JP2000299791A - Image processing apparatus having color-based misregistration correction - Google Patents

Abstract

(57) Abstract: An image processing apparatus for reducing the size of a position shift correction circuit, accelerating a position shift correction process, or correcting a position shift of image data input from an unspecified image input device for each color. To provide. SOLUTION: A color-specific image data storage unit 1 for storing image data for each color, a correction data storage unit 2 for storing misregistration correction data for each color, and a color stored in the correction data storage unit 2 A position shift correction unit for correcting a position shift for each color of the image data stored in the color-specific image data storage unit based on each position shift correction data;

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus having a function of correcting a positional shift of color image data input from an image input apparatus such as a scanner or a digital camera.

[0002]

2. Description of the Related Art In recent years, with advances in technology, opportunities for handling color images that appeal to human vision have increased. Also,
As networks are being developed, opportunities for image processing of color image data input from unspecified image input devices such as scanners and digital cameras are increasing. As an image processing apparatus for such a purpose, an apparatus configured to input unique characteristic information of an image input / output device and optimally process input image data based on the unique characteristic information has already been devised. ing. Further, an image processing apparatus having a function of correcting a color shift of color image data input from an image input apparatus has already been found (Japanese Patent Application Laid-Open No. 10-42157).

[0003]

However, even in an image processing apparatus as disclosed in Japanese Patent Application Laid-Open No. H10-42157, when color image data is input and a color shift is detected, the image processing apparatus does not. The amount of color misregistration is detected by the color misregistration detection arithmetic unit held inside, and the calculated result is set as the color misregistration correction amount. The color misregistration of color image data in which color misregistration has occurred with the set color misregistration correction amount Is corrected. Therefore, since there is a color shift correction amount table for storing the color shift correction amount for each pixel of the color image data in which the color shift has occurred, it is necessary to prepare a huge amount of memory or to detect the color shift amount. A color shift detector was required. Further, there is no measure taken such that color image data is input from an unspecified image input device connected on a network and color shift of the input color image data is corrected. Therefore, the problem to be solved by the present invention is that the amount of misregistration for each color of color image data read by an image input device such as a scanner or a digital camera has high reproducibility for each image input device. By measuring the amount of misalignment for each color of the image input device in advance, and inputting the image data for each color, and inputting the amount of misalignment for each color, The amount of memory for storing the amount is reduced, eliminating the need for a complicated misregistration detector, reducing the size of the misregistration correction circuit, increasing the speed of the misregistration correction processing, or processing image data input from unspecified image input devices. An object of the present invention is to provide an image processing apparatus having a color-based misregistration correction for achieving misregistration correction.

[0004]

According to a first aspect of the present invention, there is provided an image processing apparatus having color misregistration correction according to the first aspect of the present invention. And the position shift correction data is input to correct the position shift for each color. According to a second aspect of the present invention, in the image processing apparatus having the color-specific positional shift correction according to the first aspect, a color-specific image data storage means for storing color-specific image data, and a positional shift for each color. Correction data storage means for storing correction data, and for each color of the image data stored in the color-specific image data storage means based on the misregistration correction data for each color stored in the correction data storage means And a position shift correcting means for correcting the position shift. According to a third aspect of the present invention, in the image processing apparatus having the color-based misalignment correction according to the first or second aspect, the color-specific image data input from the image input device and the color-based misalignment correction data are input. The color components of
It is characterized by three colors of red, green and blue. Further, according to the invention described in claim 4, in claim 2 or 3
In the image processing apparatus having the misregistration correction for each color described above, the misregistration correcting means may set the image data of the color having the largest misregistration among the image data for each color to the intermediate position of the image data of the remaining colors. It is characterized by moving to. According to a fifth aspect of the present invention, in the image processing apparatus having the color-based misregistration correction according to the third aspect, the misregistration correction means uses green image data in the color-specific image data as a reference. And correcting the misalignment of the red or blue image data. Also,
According to a sixth aspect of the present invention, in the image processing apparatus having the misregistration correction for each color according to the second, third, fourth, or fifth aspect, the misalignment correction means is divided into at least two or more in one image. The correction is performed on the basis of the positional deviation correction data for each color for the different region. According to a seventh aspect of the present invention, in the image processing apparatus having the misregistration correction for each color according to the second, third, fourth, fifth, or sixth aspect, the misalignment correction means includes:
If the displacement amount of the image data for each color is within a predetermined range, the correction is not performed.

[0005]

According to the first aspect of the present invention, there is provided an image processing apparatus having color misregistration correction according to claim 1, wherein color image data and color misregistration correction data are input from an image input device. Then, since the misregistration for each color is corrected, the misregistration correction circuit is simplified, and the misregistration of color image data input from an unspecified image input device can be easily corrected. it can. According to a second aspect of the present invention, in addition to the invention of the image processing apparatus having the misregistration correction for each color configured as the first aspect, the image data is stored in the correction data storage means by the misalignment correction means. A memory that stores the amount of misregistration by eliminating the need for a complex misregistration detector because it compensates misregistration for each color of input image data based on misregistration correction data for each color. It is possible to reduce the amount and easily correct the positional deviation of the color image data input from an unspecified image input device. The invention of claim 3 is based on claim 1
Alternatively, in addition to the invention of the image processing apparatus having the misregistration correction for each color configured as described in 2 above, the color component of the image data for each color input from the image input device and the color component of the misregistration correction data for each color are set to , Green and blue, which is suitable for correcting the positional deviation of the current color image reading apparatus for each color. Further, the invention of claim 4 is based on claim 2
Or, in addition to the invention of the image processing apparatus having the misregistration correction for each color configured as described in 3 above, the misregistration correction means may be used to convert the image data of the color having the largest misregistration among the image data for each color. Since it is moved to the middle position of the image data of the remaining colors, only one color is used to correct the position shift, which simplifies the position shift correction circuit and speeds up the position shift correction processing can do. According to a fifth aspect of the present invention, in addition to the invention of the image processing apparatus having the misregistration correction for each color configured as in the third aspect, the misregistration correcting means further includes: Since the position shift of red or blue image data is corrected based on the green image data, the luminance characteristics are added to the detected image data of edge separation and halftone dot separation of the image area separation means of image processing. The uncorrected green color having close characteristics can be used, and image processing with high fidelity accuracy can be performed.

Further, the invention of claim 6 is based on claims 2, 3,
In addition to the invention of the image processing apparatus having the misregistration correction for each color configured as in 4 or 5, in addition to the above-described misregistration correction means, for each color in an area divided into at least two or more in one image Since the correction is performed based on the position shift correction data, even if the amount of position shift differs depending on the region, it is possible to perform the position shift correction with high accuracy for all the regions, It is possible to obtain an image without misalignment everywhere. According to a seventh aspect of the present invention, in addition to the invention of the image processing apparatus having the misregistration correction for each color configured as in the second, third, fourth, fifth or sixth aspect, the position of image data for each color is When the shift amount is within a predetermined range, the position shift is determined to be small and need not be corrected, and the correction is not performed by the position shift correcting means. can do.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an image read from an image input device such as a color scanner in red (hereinafter, referred to as “re”).
When output as image data of the color R (using the initial R of green), green (hereinafter, using the initial G of green), and blue (hereinafter, using the initial B of blue), color misregistration occurs. This is an example of a case where there is no color shift and a case where there is a color shift. The image reading operation of the color scanner is well known and will not be described. For example, as shown in FIG. 1A, a black line extending in the main scanning direction is read by a color scanner, and the image data of the AA 'traveling portion in the sub-scanning direction is extracted and shown in a waveform. B)
And FIG. 1 (C). FIG. 1B shows an example in which there is no displacement between the three colors RGB. When an image is read by a photoelectric conversion element such as a CDC as reflectance data, RGB read data of the scanner is obtained as a signal having a waveform that matches at the black line portion as shown in the figure.
On the other hand, FIG. 1C shows an example in which there is a displacement between the RGB colors, and the read data of the RGB colors of the scanner is obtained as signals having different peak positions as shown in the figure. After the image data in which the misregistration for each color is generated is image-processed and then sent to the image output device to output the image, the edge of the black line portion on the A side has a strong reddish tint. That is, a bluish hue appears strongly at the edge portion on the A 'side. As described above, the edge portion of the black line portion appears colored, and the black thin line appears colored, resulting in a very visually unsightly image. These positional shifts for each color have inevitably occurred due to the structure of the scanner, have occurred due to fluctuations in the speed of the carriage, or have occurred due to differences in component mounting accuracy.

FIG. 2 is a block diagram showing a main part of the image processing apparatus according to the present invention. In the figure, image data for each color separated into RGB color components and misregistration correction data for each color are input from an image input device 10 such as a color scanner. In the image processing apparatus 9, the input image data for each color is stored in the color-specific image data storage unit 1 as the color-specific image data storage unit, and the positional deviation correction data for each color is stored in the correction data storage unit as the correction data storage unit. Stored in 2. The data amount of the image data for each color stored in the color-specific image data storage unit 1 differs depending on the processing speed of the position shift correction processing and the image processing of the image processing apparatus. The position shift correction unit 3 serving as a position shift correction unit inputs image data (R, G, B data) to be subjected to position shift correction from the color-specific image data storage unit 1 and is stored in the correction data storage unit 2. The position shift is corrected for each color based on the position shift correction data, and the image data (R ′, G ′, B ′ data) for each color subjected to the position shift correction is processed by the image processing unit 4 in the next stage. Output to Further, the image processing unit 4 performs image processing on the image data (R ′, G ′, B ′ data) output from the displacement correcting unit 3 according to the preset setting conditions such as the scaling factor and the color density. And outputs image data (R ", G", B "data) for image formation to an image output unit (not shown), which outputs the R" G "B" color received from the displacement correcting unit 3. By combining and outputting the above image data, it is possible to reproduce an image without positional deviation for each color. Here, the misregistration correction data for each color input from the image input device 10 is held in the image input device 10 as characteristic information unique to the image input device 10 as described above, and is read. The apparatus outputs misregistration information for each color corresponding to a scanner mode, for example, a high-definition mode, a high-speed mode, or a zoom mode.

FIG. 3 is an example in which misregistration characteristic information for each color input from the image input device 10 is described. As the positional deviation characteristic information of the image input apparatus 10, for example, the positional deviation characteristic information (Zure: Zrx, Zr) for each color together with the image size (Size: Sx and Sy), the image resolution (Resolution: Rx and Ry), and the like.
y, Zgx, Zgy, Zbx and Zby) are described. In the present embodiment, RGB for a certain origin position
The positional deviation amounts of the color in the main scanning direction (x direction) and the sub scanning direction (y direction) are shown. Therefore, if the method of utilizing the misregistration characteristic information is shown in FIGS. 2 and 3, misregistration characteristic information for each color as shown in FIG. 3 is received from the image input device 10 and the correction data storage unit 2 of the image processing device 9 is received. To memorize. The misregistration correction unit 3 includes a color-specific image data storage unit 1.
, And corrects the position shift based on the position shift correction data stored in the correction data storage unit 2.
FIG. 4 shows a more detailed block diagram of the displacement correcting unit 3. In the figure, the correction is limited to the displacement in the sub-scanning direction for easy understanding. Here, an example will be described in which the misalignment between the R color and the B color is matched with the G color image data. That is, since the R color image data is synchronized with the G color image data as a reference, the R color image data is input to the delay means 3a, and after a predetermined delay, is transferred to the line memory 3d. The line memory 3d holds three lines and stores four lines in the sub-scanning direction (Rj + 1, Rj + 1).
(j, Rj-1, Rj-2), the data is transferred to the interpolation calculation circuit 3f, and the interpolation calculation is performed using the interpolation calculation coefficient specified by the control signal generator 3h. After that, the image data is output as the image data R ′ after the positional deviation correction. Similarly, the B color image data is input to the delay unit 3c to be synchronized with the G color image data as a reference, and after a predetermined delay, is transferred to the line memory 3e and is transferred to the sub-scanning direction. Interpolation operation circuit 3 in 4-pixel units (Bj + 1, Bj, Bj-1, Bj-2)
f and an interpolation operation is performed. Here, the interpolation calculation coefficient specified by the control signal generator 3h is any of the ten patterns shown in [Table 1]. Which of the coefficients is selected is determined by the positional deviation correction data for each color input to the control signal generator 3h.
Further, since the G color image data serving as the reference is timed between the R color and B color image data, the delay means 3
After the data is input to b and undergoes a predetermined delay, it is directly output as image data R 'from the displacement correcting unit 3.

[0010]

[Table 1] The above specific operation example will be described with reference to the flowchart of FIG. First, the control signal generating unit 3h outputs misregistration characteristic information (Zure: Zrx, Zry, Zgx, Zgy,
Zbx and Zby) are input (step S1).
Here, it is assumed that the positional shift amounts for each color in the sub-scanning direction are Zr = 0.5, Zg = 0.1, and Zb = -0.8 as shown in FIG. Next, the movement amounts Mr and Mb for matching the R and B image data with the G image data are obtained as follows (S2). Mr = Zg-Zr = 0.1-0.5 = -0.4 (1) Mb = Zg-Zb = 0.1-(-0.8) = 0.9 (2) Here, the interpolation calculation circuits 3f and 3g are:

As shown in Table 1, it is possible to perform alignment from 0 to 0.9, but it is not possible to perform calculations in a range exceeding this. Therefore, in the case of a range exceeding this range, the shift of one pixel unit is adjusted to the phase by the delay means, and the shift of less than one pixel is adjusted.

The amount to be moved is extracted from the table shown in Table 1 and moved. In the above example, the value of Mr is 0
Since it is not in the range of 0.9, an integer Dr smaller than the value of Mr
Is obtained, Dr = −1. The value of Mb is 0 to
Since it is in the range of 0.9, Db = 0 (S3). Position shift correction is performed on these integer portions by adjusting the timing by a delay circuit. Next, portions Hr and Hb less than one pixel are obtained (S4). Hr = Mr−Dr = (− 0.4) − (− 1) = 0.6 (3) Hb = Mb−Db = 0.9−0 = 0.9 (4) Hr, H determined by the above equations (3) and (4)
Interpolation calculation coefficient from the value of b

It is determined from the table shown in Table 1 (S5). Since Hr = 0.6 as the shift amount of the R color, the interpolation calculation coefficients for the R color are Rj + 1 = −0.096, Rj = 0.496, Rj−
1 = 0.744 and Rj−2 = −0.144 are selected. Similarly, since the shift amount of B color is Hb = 0.9, the interpolation calculation coefficient for B color is Bj + 1 = −0.009, Bj = 0.
109, Bj-1 = 0.981 and Bj-2 = -0.081 are selected. These interpolation calculation coefficients are stored in the control signal generator 3h.
The signal is output to the interpolation operation circuit 3f or 3g as a control signal (S6).

Next, control signals to the delay means 3a, 3b and 3c for adjusting the phase of one pixel unit are obtained. D
Since r = −1 and Db = 0, the interpolation calculation of the R color image data requires 4 lines one line before the G color and B color image data.
It is necessary to use a combination of lines. This means that the phases are matched by delaying the G and B color image data by one line. Here, Dr is 0
Dr, Dg, and Db are incremented by 1 until. As a result, Dr = 0, Dg = 1, and Db = 1 are obtained (S
7). Further, the number of lines to be delayed is output as a control signal to the delay units 3a, 3b and 3c. However, since interpolation is not performed on the G color image data, a delay of one line memory is required.
b is output as (Dg + 1) (S8). Actually, the delay means 3a does not delay because Dr = 0, the delay means 3b delays two lines because (Dg + 1) = 2, and the delay means 3c delays one line because Db = 1. Is controlled to do.

In the description of the displacement correcting unit 3 with reference to FIGS. 4 and 6, the number of reference pixels for the interpolation calculation is set to four, but the number of reference pixels is further reduced in order to reduce the circuit scale. It is also effective. Further, in order to widen the correction range of the displacement, a large number of line memories of the delay units 3a, 3b, 3c are required. However, if the correction possible range is limited, the number of in-memory can be reduced, and ,
If the correctable range is limited to the range of 0 to 1 pixel, the delay means 3a, 3b, 3c can be omitted. further,
In the present embodiment, only the displacement correction in the sub-scanning direction is described, but the displacement in the main scanning direction can be corrected in the same manner. In that case, the image data R ′ that has been subjected to the interpolation calculation process in the sub-scanning direction
For G′B ′, four pixels are sequentially extracted in the main scanning direction,
Interpolation processing may be performed. Further, the image data R′G′B ′ corrected by the displacement correcting unit 3 as is understood from the above description is input to the image processing unit 4 (see FIG. 2) at the next stage. Therefore, the image data of G color is transmitted to the image input device 10.
It is preferable to use this image data as detection data for edge separation and halftone dot separation of the image area separation circuit of the image processing unit 4. That is. FIG.
FIGS. 7A and 7B show that the image data of the color having the largest displacement among the image data for each color is moved to an intermediate position of the image data of the remaining colors to correct the displacement. It is. In FIG. 8A, the RGB image data having the largest displacement among the RGB colors is the B color image data. Therefore,
In this case, the misregistration correction unit 3 in FIG. 3 performs the correction so that the B color image data is positioned between the R color and G color image data. FIG. 8A shows a state where the correction is performed so as to be located at the middle position. That is, in terms of the peak position of the image data of each color, the peak position 11 of the B color having the largest displacement is represented by R
The image is moved so as to be halfway between the peak position 13 of the color image data and the peak position 12 of the G image data (the moving position is indicated by an arrow), and the displacement is corrected.
FIG. 8B shows the result of correcting the B-color image data having the largest displacement in FIG. 8A so as to be positioned between the R-color and G-color image data. FIG. As can be seen, by moving the image data of only one color having the largest displacement, the overall displacement is very small. By performing such a correction, it is possible to reduce the size of the position shift correction circuit and to speed up the position shift correction processing.

FIG. 5 shows, as described above, the position shift correcting section 3 for correcting only the image data of the color having the largest position shift so as to be located in the middle of the image data of the remaining colors. FIG. 3 shows a more detailed block diagram. The selector 3 that operates according to an instruction from the control signal generator 3h selects one of the RGB colors to be moved by interpolation.
selected by i. The image data selected as the color with the largest displacement is input to the delay unit 3a, and after a predetermined delay, is transferred to the line memory 3d. The line memory 3d holds three lines,
4-pixel unit in the sub-scanning direction (Nj + 1, Nj, Nj-1, Nj-2)
Is transferred to the interpolation operation circuit 3f, and the interpolation operation is performed using the interpolation operation coefficient specified by the control signal generation unit 3h, as described in FIG. Interpolation operation circuit 3f
Is transferred to the selector 3i. Also, the remaining 2
The color is input to the delay unit 3b and the delay unit 3c, and is transferred to the selector 3i after a predetermined delay. In the selector 3i, the path of the selector 3i is switched based on information indicating which color image data has been transferred to the interpolation operation circuit 3f, and R → R ′, G →
G ′, B → B ′ are controlled so as to output correctly in accordance with the input. Note that the delay means 3a, 3b, 3c
As described in (1), it is used for adjusting the phase of the shift of one pixel unit, and the number of delay lines is controlled by a control signal.

FIG. 7 is a flowchart showing a specific example of the representative operation in FIG. First, the control signal generating unit 3h outputs the positional shift characteristic information (Zure: Zr
x, Zry, Zgx, Zgy, Zbx and Zby) are input (S10). Here, for example, as shown in FIG. 3, the positional deviation amount for each color in the sub-scanning direction is Zr = 0.5, Zg
= 0.1 and Zb = -0.8. The following processing is performed to detect the most distant color. That is,
Zr, Zg, Zb are sorted in descending order, and S1, S
2, and S3. In the case of this example, S1 = Zr (=
0.5), S2 = Zg (= 0.1), S3 = Zb (= −
0.8) (S11). Next, the most distant color (Pfar) among the colors is searched, and a movement amount M for moving the color to the middle of the remaining two colors is calculated. The calculation formula is
It is as follows. If (S1−S2) ≧ (S2−S3), M = {(S2 + S3) / 2} −S1 (5) If (S1−S2) <(S2−S3), then M = ｛(S1 + S2) / 2｝ −S3 (6) Accordingly, in this case, Pfar is a B color, and the equation (6) holds, and M = {(0.5 + 0.1) / 2} − (− 0.8) = 1.1 (7) (S12). Therefore, the image data of B color is set to 1.
Only one pixel needs to be moved. However, as described above, the interpolation operation circuit can perform the alignment from 0 to 0.9, but cannot perform the operation in a range exceeding this. Therefore, the shift of one pixel unit is adjusted by the delay means at the preceding stage so that the phase is adjusted by the delay means.
The shift of 0.9 pixel is calculated by an amount to be moved so as to be corrected by an interpolation calculation circuit. Therefore, since M = 1.1 as determined by equation (7), D = 1 is determined as an integer smaller than M (S13). This integer value is
By adjusting the timing by the delay means, the position shift is corrected. Next, a portion H smaller than one pixel is obtained. H = MD = 1.1-1 = 0.1 (S14). Therefore, using the value of H obtained above,

From the table shown in Table 1, the interpolation operation coefficient of the amount to be moved is obtained. Since H = 0.1, the interpolation calculation coefficients for the B color are Nj + 1 = −0.081, Nj = 0.981, Nj−1 =
0.109 and Nj-2 = -0.009 are selected (S15). The interpolation calculation coefficient is obtained by the control signal generator 3h, and is output to the interpolation calculation circuit 3f as a control signal (S16). Also, Pfa is calculated by the interpolation arithmetic circuit 3f.
A selection instruction signal is output to the selector 3i so that r becomes the B color (S17).

Next, control signals to the delay means 3a, 3b and 3c for adjusting the phase in units of one pixel are obtained. D =
Since it is 1, it is necessary to use a combination of four lines one line after the remaining two colors (R color and G color) of the image data of the B color which is Pfar. This means that the phase can be adjusted by delaying the B color image data by one line. Specifically, when D is negative, D, D1, and D2 are incremented by one until D becomes zero. In this case, since D is a positive number, 1
Are not increased, and as a result, D ′ = 1, D1 ′ =
0 and D2 '= 0 are obtained (S18). Finally, the delay means 3a,
Output to 3b and 3c. However, since no interpolation operation is performed for the colors corresponding to D1 ′ and D2 ′,
A line delay is required. As a result, the delay means 3a
D ', (D1' + 1) to the delay means 3b, and (D2 '+ 1) to the delay means 3c (S19). Actually, the delay means 3a delays one line because D = 1, and the delay means 3b and 3c provide (D1 '+ 1) = (D
Since 2 ′ + 1) = 1, a delay of one line is performed as in the delay unit 3a. As described above, by correcting the image data of only one color having the largest displacement, it is possible to reduce the size of the correction circuit and speed up the displacement correction processing.

FIGS. 9A and 9B show an example in which one image is divided into a plurality of (four in this example) areas, and color shift characteristic information is held for each area. Show. In the description so far, only one piece of color misregistration characteristic information is stored for one piece of image information. Therefore, color reading is performed by reading the first half and the second half of the scanner or reading the right half and the left half. In some cases, for example, when the positional deviation correction data for each of them is different, the positional deviation cannot be corrected. FIG.
(A) and (B) exactly solve the problem. FIG. 9 (A) shows the area 1 as {(0, 0), (3500, 5000)} and the diagonal position coordinates of each area.
The area 2 is $ (3500, 0), (7000, 500
0)} and region 3 is {(0, 5000), (3500, 1
0000)}, region 4 is {(3500, 5000),
This is an example in which the image is divided into four (7000, 10000)｝, and color shift characteristic information is held for each area. FIG. 9B is an example in which misregistration characteristic information for each color is described for each of the divided regions as shown in FIG. 9A. In the upper part of the description, the resolution in the main scanning direction and the sub-scanning direction is 600 dpi, and an A3 size condition is described as an image. Therefore, the control signal generator 3h of FIGS. 4 and 5 outputs the optimal control signal as described above for each divided area by judging the description contents of FIG. Is configured so that an image without color shift can be obtained at any place in the image area. Further, by checking the misregistration characteristic information for each color input from the image input device 10, when the misregistration between the colors is small and there is no need to perform misregistration correction, control is performed so as not to perform misregistration correction. By doing so, speeding up of the processing can be expected.

FIG. 10 shows the relationship between the amounts of misregistration between the colors.
FIG. 7 is a flowchart illustrating main operations of the image processing apparatus that performs position shift correction and eliminates position shift correction. In the figure, first, the control signal generator 3h is connected to the image input device 1
The position shift characteristic information for each color, which is input from 0, is input (S20). Further, a positional deviation amount V between the two colors that are farthest apart is obtained (S21). It is evaluated whether or not the obtained maximum displacement V between the two colors is larger than a predetermined threshold Th (for example, 0.3 pixels) (S22). If it is larger than the predetermined threshold value Th (S22: Yes), control is performed so as to perform positional deviation correction (S23). Step S
In S22, if it is not larger than the predetermined threshold Th (S
22 No), it is determined that the positional deviation for each color is small,
Control is performed so as not to perform positional deviation correction (S24).
In this way, by checking the misregistration characteristic information for each color,
When it is not necessary to perform the positional deviation correction, control is performed so as not to perform the positional deviation correction, whereby the processing can be speeded up. Further, in the description of the embodiment of the present invention, the description has been given of an example in which image data for each color and misregistration correction data for each color are transmitted directly from the image input device 10. Image data for each color and misregistration correction data for each color are stored in a storage device such as a hard disk in advance, and the stored data is processed by an image processing apparatus having misregistration correction for each color. It is also possible.

[0018]

As described above, according to the first aspect of the present invention,
The configuration of the correction function is simple, and it is possible to easily correct the positional deviation of color image data from an unspecified number of image input devices. An image processing device can be provided. According to the invention of claim 2,
In addition to the invention of the image processing apparatus having the color misregistration correction according to claim 1, a misalignment correction storage for storing misregistration correction data without requiring a troublesome detector for detecting misregistration amount of image data. The storage capacity of the means can be reduced, and the misalignment of color image data from an unspecified number of image input devices can be easily corrected. It has become possible to provide an image processing apparatus having a misregistration correction for each color. According to the invention of claim 3, in addition to the invention of the image processing apparatus having the misregistration correction for each color according to claim 1 or 2, a current color image which outputs image data of three colors of red, green and blue is provided. It has become possible to provide an image processing apparatus having misregistration correction for each color suitable for a reading apparatus. According to the invention of claim 4, claim 2
Alternatively, in addition to the invention of the image processing apparatus having the color misregistration correction for each of the three colors, the misregistration can be corrected only for the image data of one color having the largest misregistration, thereby reducing the size of the circuit and performing the correction processing. It has become possible to provide an image processing apparatus having a color-by-color misregistration correction that achieves high speed. According to the invention of claim 5, in addition to the invention of the image processing apparatus having the misregistration correction for each color according to claim 3, an image input to the detection signal of edge separation or halftone dot separation of the image area separation means for image processing is provided. Since it is now possible to use the green color as input from the apparatus, it is possible to provide an image processing apparatus having color-based misregistration correction for performing simple and high-fidelity image correction. . According to the invention of claim 6, in addition to the invention of the image processing apparatus having the misregistration correction for each color according to claim 2, 3, 4 or 5, even if the misregistration differs for each region, the optimum for each region is determined. Since the correction can be performed, it is possible to provide an image processing apparatus having a color-based position shift correction that can obtain an image without a position shift everywhere in an image area. According to the invention of claim 7, claim 2, 3, 4, 5, or 6
In addition to the invention of the image processing apparatus having the misregistration correction for each color, when the misregistration is determined to be small and the necessity of the correction is unnecessary, the correction is not performed. It has become possible to provide an image processing apparatus having a color-by-color misregistration correction that achieves high speed.

[Brief description of the drawings]

1A is an explanatory diagram illustrating an example of an image read by an image input device, FIG. 1B is an explanatory diagram illustrating a case in which the image in FIG. 1A is read without color shift, and FIG. Figure 1 above
FIG. 4 is an explanatory diagram illustrating a case where the image of FIG.

FIG. 2 is a block diagram showing a main part of the image processing apparatus of the present invention.

FIG. 3 is an explanatory diagram illustrating a description example of misregistration characteristic information for each color input from an image input device.

FIG. 4 is a detailed block diagram of a displacement correcting unit in the image processing apparatus of the present invention.

FIG. 5 is a detailed block diagram of another displacement correcting unit in the image processing apparatus according to the present invention.

FIG. 6 is a flowchart showing a main operation of the image processing apparatus having the displacement correcting means of FIG. 4;

FIG. 7 is a flowchart showing a main operation of the image processing apparatus having the displacement correcting means of FIG. 5;

FIG. 8A is an explanatory diagram for explaining that the image data of the color having the largest displacement is shifted to an intermediate position of the image data of the remaining colors to correct the displacement, and FIG. FIG. 9 is an explanatory diagram for explaining a positional shift as a result of moving image data of a color having a larger color to an intermediate position of image data of the remaining colors.

9A is an explanatory diagram illustrating an example in which one image is divided into a plurality of regions, and color shift characteristic information is held for each region. FIG. 9B is an explanatory diagram illustrating FIG. 9A. FIG. 9 is an explanatory diagram illustrating an example in which misregistration characteristic information for each color for each region is described.

FIG. 10 is a flowchart illustrating a main operation of selecting a processing operation of a position shift correction based on a position shift amount for each color.

[Explanation of symbols]

 1: Color-specific image data storage unit (color-specific image data storage unit) 2: Correction data storage unit (correction data storage unit) 3: Position deviation correction unit (position deviation correction unit) 3a: Delay unit 1 3b: Delay unit 2 3c: delay means 3 3d: line memory 3e: line memory 3f: interpolation arithmetic circuit 3g: interpolation arithmetic circuit 3h: control signal generation unit 3i: selector 1 3j: selector 2 4: image processing unit 9: image processing device 10: image Input device

Claims (7)

[Claims] 1. An image input device which receives image data for each color and misregistration correction data for each color, and corrects misregistration for each color. Image processing apparatus. 2. A color image data storage means for storing image data for each color, a correction data storage means for storing misregistration correction data for each color, and a color data stored in the correction data storage means. 2. The image processing apparatus according to claim 1, further comprising: a position shift correction unit configured to correct a position shift for each color of the image data stored in the color image data storage unit based on the position shift correction data for each color. An image processing apparatus having a misregistration correction for each color. 3. The color components of the image data for each color input from the image input device and the position shift correction data for each color are red,
3. The image processing apparatus according to claim 1, wherein the image processing apparatus has three colors of green and blue. 4. The image processing apparatus according to claim 2, wherein the misregistration correction unit moves the image data of the color having the largest misregistration among the image data for each color to an intermediate position of the image data of the remaining colors. Or an image processing apparatus having the misregistration correction for each color according to 3. 5. The apparatus according to claim 3, wherein the displacement correcting means corrects the displacement of the red or blue image data with reference to the green image data in the image data for each color. An image processing apparatus having a misregistration correction for each color. 6. The image processing apparatus according to claim 2, wherein the misregistration correction unit performs compensation based on misregistration correction data for each color for at least two or more divided regions in one image. An image processing apparatus having the misregistration correction for each color according to 4 or 5. 7. The apparatus according to claim 2, wherein said misregistration correction unit does not perform the correction if the misregistration amount of the image data for each color is within a predetermined range.
An image processing apparatus having the misregistration correction for each color described in 3, 4, 5, or 6.