JP2004215236A - Image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain excellent color reproduction characteristics in an image processing apparatus such as a digital camera and a digital video camera. <P>SOLUTION: The image processing apparatus has: a first imaging device for receiving light from an object; a second imaging device which is capable of photo-detecting the same image as the first imaging device and has different spectral sensitivity characteristics; a color correction coefficient calculating means for calculating a color correction coefficient based upon output values photoelectric transduced by the first imaging device and the second imaging device; and a color correcting means which uses the color correction coefficient calculated by the color correction coefficient calculating means to perform color correction to the output value of the first imaging device. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus such as a digital camera or a digital video camera.

2. Description of the Related Art Conventionally, in an image processing apparatus, desired color reproduction characteristics are obtained by receiving light of three primary colors of R, G, and B, performing photoelectric conversion and color correction.
In such an image processing apparatus, in order to obtain good color reproduction characteristics, matrix conversion is performed when color correction is performed, or lookup table (hereinafter referred to as LUT) conversion is performed. (See JP 2001-203903 A and JP 2002-10095 A).
JP 2001-203903 A Japanese Patent Laid-Open No. 2002-10095

However, in the above-described image processing apparatus, there is a problem in that, for example, a color that can be identified by the human eye generates a color that cannot be identified by the image sensor due to a difference in spectral sensitivity characteristics between the image sensor and the human eye. there were.
The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an image processing apparatus capable of obtaining good color reproduction characteristics.

  The image processing apparatus according to claim 1 includes a first image sensor that receives light from a subject, and a second image sensor that can receive the same image as the first image sensor and has different spectral sensitivity characteristics. A color correction coefficient calculating means for calculating a color correction coefficient based on an output value photoelectrically converted by the first image pickup element and the second image pickup element; and the color correction coefficient calculated by the color correction coefficient calculation means. And color correction means for performing color correction on the output value of the first image sensor.

  The image processing apparatus according to claim 2 is a first image sensor that receives light from a subject, a second image sensor that can receive the same image as the first image sensor and has different spectral sensitivity characteristics, and Color correction coefficient calculation means for calculating a color correction coefficient based on an output value photoelectrically converted by the first image pickup element and the second image pickup element, and the color correction coefficient calculated by the color correction coefficient calculation means And color correction means for performing color correction on a combined output value of the first image sensor and the second image sensor.

  An image processing apparatus according to a third aspect is the image processing apparatus according to the first or second aspect, wherein the first imaging element is divided into a plurality of small areas and is made to correspond to the plurality of small areas of the first imaging element. The second image sensor is divided into a plurality of small areas, the output values of the pixels of the first image sensor and the second image sensor are integrated for each small area, and the color correction is performed using the integrated value. A coefficient is calculated.

The image processing device according to claim 4 is the image processing device according to claim 3, wherein the first image sensor and the second image sensor are used to receive light from the same subject. However, they are different.
The image processing device according to claim 5 is the image processing device according to any one of claims 1 to 4, wherein the second image sensor is used as a colorimetric sensor for measuring the color balance of the subject. It is characterized by that.

  The image processing apparatus according to claim 6 is the image processing apparatus according to any one of claims 1 to 4, wherein the second image sensor is used as a photometric sensor that measures the luminance of the subject. It is characterized by.

In the image processing apparatus of the present invention, the first and second imaging elements having different spectral sensitivity characteristics are provided, and the parameters for receiving and recognizing light from the object field are increased. Color reproduction characteristics can be obtained.
In addition, when applied to an electronic camera provided with first and second imaging elements that exist in the prior art, it is only necessary to change the signal processing method, so that it can be easily applied to an existing electronic camera.

Hereinafter, the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is an explanatory diagram showing an electronic camera incorporating the first embodiment of the image processing apparatus of the present invention.
The electronic camera 2 includes an external flash device 1 for irradiating light on a subject, and a camera body 3 that can control the external flash device 1.

  The external flash device 1 includes a xenon tube 5 that converts current energy into emission energy, and a light emission control unit 7 that controls the photocurrent of the xenon tube 5 to cause flat light emission. Further, the external flash device 1 includes a reflector 9 and a Fresnel lens 11 in order to efficiently irradiate the subject with the light beam emitted from the xenon tube 5. Further, the external flash device 1 includes a monitor sensor 13 and a glass fiber 15 for connecting the sensor 13 and the reflection plate 9 and guiding the light beam emitted from the xenon tube 5 to the sensor 13. .

The camera body 3 includes a taking lens unit 17 and a body unit 19 to which the taking lens unit 17 is attached.
The photographic lens unit 17 includes a photographic lens 21 that collects a light beam from a subject and a diaphragm 22.
The main body 19 has a half mirror 23 that is rotated to a position where the light beam transmitted through the photographing lens 21 can be received (hereinafter referred to as a closed state) and a position where the light beam cannot be received (hereinafter referred to as an open state). . The main body 19 is equipped with a silver salt film 25 capable of receiving a light beam transmitted through the photographing lens 21 among the reflected light irradiated from the external flash device 1 and reflected by the subject. The main body 19 has a shutter 27 that selectively shields light from the front surface of the film 25.

Further, the main body 19 is based on the CCD 29 which is a first image sensor arranged so as to be able to receive the light beam reflected by the shutter 27 or the film 25 among the light beams transmitted through the photographing lens 21, and the photometric result of the CCD 29. And an electric circuit 31 for controlling the external flash device 1.
Furthermore, the main body 19 has a focus glass 33 that is disposed at the imaging position of the photographic lens 21 via the half mirror 23 when the half mirror 23 is in the closed state. Further, the main body 19 includes a pentaprism 35 that can change and change the optical path of the light beam that has passed through the focus glass 33, and a finder 37 that observes the light beam from the pentaprism 35. Further, the main body 19 includes a condensing lens 39 that condenses the transmitted light of the pentaprism 35 when the pentaprism 35 is in a position different from the position where the reflected light from the pentaprism 35 is irradiated on the finder 37. The CCD 41 is a second image sensor that receives light transmitted through the condenser lens 39 and is used as a colorimetric sensor.

A contact 43 is provided as an interface between the external flash device 1 and the camera body 3.
Next, an optical system of the electronic camera 2 having such a configuration will be described.
When observing the subject with the finder 37, a part of the light beam that has passed through the photographing lens 21 is reflected by the closed half mirror 23 indicated by a broken line, passes through the focus glass 33 and the pentaprism 35, and enters the finder 37. Led.

  When a release button (not shown) is pressed during shooting, the half mirror 23 is moved to an open state indicated by a solid line, the diaphragm 22 is narrowed, and the shutter 27 is opened. At substantially the same time, the xenon tube 5 emits the main light to illuminate the subject, and the reflected light from the subject reaches the film 25 through the photographing lens 21, and the light beam reflected by the film 25 is taken into the CCD 29.

Next, FIG. 2 shows a block diagram of the first embodiment of the image processing apparatus of the present invention.
The image processing device 45 includes a CCD 29 that receives light from a subject, and a CCD 41 that can receive the same image as the CCD 29 and has different spectral sensitivity characteristics. Here, the CCD 29 and the CCD 41 have different spectral sensitivity characteristics as shown in FIG. 3, and are brought closer to the spectral sensitivity characteristics of the human eye by increasing the parameters. The CCD 29 and the CCD 41 are provided with RGB color filters having the same light transmittance.

The output of the CCD 29 is subjected to A / D conversion, correction of fluctuations in power supply voltage due to temperature changes, and the like in a signal processing unit 47. Next, the output of the signal processing unit 47 is input to the white balance unit 49 and the evaluation value generation unit 59.
The white balance unit 49 multiplies the white balance gains Kr and Kb in order to suppress the change in the output image due to the difference in the color characteristics of the light source that illuminates the subject.

In particular,
R ′ = Kr × R
G '= G
B ′ = Kb × B
R, G, B: Image signal before white balance correction R ′, G ′, B ′: Process of image signal after white balance correction.

The output of the white balance unit 49 is input to the interpolation unit 51. In the interpolation unit 51, color interpolation processing by pixel local calculation is performed, and correction is performed for all pixels. More specifically, the color of an arbitrary pixel is estimated from pixels around the arbitrary pixel.
On the other hand, the evaluation value generation unit 59 divides the image into, for example, small regions of 8 rows and 12 columns, and calculates evaluation values such as luminance values or chromaticity values for each small region. The luminance is proportional to the absolute brightness of the object color, and the chromaticity is an objective measurement of the color of the object from which the luminance information is removed.

In the first embodiment, the color correction coefficient generation unit 61 serving as a color correction coefficient calculation unit calculates the color correction coefficient based on the outputs of the CCD 41 and the evaluation value generation unit 59.
Hereinafter, a method of calculating the color correction coefficient will be specifically described with reference to the flowchart of FIG.
In step S11, coordinate transformation for non-dimensionalization is performed.
Specifically, the integrated value for each primary color of the output value for each small area of the image of the CCD 29 is Rs, Gs, Bs. Similarly, the CCD 41 is divided into small areas of 8 rows and 12 columns, for example. If the integral value for each region is Rm, Gm, Bm,
RGs = Rs / Gs
BGs = Bs / Gs
RGm = Rm / Gm
BGm = Bm / Gm
RGs, BGs, RGm, BGm: The first pseudo color correction coefficient is calculated.

In step S <b> 12, normalization is performed using the first pseudo color correction coefficients RGs, BGs, RGm, BGm and the coefficients of the coefficient table unit 63. That is,
RGs ′ = RGs × k1 + k2
BGs ′ = BGs × k1 + k2
RGm ′ = RGm × k3 + k4
BGm ′ = BGm × k3 + k4
k1, k2, k3, k4: Coefficients RGs ′, BGs ′, RGm ′, BGm ′: The second pseudo color correction coefficient is calculated.

In step S13, a color correction coefficient is calculated with reference to the LUT based on the second pseudo color correction coefficients RGs ′, BGs ′, RGm ′, and BGm ′.
Specifically, the coefficient numbers are acquired using the LUT of FIG. 5 based on the second pseudo color correction coefficients RGs ′, BGs ′, RGm ′, and BGm ′. Next, using the table shown in FIG. 6, color correction coefficients CC0 to CC8 that match the coefficient number selected in FIG. 5 are selected.

In this way, the calculation of the color correction coefficient is completed.
In the table of FIG. 5, coefficient numbers are taken in the vertical direction, and second pseudo color correction coefficients RGs ′, BGs ′, RGm ′, and BGm ′ are taken in the horizontal direction.
Also, coefficient numbers are taken in the vertical direction of the table of FIG. 6, and color correction coefficients CC0 to CC8 are taken in the horizontal direction.

The coefficient interpolation unit 65 performs coefficient interpolation in order to reduce steps due to differences in the color correction coefficients CC0 to CC8 calculated by the color correction coefficient generation unit 61 at the boundary of each small region. This coefficient interpolation is performed by performing linear interpolation using the coefficients of nearby small regions. In addition, the color correction coefficient after coefficient interpolation is expressed as CC′0 to CC′8 below.
In the color correction unit 53 that is a color correction unit, the image signals R ″, G ″, and B ″ output from the interpolation unit 51 and the color correction coefficients CC′0 to CC ′ calculated by the coefficient interpolation unit 65 are displayed. 8 performs a color correction calculation as shown below.

R ′ ″ = R ″ × CC′0 + G ″ × CC′1 + B ″ × CC′2
G ′ ″ = R ″ × CC′3 + G ″ × CC′4 + B ″ × CC′5
B ′ ″ = R ″ × CC′6 + G ″ × CC′7 + B ″ × CC′8
The γ correction unit 55 corrects the γ characteristic. The γ characteristic is appropriately selected according to the contrast of the subject. More specifically, it is calculated based on the luminance value calculated by the evaluation value generation unit 59.

The contour emphasizing unit 57 performs processing that enhances the contour of the image.
In the first embodiment, the CCDs 29 and 41 having different spectral sensitivity characteristics are provided, and the parameters for receiving and recognizing light from the object field are increased. Close to the eyes, good color reproduction characteristics can be obtained. Furthermore, when applying to an existing electronic camera equipped with CCDs 29 and 41, it is only necessary to change the signal processing method, so that it can be easily applied to an existing electronic camera.

In the first embodiment, the number of pixels used for receiving light from the same subject is different between the CCD 29 and the CCD 41. However, since the CCD 29 and the CCD 41 are used for observation, either one of them is used. Even if the number of pixels is reduced, it is possible to prevent the image from becoming rough. Therefore, the time required for image processing can be shortened.
Further, in the first embodiment, the CCD 29 is divided into a plurality of small areas, the CCD 41 is divided into a plurality of small areas corresponding to the plurality of small areas of the CCD 29, and the output values of the pixels of the CCD 29 and the CCD 41 are set for each small area. Since the color correction coefficient is calculated using this integrated value, the time required for image processing can be shortened appropriately compared with the case of obtaining the color correction coefficient for each pixel.
(Second Embodiment)
FIG. 7 shows a block diagram of a second embodiment of the image processing apparatus of the present invention. The second embodiment differs from the first embodiment only in the signal processing method.

In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The image processing device 67 includes CCDs 29 and 41 having RGB color filters that receive light from a subject.
The outputs of the CCDs 29 and 41 are subjected to A / D conversion and correction of fluctuations in the power supply voltage due to temperature changes in the signal processing units 47 and 47A. Next, the outputs of the signal processing units 47 and 47A are input to the signal synthesis unit 69 and the evaluation value generation units 59 and 59A.

In the signal synthesis unit 69, the two signals are synthesized into an image signal closer to the human eye. Next, the output of the signal synthesis unit 69 is input to the color correction unit 53 via the white balance unit 49 and the interpolation unit 51.
On the other hand, the evaluation value generation units 59 and 59A divide the image into, for example, small areas of 8 rows and 12 columns, and calculate evaluation values such as luminance values or chromaticity values for each small area.

The color correction coefficient generation unit 61 calculates a color correction coefficient based on the outputs of the evaluation value generation units 59 and 59A and the coefficient table unit 63.
The coefficient interpolation unit 65 performs coefficient interpolation in order to reduce steps due to differences in the color conversion coefficients CC0 to CC8 calculated by the color correction coefficient generation unit 61 at the boundary of each small region. Then, color correction coefficients CC′0 to CC′8 are calculated.

In the color correction unit 53, color correction calculation is performed using the image signal output from the interpolation unit 51 and the color correction coefficients CC ′ 0 to CC ′ 8 calculated by the coefficient interpolation unit 65. The output of the color correction unit 53 is sequentially transmitted to the γ correction unit 55 and the contour enhancement unit 57.
This image processing device 67 can achieve the same effects as those of the first embodiment.
In the image processing apparatus of the second embodiment, the color correction unit 53 performs color conversion on the combined output values of the CCD 29 and the CCD 41 having different spectral sensitivity characteristics. Compared with the case where the output signal of one CCD 29 is multiplied by the color correction coefficient, it is possible to multiply the image signal closer to human eyes by the color correction coefficient.
(Third embodiment)
FIG. 8 is an explanatory view showing an electronic camera incorporating a third embodiment of the image processing apparatus of the present invention.

In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The electronic camera 2A includes a photographing lens unit 17 and a main body unit 19 to which the photographing lens unit 17 is attached.
The photographic lens unit 17 includes a photographic lens 21 that collects a light beam from a subject and a diaphragm 22.

The main body 19 has a mirror 23 </ b> A that is rotated to a position where the light beam transmitted through the photographing lens 21 can be received (hereinafter referred to as a closed state) and a position where it cannot be received (hereinafter referred to as an open state).
The main body 19 is provided with a CCD 29 </ b> A that is a first image sensor that can receive a light beam that has passed through the photographing lens 21. The subject is imaged by the CCD 29A. A shutter 27 is disposed in front of the CCD 29A.

Furthermore, the main body 19 has a focus glass 33 that is disposed at the imaging position of the photographing lens 21 via the mirror 23A when the mirror 23A is in the closed state. The main body 19 includes a pentaprism 35 that changes the optical path of the light beam that has passed through the focus glass 33, and a finder 37 for observing the light beam from the pentaprism 35.
Further, the main body 19 includes a condenser lens 39 that condenses the light transmitted through the pentaprism 35, and a CCD 41 that is a second image sensor that receives the light transmitted through the condenser lens 39 and is used as a colorimetric sensor. have. Exposure control is performed by the colorimetric signal from the CCD 41.

Next, an optical system of the electronic camera 2A having such a configuration will be described.
When observing the subject with the finder 37, a part of the light beam that has passed through the photographing lens 21 is reflected by the closed mirror 23 </ b> A indicated by a broken line, passes through the focus glass 33 and the pentaprism 35, and is guided to the finder 37. It is burned.
When a release button (not shown) is pressed during shooting, the mirror 23A is moved to an open state indicated by a solid line, the aperture 22 is reduced, and the shutter 27 is opened. Then, light from the subject that has passed through the photographing lens 21 is imaged on the CCD 29A, and imaging is performed.

Next, FIG. 9 shows a block diagram of a third embodiment of the image processing apparatus of the present invention.
The image processing apparatus 45A includes a CCD 29A that receives light from a subject, and a CCD 41 that can receive the same image as the CCD 29A and has different spectral sensitivity characteristics. Here, the CCD 29A and the CCD 41 have different spectral sensitivity characteristics as shown in FIG. The CCD 29A and the CCD 41 are provided with RGB color filters having the same light transmittance.

The output of the CCD 29A is output to the signal processing unit 47, where A / D conversion, clamping, sensitivity correction, and the like are performed. Next, the output of the signal processing unit 47 is input to the white balance unit 49 and the evaluation value generation unit 59.
The white balance unit 49 multiplies the white balance gains Kr and Kb in order to suppress the change in the output image due to the difference in the color characteristics of the light source that illuminates the subject.

In particular,
R ′ = Kr × R
G '= G
B ′ = Kb × B
R, G, B: Image signal before white balance correction R ′, G ′, B ′: Process of image signal after white balance correction.

The output of the white balance unit 49 is input to the interpolation unit 51. In the interpolation unit 51, color interpolation processing by pixel local calculation is performed, and correction is performed for all pixels. More specifically, the color of an arbitrary pixel is estimated from pixels around the arbitrary pixel.
On the other hand, the evaluation value generation unit 59 divides the image into, for example, small areas of 8 rows and 12 columns, and calculates an evaluation value such as a luminance value or a chromaticity value for each small area. The luminance is proportional to the absolute brightness of the object color, and the chromaticity is an objective measurement of the color of the object from which the luminance information is removed.

In the third embodiment, the color correction coefficient generation unit 61 that is a color correction coefficient calculation unit calculates the color correction coefficient based on the outputs of the CCD 41 and the evaluation value generation unit 59. The output of the CCD 41 is output to the color correction coefficient generation unit 61 after A / D conversion, clamping, sensitivity correction, and the like are performed in the signal processing unit 47A.
Hereinafter, a method for calculating the color correction coefficient will be described in detail with reference to the flowchart of FIG.

In step S11, coordinate transformation for non-dimensionalization is performed.
Specifically, the integrated value for each primary color of the output value for each small area of the image of the CCD 29A is Rs, Gs, Bs. Similarly, the CCD 41 is also divided into small areas of 8 rows and 12 columns, for example. If the integral value for each region is Rm, Gm, Bm,
RGs = Rs / Gs
BGs = Bs / Gs
RGm = Rm / Gm
BGm = Bm / Gm
RGs, BGs, RGm, BGm: The first pseudo color correction coefficient is calculated.

In step S <b> 12, normalization is performed using the first pseudo color correction coefficients RGs, BGs, RGm, BGm and the coefficients of the coefficient table unit 63. That is,
RGs ′ = RGs × k1 + k2
BGs ′ = BGs × k1 + k2
RGm ′ = RGm × k3 + k4
BGm ′ = BGm × k3 + k4
k1, k2, k3, k4: Coefficients RGs ′, BGs ′, RGm ′, BGm ′: The second pseudo color correction coefficient is calculated.

In step S13, a color correction coefficient is calculated with reference to the LUT based on the second pseudo color correction coefficients RGs ′, BGs ′, RGm ′, and BGm ′.
Specifically, the coefficient numbers are acquired using the LUT shown in FIG. 5 based on the second pseudo color correction coefficients RGs ′, BGs ′, RGm ′, and BGm ′. Next, using the table shown in FIG. 6, color correction coefficients CC0 to CC8 that match the coefficient number selected in FIG. 5 are selected.

In this way, the calculation of the color correction coefficient is completed.
The coefficient interpolation unit 65 performs coefficient interpolation in order to reduce steps due to differences in the color correction coefficients CC0 to CC8 calculated by the color correction coefficient generation unit 61 at the boundary of each small region. This coefficient interpolation is performed by performing linear interpolation using the coefficients of nearby small regions. In addition, the color correction coefficient after coefficient interpolation is expressed as CC′0 to CC′8 below.

In the color correction unit 53 that is a color correction unit, the image signals R ″, G ″, and B ″ output from the interpolation unit 51 and the color correction coefficients CC′0 to CC ′ calculated by the coefficient interpolation unit 65 are displayed. 8 performs a color correction calculation as shown below.
R ′ ″ = R ″ × CC′0 + G ″ × CC′1 + B ″ × CC′2
G ′ ″ = R ″ × CC′3 + G ″ × CC′4 + B ″ × CC′5
B ′ ″ = R ″ × CC′6 + G ″ × CC′7 + B ″ × CC′8
The image signals R ′ ″, G ′ ″, and B ′ ″ that have been subjected to color correction by the color correction unit 53 are processed by the γ correction unit 55, the color space conversion unit 56, and the contour enhancement unit 57. The data is recorded on the recording medium sequentially.

  In the third embodiment, the CCDs 29A and 41 having different spectral sensitivity characteristics are provided, and the parameters for receiving and recognizing light from the object field are increased. Close to the eyes, good color reproduction characteristics can be obtained. In addition, when applied to an existing electronic camera equipped with CCDs 29A and 41, it is only necessary to change the signal processing method, so that it can be easily applied to an existing electronic camera.

  In this embodiment, the CCD 29A is divided into a plurality of small areas, the CCD 41 is divided into a plurality of small areas corresponding to the plurality of small areas of the CCD 29A, and the output values of the pixels of the CCD 29A and the CCD 41 are integrated for each small area. In addition, since the color correction coefficient is calculated using this integral value, even when the number of pixels of the CCD 29A and the CCD 41 is different, good color reproduction characteristics can be obtained easily and reliably. .

In the above-described embodiment, the example in which the CCD 41 is used as a colorimetric sensor has been described. However, the CCD 41 may be used as a photometric sensor that measures the luminance of a subject.
In the above-described embodiment, the function calculation using the coefficients k1 to k4 is performed for normalization in the color correction coefficient generation unit 61. However, a one-dimensional LUT or a multidimensional LUT may be used.
In the above-described embodiment, the color correction coefficients CC0 to CC8 for performing the 3 × 3 matrix operation are selected. However, in order to perform color correction with higher accuracy, for example, a multidimensional LUT is selected. , Arithmetic processing may be performed.

It is explanatory drawing which shows the electronic camera with which 1st Embodiment of the image processing apparatus of this invention was incorporated. It is a block diagram which shows the process of 1st Embodiment of the image processing apparatus of this invention. It is explanatory drawing which shows the spectral sensitivity characteristic of CCD of embodiment of the image processing apparatus of this invention. 3 is a flowchart showing processing in a color correction coefficient generation unit in FIG. 2. It is explanatory drawing which shows LUT of embodiment of the image processing apparatus of this invention. It is explanatory drawing which shows the color correction coefficient selection table of embodiment of the image processing apparatus of this invention. It is a block diagram which shows the process of 2nd Embodiment of the image processing apparatus of this invention. It is explanatory drawing which shows the electronic camera with which 3rd Embodiment of the image processing apparatus of this invention was incorporated. It is a block diagram which shows the process of 3rd Embodiment of the image processing apparatus of this invention. It is explanatory drawing which shows the spectral sensitivity characteristic of CCD of 3rd Embodiment of the image processing apparatus of this invention. 10 is a flowchart showing processing in a color correction coefficient generation unit in FIG. 9.

Explanation of symbols

29, 29A, 41 CCD
53 color correction unit 61 color correction coefficient generation unit

Claims (6)

A first image sensor that receives light from a subject;
A second image sensor capable of receiving the same image as the first image sensor and having different spectral sensitivity characteristics;
Color correction coefficient calculating means for calculating a color correction coefficient based on an output value photoelectrically converted by the first image sensor and the second image sensor;
Color correction means for performing color correction on the output value of the first image sensor using the color correction coefficient calculated by the color correction coefficient calculation means;
An image processing apparatus comprising: A first image sensor that receives light from a subject;
A second image sensor capable of receiving the same image as the first image sensor and having different spectral sensitivity characteristics;
Color correction coefficient calculating means for calculating a color correction coefficient based on an output value photoelectrically converted by the first image sensor and the second image sensor;
Color correction means for performing color correction on a combined output value of the first image sensor and the second image sensor using the color correction coefficient calculated by the color correction coefficient calculator;
An image processing apparatus comprising: The image processing apparatus according to claim 1 or 2,
The first imaging element is divided into a plurality of small areas, the second imaging element is divided into a plurality of small areas corresponding to the plurality of small areas of the first imaging element, and the first imaging element and the second imaging element An image processing apparatus, wherein an output value of each pixel of an element is integrated for each of the small regions, and the color correction coefficient is calculated using the integrated value. The image processing apparatus according to claim 3.
The image processing apparatus according to claim 1, wherein the first image sensor and the second image sensor have different numbers of pixels used to receive light from the same subject. The image processing apparatus according to any one of claims 1 to 4,
The image processing apparatus, wherein the second image sensor is used as a colorimetric sensor that measures the color balance of the subject. The image processing apparatus according to any one of claims 1 to 4,
The image processing apparatus, wherein the second image sensor is used as a photometric sensor that measures the luminance of the subject.

Images