JPH0622158A - Picture reader - Google Patents

Abstract

PURPOSE:To improve the picture quality regardless of read magnification by adding a weight mean processing with a ratio in response to a read magnification to picture data of plural lines read by an image sensor and outputting the obtained picture data as picture data of a line corresponding to other image sensor. CONSTITUTION:A selector 131 in a position correcting part 130 sends picture data corresponding to a CCD array at the side reading an original taking precedence over other among 2-color picture data selected to a line delay section 133, in which the data are delayed for a prescribed time. A data interpolation section 135 uses an interpolation coefficient designated by interpolation ratio data DH as to one of two color picture data to generate interpolation data with the weight mean of the data of each picture element of two adjacent lines and outputs the interpolation data as picture data corresponding to the other picture data to a color discrimination section. Thus, the picture with high picture quality and excellent reproducibility is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line scanning type image reading apparatus used as image inputting means for digital copying machines, facsimile machines, filing systems and the like.

[0002]

2. Description of the Related Art A line scanning type image reading apparatus has a one-dimensional image sensor composed of a large number of light receiving elements arranged in a main scanning direction, and an image sensor or an optical system for guiding scanning light to the image sensor is provided for an original. The document is subdivided into pixels and read by moving the document relatively in the sub-scanning direction.

Conventionally, there is known an image reading apparatus of this type in which a plurality of image sensors are arranged parallel to each other in the sub-scanning direction. That is, in the case of reading a multicolor original including full color and performing color discrimination, a three-color integrated sensor in which image sensors of R (red), G (green), and B (blue) are integrated into one chip is used. ing. Even in the case of mono-color reading, when the optical system is of the same size, in order to make the reading length in the main scanning direction sufficiently long, multiple image sensors are staggered along the main scanning direction. A pseudo one-dimensional contact-type image sensor arranged at is used.

When a plurality of image sensors are arranged in the sub-scanning direction as described above, a reading time difference occurs depending on the distance (gap) between the image sensors. That is, the image sensor on one end side in the arrangement direction reads the original document ahead of the image sensor on the other end side, and the reading position (line) of the original document at each image sensor at the same time is different.

Therefore, the image data of the same line in the original read by each image sensor (a signal obtained by quantizing the photoelectric conversion output of the image sensor) is output at the same time, or based on the image data of two colors for the same pixel. In order to determine the color of the pixel, it is necessary to make a correction corresponding to the difference in the reading position.

In the conventional image reading apparatus, as such correction, the transmission of image data corresponding to the image sensor which reads the original document in advance is delayed by a delay memory (FIFO or the like).
The process of delaying is performed by the line unit.

That is, assuming that the gap between the image sensors is g, the magnification of the optical system (projection magnification of the document) is F, and the read pixel density (the number of lines / unit length) in the sub-scanning direction on the document is Dy. , A reading position shift corresponding to the number of lines n expressed by the equation (1) occurs between the image sensors.

N = (g / F) × Dy (1) Therefore, in the conventional image reading apparatus, the image data for n lines of the image sensor which reads the original document is temporarily stored in the delay memory and then sequentially. It was configured to read.

[0009]

Now, for example, in an image reading apparatus incorporated in a copying machine, the reading magnification M is changed according to the copying magnification. That is, the read pixel density Dy in the sub-scanning direction is changed to a value (Dy = Ds × M) obtained by multiplying the reference read pixel density Ds when the read magnification is “1” (100%) by the read magnification M. . As a method of changing the read pixel density, there is a method of changing the relative moving speed of the image sensor or the optical system and the document to 1 / M of the reference speed while keeping the read cycle (driving timing of the image sensor) constant. It is common. There is also a method of changing the reading cycle while keeping the relative movement speed constant.

Normally, the reference read pixel density Ds and the magnification F of the optical system are set so that the number of lines (hereinafter referred to as the number of different lines) n corresponding to the deviation of the reading position is an integer. Therefore, the read magnification M is an integer (however,
In the case of (except 0), the number of different lines n is also an integer, so by delaying the period corresponding to the scanning of n lines as described above, the inconvenience caused by the gap between the image sensors is completely eliminated. Will be resolved.

However, the read magnification M is a decimal (for example, 0.
(8, 1.4, etc.), the difference line number n rarely becomes an integer, and in most cases, the difference line number n becomes a decimal number. This means that the line read by each image sensor has a positional (positional) displacement on the document in addition to the temporal displacement of the reading. For example, if the difference line number n is 13.5,
The 13th line read by one of the image sensors,
Between the first line read by the other image sensor and the first line to be read, 0.
A positional shift of 5 lines occurs.

That is, when the read magnification M is a decimal number,
As shown in JP-A-3-22677, the difference line number n (decimal number) is replaced with an integer close to it, and then n
By delaying by the amount of lines, for example, the image data of the image sensors that are simultaneously output can be used as the information of the adjacent positions on the document, but cannot be used as the information of the completely same position.

Therefore, in the image reading apparatus for reading in full color, when the image is reproduced based on the output image data of the three colors of R, G and B, there is a problem that the color is not reproduced correctly. In an image reading apparatus that performs color discrimination of pixels, there is a problem that erroneous discrimination occurs, and when the image is reproduced based on the color discrimination data, the contour portion of the region of the discrimination target color is disturbed. Further, even in an image reading apparatus which reads by a plurality of staggered image sensors, there is a problem that an image reproduced based on output image data is disturbed.

In view of the above problems, it is an object of the present invention to provide an image reading apparatus which outputs high quality image information excellent in image reproducibility regardless of the reading magnification.

[0015]

In order to solve the above-mentioned problems, the apparatus according to the invention of claim 1 is a line scanning type image reading apparatus having a plurality of parallel image sensors arranged in the sub-scanning direction. In order to compensate for the difference in the reading position of each image sensor, a weighted average processing of a ratio according to the reading magnification is applied to the image data of a plurality of lines read by at least one image sensor to obtain A data interpolating unit that outputs the obtained image data as image data of a line corresponding to a line read by another image sensor is provided.

The apparatus according to the second aspect of the present invention comprises a delay memory for delaying the transmission of image data corresponding to the image sensor that reads the original document in advance. An apparatus according to a third aspect of the present invention includes delay control means for changing the delay amount of the delay of the image data by the delay memory according to the reading magnification.

According to a fourth aspect of the present invention, there is provided a first and a second image sensor which are arranged in the sub-scanning direction and which are different in reading color and are parallel to each other. Image data corresponding to the first image sensor is obtained. An image reading apparatus configured to output the density data of each pixel of a document and determine the color of the document based on the image data corresponding to each image sensor, wherein the reading position of each image sensor is different. In order to enable color discrimination by compensating for the above, the weighted average processing of a ratio according to the reading magnification is applied to the image data of the plurality of lines read by the second image sensor, and the obtained image data is The first image sensor is provided with data interpolating means for outputting as image data of a line corresponding to the line read by the image sensor.

[0018]

There is a case where a line read by each image sensor is misaligned due to the relationship between the gap between the image sensors arranged in the sub-scanning direction and the reading magnification.

Here, as shown in FIG. 12, a line L20 read by one of the image sensors is different from a line L20 read by another image sensor on the front side in the sub-scanning direction with a line width Y (the sub-pixel of the pixel q). (Length in scanning direction) 4
An example will be described in which the position is deviated by one-half the length, that is, the position shift of 0.25 line occurs between the image sensors. In the case of this example, the line L10 and the line L20
Overlap each other by 75%.

The data interpolating means is a line L1 as shown in the figure.
In order to correct the positional deviation between 0 and the line L20, a weighted average process is applied to the image data from one image sensor, and the processed image data is output as image information corresponding to the image data from the other image sensor. .

That is, for example, for the image data of the line L10 and the next line L11, a ratio (0.75 and 0.2) according to the degree of overlap with the line L20.
A process of adding content by multiplying the coefficient of 5) is added, and the obtained image data is output as image data corresponding to the line L20.

By the way, in principle, the image sensor to be subjected to the load averaging process may be either the front side or the rear side in the sub-scanning direction. However,
In the case of a configuration in which one image sensor is used both for reading the density information of a document and for reading for color discrimination, the image data of the image sensor which is also used for holding the density information should be as much data as possible. It is preferable to avoid processing. Therefore, in the image reading apparatus according to the fourth aspect of the present invention, the weighted average processing is applied to the image data of the image sensor used only for color discrimination.

The delay memory compensates for the reading time difference between the image sensors. The delay amount of the delay memory is changed by the delay control means according to the reading magnification.

[0024]

1 is a front view showing a schematic structure of an image reader 1 according to the present invention. The image reader 1 is a line scanning type image reading device having a full-color image sensor (hereinafter referred to as “image sensor”) 16, and is a page printer (not shown) as an image input unit of a digital copying machine having a multicolor copying function. Used in combination with.

The optical system 10 for projecting a document image on the image sensor 16 is composed of a scanner 11, mirrors 13 and 14, a main lens 15 and the like which can reciprocate below a document table glass 18. The scanner 11 has an exposure lamp 12 that irradiates a document with scanning light, and is driven by a motor 17. The scanning light reflected on the document surface is reflected by the mirror 13,
It is incident on the image sensor 16 via 14 and the main lens 15.

The image of the original is read by the image sensor 16 as color signals of three primary colors of additive colors R (red), G (green) and B (blue). The photoelectric conversion signal output from the image sensor 16 is quantized by the signal processing unit 100, subjected to various signal processing depending on the copy mode, and then sent to the page printer as image data VIDEO.

The multicolor copy mode of the copying machine using the image reader 1 will be described below. In the normal copy mode, the copying machine forms a standard color (generally black) monocolor image regardless of the color of the original. On the other hand, in the multicolor copy mode, the designated color portion in the original image is copied in a color other than the standard color (for example, red), and the other color portions are copied in the standard color. That is, a two-color image is formed. At this time, two colors, red and blue, can be selected as the designated colors. The designated color is selected by the operator using the keys on the operation panel.

In order to realize such multicolor copying,
In the image reader 1, the color of each pixel of the original image is discriminated (color discrimination) in the signal processing unit 100 described later. Then, the color data Dco obtained by the discrimination is output to the page printer in synchronization with the image data VIDEO.

2A and 2B show the image sensor 1.
It is a top view which shows the structure of No. 6 typically. FIG. 2B is an enlarged view of a part of FIG. Image sensor 16
Is a one-chip solid-state imaging device in which three CCD arrays 16R, 16G, and 16B extending in the main scanning direction of document scanning are integrally formed in a substrate. Each CCD array 16R, 16
G and 16B are C corresponding to 5000 pixels, respectively.
It has a CD element and can read A3 size originals at a resolution of 16 lines / mm. CCD array 16R, 1
Spectral filters that transmit R, G, and B light are provided on the light receiving surfaces of 6G and 16B, respectively, in order to separate the original image into three primary colors for reading.

In the image sensor 16, the CCD array 1
6R, 16G, and 16B are arranged in parallel with each other at a pitch of 12 pixels in the sub-scanning direction. Therefore, with respect to the same pixel, the output timing of the photoelectric conversion signal by the CCD array 16G is set to a certain time (1 when the reading magnification is "1") with respect to the output timing of the CCD array 16R.
The output timing of the CCD array 16B is delayed by the same time as the output timing of the CCD array 16G. That is, the information of each color read by separating the pixel into three colors is R,
The signals are output in the order of G and B with a certain time delay. Since the sub-scanning speed is changed according to the copy magnification, the deviation of the output timing of each color also increases or decreases according to the copy magnification.

FIG. 3 is a block diagram showing the configuration of the signal processing unit 100. The signal processing unit 100 includes an image reader 1
Centering on a CPU (central processing unit) 101 for controlling the entire of the above, an AD conversion unit 110, a shading correction unit 120,
Position correction unit 130, image processing unit 140, output interface unit 150, color discrimination unit 160, and black generation unit 1
It is composed of 80 and the like.

The image sensor 16 described above, according to the CCD drive signal supplied from the black generator 180,
The photoelectric conversion signals of R, G, and B colors are sent in parallel to the signal processing unit 100.

In the signal processing unit 100, the AD conversion unit 110 first quantizes the photoelectric conversion signal of each color. That is, the AD conversion unit 110 amplifies the photoelectric conversion signal of each color to a predetermined level, performs sampling at a timing according to the pixel clock, and converts the photoelectric conversion signal into image data of 8 bits (256 gradations) for each color. . The pixel clock is also generated by the clock generator 180.

After that, various processes are performed using the image data generated by the AD converter 110 as original information.
The operation of each unit will be described below. The shading correction unit 120 performs shading correction on the image data of three colors, which corresponds to uneven light distribution of the exposure lamp 12 and sensitivity difference between pixels of the CCD array, and correction for normalizing the dynamic range of each color. And do.

The position correction section 130 selects image data of two colors (G and R or G and B) required for color discrimination from the image data of three colors, and selects the image data of the selected image data. Delay processing and interpolation processing for compensating for the differences in the reading positions of the CCD arrays 16R, 16G, 16B are performed. Then, the position correction unit 130 extracts the image data of G, which has the highest relative luminous efficiency among R, G, and B, as monochrome read information (density data) of the document and outputs it to the image processing unit 140. The image data of R or B is converted into the color discrimination unit 160.
Output to.

For such a position correction unit 130, C
The PU 101 has a select signal SS, delay amount data DL,
And interpolation ratio data DH are given. The position correction unit 1
Details of the configuration of 30 will be described later.

The color discriminating unit 160 is composed of a ROM in which predetermined data is stored as a look-up table (LUT), and the image data of the two colors selected by the position correcting unit 130 and the designated color bit signal Sco input from the CPU 101.
Based on the above, the color discrimination data for discriminating the color of the original image for each pixel is output. That is, in the ROM, at the addresses designated by the value of the designated color signal bit Sco and the respective values “0” to “255” of the two-color image data,
Data indicating the value of the color discrimination data is stored in each.

The image processing section 140 performs various image processing on the G image data, including gamma correction for accurately reproducing the density of the original image and filtering processing such as edge enhancement and smoothing for improving image quality. Add.

Further, the image processing section 140 includes a scaling section 14 for performing pixel density conversion in the main scanning direction (scaling processing for overlapping pixels or thinning pixels) according to the scaling data MAG.
5 are provided. The scaling data MAG is the CPU 10
It is given by 1 and its value is appropriately changed according to the reading magnification according to the copying magnification.

To the scaling unit 145, the color discrimination data by the color discrimination unit 160 is also input in synchronization with the G image data, and this output data is also subjected to the scaling process in the same manner as the image data.

The G image data and the color discrimination data output from the image processing unit 140 are respectively the image data VID.
The EO and color data Dco are transferred to the page printer via the output interface unit 150.

The output form of the image data VIDEO may be an 8-bit digital signal indicating the image density as it is, or bit data binarized by a dither method or the like. It can also be an analog signal.

In parallel with the control of the signal processing unit 100 having the above configuration, the CPU 101 controls the scanning speed in order to set the pixel density in the sub-scanning direction to a value according to the reading magnification. That is, the CPU 101 causes the driver 17D that drives the scanning motor 17 to output the switching signal S
The on / off control is performed by d, and the motor 17 based on the output pulse signal F / G of the motor rotation sensor 17S.
Is detected, and the speed control signal Sv is given to the driver 17D so that the scan speed becomes a constant speed according to the reading magnification.

The scan speed is set to the value represented by the equation (2). V = Vs / M (2) Here, Vs is the reference scan speed when the read magnification is "1" (100%), and M is the read magnification.

That is, the reading magnification is "2" (200%).
If so, the scan speed is half the reference scan speed.
If the reading magnification is “0.5” (50%), the scanning speed is twice the reference scanning speed.

By setting the scan speed in this way, as described above, the read pixel density Dy in the sub-scanning direction becomes the reference read pixel density Ds when the read magnification is "1" and the read magnification M. Value multiplied by (Dy = Ds
XM).

FIG. 4 is a block diagram showing the configuration of the position correction unit 130 of FIG. The position correction unit 130 selects the image data of two colors out of three colors, and outputs the selected selector 131.
A selector 132 for switching transmission destinations of image data of two colors, a line delay unit 133 for delaying data for a plurality of lines, and a line memory 1 for delaying data for one line.
34 and a data interpolating unit 135 that performs a weighted average process as the interpolation process.

In the selector 131, the R and G image data are selected when the designated color for color discrimination is red, and the G and B image data are selected when the designated color is blue. Of the image data of the two colors selected in this way, the image data corresponding to the CCD array on the side that reads the document first is sent to the line delay unit 133, and the other image data is selected to the selector 132. Sent as input.

The line delay unit 133 receives the delay amount data DL.
In accordance with the above, the input image data is delayed by a predetermined time for each line and output. The number k of delay lines of the line delay unit 133, that is, the value of the delay amount data DL is set to the same number as the number n of different lines (the number of lines corresponding to the gap between the CCD arrays) or an integer closest thereto.

For example, when the reading magnification is "1",
The difference line number n is “12”. Therefore, at this time, the CPU 101 sets “12” as the delay line number k.
To set. Then, the line delay unit 133 sequentially stores the image data of 12 lines in the internal memory, reads the image data of the first line in parallel with the storage of the 13th line, and inputs it to the selector 132 as the other selection input. send. Further, when the reading magnification M is "2", the scanning speed becomes one half of the normal speed, so the number n of different lines is "24" (12 x 2). Therefore, at this time, the line delay unit 133 delays by 24 lines.

When the number of different lines n becomes an integer due to such line-by-line delay, the image data of the two colors input to the selector 132 becomes information obtained by reading the same line on the original.

However, the number of different lines n may be a decimal number depending on the value of the read magnification M. For example, when the reading magnification M is “1.10”, the difference line number n is “1”.
3.2 "(12 x 1.10).

In such a case, a difference occurs between the difference line number n and the delay line number k. This is selector 1
As shown in FIG. 12, the two-color image data input to 32 is the information of the line shifted by a distance x (0 <x <Y) smaller than the line width (line pitch) Y on the document. means.

On the other hand, even if the reading magnification M is an integer, if the scanning speed becomes uneven, the positions on the original corresponding to the two-color image data are slightly different, and the line number n is delayed. There is a difference with the number of lines k.

That is, considering the unevenness of the scanning speed, the difference line number n can be expressed as in the equation (3). n = 12 × M ± α (3) Here, α is a value that depends on the unevenness of the scanning speed.

Therefore, the data interpolating unit 135 is provided to compensate for the difference between the difference line number n and the delay line number k. The data interpolating unit 135 generates interpolated data for one of the two color image data by weighted averaging the data values of the pixels of the adjacent two lines, and uses the interpolated data as image data corresponding to the other image data. It is sent to the color discrimination unit 160. The weighting factor of the weighted average is designated by the interpolation ratio data DH. For example, if the difference between the difference line number n and the delay line number k is "0.25", the data interpolation unit 135 uses 0.25 to 0 based on the data of two lines, as described with reference to FIG. The weighted average processing of the ratio of 0.75 is performed to generate the interpolation data of one line. The line memory 134 is provided as a delay unit for performing a weighted average of two lines.

Now, the selector 132 sends one of the R or B image data out of the input two-color image data to the data interpolating unit 135 and the other G image data as it is to the image processing unit 140. To switch the transmission path.

In other words, the position correction section 130 holds the information content of the G image data as the image data VIDEO as much as possible to improve the reproducibility of the image.
The image data of G is excluded from the weighted average (interpolation process).

FIG. 5 is a circuit diagram showing the configuration of the line delay unit 133 of FIG. In FIG. 5, the line delay unit 133
Is a FIFO memory 310 having a storage capacity capable of storing image data for 52 lines, a sub-scanning counter 320 for counting a horizontal synchronizing signal Hsync input every scanning of one line, comparators 330 and 340, and various logic circuits. 351 to 355.

For example, when the reading magnification is "1", first the comparison target value of the comparator 330 is "5".
2 ”(fixed number of lines) is set, and the comparator 340
The value "12" (the number of delay lines) of the delay amount data DL is set as the comparison target value.

Next, when the scan start instruction signal SCAN is input, the count value of the sub-scanning counter 320 is cleared. As a result, all the bits indicating the count value of the sub-scanning counter 320 become "0", and the write reset signal WRST for the FIFO memory 310 becomes active. Therefore, the write address of the FIFO memory 310 is reset, and the input image data is
The data is written in the memory 31 in order from the top address.

After the reset of the write address, the read reset signal RRST becomes active at the time of scanning the 12th line, and the write address of the FIFO memory 310 is reset. Therefore, thereafter, reading is performed in order from the start address.

After that, at the time of scanning the 52nd line, the output of the comparator 330 becomes active, and the FIFO is again activated.
The write address of the memory 310 is reset. That is, writing and reading of image data are repeatedly performed at a cycle of 52 lines.

FIG. 6 is a block diagram showing an example of the data interpolation unit 135 of FIG. 4, and FIGS. 7 and 8 are block diagrams showing other examples of the data interpolation unit 135 of FIG. 4, respectively. In addition,
7 and 8, constituent elements having the same functions as those in FIG. 6 are designated by the same reference numerals, and constituent elements corresponding to FIG. 6 are designated by the same reference numerals with alphabets “a” and “b”. I am doing it.

In FIG. 6, the data interpolating unit 135 outputs 2
It is composed of two multipliers 511 and 512 and an adder 513. The multiplier 511 is the selector 13 shown in FIG.
The image data having a value obtained by multiplying the value of the image data of the (N + 1) th line directly input from 2 by the weighting factor DC2 is output. In addition, the multiplier 512 uses the line memory 134.
The image data having a value obtained by multiplying the value of the Nth image data delayed by by the weighting factor DC1 is output.

The adder 513 is provided for each of the multipliers 511 and 512.
The interpolated data having a value obtained by adding the output of is output as image data. If the weighting factors of the weighting factors DC1 and DC2 are a% and (100−a)%, the interpolation data is [N +
The image data corresponds to the (100-a) / 100] th line.

Although the configuration using the multipliers 511 and 512 is illustrated in FIG. 6, the multipliers 511 and 51 are used as shown in FIG.
Instead of 2, lookup table ROMs 511a, 51
2a may be used. 6 and 7, the multipliers 511 and 512 or the look-up table ROM 5
If the bit configurations of 11a and 512a are appropriately selected, fine interpolation can be realized.

Further, as shown in FIG. 8, the selector 521
It is also possible to combine ˜523, the adder 531 and the multiplier 540 to perform interpolation. In the example of FIG. 8, assuming that the data values of the Nth line and the (N + 1) th line are A and B, respectively, A, (3A + B) / 4, (2A + 2) depending on the combination of the select signals SS1 to SS3.
It is possible to obtain four types of interpolated data of B) / 4 and (A + 3B) / 4. That is, it is possible to realize interpolation on a quarter line basis. It should be noted that by increasing the number of selectors and adders, it is possible to perform interpolation with an accuracy of a quarter line unit or more. In that case, it is preferable to make the interpolation accuracy in units of one line, which is a power of two, in order to simplify the circuit configuration.

FIG. 9 is a flow chart showing an outline of the interpolation ratio setting process executed by the CPU 101. CPU10
1 generates the interpolation ratio data DH according to the read magnification M in consideration of the unevenness of the scanning speed as described above.

That is, the CPU 101 detects the scan speed by measuring the pulse cycle of the output pulse signal F / G by the internal timer, and based on the difference between the normal speed according to the read magnification M and the measured value, the predetermined value is obtained. By calculating the amount of positional deviation of reading due to uneven scanning speed (#
10).

There may be a case where a delay is required for the image data depending on the relationship between the scan speed detection time depending on the processing speed of the CPU 101 and the transmission timing of the image data.

Next, the CPU 101 determines the number of delay lines k and the weighting factors DC1 and DC2 (# 20). For example, when the read magnification M is "1" and the amount of positional deviation due to uneven scan speed is "+0.1", that is, when the scan speed is faster by 0.1 line, the difference line number n is ". Therefore, the number k of delay lines is set to “11”, the weighting factor DC1 corresponding to the Nth line is set to “0.1”, and the weighting factor DC1 corresponding to the (N + 1) th line is set to Set to "0.9".

Further, when the reading magnification M is "1", the amount of positional deviation due to uneven scanning speed is "-0.
When the scanning speed is 1 line, that is, when the scanning speed is slow by 0.1 line, the difference line number n becomes "12.1". Therefore, the delay line number k is set to "12" and the weighting factor D is set.
C1 and DC2 are set to "0.9" and "0.1", respectively.

Further, when the read magnification M is "1.1" and the amount of positional deviation due to uneven scanning speed is "+0.1", the number of different lines n is "13.
Since it is 1 ”(12 × 1.1−0.1), the delay line number k is set to“ 13 ”and the weighting factors DC1 and DC2 are set to“ 0.9 ”and“ 0.1 ”, respectively.

Then, the CPU 101 determines the number of delay lines k.
Is the delay amount data DL, and the weighting factors DC1 and DC2 are the interpolation ratio data DH.
It is given to each part of 30 (# 30).

FIG. 10 is a block diagram showing the configuration of a signal processing unit 100A according to another embodiment of the present invention, and FIG. 11 is FIG.
3 is a block diagram showing the configuration of a position correction unit 130A of FIG.
In these drawings, the components having the same functions as those in FIGS. 3 and 4 are designated by the same reference numerals, and the components corresponding to FIGS. 3 and 4 are designated by the same reference numeral with the alphabet “A”. I am doing it.

In FIG. 10, the signal processing unit 100A is
Three-color image data V for full-color image reproduction
It is configured to output IDEO. The position correction unit 130A is provided to compensate for the difference in the read position of the three-color image data input from the shading correction unit 120. For this position correction unit 130A, the CPU
101A is the delay amount data DLA and the interpolation ratio data D
H1 and DH2 are given.

The image processing section 140A has a scaling section 145A, and performs various image processing including pixel density conversion in the main scanning direction. Then, the three-color image data VIDEO processed by the image processing unit 140A is output in parallel via the output interface unit 150A.

As shown in FIG. 11, the position correction unit 130A
Is a delay memory 31 provided for R image data.
1, a line memory 134, an interpolation unit 135, a delay memory 312 provided for the image data of G, a line memory 134, an interpolation unit 135, and delay memories 311 and 31.
The delay control unit 313 for controlling the number 2 is provided, and is configured to compensate the positional deviation of the reading of the R and G image data with respect to the B image data.

Since the CCD arrays 16R, 16G and 16B are arranged at equal intervals, the difference line number n related to the R image data is twice the difference line number n related to the G image data. Therefore, the delay memory 311 stores the delay line number kR in the delay memory 312 as the delay line number kG.
Is set to twice the value of. Similarly, each interpolation unit 135
A weighting factor is set for.

For example, when the read magnification M is "1.1", it is assumed that there is no scan speed unevenness, the number of different lines n relating to the G image data is "13.2", and the R image data is The difference line number n related to is 26.4. Therefore, the G image data is delayed by 13 lines by the delay memory 312, and the interpolation unit 1
35 for the Nth and (N + 1) th lines.
A weighted average process with a ratio of 8: 0.2 is performed. Also, R
Image data of 26
The line is delayed, and the interpolator 135 performs the weighted averaging process with a ratio of 0.6 to 0.4 on the Nth and (N + 1) th lines.

According to the embodiment of FIG. 3 described above, the image data of G having the highest relative luminous efficiency among the three colors is output as the density data without applying the weighted average processing. A grayscale image can be reproduced.

According to the above-described embodiment, since the one-chip image sensor 16 in which the CCD arrays 16R, 16G, 16B corresponding to R, G, B are integrated is used, an individual image sensor for each color is used. Compared with the case where the light-receiving surface is provided, the relative positional accuracy of the light-receiving surfaces of the respective colors is high, and the influence of lens aberration and temperature change is small, so that image data in which the original image is color-separated can be obtained. Therefore, there is no mistake in color discrimination, and no color ghost is generated due to the mistaken discrimination.

Although the image reader 1 using the full-color image sensor 16 has been illustrated in the above-described embodiments, the present invention is also applicable to an image reading apparatus for performing mono-color reading using a plurality of image sensors arranged in a staggered pattern. The invention can be applied.

In the above embodiment, a predetermined delay can be performed by using a delay means other than the FIFO memory.
For three colors, for example, one page (one original)
It is also possible to store each of the image data of 1) in the page memory, select an appropriate line, and read out three colors at the same time.

Although the image reader 1 for the copying machine is illustrated in the above embodiment, the application of the image reading apparatus according to the present invention is not limited to this. For example, it may be an image reader device that constitutes a filing system together with an external host computer.

In the above embodiment, the image data of G was extracted as the density data, but the image data of other colors may be extracted and excluded from the interpolation processing depending on the use. it can. .

[0088]

According to the present invention, it is possible to output high-quality image information excellent in image reproducibility regardless of the reading magnification.

According to the second aspect of the invention, the correction corresponding to the difference in the reading position of each image sensor can be performed regardless of the distance between the plurality of image sensors.
According to the invention of claim 3, regardless of the distance between the plurality of image sensors, it is possible to perform highly accurate correction corresponding to the difference in the reading position of each image sensor.

According to the fourth aspect of the present invention, since the weighted average processing is not applied to the image information obtained by reading the lightness and darkness of the original, the information content of the image information is highly retained, and a high-quality light and dark image is obtained. It can be reproduced.

When the color discrimination information is secondarily output together with the main image information obtained by reading the lightness and darkness of the original, the weighted average processing is not applied to the main image information, so that a high-quality light and shade image can be reproduced. Becomes

Since there is no positional or optical deviation between the R, G, and B colors in the color separation of the original image,
Highly accurate color discrimination is possible. Moreover, the position of the read pixel and the position of the color-determined pixel can be completely matched.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an image reader according to the present invention.

FIG. 2 is a plan view schematically showing the configuration of a full-color image sensor.

FIG. 3 is a block diagram showing a configuration of a signal processing unit.

4 is a block diagram showing a configuration of a position correction unit in FIG.

5 is a circuit diagram showing a configuration of a line delay unit of FIG.

6 is a block diagram showing an example of a data interpolation unit of FIG.

FIG. 7 is a block diagram showing another example of the data interpolation unit of FIG.

FIG. 8 is a block diagram showing another example of the data interpolation unit of FIG.

FIG. 9 is a flowchart showing an outline of an interpolation ratio setting process executed by a CPU.

FIG. 10 is a block diagram showing a configuration of a signal processing unit according to another embodiment of the present invention.

11 is a block diagram showing a configuration of a position correction unit in FIG.

FIG. 12 is a diagram for explaining the content of weighted average processing.

[Explanation of symbols]

1 Image Reader (Image Reading Device) 16R, 16G, 16B CCD Array (Image Sensor) 135 Interpolation Unit (Data Interpolation Means) 310 FIFO Memory (Delay Memory) 311, 312 Delay Memory 101, 101B CPU (Delay Control Means)

Claims (4)

[Claims] 1. A line scanning type image reading apparatus having a plurality of parallel image sensors arranged in a sub-scanning direction, wherein at least one image is read in order to compensate for a difference in reading position of each image sensor. Weighted averaging of a ratio according to the reading magnification is applied to image data of a plurality of lines read by the sensor, and the obtained image data is output as image data of a line corresponding to a line read by another image sensor. An image reading apparatus comprising data interpolating means. 2. An image reading apparatus according to claim 1, further comprising a delay memory for delaying transmission of image data corresponding to an image sensor which reads a document in advance. 3. The image reading apparatus according to claim 2, further comprising delay control means for changing a delay amount of the delay of the image data by the delay memory according to a reading magnification. 4. A first image sensor and a second image sensor, which are arranged in the sub-scanning direction and have different reading colors and which are parallel to each other. Image data corresponding to the first image sensor is used as density data of each pixel of a document. An image reading apparatus configured to perform color discrimination of a document based on image data corresponding to each image sensor while outputting, and capable of color discrimination by compensating for a difference in reading position of each image sensor. In order to do so, the image data of a plurality of lines read by the second image sensor is subjected to weighted average processing at a ratio according to the reading magnification, and the obtained image data is read by the line read by the first image sensor. An image reading apparatus comprising a data interpolation means for outputting as image data of a corresponding line.