning of the CCD 19, and the correction data is supplied to the selector 29, the D / A converter 30, the current / voltage conversion circuit 3
1 and a selector 25 via an A / D converter 28 as a reference voltage.

Therefore, the A / D converter 28 performs the shading distortion correction simultaneously with the A / D conversion of the analog image signal.
Is obtained by the B area 14c on the reference correction plate 14 of the hue corresponding to the B filter 11c, and the level difference between the analog image signal and the correction data becomes small. A / D
The digital image signal from the converter 28 is supplied to an image processing circuit 35.
Is subjected to predetermined processing and is output to, for example, a printing press,
Three plates of Y, M and C are printed.

In this embodiment, since the level difference between the analog image signal of R, G, and B and the correction data is reduced, not only can the shading distortion of the image signal be accurately corrected, but also the R, G, and B signals can be corrected. Of the balance of each image information can be accurately corrected. For this reason, the printing machine uses the digital image signal from the image processing circuit 35 to output Y,
In the case of printing the three plates M and C, the printed matter does not have extra ink on highlight portions with low density, such as the background of the document, and a high quality printed material can be obtained.

When an original is read in the monochrome mode, the dichroic filter 11 is provided in front of the lens 12.
None of the filters are set. Then, prior to reading the original, correction data is obtained in the same manner as described above and stored in the line memory. In this case, the reference correction plate 14
The upper W region 14d is illuminated by the light source 15, and the reflected light passes through mirrors 16 to 18 and is CCD by the lens 12.
19 is formed.

The output signal of the amplifier circuit 21 is input to a peak hold circuit (not shown) by a selector 23.
This peak hold circuit detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value is input as a reference voltage to an A / D converter 28 through selectors 24 and 25, and the A / D converter 28 converts the output signal of the amplifier circuit 21 into an A / D converter based on the reference voltage. I do.
The output data of the A / D converter 28 is input to a line memory (not shown) by the selector 27 and stored as correction data.

Next, when reading a document, the document 34 on the document table 13 is read in the same manner as described above. In this case, the output signal of the amplifier circuit 21 is input to a peak hold circuit (not shown) by the selector 23, and the peak hold circuit detects and holds the maximum signal voltage value of the output signal of the amplifier circuit 21. This maximum signal voltage value is supplied to the D / A converter 30 through the selector 24 as a reference voltage. Also,
Correction data in a line memory (not shown) is repeatedly read out in accordance with the main scanning of the CCD 19, and the correction data is supplied to the A / A converter via a selector 29, a D / A converter 30, a current / voltage conversion circuit 31, and a selector 25. The D converter 28 is provided as a reference voltage. Therefore, the A / D converter 28 performs the shading distortion correction simultaneously with the A / D conversion of the analog image signal.

FIG. 4 shows the correction area 14 of the reference correction plate 14.
5 shows examples of spectral characteristics of the color filters 11 a to 11 c of the dichroic filter 11. The spectral characteristics of the ink used in the original 34 to be read and the correction areas 14 a to 14
It is desirable that the spectral characteristics of the ink used in 14d match or be close to it, but in many cases they do not actually match. For this reason, in this embodiment,
A mechanism that allows the reference correction plate 14 to be attached and detached so that more optimal input conditions can be set by appropriately replacing the reference correction plate 14 is adopted.

FIG. 6 shows a hard copy in the case where a color original is read in the color mode and a hard copy is output by a printing machine in accordance with an output signal of the image processing circuit 35 in this embodiment. This corresponds to the R region 14 of the R filter and the reference correction plate 14.
a, the color original is 0 for each of the seven colors of black, Y, M, C, R, G, and B.
Those with a 100% concentration scale were used. FIG.
Indicates a hard copy when the same color original is read in a color mode by a conventional color image input device and a hard copy is output by a printing machine based on an output signal of the image processing circuit 35. Comparing this with that of FIG. 6, in the case of FIG. 6, unnecessary density components are cut off in the highlight portion having a lower density than in FIG.
The density scale portions of Y, M, and R were almost completely removed, and R became transparent.

FIG. 8 shows a reference chart 36 according to another embodiment of the present invention. This embodiment has the same configuration as that of the above embodiment except for the reference correction plate 14.
Is replaced by the reference chart 36. The reference chart 36 includes an R area 36a, a G area 36b, and a B area 36.
c, W region 36d having four hue correction regions,
The document is placed at a fixed position on the document table 13, for example, a predetermined position where the document 34 is not placed. When the original is read in the color mode, the R filter 1 of the dichroic filter 11 is used.
When 1a is selected by the select switch on the operation panel, the scanning units 15 to 18 are driven by the scanning unit drive unit to obtain the correction data prior to the reading of the document, and the R area 36a on the reference chart 36 is set. Is moved to a predetermined position.

The R area 36a on the reference chart 36 is illuminated by the light source 15, and its reflected light is reflected by the mirrors 16-1.
8. The selected R filter of the dichroic filter 1
An image is formed on the CCD 19 by the lens 12 through 1a. After the correction data is obtained and stored in the line memory 26a in the same manner as in the above embodiment, the document 34 on the document table 13 is read, and the correction data in the line memory 26a is stored in the selector 29 and the D / A converter 30. , A current / voltage conversion circuit 31 and a selector 25 to provide the A / D converter 28 with a reference voltage.
A / D conversion is performed on the analog image signal from No. 1.

Next, when the G filter 11b of the dichroic filter 11 is selected by the select switch on the operation panel, the scanning units 15 to 18 are driven by the scanning unit drive unit when obtaining correction data prior to reading of the original. It is moved to a predetermined position where the G area 36b on the reference chart 36 is installed. The G area 36b on the reference chart 36 is illuminated by the light source 15, and the reflected light is imaged on the CCD 19 by the lens 12 through the mirrors 16 to 18 and the G filter 11b selected by the dichroic filter.

After the correction data is obtained and stored in the line memory 26b in the same manner as in the above embodiment,
3 is read, and the correction data in the line memory 26b is stored in the selector 29, the D / A converter 30,
The voltage is supplied as a reference voltage to the A / D converter 28 via the voltage conversion circuit 31 and the selector 25, and the A / D converter 28 A / D converts the analog image signal from the amplifier 21.

Next, when the B filter 11c of the dichroic filter 11 is selected by the select switch on the operation panel, the scanning units 15 to 18 are driven by the scanning unit drive unit when obtaining correction data prior to reading the original. It is moved to a predetermined position where the B region 36c on the reference chart 36 is installed. The B area 36c on the reference chart 36 is illuminated by the light source 15, and the reflected light is imaged on the CCD 19 by the lens 12 through the mirrors 16 to 18 and the selected B filter 11c of the dichroic filter.

After the correction data is obtained and stored in the line memory 26c as in the above embodiment, the original table 1
3 is read, and the correction data in the line memory 26c is stored in the selector 29, the D / A converter 30,
The voltage is supplied as a reference voltage to the A / D converter 28 via the voltage conversion circuit 31 and the selector 25, and the A / D converter 28 A / D converts the analog image signal from the amplifier 21.

When the original is read in the monochrome mode, the scanning units 15 to 18 are driven by the scanning unit driver to obtain the correction data prior to the reading of the original, thereby setting the W area 36 d on the reference chart 36. Is moved to a predetermined position. The W area 36 d on the reference chart 36 is illuminated by the light source 15, and the reflected light passes through mirrors 16 to 18 and passes through the lens 12.
To form an image on the CCD 19.

Then, similarly to the above embodiment, the correction data is obtained and stored in a line memory (not shown), and then the original 34 on the document table 13 is read, and the correction data in the line memory (not shown) is selected by selectors 29 and D. / A converter 3
0, which is supplied as a reference voltage to the A / D converter 28 via the current / voltage conversion circuit 31 and the selector 25, and the A / D converter 28 converts the analog image signal from the amplifier 21 into an A / D signal.
Convert.

The reference chart 36 has a correction area 36a.
The spectral characteristics of the inks used in the originals
It is ideal to prepare an ink that matches the spectral characteristics of the ink used in the above. However, this is often impossible in practice, and therefore, by replacing the reference chart 36, more optimal input conditions can be obtained. Set.

In this embodiment, R,
Since the level difference between the G and B analog image signals and the correction data is reduced, not only can the shading distortion of the image signal be accurately corrected, but also the imbalance of the R, G and B image information can be accurately corrected. Can be corrected.
In the above embodiment, the W area 36d of the reference chart 36 may be omitted when the original is read only in the color mode. Also, the R region 14 on the reference correction plate 14
a, G area 14b, B area 14c are Y area, M area, C area
Alternatively, the R area 36a, the G area 36b, and the B area 36c on the reference chart 36 may be Y areas, M areas, and C areas.

[0050]

As described above, according to the first aspect of the present invention, the light source for illuminating the original, the color separating means for separating the reflected light from the original into three primary colors, and the color separation by the color separating means. Photoelectric conversion means for photoelectrically converting the reflected light, a reference correction member used for shading distortion correction of image information and illuminated by the light source, and a document based on information from the photoelectric conversion means for reflected light from the reference correction member. Correction means for correcting shading distortion of image information from the photoelectric conversion means with respect to reflected light from the light source, wherein the reference correction member corrects three different hues selectively illuminated by the light source. not have the area
And the light source is mounted on the reference correction member.
Of the three hue correction areas,
Illuminating the correction region of the corresponding hue, the correction means,
For each color , among the three hue correction areas of the correction area,
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the original based on the information from the photoelectric conversion unit with respect to the reflected light from the correction region of the hue corresponding to the separation color of the color separation unit, and the original information of each color , The shading distortion of the image information and the imbalance of the image information of each color can be accurately corrected , and the color fogging and color contamination of the white background portion and the highlight portion at the time of recording can be corrected.
Can be suppressed or eliminated. Moreover, the reference correction unit
The material is removable and can be used in a wide variety of color manuscripts or aging
It can respond to changes and the like.

According to the second aspect of the present invention, the light source for illuminating the original, the color separating means for separating the reflected light from the original on the platen into three primary colors, and the color separating means A color image input apparatus comprising: a photoelectric conversion unit that performs photoelectric conversion of the reflected light; and a correction unit that corrects shading distortion of image information from the photoelectric conversion unit.
Complementary to three different hues, replaceably mounted on the manuscript stand
A positive region, and among the three hue correction regions,
The correction area of the hue corresponding to the separation color of the color separation means is the light
A reference chart illuminated by a light source is provided, and the correction means determines , for each color, a correction area of three hues of the correction area.
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the document based on the information from the photoelectric conversion unit with respect to the reflected light from the correction region of the hue corresponding to the separation color of the color separation unit. and since the balance correction for each color document information, the imbalance of the shading distortion and image information of each color image information can be accurately corrected, the color fog-white background portion and the highlighted portion of the recording
Color stains can be suppressed and removed. Moreover, the standard
The chart is removable and can be used for a wide variety of color documents or
It can respond to aging and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric circuit unit according to one embodiment of the present invention.

FIG. 2 is a front view showing the optical system of the embodiment.

FIG. 3 is a perspective view showing a reference correction plate of the embodiment.

FIG. 4 is a characteristic diagram showing a spectral characteristic of each color region of the reference correction plate in the embodiment.

FIG. 5 is a characteristic diagram showing spectral characteristics of the dichroic filter in the example.

FIG. 6 is a diagram showing an example of a hard copy using an output signal of the embodiment.

FIG. 7 is a diagram illustrating an example of a hard copy using an output signal of a conventional color image input device.

FIG. 8 is a perspective view showing a reference chart in another embodiment of the present invention.

FIG. 9 is a front view showing an optical system of a conventional color image input device.

[Explanation of symbols]

 Reference Signs List 11 dichroic filter 14 reference correction plate 15 light source 19 CCD 22a to 22c peak hold circuit 23, 24, 25, 27, 29 selector 26a to 26c line memory 28 A / D converter 30 D / A converter 31 current / voltage conversion circuit 36 Standard Chart

Continuation of the front page (72) Inventor Toshiaki Watanabe 10 Ricoh Applied Electronics Research Laboratories Co., Ltd., located at No. 5, Takadate Kumanodo, Natori City, Miyagi Prefecture (56) References JP-A-62-101181 JP-A-2-170670 (JP, A) JP-A-2-226966 (JP, A) JP-A-5-300311 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/40-1/409 H04N 1/46 H04N 1/60

Claims (2)

(57) [Claims] 1. A light source for illuminating a document, color separation means for separating light reflected from the document into three primary colors, photoelectric conversion means for photoelectrically converting the reflected light color-separated by the color separation means, and image information A reference correction member used for shading distortion correction and illuminated by the light source, and information of image information from the photoelectric conversion unit with respect to reflected light from the document based on information from the photoelectric conversion unit with respect to light reflected from the reference correction member. A correction means for correcting shading distortion, wherein the reference correction member defines correction areas of three different hues selectively illuminated by the light source.
The light source is provided detachably.
Of the three hue correction areas on the material,
The correction area of the hue corresponding to the color separation is illuminated, and the correction unit determines , for each color , three correction areas of the hue of the correction area.
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the document based on the information from the photoelectric conversion unit with respect to the reflected light from the correction region of the hue corresponding to the separation color of the color separation unit. And a color image input device for performing a balance correction of document information of each color. 2. A light source for illuminating a document, color separation means for separating light reflected from the document on a document table into three primary colors, and photoelectric conversion means for photoelectrically converting the reflected light color-separated by the color separation means. If, in the color image input device and a correcting means for correcting the shading distortion of the image information from the photoelectric conversion means, three are capable placed replaced on the platen
Correction areas of different hues, and
Of the hue corresponding to the separation color of the color separation unit in the positive region
A reference chart in which a correction area is illuminated by the light source is provided, and the correction unit performs three corrections for the correction area for each color .
The hue correction area corresponds to the separation color of the color separation unit.
The shading distortion correction of the image information from the photoelectric conversion unit with respect to the reflected light from the document and the balance correction of the document information of each color with the information from the photoelectric conversion unit with respect to the reflected light from the hue correction area. Color image input device.