JP2017112421A - Image processing apparatus, imaging device and image processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of avoiding achromatic coloring.SOLUTION: An image processing apparatus includes a white balance adjustment section performing white balance adjustment of image data having pixel values of first, second and third color components in each pixel, and a processing section for changing the pixel values of the second and third color components of some pixels, out of the pixels where the pixel value of the first color component of the image data subjected to the white balance adjustment is a first saturated value, and the pixel values of the second and third color components are larger than the first saturated value.SELECTED DRAWING: Figure 1

Description

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

  An imaging apparatus that performs white balance adjustment is known (Patent Document 1). There is a known problem that false color may occur due to white balance adjustment.

Japanese Patent No. 3934719

According to the first aspect of the present invention, the image processing apparatus includes: a white balance adjustment unit that performs white balance adjustment on image data having pixel values of first, second, and third color components in each pixel; The pixel value of the first color component of the image data subjected to balance adjustment is a first saturated value, and the pixel values of the second and third color components are both the first saturated value. A processing unit that changes pixel values of the second and third color components of some of the larger pixels.
According to a second aspect of the present invention, an imaging apparatus includes the image processing apparatus according to any one of claims 1 to 10 and an imaging unit that captures a subject image and generates image data.
According to the third aspect of the present invention, the image processing program causes a computer to function as the image processing apparatus according to any one of claims 1 to 10.

1 is a block diagram illustrating a configuration example of an imaging apparatus having an image processing apparatus according to an embodiment of the present invention. It is a flowchart which shows the flow of an image process. It is a figure which shows the RGB space which shows the image data after white balance gain multiplication. It is a figure which shows the straight line L which passes along the white point W in RGB space. It is a figure which shows the clip plane in RGB space. It is a figure which shows the point P on the high-intensity side in RGB space. It is a figure which shows the specific example of the intersection C of the straight line WM in RGB space, and the plane G = Gi. It is a figure which shows the specific example of a clip process. It is a figure which shows the line which passes along the white point W in RGB space which concerns on a modification. It is a figure which shows the clip plane in the RGB space which concerns on a modification.

  FIG. 1 is a block diagram illustrating a configuration example of an imaging apparatus having an image processing apparatus according to an embodiment. A digital camera 10, which is an example of an imaging apparatus, includes an imaging optical system 11, an imaging element 12, an analog signal processing unit 13, an image processing unit 30, an operation unit 17, a memory IF unit 18, and a display unit 19. The control unit 20 is provided.

  The imaging optical system 11 includes a plurality of lenses, a lens driving unit, a diaphragm, and the like, and forms a subject image on the imaging surface of the imaging element 12. In FIG. 1, for the sake of simplicity, the imaging optical system 11 is illustrated as a single lens.

  The image pickup device 12 is an image pickup device such as a CCD or a CMOS image sensor, picks up a subject image formed by the image pickup optical system 11 and outputs an analog image signal. In the imaging element 12, imaging pixels each provided with R (red), G (green), and B (blue) color filters are arranged according to a Bayer array, for example.

  The analog signal processing unit 13 performs signal processing on the analog image signal output from the image sensor 12. The analog signal processing unit 13 performs signal processing such as correlated double sampling (CDS), gain adjustment, analog digital (AD) conversion, and color separation, for example. In the AD conversion process, an analog image signal is converted into a digital image signal. In the color separation process, RAW image data corresponding to each color is generated by separating the image signal for each of R, G, and B color filters.

  The image processing unit 30 includes a white balance (WB) adjustment unit 14, a clip processing unit 15, a correction processing unit 16, and the like, and performs image processing such as white balance adjustment, clip processing, and gamma correction. For example, part or all of the image processing unit 30 is configured as an ASIC (Application Specific Integrated Circuit).

  The white balance (WB) adjustment unit 14 performs white balance adjustment on Raw image data having pixel values of each color component. The white balance (WB) adjustment unit 14 performs white balance adjustment, for example, by multiplying the raw image data of each color by a white balance gain value.

  The clip processing unit 15 includes a surface setting unit 31, an upper limit determination unit 32, and a correction unit 33, and performs processing for changing the pixel value of each color component with respect to image data after white balance adjustment. The surface setting unit 31 sets a surface (clip surface) that passes through the white point in the RGB color space. The upper limit determination unit 32 determines the upper limit (clip value) of the image data after white balance adjustment based on the clip plane set by the plane setting unit 31. The correction unit 33 performs processing for correcting the image data after white balance adjustment based on the clip value determined by the upper limit determination unit 32.

  The correction processing unit 16 performs image processing on the image data output from the clip processing unit 15. The correction processing unit 16 performs image processing such as color gradation processing and contour enhancement processing, for example.

  The control unit 20 includes a CPU, a memory, a peripheral circuit, and the like, and controls each unit of the digital camera 10. The CPU controls each part of the digital camera 10 by reading and executing a control program and parameters from the memory. Examples of the memory include flash memory and DRAM. The flash memory is a non-volatile storage medium, and stores a predetermined control program and various parameters in advance. The DRAM is a volatile storage medium, and is used as a work area for the CPU or for temporarily storing data.

  The operation unit 17 includes various operation members, and outputs an operation signal corresponding to the operation of the operation member to the control unit 20. The control unit 20 controls each unit of the digital camera 10 based on the input operation signal. The memory IF unit 18 has a connector (not shown) to which a storage medium such as a memory card is connected. The memory IF unit 18 writes image data to the connected storage medium and reads image data from the storage medium. The display unit 19 includes, for example, a liquid crystal monitor and displays an image based on an image signal generated by imaging, a setting menu for setting the digital camera 10, and the like.

  Currently, in many digital cameras, imaging is performed using Bayer array imaging elements, and Bayer interpolation, white balance processing, and color gradation processing are performed, and an image is recorded. In the white balance process, the white balance is adjusted so that the RGB image data when an achromatic color is captured is 1: 1: 1. Thereafter, conversion according to the reproduction intention, such as a favorite color or a faithful color, is applied by color gradation processing. In many cases, color gradation processing assumes an image with adjusted white balance as its input.

  When an achromatic color is photographed, the raw data, which is the raw image output, varies depending on the light source, and therefore the white balance processing is applied corresponding to the light source. A digital white balance function that automatically determines the light source, a manual white balance function that is manually set by the photographer, and a preset white balance function that is performed by pre-shooting an achromatic object The camera 10 is provided.

  Specifically, as the white balance processing, a method of multiplying Raw data by a white balance gain value for each channel is known. In this case, when an achromatic object is photographed, the raw data is multiplied by the white balance gain value for each channel so that the image data becomes 1: 1: 1. The white balance gain value is calculated by the digital camera 10 when the auto white balance function is used, and the white balance gain value stored in advance in the digital camera 10 is used when the manual white balance function is used.

  As long as the original raw data is not saturated, the image data after white balance gain multiplication can be 1: 1: 1 for an achromatic subject. However, when an achromatic subject is photographed, if any channel of the original raw data is saturated, the image data after multiplication cannot be 1: 1: 1.

  For example, if Raw data is 12 bits (maximum 4095) and (240, 480, 300) and the gain value is (2.00, 1.00, 1.60), the image data after multiplication is (480, 480, 480), and 1: 1: 1. However, the Raw data when an achromatic color in a high-luminance part is photographed may be a case where the G channel is saturated at the time of imaging, for example (2400, 4095, 3000). The image data of (4800, 4095, 4800) becomes 1: 1: 1. As a result, a coloring phenomenon occurs in which a high-intensity portion of an achromatic color, which is a kind of false color, is colored.

  In order to prevent such a phenomenon from occurring, a clipping process is known in which image data is clipped by a limit value after multiplication by a white balance gain. For example, when 4095 is set as a limit value, image data exceeding 4095 is limited to 4095. When clip processing is performed, the raw data (2400, 4095, 3000) in the above example is not (4800, 4095, 4800) but (4095, 4095, 4095), and 1: 1: 1. And achromatic coloring phenomenon can be avoided.

  As described above, the clipping process can prevent the achromatic coloring phenomenon with respect to the high brightness achromatic object. However, there are cases in which a low-luminance chromatic subject is subject to color rotation, which is a kind of false color, or a reduction in saturation. For example, when the white balance gain is (2.00, 1.00, 1.60) and the raw data is (3000, 1000, 1500), 4095 is limited by multiplying the white balance gain. Consider performing clip processing with values. For the R channel, 3000 × 2.00 = 6000, which exceeds 4095. Therefore, when clip processing is performed after white balance gain multiplication, the image data is (4095, 1000, 2400). Since the RGB image data ratio is changed by the clipping process, color rotation occurs. If the same processing is performed when the G component and the B component of the raw data are extremely small relative to the R component, for example, when the raw data is (3000, 100, 100), the processed image The data becomes (4095, 100, 160), and the decrease in saturation becomes conspicuous.

  In the imaging apparatus described in Patent Document 1, the clip level of another color signal after white balance adjustment is set according to the level of one color signal before or after white balance adjustment. For this reason, when the level of one color signal as a reference is high, the image data is clipped, which causes a decrease in color and saturation. Therefore, in the embodiment of the present invention, by setting a clip plane that passes through the white point in the color space as shown in FIG. 5, a decrease in color rotation and saturation is avoided under a wide range of conditions.

In the present embodiment, a clip value is obtained with reference to a plane in an RGB space indicating image data after white balance gain multiplication. First, this plane (hereinafter referred to as clip plane) will be described. When the maximum value of the Raw data is normalized to 1.0, the image data multiplied by the white balance gain value (R channel: Rg, B channel: Bg) is 0 ≦ R ≦ Rg in the RGB space.
0 ≦ G ≦ 1.0
0 ≦ B ≦ Bg
Is a rectangular parallelepiped (shown in FIG. 3 for the case of Rg = 2.0, Bg = 1.6). The white point W becomes (1.0, 1.0, 1.0). The clip plane is defined in this RGB space. The clip plane calculation method will be described below.

A straight line L having a predetermined slope m is obtained through the white point W (1.0, 1.0, 1.0) within the G = 1.0 plane. This straight line L is expressed in the RB coordinate system.
B = m · (R−1.0) +1.0 (1)
This is -mR + B = 1.0-m (2)
It can be expressed. This straight line L is shown in FIG.

The clip plane includes a straight line represented by the formula (2). The expression indicating the plane is an expression indicating the straight line when G = 1.0. Therefore, using the real number p, the following equation (3) is obtained.
-MR + p (1.0-G) + B = 1.0-m (3)

The clip plane passes through a predetermined point M (Rg, Gn, Bg) satisfying G = Gn (0 <Gn <1.0) on a straight line indicating an intersection line between the plane R = Rg and the plane B = Bg. Shall. Therefore, the following expressions (4) and (5) are obtained.
-MRg + p (1.0-Gn) + Bg = 1.0-m (4)
p = (mRg−Bg + 1.0−m) / (1.0−Gn) (5)

FIG. 5 shows the clip plane. Here, assuming that m = −1.0 and Gn = 0.5 for the predetermined values m and Gn,
p = (-Rg-Bg + 2.0) / (1.0-0.5)
= -2Rg-2Bg + 4.0 (6)
Therefore, the expression of the clip plane is
R + (-2Rg-2Bg + 4.0) (1.0-G) + B = 1.0-m (7)
R + (2Rg + 2Bg−4.0) G + B = 2Rg + 2Bg−2.0 (8)
It becomes. The above is the calculation method of the clip plane. The clip plane is determined by the white balance gain value applied to the image. Information is stored in the digital camera 10 so that the above-described plane calculation can be performed using the white balance gain value as an input.

  Next, an operation flow in the digital camera 10 will be described with reference to FIG. In this embodiment, it is assumed that the white balance gain values Rg and Bg of the R and B channels are 2.0 and 1.6, respectively.

  In step 1 (S 1), the photographer takes a picture, and Raw data (12 bits) is stored in the storage area of the digital camera 10.

  In step 2 (S2), Bayer interpolation is performed on the Raw data, and data of three colors per pixel is created and stored in the storage area.

  In step 3 (S3), the white balance gain value is determined. The white balance gain value is determined by a white balance mode (auto white balance, manual white balance, etc.). Here, as described above, the white balance gain values Rg and Bg of the R and B channels are 2.0 and 1.6, respectively.

In step 4 (S4), an expression of the clip plane is obtained. Substituting Rg = 2.0 and Bg = 1.6 into the equation (8), the following equation (9) is obtained.
R + 3.2 · G + B = 5.2 (9)

  In step 5 (S5), the raw data is multiplied by the white balance gain. Further, the image data is normalized by being divided by the upper limit value 4095 of the Raw data. The maximum value of the image data after multiplication is (R, G, B) = (2.0, 1.0, 1.6). Hereinafter, the processing of step 6 (S6) to step 9 (S9) is processing according to the pixel value, and processing is performed for each pixel.

  In step 6 (S6), when the image data (Ri, Gi, Bi) after white balance gain multiplication is represented by a point in the RGB space, that point is on the higher brightness side than the clip plane R + 3.2G + B = 5.2 ( It is determined whether the point is P (2.0, 1.0, 1.6) side (FIG. 6). If it is on the high luminance side, the process proceeds to step 7 (S7), and if not, the process proceeds to step 9 (S9) assuming that the clipping process is not performed.

In step 7 (S7), Rs and Bs are calculated. Rs and Bs are the RGB space, point W (1.0, 1.0, 1.0) and point M (Rg, Gn, Bg) (= (2.0, 0.5, 1.6)) And the R and B coordinates of the intersection C (Rs, Gi, Bs) between the straight line passing through (straight line WM) and the plane G = Gi (FIG. 7). The straight line WM uses the real number α,
(R, G, B) = (1.0,1.0,1.0) + α ((2.0,0.5,1.6)-(1.0,1.0,1.0)) (10)
Call it.

Since (Rs, Bs) is the R coordinate and B coordinate of the intersection of the straight line WM and the plane G = Gi, α is obtained by substituting G = Gi into the equation of the straight line WM, and the obtained α is used. Thus, (Rs, Bs) is obtained. For example, when Gi = 0.7, α is obtained from equation (10).
0.7 = 1.0 + α · (0.5−1.0) (11)
α = 0.6 (12)
Furthermore, α = 0.6 is substituted into the equation (10) to obtain (Rs, Bs).
(Rs, Bs) = (1.0,1.0) +0.6 ・ ((2.0,1.6)-(1.0,1.0)) = (1.6,1.36)
Further, for example, when Gi = 1.0, (Rs, Bs) = (1.0, 1.0), and when Gi = 0.5, (Rs, Bs) = (2.0, 1). .6).

  In step 8 (S8), clip processing is executed. If Ri> Rs and Bi> Bs, clip to Ri = Rs and Bi = Bs.

If Ri> Rs and Bi ≦ Bs, the R channel clip value is obtained and clipped. For the clip value, R is obtained by substituting B = Bi and G = Gi into the expression of the clip plane, and clipping is performed using this as the clip value. For example, when (Rs, Bs) = (1.6, 1.36) and (Ri, Gi, Bi) = (1.9, 0.7, 1.1), ,
R = 5.2-3.2.0.7-1.1 = 1.86
Therefore, Ri = 1.9 is clipped to 1.86.

When Ri ≦ Rs and Bi> Bs, the clip value of the B channel is obtained and clipped. The clip value is obtained by substituting R = Ri and G = Gi into the expression of the clip plane to obtain B, and clips this as the clip value. For example, when (Rs, Bs) = (1.6, 1.36) and (Ri, Gi, Bi) = (1.5, 0.7, 1.55), from equation (9) ,
B = 5.2-3.2 ・ 0.7-1.5 = 1.46
Therefore, Bi = 1.55 is clipped to 1.46.

  In the case of Ri ≦ Rs and Bi ≦ Bs, the determination in step S6 (S6) is N, so the processing is not performed in step 8 (S8).

  FIG. 8 shows clip processing when Gi = 0.7 and (Rs, Bs) = (1.6, 1.36). When Ri> Rs and Bi> Bs, the clip is made to (Rs, Bs) = (1.6, 1.36). In the case of Ri> Rs and Bi ≦ Bs, only Ri is clipped at the intersection of the clip plane and the plane G = Gi (= 0.7) while maintaining the value of Bi. When Ri ≦ Rs and Bi> Bs, the value of Ri is maintained and only Bi is clipped to the intersection line between the clip plane and the plane G = Gi (= 0.7).

  In step 9 (S9), an end determination is made, and if the processing of step 6 (S6) and subsequent steps is performed for all pixels, the process proceeds to step 10 (S10). Otherwise, the process proceeds to step 6 (S6) for the next pixel. I do.

  In step 10 (S10), normalization is performed to return to a 12-bit value. That is, 4095 is multiplied. The above is the white balance processing and clip processing in the present embodiment.

For example, in this embodiment, when the white balance gain value is (2.00, 1.00, 1.60), (Ri, Gi, Bi), R + 3.2 · G + B for the following four Raw data: The presence or absence of clip processing is as follows.
Raw data (Ri, Gi, Bi) R + 3.2G + B Clip processing
(2400,4095,3000) → (1.172,1.000,1.172) → 5.544 → Yes
(3000,1000,1500) → (1.465,0.2442,0.5860) → 2.832 → None
(3000,4000,1500) → (1.465,0.9768,0.5860) → 5.177 → None
(2000,3500,3800) → (0.9768,0.8547,1.484) → 5.196 → None

When the raw data is (2400, 4095, 3000), the Rs and Bs values are both 1.0, and therefore Ri and Bi are both clipped to 1.0 in the processing of this embodiment. Therefore, the post-processing RGB data after application of the present embodiment and the presence or absence of false colors are as follows.
Raw data Data after processing False color
(2400,4095,3000) → (4095,4095,4095) None (Natural coloring)
(3000,1000,1500) → (6000,1000,2400) None (around chromatic colors)
(3000,4000,1500) → (6000,4000,2400) None (around chromatic colors)
(2000,3500,3800) → (4000,3500,6080) None (around chromatic colors)

  As described above, in the processing according to the present embodiment, not only when the value of the G channel is low but also when it is high, clipping can be avoided and chromatic color rotation can be avoided. Further, when the G channel is saturated at the time of imaging, such as (2400, 4095, 3000), it can be 1: 1: 1 in this embodiment, and achromatic coloring can be avoided. . That is, it is possible to reduce coloring caused by saturation at the time of imaging, and it is possible to reduce color rotation and saturation reduction due to clip processing after white balance multiplication.

  In the imaging apparatus described in Patent Document 1, the clip level of another color signal after white balance adjustment is set according to the level of one color signal before or after white balance adjustment. Here, the channel with the highest Raw data level when an achromatic subject is photographed is the C1 channel, the next highest channel is the C2 channel, and the lowest channel is the C3 channel. In this prior art, the clip level for the C2 channel (for example, R) and the C3 channel (for example, B) is made variable according to the raw data for the C1 channel (for example, G), and the raw data for the C1 channel (G) is low. Increases the clip level, and lowers the clip level when the Raw data of the C1 channel (G) is high.

If the white balance gain of the R and B channels is Rgain and Bgain, respectively, for example, if the Raw data of the C1 channel (G) is 2047 or less, the clip level for the C1 channel (R) is 4095 × Rgain (substantially clip Equivalent to no processing). When the Raw data of the C1 channel (G) is 4095, the clip level is set to 4095. When the Raw data of the C1 channel (G) is greater than 2047 and less than 4095, 4095 × Rgain and 4095 are set to values obtained by linear interpolation. Assuming that Rgain is 2.0 and Bgain is 1.6, the R channel clip level ClipR for linear interpolation and the B channel clip level ClipB for linear interpolation are expressed by the following equations (13), It will be represented by (14).
ClipR = {(4095-4095 × 2.0) / (4095-2047)} (G-4095) +4095 (13)
ClipB = {(4095-4095 × 1.6) / (4095-2047)} (G-4095) +4095 (14)

In the prior art of Patent Document 1, when the Raw data of the C1 channel (G) is high, it may be clipped. For example, when the Raw data is (3000, 4000, 1500), according to the above equations (13) and (14), the clip value is
ClipR = {(4095-4095 × 2.0) / (4095-2047)} (4000-4095) + 4095 = 4284
ClipB = {(4095-4095 × 1.6) / (4095-2047)} (4000-4095) + 4095 = 4208
Therefore, the image data after the white balance gain multiplication is processed as follows.
R: 6000 (3000 × 2.0) → Clipped to 4284 B: 2400 (1500 × 1.6) → Not clipped For example, if Raw data is (2000, 3500, 3800), clip Since the values are ClipR = 5284 and ClipB = 4808, the image data after white balance gain multiplication is processed as follows.
R: 4000 (2000 × 2.0) → Not clipped B: 6080 (3800 × 1.6) → Clipped to 4808

Thus, in the prior art, when the level of the Raw data of a specific channel (C1 channel) is high, the image data is clipped, which causes a decrease in color and saturation. . In the prior art, when the white balance gain value is (2.00, 1.00, 1.60), the RGB data after processing and the presence / absence of false color are as follows for the following four Raw data: .
Raw data Data after processing False color
(2400,4095,3000) → (4095,4095,4095) None (Natural coloring)
(3000,1000,1500) → (6000,1000,2400) None (colored around chromatic colors)
(3000,4000,1500) → (4284,4000,2400) Yes (around chromatic colors)
(2000,3500,3800) → (4000,3500,4808) Yes (around chromatic colors)
On the other hand, in the present embodiment, as described above, it is not limited to the case where the data of a specific channel is low, and it is possible to avoid a decrease in color rotation and saturation under a wide range of conditions.

According to the embodiment described above, the following operational effects can be obtained.
(1) The image processing apparatus includes a white balance adjustment unit 14 that performs white balance adjustment on image data having pixel values of the first, second, and third color components in each pixel, and image data that has undergone white balance adjustment. The pixel values of the first color component are the first saturated value, and the pixel values of the second and third color components are both larger than the first saturated value. And a processing unit 15 that changes the pixel values of the second and third color components. Since it did in this way, a pixel value can be changed based on the pixel value of each color component.
(2) The processing unit 15 changes the pixel value of the pixel by reducing the pixel values of the first, second, and third color components. Since this is done, achromatic coloring due to Raw data saturation can be avoided. In addition, it is possible to avoid a reduction in color and saturation.

(3) The image processing apparatus includes a white balance adjustment unit 14 that performs white balance adjustment on image data having pixel values of the first, second, and third color components in each pixel, and the first, second, and third. In the color space based on the color component, the surface setting unit 31 that sets a surface that passes through the white point in the color space or a point near the white point, and the image data that has undergone white balance adjustment are set by the surface setting unit 31. And a correction unit 33 that performs correction using an upper limit value generated from the surface. Since it did in this way, the image data after white balance adjustment can be correct | amended based on the clip surface which passes the white point in a color space, or the point near a white point.
(4) The correction unit 33 corrects the image data after the white balance adjustment to a value within the upper limit value generated from the surface set by the surface setting unit 31. Since it did in this way, achromatic coloring can be avoided. Further, the present invention is not limited to the case where the data of a specific channel is low, and it is possible to avoid a decrease in color rotation and saturation under a wide range of conditions.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In the embodiment described above, the number of clip surfaces is one in FIG. 5, but a plurality of surfaces may be connected.
(Modification 2)
In the embodiment described above, the straight line L in FIG. 4 is a single straight line, and the clip surface in FIG. 5 is a single plane, but instead of the straight line L, a bent line as shown in FIG. You may use what connected two planes as a clip surface like FIG.

(Modification 3)
In the above-described embodiment, the clip surface is a flat surface in FIG. 5, but this curved surface can also be referred to when a clip value is obtained using a curved surface.
(Modification 4)
In the embodiment described above, the clip surface passes through the white point, but may pass through a point near the white point.
(Modification 5)
In the above-described embodiment, the example in which the clipping process of the image data is performed in the RGB color space is shown, but the image data may be performed in another space such as a CMY (cyan, magenta, yellow) color space.

(Modification 6)
In the above-described embodiment, the example in which the image processing device is mounted on the imaging device has been described. However, the image processing device may be configured by a computer. The image processing apparatus is configured by causing a computer (or a CPU or the like) to execute a program that performs processing based on the flowchart illustrated in FIG. When a program is used by being taken into a computer, the program is executed after being loaded into a data storage device of the computer.

  The program may be loaded into the computer by setting a storage medium such as a CD-ROM storing the program in the computer, or may be loaded into the computer by a method via a communication line such as a network. When passing through a communication line, the program is stored in a storage device of a server (computer) connected to the communication line. The program can be supplied as various forms of computer program products such as provision via a storage medium or a communication line.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Digital camera, 11 ... Imaging optical system, 12 ... Imaging device, 13 ... Analog signal processing part, 14 ... White balance (WB) adjustment part, 15 ... Clip processing part, 16 ... Correction processing part, 17 ... Operation part, DESCRIPTION OF SYMBOLS 18 ... Memory IF part, 19 ... Display part, 20 ... Control part, 30 ... Image processing part, 31 ... Surface setting part, 32 ... Upper limit determination part, 33 ... Correction part

Claims (12)

A white balance adjustment unit that performs white balance adjustment on image data having pixel values of the first, second, and third color components for each pixel;
The pixel value of the first color component of the image data subjected to the white balance adjustment is a first saturated value, and the pixel values of the second and third color components are both the first saturation. A processing unit that changes pixel values of the second and third color components of some of the pixels that are larger than the calculated value;
An image processing apparatus comprising: The image processing apparatus according to claim 1.
The processing unit is further configured such that a pixel value of the first color component among pixels of the image data subjected to the white balance adjustment is between a first predetermined value and a first saturated value. The pixel value of the second color component is between a second predetermined value and a second saturated value, and the pixel value of the third color component is between a third predetermined value and a third saturated value. A range that does not include pixels in which the pixel values of the first, second, and third color components are the first predetermined value, the second predetermined value, and the third predetermined value. An image processing apparatus that changes the pixel value of the pixel to a pixel value outside the range. The image processing apparatus according to claim 1 or 2,
The image processing apparatus, wherein the processing unit changes a pixel value of the pixel by reducing a pixel value of the first, second, and third color components. A white balance adjustment unit that performs white balance adjustment on image data having pixel values of the first, second, and third color components for each pixel;
A surface setting unit that sets a surface that passes through a white point in the color space or a point near the white point in the color space of the first, second, and third color components;
A correction unit that corrects the image data subjected to the white balance adjustment with an upper limit value generated from the surface set by the surface setting unit;
An image processing apparatus comprising: The image processing apparatus according to claim 4.
The correction unit corrects the image data after the white balance adjustment to a value within an upper limit value generated from the surface set by the surface setting unit. The image processing apparatus according to claim 4 or 5,
The color space has first, second and third coordinate axes corresponding respectively to the first, second and third color components;
The white point or the neighboring point is located in a plane parallel to a plane defined by two of the first, second and third coordinate axes;
The image processing apparatus, wherein the surface includes a line having a predetermined inclination through the white point or the neighboring point in the parallel plane, and intersects the parallel plane. The image processing apparatus according to claim 6.
The line is an image processing apparatus including at least one of a straight line, a curved line, and a broken line. The image processing apparatus according to claim 6 or 7,
The surface includes, as vertices, points on an axis parallel to the first coordinate axis, points on an axis parallel to the second coordinate axis, and points on an axis parallel to the third coordinate axis. Processing equipment. The image processing apparatus according to claim 8.
The variables corresponding to the first, second, and third coordinate axes are R, G, and B, respectively, and the coefficients are s (s> 0), t (t> 0), u (u> 0), and K (K > 0)
The image processing apparatus, wherein the surface is a plane represented by a plane expression sR + tG + uB = K. The image processing apparatus according to claim 9.
Regarding the image data of the first, second and third color components in the Raw image data corresponding to the achromatic color, the image data is the maximum among the image data of the first, second and third color components. Is a reference color component, the maximum value of the image data after the white balance adjustment of the reference color component is a first maximum value, and the other of the two other color components different from the reference color component When the maximum value of the image data after the white balance adjustment of one color component is the second maximum value, and the maximum value of the image data of the other color component after the white balance adjustment is the third maximum value ,
The parallel plane is orthogonal to the coordinate axis corresponding to the reference color component at a coordinate value corresponding to the first maximum value on the coordinate axis corresponding to the reference color component;
The surface includes a plane orthogonal to the coordinate axis corresponding to the one color component in a coordinate value corresponding to the second maximum value on the coordinate axis corresponding to the one color component, and the other color component. A point on a straight line orthogonal to a plane orthogonal to the coordinate axis corresponding to the other color component in the coordinate value corresponding to the third maximum value on the corresponding coordinate axis, as the vertex,
The point on the straight line is an image processing apparatus in which a coordinate value of the coordinate axis corresponding to the reference color component is larger than 0 and smaller than a coordinate value corresponding to the first maximum value. The image processing apparatus according to any one of claims 1 to 10,
An imaging unit that captures a subject image and generates image data;
An imaging apparatus comprising:   An image processing program for causing a computer to function as the image processing apparatus according to claim 1.

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