JP2015216500A - Image processing apparatus, imaging device, image processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to suppress the occurrence of false colors while suppressing an increase in circuit scale and processing load.SOLUTION: There is provided an image processing apparatus processing image data including a first color component and a second color component and subjected to magnification chromatic aberration correction to the first color component, the image processing apparatus comprising: smoothing means for performing smoothing processing to the second color component of the image data to create a smoothed second color component; and creation means for creating, for predetermined pixels of the image data, a first color difference signal from the first color component and the smoothed second color component.

Description

  The present invention relates to an image processing device, an imaging device, an image processing method, and a program.

  In an imaging apparatus such as a digital camera, coloring (false color) that does not originally exist may occur around a pixel having a large luminance difference. For example, when magnification chromatic aberration correction is performed, the red pixel and the blue pixel are moved with respect to the green pixel, so that the red pixel and the blue pixel may be blurred and a false color may be generated at the high luminance edge portion.

  Patent Document 1 is known as a document disclosing a false color countermeasure method. The imaging device disclosed in Patent Document 1 detects a high-luminance portion where a false color may exist, detects whether there is a predetermined false-color pixel in the vicinity of the high-luminance portion, and detects a false-color pixel. It is configured to eliminate false colors.

JP 2002-262299 A

  In the technique of Patent Document 1, it is necessary to perform detection processing on a wide area of image data in order to detect whether there are false color pixels. For this reason, there has been a problem that the circuit scale, processing load, and the like increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for suppressing generation of false colors while suppressing an increase in circuit scale, processing load, and the like.

  In order to solve the above-described problems, the present invention processes image data that includes a first color component and a second color component, and that has been subjected to magnification chromatic aberration correction for the first color component. An image processing apparatus, comprising: smoothing means for generating a smoothed second color component by performing a smoothing process on the second color component of the image data; An image processing apparatus comprising: a generating unit configured to generate a first color difference signal from the first color component and the smoothed second color component.

  Other features of the present invention will become more apparent from the accompanying drawings and the following description of the preferred embodiments.

  According to the present invention, it is possible to suppress the occurrence of false colors while suppressing an increase in circuit scale and processing load.

1 is a block diagram showing a configuration of an imaging apparatus according to a first embodiment. 3 is a block diagram showing details of a color difference signal generation unit 1005. FIG. The conceptual diagram of operation | movement of the color interpolation circuit 2000. FIG. (A) A diagram showing data before being input to the magnification chromatic aberration correction unit 1003 (when the sampling position is not considered), (b) a diagram showing data before being input to the magnification chromatic aberration correction unit 1003 (taking the sampling position into consideration) And (c) a diagram illustrating data after output from the magnification chromatic aberration correction unit 1003, and (d) a diagram illustrating processing in the LPF 2004 and the color difference signal generation circuit 2002. The figure which rewrote FIG.4 (a)-FIG.4 (d) to the table format. 6 is a flowchart showing a flow of processing for generating a final color difference signal. The flowchart which shows the detail of a process of S103 of FIG. 6A based on 1st Embodiment. The figure which shows the relationship between minimum value DIFF_G of a difference absolute value, and MIX ratio (alpha). The figure which illustrates various filters. The flowchart which shows the detail of a process of S103 of FIG. 6A based on 2nd Embodiment. The conceptual diagram of the magnification chromatic aberration correction which concerns on 2nd Embodiment. The figure which shows the relationship between the correction amount (movement amount) of magnification chromatic aberration, and Thres1.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The technical scope of the present invention is determined by the claims, and is not limited by the following individual embodiments. In addition, not all combinations of features described in the embodiments are essential to the present invention.

[First Embodiment]
An embodiment in which the image processing apparatus of the present invention is applied to an imaging apparatus such as a digital camera will be described. FIG. 1 is a block diagram illustrating a configuration of the imaging apparatus according to the first embodiment. FIG. 1 shows components for image processing, in particular, in the image pickup apparatus, and components unnecessary for the description of the present embodiment are omitted.

  The imaging unit 1000 includes an imaging element in which RGB (red, green, and blue) pixels are arranged in a Bayer array. An analog signal output from the imaging unit 1000 is converted into a digital signal by the A / D conversion unit 1001. The image signal converted into a digital signal by the A / D conversion unit 1001 is subjected to white balance adjustment by a white balance (WB) unit 1002 according to any known technique.

  The image signal output from the WB unit 1002 is input to the magnification chromatic aberration correction unit 1003, and magnification chromatic aberration correction processing is performed. Lateral chromatic aberration is a phenomenon in which light incident off the axis of a lens forms an image at different image heights depending on the wavelength. For example, Japanese Patent Laid-Open No. 11-161773 is known as a technique for correcting chromatic aberration of magnification. This technology uses a green pixel (G pixel) as a reference, and holds the color shift amounts of a red pixel (R pixel) and a blue pixel (B pixel) in advance for each image height in sub-pixel units. The correction is performed according to the following.

  The correction signal corrected by the magnification chromatic aberration correction unit 1003 is input to the luminance signal processing unit 1004, and luminance signal processing such as gamma correction is performed according to any known technique. The correction signal corrected by the magnification chromatic aberration correction unit 1003 is also input to the color difference signal generation unit 1005. The color difference signal generation unit 1005 performs color difference signal generation processing described later, and converts the input correction signal into color difference signals V (R−Y), U (B−Y), and the like. The color difference signal output from the color difference signal generation unit 1005 is input to the color signal processing unit 1006, and color correction processing such as color conversion matrix processing and color suppression processing is performed according to any known technique.

  Here, the details of the color difference signal generation unit 1005 will be described with reference to FIG. The correction signal (image data) output from the magnification chromatic aberration correction unit 1003 is input to the color interpolation circuit 2000. The operation of the color interpolation circuit 2000 will be described with reference to FIG. As shown in FIG. 3, in the image data input to the color interpolation circuit 2000, a red component (R component), a green component (G component), and a blue component (B component) are arranged in a Bayer array. The G component is divided into a Gr component existing in the same row as the R component and a Gb component existing in the same row as the B component. However, if it is not necessary to distinguish between them, one or both of the Gr component and the Gb component are simply referred to as a G component.

  The color interpolation circuit 2000 decomposes the data input in the Bayer array for each color filter R, Gr, Gb, B. Thereafter, the color interpolation circuit 2000 generates signals for the R, Gr, Gb, and B color planes by performing an interpolation LPF process using, for example, a digital filter as shown in FIG.

  Returning to FIG. 2, R, Gr, Gb, and B signals output from the color interpolation circuit 2000 are input to the color difference signal generation circuit 2001. The color difference signal generation circuit 2001 generates a color difference signal according to a technique described in, for example, Japanese Patent Application Laid-Open No. 2002-300590. Specifically, the color difference signal generation circuit 2001 compares (R−Gr) and (R−Gb), and according to the difference between (R−Gr) and (R−Gb), (R−Gr). And (R−Gb) are mixed or selected to generate a final color difference signal (R−G). Similarly, the color difference signal generation circuit 2001 compares (B-Gr) and (B-Gb), and according to the difference between (B-Gr) and (B-Gb), (B-Gr) and ( B-Gb) is mixed or selected to generate the final color difference signal (B-G).

  The R and B signals output from the color interpolation circuit 2000 are also input to the color difference signal generation circuit 2002. Further, the Gr signal output from the color interpolation circuit 2000 is also input to the LPF 2004 and the MIX ratio calculation circuit 2003. Further, the Gb signal output from the color interpolation circuit 2000 is also input to the LPF 2005 and the MIX ratio calculation circuit 2003.

  The Gr and Gb signals input to the LPF 2004 and the LPF 2005 are smoothed by a filter such as that shown in FIG. The output of the LPF 2004 is input to a color difference signal generation circuit 2002 and a MIX ratio calculation circuit 2003. Similarly, the output of the LPF 2005 is also input to the color difference signal generation circuit 2002 and the MIX ratio calculation circuit 2003. The operation of the color difference signal generation circuit 2002 is the same as that of the color difference signal generation circuit 2001 except that the Gr and Gb signals smoothed by the LPF 2004 and the LPF 2005 are used.

Here, with reference to FIGS. 4 and 5, detailed operations of the magnification chromatic aberration correction unit 1003, the color difference signal generation circuit 2001, and the color difference signal generation circuit 2002 will be described. Here, Gr, Gb, and R signals will be described. The graphs of FIGS. 4A to 4D are obtained by plotting pixel positions on the horizontal axis and pixel values on the vertical axis. 4 (a) and 4 (b) show data before being input to the magnification chromatic aberration correction unit 1003, assuming that the G pixel is shifted by one pixel from the R pixel. ing. In FIG. 4A, the R pixel value R [x] and the G pixel value G [x] at the pixel position x (x = 0, 1, 2, 3, 4, 5, 6) are
G [0] = G [1] = G [2] = R [0] = R [1] = R [2] = R [3] = S ₁
G [3] = R [4] = S ₄
G [4] = G [5] = G [6] = R [5] = R [6] = S ₆
It is expressed. When the sampling positions of R and Gb are pixel positions 1, 3, and 5 and the sampling positions of Gr are pixel positions 0, 2, 4, and 6, as shown in FIG.
Gr [0] = Gr [2] = Gb [1] = R [1] = R [3] = S ₁
Gb [3] = S ₄
Gr [4] = Gr [6] = Gb [5] = R [5] = S ₆
It becomes.

Next, FIG. 4C shows data after output from the magnification chromatic aberration correction unit 1003. When the chromatic aberration correction unit 1003 moves the R pixel to the left by one pixel, the R pixel value R ′ [x] after correcting the chromatic aberration of magnification is
R ′ [x] = R [x + 1]
It is expressed. If the pixels between R are made by known linear interpolation, in FIG.
R ′ [1] = R [2] = (R [1] + R [3]) / 2 = S ₁
R ′ [3] = R [4] = (R [3] + R [5]) / 2 = (S ₁ + S ₆ ) / 2
R ′ [5] = R [6] = (R [5] + R [7]) / 2 = S ₆
It becomes.

Reference is now made to FIG. FIG. 5 is a table rewritten from FIG. 4A to FIG. 4D. Although Gb is omitted in FIG. 5, the basic idea is the same as that of Gr. The rows of “input R” and “input Gr” respectively represent R and Gr signals input to the magnification chromatic aberration correction unit 1003, and correspond to FIG. 4B. The row “R after aberration correction” represents an R signal output by the magnification chromatic aberration correction unit 1003 and corresponds to FIG. For example, when attention is paid to the horizontal pixel number 3 (ie, R ′ [3]) after R after aberration correction, this is generated by moving the input R one pixel to the left and performing linear interpolation. Therefore, R ′ [3] is an average value of horizontal pixel numbers 3 and 5 of “input R” indicated by an ellipse, that is, (S ₁ + S ₆ ) / 2. Thus, the magnification chromatic aberration correction of the present embodiment involves a smoothing process, which contributes to the generation of a false color described later.

Referring to FIG. 4C again, attention is paid to the position of pixel position 2 after color interpolation output from the color interpolation circuit 2000. The value of pixel position 2 after color interpolation is R ′ [2] = (R ′ [1] + R ′ [3]) / 2 = S ₃ = (3S ₁ + S ₆ ) / 4, respectively.
Gr [2] = S ₁
Gb [2] = (Gb [1] + Gb [3]) / 2 = S ₂ = (S ₁ + S ₄ ) / 2
It becomes. _Here, when _{S 1 = 0, S 4 =} S 6/4,
R ′ [2] = S _6/4
Gr [2] = 0
_{Gb [2] = S 6/} 8
It becomes.

Therefore, as the color difference signals Cr1 which the color difference signal generation circuit 2001 outputs, when R'-Gr is selected, the Cr1 = R '[2] -Gr [2] = S 6/4. As the color difference signals Cr1, if R'-Gb is selected, the Cr1 = R '[2] -Gb [2] = S 6/8. That is, a non-zero color difference signal is generated at the pixel position 2 regardless of the ratio of R′-Gr and R′-Gb. As shown in FIG. 4A, there is essentially no color difference at the pixel position 2. Therefore, the color difference signals obtained from R′-Gr and R′-Gb are false colors.

Next, processing in the LPF 2004 and the color difference signal generation circuit 2002 will be described with reference to FIG. The LPF 2004 applies a [1 0 1] filter in the horizontal direction to the Gr signal after interpolation by the color interpolation circuit 2000 as shown in FIG. Since this filter is the same filter as the linear interpolation for the pixels other than the sampling position, the pixel value does not change. On the other hand, for the pixel at the sampling position,
GrLPF [2] = (Gr [1] + Gr [3]) / 2
= (Gr [0] + Gr [2] + Gr [2] + Gr [4]) / 4
= S _6/4
GrLPF [4] = (Gr [3] + Gr [5]) / 2
= (Gr [2] + Gr [4] + Gr [4] + Gr [6]) / 4
= _3S 6/4
(When S ₁ = 0). At this time, when R′−GrLPF is selected as the color difference signal Cr2 output from the color difference signal generation circuit 2002, Cr2 = R ′ [2] −GrLPF [2] = 0, and the pixel position 2 is false. Color does not occur. Although explanation of Gb is omitted, in any case, as long as R′-GrLPF is selected, generation of false color can be prevented.

  Referring to FIG. 5 again, attention is paid to “R after interpolation”, “Gr after interpolation”, and “GrLPF” of horizontal pixel number 2 surrounded by a square. Due to the influence of the aberration correction process, a difference occurs between “R after interpolation” and “Gr after interpolation”, and this difference is a false color. However, there is no difference between “R after interpolation” and “GrLPF”, and no false color is generated.

  As described above, the color difference signal generation circuit 2002 generates the color difference signal based on the signal obtained by applying the LPF filter to the G signal and the R signal, thereby reducing the false color generated in the high luminance edge portion. . The same applies to the color difference signal generated from the B signal and the G signal. Here, in order to make the explanation easy to understand, a case has been described in which the displacement amount of the chromatic aberration of magnification is one pixel and no false color is generated in a specific pixel by selecting GrLPF. However, it is not always possible to prevent the occurrence of false colors in all cases, and some false colors may remain. However, as will be described later, when the band of the R pixel signal is greatly reduced with respect to the G pixel signal, it is highly possible that the suppression of false color can be reduced by selecting the GrLPF.

  After generating the color difference signals Cr1 and Cr2 in the color difference signal generation circuit 2001 and the color difference signal generation circuit 2002, the combining unit 2006 follows the MIX ratio (predetermined ratio for combining) determined by the MIX ratio calculating circuit 2003. Synthesize Cr1 and Cr2. As a result, a final color difference signal Cr is generated.

  FIG. 6A is a flowchart showing a flow of processing for generating a final color difference signal. In step S <b> 101, the color difference signal generation circuit 2001 calculates the color difference signal Cr <b> 1 using the R, Gr, Gb, and B signals output from the color interpolation circuit 2000. In step S102, the color difference signal generation circuit 2002 calculates the color difference signal Cr2 using the R and B signals output from the color interpolation circuit 2000 and the LPF processed Gr and Gb signals output from the LPF 2004 and LPF 2005. To do. In S103, the MIX ratio calculation circuit 2003 outputs the MIX ratio α.

  A method of calculating the MIX ratio α will be described with reference to the flowchart of FIG. 6B. In step S201, the MIX ratio calculation circuit 2003 calculates a difference absolute value | DIFF_Gr | = | GrLPF−Gr | from the signal Gr_LPF multiplied by LPF and the original signal Gr in the target pixel. Similarly, the MIX ratio calculation circuit 2003 calculates | DIFF_Gb | = | GbLPF−Gb | from Gb_LPF and Gb.

  In S202, the MIX ratio calculation circuit 2003 calculates the smaller one of | DIFF_Gr | and | DIFF_Gb | as the minimum value DIFF_G of the difference absolute value. Although the minimum value is calculated here, the maximum value or the intermediate value may be calculated instead.

  In step S203, the MIX ratio calculation circuit 2003 determines whether DIFF_G is smaller than the threshold value Thres1. When DIFF_G is smaller than the threshold Thres1, the process proceeds to S205, and the MIX ratio calculation circuit 2003 sets the MIX ratio α = 0.

  On the other hand, if DIFF_G is greater than or equal to the threshold Thres1 in S203, the process proceeds to S204, and the MIX ratio calculation circuit 2003 determines whether DIFF_G is greater than the threshold Thres2. When DIFF_G is larger than the threshold value Thres2, the process proceeds to S206, and the MIX ratio calculation circuit 2003 sets the MIX ratio α = 1. On the other hand, if DIFF_G is equal to or smaller than the threshold Thres2 in S204, the process proceeds to S207, and the MIX ratio calculation circuit 2003 obtains the MIX ratio α by performing linear interpolation between Thres1 and Thres2. Note that Thres2 is larger than Thres1.

FIG. 7 shows the relationship between the minimum value DIFF_G of the absolute difference value and the MIX ratio α. As shown in FIG. 7, when DIFF_G is smaller than the threshold Thres1, the MIX ratio α is 0, and when DIFF_G is larger than the threshold Thres2, the MIX ratio α is 1. And if DIFF_G is between the threshold Thres1 and Thers2,
MIX ratio α = (DIFF_G−Thres1) / (Thres2−Thres1)
It becomes.

Returning to the flowchart of FIG. 6A again. After obtaining the MIX ratio α in S103, in S104, the synthesizing unit 2006 calculates the final color difference signal Cr by synthesizing Cr1 and Cr2 calculated in S101 and S102 based on the MIX ratio α. To do. In particular,
Cr = (1-α) × Cr1 + α × Cr2
It is. That is, as DIFF_G is smaller and α is smaller, the ratio of Cr1 in the synthesis of Cr1 and Cr2 increases, and Cr approaches Cr1. On the contrary, as DIFF_G is larger and α is larger, the ratio of Cr2 in the synthesis of Cr1 and Cr2 increases, and Cr approaches Cr2.

  As described above, the color difference signal generation unit 1005 calculates the difference between the signal obtained by applying the LPF to the G signal and the original signal, and determines that there is a high possibility that a false color is generated at the high luminance edge when the difference is large. The color difference signal is calculated so that the contribution of the signal obtained by applying the LPF to the G signal is increased. On the contrary, when the difference is small, it is determined that there is a high possibility that a false color is generated at the high luminance edge, and the color difference signal is calculated so that the contribution of the original G signal is increased. As a result, it is possible to suppress the occurrence of false colors while suppressing an increase in circuit scale and processing load. In addition, the configuration of the present embodiment is particularly effective when a process for blurring the R pixel as compared to the G pixel, such as correction of chromatic aberration of magnification, is performed (that is, when the band between the G pixel and the R pixel is changed). Further, since the G signal to which the LPF is applied is not used for the luminance signal processing, there is no problem that the luminance signal band is reduced.

  In the present embodiment, the color difference signal calculated from the G signal and the R signal has been mainly described, but the same applies to the color difference signal calculated from the G signal and the B signal.

  In the present embodiment, the configuration shown in FIG. 8B is shown and described as an example of the LPF. However, the present invention is not limited to this, and the LPF only in the vertical direction as shown in FIG. An LPF combining 8 (b) and FIG. 8 (c) may be used.

  In the present embodiment, the chromatic aberration of magnification correction is given as an example in which the band of the G pixel and the R pixel is changed. However, the present invention is not limited to this, and the R pixel and the G pixel have different bands from the lens design information. You may apply to the aberration correction which applies a digital filter.

[Second Embodiment]
Hereinafter, the second embodiment will be described. The basic configuration of the imaging apparatus of the present embodiment is the same as that of the first embodiment (see FIGS. 1 and 2). Hereinafter, differences from the first embodiment will be mainly described.

  In the second embodiment, the process in S103 of FIG. 6A is different from that of the first embodiment. More specifically, in the first embodiment, the threshold values Thres1 and Thres2 for determining the MIX ratio α are fixed values, but in the second embodiment, Thres1 and Thres2 are corrections for magnification chromatic aberration correction. It is a value that changes according to the amount.

  FIG. 9 is a flowchart showing details of the process of S103 of FIG. 6A according to the second embodiment. In this flowchart, steps that are the same as or similar to those in FIG. 6B are denoted by the same reference numerals as those in FIG. 6B and description thereof is omitted.

In step S <b> 301, the MIX ratio calculation circuit 2003 calculates Thres <b> 1 and Thres <b> 2 according to the correction amount of the magnification chromatic aberration correction performed by the magnification chromatic aberration correction unit 1003. Details of this processing will be described with reference to FIG. In this embodiment, it is assumed that the G pixel is shifted by 2 pixels from the R pixel. The graphs of FIGS. 10A to 10C are obtained by plotting the pixel position on the horizontal axis and the pixel value on the vertical axis. FIGS. 10A and 10B show data before being input to the magnification chromatic aberration correction unit 1003. In FIG. 10A, the pixel position x (x = 0, 1, 2, 3). , 4, 5, 6, 7), the R pixel value R [x] and the G pixel value G [x]
G [0] = G [1] = G [2] = R [0] = R [1] = R [2] = R [3] = R [4] = S ₁
G [3] = R [5] = S ₄
G [4] = G [5] = G [6] = G [7] = R [6] = R [7] = S ₆
It is expressed. When the sampling positions of R and Gb are pixel positions 1, 3, 5, and 7 and the sampling positions of Gr are pixel positions 0, 2, 4, and 6, as shown in FIG.
Gr [0] = Gr [2] = Gb [1] = R [1] = R [3] = S ₁
Gb [3] = R [5] = S ₄
Gr [4] = Gr [6] = Gb [5] = Gb [7] = R [7] = S ₆
It becomes.

Next, FIG. 10C shows data after output from the magnification chromatic aberration correction unit 1003. Since the lateral chromatic aberration correction unit 1003 moves the R pixel to the left by 2 pixels, the R pixel value R ′ [x] after the lateral chromatic aberration correction is
R ′ [x] = R [x + 2]
It is expressed. Assuming that pixels between R are formed by a known linear interpolation, in FIG.
R ′ [1] = R [3] = S ₁
R ′ [3] = R [5] = S ₄
R ′ [5] = R [7] = S ₆
It becomes.

Here, attention is paid to the position of pixel position 2 after color interpolation output from the color interpolation circuit 2000. The value of pixel position 2 after color interpolation is R ′ [2] = (R ′ [1] + R ′ [3]) / 2 = S ₂ = (S ₁ + S ₄ ) / 2, respectively.
Gr [2] = S ₁
Gb [2] = (Gb [1] + Gb [3]) / 2 = S ₂ = (S ₁ + S ₄ ) / 2
It becomes.

Therefore, when R′−Gr is selected as the color difference signal Cr1 output from the color difference signal generation circuit 2001, Cr1 = R ′ [2] −Gr [2] = (S ₄ −S ₁ ) / 2. . When R′−Gb is selected as the color difference signal Cr1, Cr1 = R ′ [2] −Gb [2] = 0. Therefore, if R′−Gb is selected, no false color is generated at the pixel position 2.

  As described above, when the movement amount of the magnification chromatic aberration correction of the R pixel is an even pixel, a false color is generated at the pixel position 2 as compared with the case of the odd pixel described with reference to FIG. 4 in the first embodiment. It becomes difficult to do. Therefore, the MIX ratio calculation circuit 2003 makes Thres1 and Thres2 larger when the movement amount is an even pixel than when it is an odd pixel. As a result, the value of α decreases, and the contribution of Cr1 increases in the calculation of the final color difference signal Cr.

  FIG. 11 shows the relationship between the correction amount (movement amount) of chromatic aberration of magnification and Thres1. Although illustration of Thres2 is omitted, the basic concept is the same as Thres1. In FIG. 11, the horizontal axis represents the correction amount of the lateral chromatic aberration, and the vertical axis represents the threshold value Thres1. When the correction amount of lateral chromatic aberration is an odd number of pixels such as 1 and 3, Thres1_MAX is selected as the threshold Thres1. When the lateral chromatic aberration correction amount is an even number of pixels such as 0, 2, and 4, Thres1_MIN is selected as the threshold Thres1. When the lateral chromatic aberration correction amount is in sub-pixel units, the threshold value Thres1 is calculated by an interpolation operation between Thres1_MAX and Thres1_MIN.

  As described above, according to the second embodiment, the MIX ratio calculation circuit 2003 changes the thresholds Thres1 and Thres2 for obtaining the MIX ratio α according to the correction amount of the lateral chromatic aberration. Specifically, when the correction amount of the lateral chromatic aberration is an odd number (that is, in a condition where false colors are more likely to occur), the MIX ratio calculation circuit 2003 increases α by decreasing Thres1 and Thres2. Accordingly, the MIX ratio calculation circuit 2003 calculates the color difference signal so that the contribution of the signal obtained by multiplying the G signal by LPF becomes large. On the other hand, when the correction amount of the chromatic aberration of magnification is an even number (that is, when the false color is less likely to occur), the MIX ratio calculation circuit 2003 decreases α by increasing Thres1 and Thres2. Accordingly, the MIX ratio calculation circuit 2003 calculates the color difference signal so that the contribution of the signal obtained by applying the LPF to the G signal becomes small. As a result, it is possible to suppress image quality degradation when it is difficult for false colors to occur while suppressing the occurrence of false colors.

[Other Embodiments]
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

  2000 ... color interpolation circuit, 2001 ... color difference signal generation circuit, 2002 ... color difference signal generation circuit, 2003 ... MIX ratio calculation circuit, 2004 ... LPF, 2005 ... LPF, 2006 ... synthesis unit

Claims (12)

An image processing apparatus that processes image data including a first color component and a second color component that has been subjected to magnification chromatic aberration correction for the first color component,
Smoothing means for generating a smoothed second color component by performing a smoothing process on the second color component of the image data;
Generating means for generating a first color difference signal from the first color component and the smoothed second color component for a predetermined pixel of the image data;
An image processing apparatus comprising:   The generation means generates a second color difference signal from the first color component and the second color component for a predetermined pixel of the image data, and the first color difference signal and the second color difference signal The image processing apparatus according to claim 1, wherein a color difference signal is generated by combining the two. The combination ratio is determined such that the larger the absolute value of the difference between the second color component of the predetermined pixel and the smoothed second color component, the larger the ratio of the first color difference signal. The image processing apparatus according to claim 2, further comprising a determination unit that performs the determination. The first color component is a red component or a blue component,
The image processing apparatus according to claim 1, wherein the second color component is a green color component. The image data is obtained by applying the magnification chromatic aberration correction to image data in which the pixels of the first color component, the pixels of the second color component, and the pixels of the third color component are arranged in a Bayer array. Generated by
The second color component includes a first green component obtained from pixels existing in the same row as the red component pixels and a second green component obtained from pixels present in the same row as the blue component pixels. Including
The image processing apparatus according to claim 4, wherein the smoothing unit performs the smoothing process on each of the first green component and the second green component.   The generation unit mixes the difference between the first color component and the smoothed first green component, and the difference between the first color component and the smoothed second green component. The image processing apparatus according to claim 5, wherein the first color difference signal is generated by selecting or selecting one of them. The image data is obtained by applying the magnification chromatic aberration correction to image data in which the pixels of the first color component, the pixels of the second color component, and the pixels of the third color component are arranged in a Bayer array. Generated by
The third color component is a blue component when the first color component is a red component and the second color component is a green component, and the first color component is a blue component. And when the second color component is a green component, it is a red component,
The determining means is configured to increase the ratio of the first chrominance signal when the moving amount of the first color component pixel in the magnification chromatic aberration correction is an odd number than when the moving amount is an even number. The image processing apparatus according to claim 3, wherein a composition ratio is determined. When the difference absolute value is smaller than a first threshold, the determining unit determines the combination ratio so that a ratio of the first color difference signal is 0, and the difference absolute value is the first threshold. The image processing apparatus according to claim 7, wherein the ratio of the combination is determined so that the ratio of the second color difference signal becomes 0 when the second threshold value is larger than the second threshold value. The determination means makes the first threshold value and the second threshold value smaller when the moving amount of the pixel of the first color component in the magnification chromatic aberration correction is an odd number than when the moving amount is an even number. The image processing apparatus according to claim 8. An image processing apparatus according to any one of claims 1 to 9,
Imaging means;
Correction means for applying the magnification chromatic aberration correction to image data including the first color component and the second color component generated by the imaging means;
An imaging apparatus comprising: An image processing method in an image processing apparatus for processing image data including a first color component and a second color component, the chromatic aberration of magnification being corrected for the first color component,
A smoothing step in which a smoothing unit of the image processing device generates a smoothed second color component by performing a smoothing process on the second color component of the image data;
A generating step of generating a first color difference signal from the first color component and the smoothed second color component with respect to a predetermined pixel of the image data;
An image processing method comprising:   The program for functioning a computer as each means of the image processing apparatus of any one of Claim 1 thru | or 9.

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