JP2002281324A - Document reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress influence of gap compensation to the respective color component signals to image degradation even when the gap compensation is performed by an interpolation processing between two points. SOLUTION: In this document reader having a three-line solid-state imaging device 17 corresponding to the respective color components R, G, B, to compensate dislocation of the respective color component signals by unit of line by a line delay processing and to compensate dislocation by less than one line to be caused in accordance with increase/decrease of scan speed by the interpolation processing between two points, interpolation processing circuits 23R, 23B to perform interpolation between two points are provided only to an output system of an R color component signal and to an output system of a B color component signal from the three-line solid state imaging element 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original reading apparatus for optically reading an image drawn on an original from an original to be read.

[0002]

2. Description of the Related Art In general, as a document reading device, a CCD such as a copying machine or a scanner device is used.
(Charge Coupled Device) It is widely known that a document to be read is scanned by using a solid-state image sensor such as a line sensor to read an image from the document. In recent years, for example, as shown in FIG. 6, three line sensors corresponding to R (red), G (green), and B (blue) color components are arranged at predetermined intervals (for example, in the sub-scanning direction n).
Document reading devices that also support reading of color images using three-line solid-state imaging devices arranged side by side at line intervals (n is a natural number) are widely used.

In a three-line solid-state imaging device,
Since a predetermined interval (gap) exists between the line sensors, a positional shift corresponding to the gap occurs between the color component signals. Therefore, in a document reading apparatus supporting a color image, it is indispensable to perform positional deviation correction (gap correction) between color component signals.

The gap correction between the color component signals may be performed by line delay processing because the interval between the line sensors is n lines in the sub-scanning direction. The line delay processing is, for example, a FIFO (First In / First O
ut) A process of using a memory to delay the output timing of each color component signal on a line-by-line basis.

However, some document reading apparatuses include, for example, as disclosed in Japanese Patent No. 2817909.
In performing enlargement reading or reduction reading of a document image, there is a method in which the document scanning speed in the sub-scanning direction is increased or decreased according to the reading magnification. In this type of document reading apparatus, since the apparent gap of each line sensor does not become a line unit as the scanning speed increases or decreases, the gap correction is performed by performing not only the line delay processing but also the interpolation processing between two points. It corresponds to. The point-to-point interpolation process is a process of performing a predetermined operation based on a color component signal on a certain line in the sub-scanning direction and a color component signal on a preceding line, and calculating the result of the calculation on the color component between each line. This is a process of correcting a gap of less than one line caused by increasing or decreasing the scanning speed by simulating a signal.

Here, the gap correction by the line delay processing and the two-point interpolation processing will be described in detail. For example, line sensors corresponding to each of the R, G, and B color components are arranged in order from the leading side in the sub-scanning direction of the document image, and a gap of four lines exists between each line sensor. Original image enlargement / reduction ratio specification is 7
Consider the case of 0%. At this time, the apparent gap between RG and GB is 4 × 0.7 =
2.8 lines.

In this case, in the conventional document reading apparatus, since the line sensor x corresponding to the B color component is located at the rearmost end in the sub-scanning direction, the other color component signals are adjusted to the B color component signal. As described above, the gap correction between them is performed. For example, for the G color component signal, of the 2.8 line gap between GB, two lines are corrected by line delay processing, and 0.8 lines are corrected by two-point interpolation processing.

More specifically, as shown in FIG. 7, first, the G color component signal is delayed by two lines by line delay processing. Thus, the gap between the delayed G color component signal G1 and B color component signal B1 is equivalent to 0.8 lines. Then, based on the delayed G color component signal G1 and the G color component signal G0 in the preceding line, gap correction for 0.8 lines is performed by two-point interpolation processing.
That is, it is located at the position of the B color component signal B1 based on the distance ratio (0.8 line, 0.2 line) between the G color component signal G1, the G color component signal G0, and the B color component signal B1. A possible G color component signal is calculated. Thereby, the gap correction between the G color component signal and the B color component signal is completed. The correction of the gap between the R color component signal and the B color component signal is performed in exactly the same manner.

[0009]

However, in the conventional document reading apparatus, two-point interpolation is performed based on the color component signal from the line sensor located at the rearmost end in the sub-scanning direction. The point-to-point interpolation process must be applied to the G color component signal, which may cause unnecessary image quality degradation. This is because the G color component signal is used as a main component when generating a lightness (luminance) signal representing the brightness of an image, and thus the G color component signal is regarded as the most important signal level among the color component signals. That is, if the G color component signal is attenuated by approximation in the point-to-point interpolation processing, it will have a great effect on image quality deterioration as a result.

To deal with this, for example, it is conceivable to arrange a line sensor corresponding to the G color component at the rearmost end in the sub-scanning direction. However, in the three-line solid-state imaging device, the line sensor at the center of the three lines is least affected by vibration during scanning. That is, if the line sensor corresponding to the G color component is disposed at the rearmost end in the sub-scanning direction, the G color component signal is easily affected by vibration during scanning, and as a result, the image quality is reduced in the same manner as described above. This will have a significant effect on degradation.

In order to cope with the increase or decrease of the scanning speed in the sub-scanning direction in accordance with the reading magnification of the original image, the present invention is applicable to a case where the gap correction for each color component signal is performed by a two-point interpolation process. An object of the present invention is to provide a document reading apparatus capable of minimizing the influence on image quality deterioration.

[0012]

SUMMARY OF THE INVENTION The present invention is a document reading device devised to achieve the above object. That is, a three-line type solid-state imaging device corresponding to each of the R, G, and B color components is provided, and the positional deviation of each color component signal on a line basis is corrected by line delay processing, and at the same time as the scanning speed increases and decreases. In a document reading apparatus that corrects a positional deviation of less than a line by an interpolation process between two points,
An interpolation processing circuit for performing point-to-point interpolation processing is provided only in the output system of the R color component signal and the output system of the B color component signal from the three-line solid-state imaging device.

According to the document reading apparatus having the above configuration, the interpolation processing circuit for performing the two-point interpolation processing is provided only for the output system of the R color component signal and the output system of the B color component signal.
Interpolation between two points is performed with reference to the G color component signal to correct a positional shift (gap) between the color component signals. Therefore, even if the two-point interpolation processing is performed, the G color component signal is not attenuated by approximation in the processing.

Further, the present invention includes a three-line solid-state imaging device corresponding to each of the R, G, and B color components, and corrects the positional deviation of each color component signal in line units by line delay processing, and performs scanning speed correction. In a document reading apparatus that corrects a positional shift of less than one line due to increase / decrease by two-point interpolation processing, two points provided in each output system of each color component signal from the three-line type solid-state imaging device. And a control circuit for determining whether or not the interpolation processing circuit in the output system of the G color component signal performs the two-point interpolation processing. is there.

According to the above-described document reading apparatus, the control circuit determines whether or not the interpolation processing circuit in the output system of the G color component signal performs the two-point interpolation process. If it is determined that the two-point interpolation processing is not performed by the interpolation processing circuit in the output system, the interpolation processing circuit in the output system of the R color component signal and the interpolation processing circuit in the output system of the B color component signal Interpolation processing between two points is performed based on the color component signals to correct a positional shift (gap) between the color component signals. Therefore, 2
Even if the point-to-point interpolation processing is performed, the G color component signal is not attenuated by approximation in the processing.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an original reading apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a functional configuration of a document reading apparatus according to the present invention.
FIG. 2 is a side sectional view showing an example of a schematic configuration of a scanning optical system in the document reading apparatus.

First, the scanning optical system in the document reading device will be described. The document reading device described here is for optically reading an image drawn on a document from a sheet-shaped document. For this purpose, as shown in FIG. 2, the document reading apparatus scans a reading surface of a document placed on a document table glass 11 with a full-rate carriage 12 and scans at a half speed of the full-rate carriage 12. A half-rate carriage 13, a light source 14 mounted on the full-rate carriage 12 for irradiating the original on the platen glass 11, and a full-rate carriage 1 for converting the optical axis direction of the reflected light from the original.
2, a mirror 15 mounted on the half-rate carriage 13, a lens 16 for condensing the reflected light obtained via the mirror 15, a three-line solid-state imaging device 17 for receiving the condensed reflected light, and a motor drive. A control board 18,
And a video signal processing board 20.

In the document reading apparatus 10 having such a configuration,
When a document is placed on the platen glass 11, the full-rate carriage 12 and the half-rate carriage 13
The original on the platen glass 11 is scanned. As a result of this scanning, the three-line solid-state imaging device 17 receives the reflected light from the original via the mirror 15 mounted on the full-rate carriage 12 and the half-rate carriage 13 and reads the image drawn on the original. Will be done.

At this time, the full rate carriage 12 and the half rate carriage 13 are driven by a carriage drive motor (not shown). However, the driving speed, that is, the scanning speed of the original on the original platen glass 11 is controlled by the motor drive control board 18 to increase or decrease according to the reading magnification of the original image.

The three-line solid-state imaging device 17 reads an image from a document by a photoelectric conversion process.
In order to cope with reading of a color image, a three-line configuration corresponding to the spectral sensitivity characteristics of each of R, G, and B colors is adopted. In the three-line type solid-state imaging device 17, a line sensor corresponding to the G color component is disposed at the center of the three lines, so that the G color component signal is minimized from being affected by vibration during scanning. are doing. It is also assumed that a gap of, for example, four lines exists between the three line sensors (see FIG. 6).

The R, G, and B color component signals obtained by the three-line solid-state imaging device 17 are processed by the video signal processing board 20.

The video signal processing board 20 performs processing for each of the R, G, and B color component signals. As shown in FIG. 1, an A / D converter 21 and a light amount distribution correction circuit provided for each color component are provided. A circuit 22, a gap correction unit 23, a color conversion processing unit 24, a sub-scanning enlargement / reduction unit 25, a solid-state imaging device driving circuit unit 26, a user interface control unit 27, a motor drive control unit 28, a CPU ( Centra
l Processing Unit) 29.

The A / D converter 21 performs A / D conversion on each color component signal. The light quantity distribution correction circuit 22 performs light quantity distribution correction (for example, shading correction) on the digital signal after the A / D conversion. The A / D converter 21 may be provided outside the video signal processing board 20.

The gap correction section 23 is based on digital signals corresponding to the respective color components after the light quantity distribution correction, and the three-line solid-state imaging device 17 has
This is for correcting the gap between the line sensors.

The color conversion processing section 24 includes a gap correction section 23
Each of the R, G, and B color component signals after the gap has been corrected is converted to a signal in a different color space. Examples of signals in different color spaces include a Lab signal, a Luv signal, an XYZ signal, an s-RGB signal, and the like. For such a color space conversion, the color conversion processing unit 24 performs an ACS / AE determination that realizes a color original detection function (ACS) and a background detection function (AE) by a look-up table (LUT), a matrix operation, or the like. Part 24a
A brightness conversion unit 24b for converting the brightness of each of the R, G, and B color components in accordance with the detection determination result of the ACS / AE determination unit 24a; and converting the color component signals after the brightness conversion into a predetermined color space signal. And a color conversion unit 24c for conversion.

The sub-scanning enlargement / reduction unit 25 is adapted to cope with a scanning speed which increases or decreases according to the reading magnification of the original image.
A predetermined color space signal converted by the color conversion processing unit 24 is subjected to enlargement or reduction processing in the sub-scanning direction as necessary, and the processed signal is sent to a subsequent processing circuit unit (not shown). It is. For this purpose, the sub-scanning scaling unit 25 has a scaling circuit 25a provided for each color component in the converted color space signal.

The solid-state image sensor drive circuit 26 drives the three-line type solid-state image sensor 17 and controls the same. The user interface control unit 27 controls a user interface such as an operation panel. The motor drive control unit 28 controls driving of a carriage drive motor, that is, controls the motor drive control board 18. The CPU 29 controls the operations of the above-described units, that is, the entire document reading apparatus, by executing a predetermined program.

By the way, the document reading apparatus 10 according to the present embodiment configured as described above has a gap correction unit 23.
Has a great feature.

In correcting the gap between the three line sensors of the three-line solid-state imaging device 17, the gap correction unit 23 adjusts the gap for each line in the sub-scanning direction in substantially the same manner as in the related art. Is performed by a line delay process, and a gap correction for less than one line caused by an increase or decrease in the scanning speed is performed by a two-point interpolation process.

For this reason, the gap correction section 23 uses R,
It has a FIFO memory 23a for appropriately performing a line delay process on each of the G and B color component signals. However,
Sub-scanning two-point interpolation circuit 23 for performing two-point interpolation processing
R and 23B are provided only in the output system of the R color component signal and the output system of the B color component signal from the three-line solid-state imaging device 17, and are not provided in the output system of the G color component signal.

That is, in the gap correction section 23 in the present embodiment, the sub-scanning two-point interpolation circuits 23R and 23B are provided only in the output system of the R color component signal and the output system of the B color component signal. Sub-scanning 2-point interpolation circuit 23
The R and 23B perform a two-point interpolation process based on the G color component signal, thereby correcting the gap between the color component signals.

Here, the gap correction by the gap correction unit 23 will be described in more detail. FIG. 3 is an explanatory diagram showing an outline of gap correction in the document reading apparatus according to the present invention.

For example, in the three-line type solid-state imaging device 17, R, G, B are sequentially arranged from the leading side in the sub-scanning direction of the original image.
Line sensors corresponding to each color component are arranged,
Consider a case in which there is a gap of four lines between each line sensor, and the original image enlargement / reduction magnification designation is 70%. At this time, between apparent RG, G
The gap between B is 4 × 0.7 = 2.8 lines.

In this case, the gap correction unit 23 performs the two-point interpolation process based on the G color component signal as described above. However, for that purpose, as shown in FIG. 3, for example, for a gap between GB, the apparent B-color component signal B1 must pass the position of the G-color component signal. This is because the point-to-point interpolation processing has to be performed only with the G color component signal B0 in the previous line.

Therefore, when performing the gap correction between GB, the gap correction section 23 first converts the B color component signal into F
The line is delayed by three lines by the line delay processing in the IFO memory 23a. Thus, the delayed B color component signal B
The gap between 1 and the G color component signal G1 is 0.2 lines. Then, based on the delayed B-color component signal B1 and the B-color component signal B0 in the preceding line, a two-line interpolation process in the sub-scanning two-point interpolator 23B performs a gap for 0.2 lines. Make corrections. That is, it is located at the position of the G color component signal G1 based on the distance ratio (0.2 line, 0.8 line) between the B color component signal B1, the B color component signal B0, and the G color component signal G1. A possible B color component signal is calculated.

This calculation will be described in more detail.
FIG. 4 is an explanatory diagram showing one specific example of gap correction in the document reading apparatus according to the present invention. When performing the gap correction between the GBs, the sub-scanning two-point
Since the line sensor corresponding to the B color component is arranged at a position where reading is performed after the line sensor corresponding to the G color component of the line type solid-state imaging device 17, the data of the previous line by the line sensor corresponding to the B color component is transferred. Assuming that D2a and the current data are D2b, in performing the interpolation processing between two points,
Target position signal data (data after two-point interpolation processing) D
2x is calculated using the following equation (1).

D2x = (1−R) × D2a + R × D2b (1)

At this time, R is the interpolation ratio of each color component, that is, the decimal portion of the B color component (for example, 0.
The correction amount is 2), which can be obtained by the following equation (2), where Gap_GB is the number of line gaps between GB at the time of 100% reading, and Y is the designated magnification at the time of reading.

R = Gap_GB × Y / 100−n (2)

For the gap correction between RG,
The sub-scanning two-point interpolation circuit 23R performs the following operation.
That is, in the sub-scanning two-point interpolation circuit 23R, the line sensor corresponding to the R color component is disposed at a position where the reading is performed earlier than the line sensor corresponding to the G color component of the three-line solid-state imaging device 17. , The data for the previous line by the line sensor corresponding to the R color component is D1a, and the current data is D1a.
1b, the signal data of the target position (data after the two-point interpolation processing) D1 in performing the two-point interpolation processing
x is calculated using the following equation (3).

D1x = R × D1a + (1−R) × D1b (3)

Note that R is the same as in the case between GB.

As described above, in the gap correction unit 23, the sub-scanning two-point interpolation circuits 23R and 23B
Interpolation processing between two points based on the color component signal is performed, whereby the gap correction between GB and between RBs is completed.

Next, another embodiment of the document reading apparatus according to the present invention will be described. FIG. 5 is a block diagram showing another example of the functional configuration of the document reading apparatus according to the present invention. The document reading apparatus described here differs from the above-described embodiment in the configuration of the gap correction unit 23 'in the video signal processing board 20' and the control function of the CPU 29 '.

In the above-described gap correction section 23, the sub-scanning two-point interpolation circuits 23R and 23B are provided only in the output system of the R color component signal and the output system of the B color component signal. The unit 23 'is a sub-scanning two-point interpolation circuit 23R, 23G, 23B for performing a two-point interpolation process on each of the output systems of the R, G, and B color component signals.
Is provided. In response to this, the CPU 2
Reference numeral 9 'has a function of determining whether or not the two-point sub-scanning interpolation circuit 23G in the output system of the G color component signal should perform the two-point interpolation processing.

When correcting the gap between the three line sensors of the three-line type solid-state imaging device 17 in the document reading apparatus having such a configuration, first, the CP
U29 'determines whether to cause the sub-scanning two-point interpolation circuit 23G to perform the two-point interpolation processing. When it is determined that the two-point interpolation process is to be performed, the gap correction unit 23 'performs the gap correction in substantially the same manner as in the related art.

It should be noted that the sub-scanning two-point
If it is determined not to perform the point interpolation processing, the CPU 2
9 'gives an instruction to the gap correction unit 23' so as not to operate the inter-subscanning-two-point interpolation circuit 23G.

The CPU 29 'operates the interpolation circuit 23 between the sub-scanning two points.
As a case where it is determined that G is not to perform the two-point interpolation processing, for example, when the monochrome mode is supported, that is, when the user interface control unit 27 notifies that the monochrome image reading is supported. It is also conceivable to prevent the sub-scanning two-point interpolating circuit 23G from performing the two-point interpolation process when the enlargement / reduction of the document image, that is, the increase / decrease of the document scanning speed in the sub-scanning direction is instructed.

When the CPU 29 'determines that the two-point sub-scanning interpolating circuit 23G does not perform the two-point interpolating process, the gap correction unit 23' executes the sub-scanning in substantially the same manner as in the above-described embodiment. Using only the two-point interpolation circuits 23R and 23B, two-point interpolation processing is performed based on the G color component signal, thereby completing the gap correction between GB and RB.

As described above, in any of the above-described embodiments, the gap correction units 23 and 23 'interpolate between the two points of sub-scanning in the output system of the R color component signal and the output system of the B color component signal. The circuits 23R and 23B perform a point-to-point interpolation process on the basis of the G color component signal, and can correct a gap between the color component signals.
Therefore, even if the point-to-point interpolation processing is performed, the G color component signal which is regarded as the most important signal level, that is, the G color component signal whose deterioration is easily visually perceived, is attenuated by approximation in the processing. Therefore, the influence on image quality degradation can be minimized.

In addition, since the line sensor corresponding to the G color component in the three-line type solid-state imaging device 17 can be arranged at the center of the three lines, the G color component signal is hardly affected by vibration during scanning. This is preferable in further suppressing the influence on the image quality deterioration.

In other words, according to the document reading apparatus in each of the above-described embodiments, the gap correction for each color component signal is performed by two-point interpolation processing in order to cope with an increase or a decrease in the scanning speed in the sub-scanning direction according to the reading magnification of the document image. Is performed, the effect on the image quality degradation can be minimized by performing the two-point interpolation processing based on the G color component signal. At this time, strictly speaking, by using the G color component signal as a reference, there is a positional deviation from the conventional case where the last color component signal of three lines (for example, a B color component signal) is used as a reference. However, the positional shift is relative to the entire image, and the shift amount is one line or less, so that it has almost no visual effect.

In particular, when the monochrome mode is supported, information on the color (hue, saturation, etc.) is removed from each color component signal acquired by the three-line solid-state imaging device 17, and lightness (luminance) is obtained.
Therefore, if the G color component signal used as the main component when generating the brightness signal is attenuated, the influence on the image quality deterioration will be very large. Therefore, when the monochrome mode is supported, if the two-point interpolation processing based on the G color component signal is performed using only the sub-scanning two-point interpolation circuits 23R and 23B, the two-point interpolation processing based on the G color component signal is performed. The advantage obtained by the point-to-point interpolation processing appears more remarkably.

In each of the above-described embodiments, after the gap correction by the gap correction units 23 and 23 ', the color conversion processing unit 24 converts the R, G, and B color component signals into signals in a different color space. Although the case of conversion has been described as an example, the present invention is not limited to this, and it is needless to say that the present invention can be applied to a document reading apparatus that does not include the color conversion processing unit 24. However, for example, when the color conversion processing unit 24 performs conversion into a Lab signal, a G color component signal used as a main component when generating a lightness signal greatly affects the conversion result. Therefore,
The present invention, as in each of the above-described embodiments,
This can be said to be particularly suitable when applied to a document reading apparatus provided with a color conversion processing unit 24 which is means for converting the color space of each color component signal.

[0055]

As described above, in the original reading apparatus according to the present invention, the respective interpolation processing circuits in the output system of the R color component signal and the output system of the B color component signal use the G color component signal as a reference. In this way, interpolation processing between two points is performed, and gap correction between the respective color component signals is performed. Therefore, even when the gap correction for each color component signal is performed by the two-point interpolation process in order to cope with the increase or decrease of the scanning speed in the sub-scanning direction according to the reading magnification of the original image, the signal level is regarded as the most important as the signal level. Since the G color component signal is not attenuated, it is possible to minimize the influence on the image quality deterioration.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a functional configuration of a document reading apparatus according to the present invention.

FIG. 2 is a side sectional view showing an example of a schematic configuration of a scanning optical system in the document reading apparatus according to the present invention.

FIG. 3 is an explanatory diagram showing an outline of gap correction in the document reading apparatus according to the present invention.

4A and 4B are explanatory diagrams showing a specific example of gap correction between GB in the document reading apparatus according to the present invention, wherein FIG. 4A is a diagram showing gap correction between GB, and FIG. FIG.

FIG. 5 is a block diagram showing another example of the functional configuration of the document reading apparatus according to the present invention.

FIG. 6 is an explanatory diagram illustrating a configuration example of a general three-line solid-state imaging device.

FIG. 7 is an explanatory diagram showing an outline of gap correction in a conventional document reading apparatus.

[Explanation of symbols]

10: Document reading device, 17: 3-line solid-state imaging device,
20, 20 '... video signal processing board, 23, 23' ... gap correction unit, 23a ... FIFO memory, 23R, 23
G, 23B: two-point sub-scanning interpolation circuit, 24: color conversion processing unit, 29, 29 ': CPU

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 AA11 BA19 CA01 CB01 CE16 DB02 DB06 5C072 AA01 BA19 EA05 FA07 FB23 FB27 5C077 MM03 MP08 PP32 PQ24 RR19 5C079 HA13 HB01 JA03 JA23 LA28 LB11 MA11 NA02

Claims (5)

[Claims] 1. A three-line solid-state imaging device corresponding to each of R, G, and B color components is provided, and a line shift of each color component signal in a line unit is corrected by a line delay process. In a document reading apparatus for correcting a positional displacement of less than one line caused by two-point interpolation processing, an interpolation processing circuit for performing two-point interpolation processing includes an output system of an R-color component signal from the three-line solid-state imaging device. And a document reading device provided only in an output system for a B-color component signal. 2. A three-line type solid-state imaging device corresponding to each of R, G, and B color components is provided. Line displacement of each color component signal is corrected by line delay processing, and the scanning speed is increased or decreased. A document reading apparatus that corrects a position shift of less than one line caused by two-point interpolation processing by two-point interpolation processing provided in each output system of each color component signal from the three-line solid-state imaging device. An original reading apparatus, comprising: an interpolation processing circuit for performing the interpolation; and a control circuit for determining whether or not the interpolation processing circuit in the output system of the G color component signal performs the two-point interpolation processing. 3. The document reading apparatus according to claim 2, wherein the control circuit does not cause the interpolation processing circuit in the output system of the G color component signal to perform the point-to-point interpolation process in the monochrome mode. 4. A color conversion means for converting each color component signal, whose position shift has been corrected by the line delay process and the two-point interpolation process, into a signal in a color space different from each color component signal. Any one of claims 1 to 4
The document reading device according to the item. 5. The three-line solid-state imaging device according to claim 3, wherein
At the center of the line, a solid-state image pickup device
A first solid-state imaging device corresponding to the first color component is located at a position where reading is performed earlier than a solid-state imaging device corresponding to the color component, and a second color component is located at a position where reading is performed after the solid-state imaging device corresponding to the G color component. When the solid-state image sensors corresponding to the first color component are respectively arranged, the data of the previous line by the solid-state image sensor corresponding to the first color component is D1a, the current data is D1b, and the data before the solid-state image sensor corresponding to the second color component is D1a. Assuming that the data for the line is D2a, the current data is D2b, and the interpolation ratio of each color component is R, the data D1 after the two-point interpolation of the first color component is used in performing the two-point interpolation.
x is calculated as D1x = R × D1a + (1−R) × D1b, and data D2x of the second color component after the inter-point interpolation processing is calculated as D2x = (1−R) × D2a + R × D2b. The document reading apparatus according to any one of claims 1 to 5, wherein: