JP2011029858A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply perform color correction processing of a photography image with high precision. <P>SOLUTION: An imaging apparatus for photographing a subject includes an imaging element 110 for photographing a subject and a spectrometer 113 for measuring spectral characteristics of a subject and external light around a camera in the same camera case 102, so that photography and spectral characteristic measurement are performed with the same photography lens 101 by using a flip-up mirror 103. A color correction coefficient is calculated on the basis of the spectral characteristics measured by the spectrometer 113 to perform color correction processing of an image photographed by the imaging element 110. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to a single-plate color imaging apparatus having a spectroscopic measurement function and a color correction function.

  Conventionally, there has been a problem that the accuracy of color correction in a camera is lowered due to various causes. Therefore, in Patent Document 1 and Patent Document 2 and the like, a photographing system that performs color correction of an input image using spectral spectrum information of a subject is proposed.

Japanese Patent No. 3614126 JP 2005-341175 A Japanese Unexamined Patent Publication No. 53-40522

  However, in Patent Document 1, the colorimeter and the camera are separated, and there is a problem that it is difficult to measure a correct spectral spectrum of the subject. In Patent Document 2, although the spectrometer and the camera are connected to each other, different optical lenses are used, and it is difficult to match the photographing positions of the two, and there is a problem that the characteristics of the lenses are different.

  An object of the present invention is to perform photographing of a subject and measurement of spectral characteristics through the same optical lens, and easily perform measurement of spectral characteristics. At the same time, it is to improve the color correction accuracy of the photographed image. Further, by measuring the spectral characteristics of not only the subject but also the light source around the camera, it is possible to perform color correction even when the camera is shooting when the type of the light source around the subject matches the type of light source around the camera.

  In order to achieve the above-mentioned object, a mechanism that guides a picked-up image to a spectrometer through a flip-up mirror or a rotating mirror and ground glass, and performs color correction processing from the measured spectral characteristics.

  According to the present invention, there is an effect that the color correction processing of a photographed image can be performed simply and with high accuracy.

First embodiment of the present invention Second embodiment of the present invention (when the opening position of the rotary mirror is in the upper half and the incident light from the lens is reflected to the spectrometer side) Second embodiment of the present invention (when the opening position of the rotating mirror is in the lower half and the incident light from the lens is transmitted to the image sensor side)

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

  An image pickup apparatus according to a first embodiment using the present invention will be described with reference to FIG.

  The light that has entered the camera housing 102 from the photographing lens 101 passes through the flip-up mirror mechanism, and the flip-up mirror 103 (hereinafter sometimes referred to as “mirror 103”) is lowered (FIG. 1). ), The optical image is reflected by the mirror 103 and formed on the ground glass 104 provided at the upper part of the mirror structure with the focal length from the photographing lens 101 equal to that of the image sensor 110. In this embodiment, the image sensor 110 is a single-plate color image sensor. The image on the frosted glass 104 is further divided into two by a half mirror 105 (beam splitter) installed on the top thereof, and one image thereof is a spectrometer 113 (for example, Edmund Optics Japan) installed in the horizontal direction of the half mirror 105. It is incident on a spectroradiometer (spectroradiometer, etc.) sold by a corporation, and the other image can be observed from an opening 106 serving as a viewfinder port installed above the half mirror 105. ing. Thus, when the mirror 103 is lowered, the spectral characteristics of the subject being photographed through the photographing lens 101 can be measured by the spectrometer 113. At this time, since the viewfinder port also serves as the opening 106 for taking in the outside light from the camera, there is a possibility that the outside light slightly leaks from the opening 106 while the mirror 103 is lowered. In order to prevent this, when observing from the opening 106 while the mirror 103 is lowered, the eyepiece hood 107 is used together, or the opening 106 is shielded by the eyepiece hood 107 and the lid, or the rotary shading lid 108 is opened. You may install in the part. However, normally, only a small amount of light leaks from the opening during eye contact, and part of the leaked light is reflected by the half mirror 105 and absorbed by the dark curtain 109.

  On the other hand, when the mirror 103 is flipped up (in the case of the dotted line in FIG. 1), the optical image from the photographing lens 101 is formed on the surface of the image sensor 110 through the mirror mechanism. The image sensor 110 converts an optical image into an electrical signal by the image sensor drive circuit 111, and the signal is converted into a camera video signal by the camera process circuit 111 and output through the color correction circuit 112.

  When outside light is taken in from the opening 106 while the mirror 103 is jumping up, a part of the outside light is transmitted through the half mirror 105 and diffused on the ground glass 104. Further, the light transmitted through the frosted glass 104 is also reflected by the mirror 103 and diffused by the frosted glass 104 again. Some of these diffused light is further reflected by the half mirror 105 and is incident on the spectrometer 113. As described above, when the mirror 103 is raised, the spectral characteristic of the external light incident from the opening 106 at the top of the camera can be measured by the spectrometer 113.

  The spectral characteristics of the subject and the camera periphery obtained in this way are obtained by the color correction coefficient calculation circuit 114 based on the concept of color engineering, and an appropriate color corresponding to the light source is obtained by the color correction circuit 112. Perform correction processing.

  When the image sensor 110 is a single-plate color image sensor as in this embodiment, the color correction coefficient calculation circuit 114 uses the spectral characteristics measured by the spectrometer 113 and the image pickup apparatus (single image sensor) of this embodiment measured in advance. Color correction that brings the color reproducibility of the image pickup apparatus of this embodiment closer to the color reproduction characteristics of a three-plate color camera from the spectral characteristics of a single-plate color camera using a plate color image sensor and the spectral characteristics of a three-plate color camera. The coefficient is calculated, and the color correction circuit 112 performs color correction of the video signal from the image sensor 110 using the color correction coefficient calculated by the color correction coefficient calculation circuit 114. Thereby, even a single-plate color camera using a single-plate color image sensor can obtain color reproduction characteristics close to those of a three-plate color camera.

The principle will be briefly described below. The subject of the camera is illuminated by a light source such as illumination or the sun, and the reflected light is incident on the image sensor through the photographing lens of the camera. At this time, the illumination has a spectral intensity distribution P (λ) determined by the light source and having an intensity corresponding to the wavelength λ of light (hereinafter, P (λ) may be referred to as a spectral characteristic of the light source). The subject also has a spectral reflectance ρ (λ). The product of both is incident on the television camera as reflected light Cs (λ) from the subject. The television camera captures the reflected light with a color sensor in which pixels of the image sensor corresponding to, for example, R, G, and B have spectral sensitivities S _R (λ), S _G (λ), and S _B (λ), respectively. The output corresponding to the integrated value is output as the R, G, B color channel output signals. This can be expressed by the following equation (1).

  At this time, the reflected light Cs (λ) from the subject is obtained by flattening the spectral reflectance ρ (λ) of the subject as much as possible using a standard white plate or by calibrating with known data if possible. The characteristic can reflect the spectral distribution P (λ) of the light source as much as possible. That is, by measuring the spectrum of Cs (λ), it is possible to estimate the spectral characteristics of the light source in the shooting environment. If the spectral imaging characteristics of the RGB sensor are measured in advance, the sensor output RGB value can be obtained by calculation. Therefore, using data with known reflection spectral characteristics ρ (λ) such as a Macbeth chart, the reproduction color of the Macbeth chart photographed with the camera under each illumination condition can be created by calculation only by measuring the spectral characteristics of the light source. Can do. Hereinafter, an example using a Macbeth chart will be described, but it goes without saying that other color charts may be used.

  In general, when shooting with a broadcast camera, in order to adjust the white balance of the camera according to the shooting environment, an achromatic reflection subject such as a gray or white standard reflection chart is shot before shooting, and the RGB signal intensity at that time To adjust the RGB amplifier gain settings.

  Therefore, an achromatic standard reflection chart is first photographed in a state where the flip-up mirror is lowered (solid line state in FIG. 1), that is, in a state where the spectrometer 113 measures the spectral characteristics of the subject through the photographing lens 101. Light that enters the camera housing 102 from the photographing lens 101 is reflected by the mirror 103 and forms an image on the ground glass 104. The image on the frosted glass 104 is divided into two by the half mirror 105, and one image enters the spectrometer 113. The spectrometer 113 outputs the spectral characteristic P (λ) of the light source. The spectral characteristic P (λ) of the light source output from the spectrometer 113 is input to the color correction coefficient calculation circuit 114.

In the color correction coefficient calculation circuit 114, the spectral characteristic P (λ) of the light source obtained by the spectrometer 113, the known Macbeth chart reflection spectral characteristic ρ (λ), and the imaging device (single plate) of this embodiment measured in advance. Macbeth photographed with the single-plate color camera of this embodiment by integrating the color spectral sensitivity characteristics S _R1 (λ), S _G1 (λ), and S _B1 (λ) of a single-plate color camera using a color image sensor. RGB values corresponding to the chart image are generated by calculation (see Equation 1). Further, the spectral characteristic P (λ) of the light source obtained by the spectrometer 113, the known Macbeth chart reflection spectral characteristic ρ (λ), and the color spectral sensitivity characteristic S _R2 (λ of a general broadcasting three-plate color camera) ), S _G2 (λ) and S _B2 (λ) are integrated to generate an RGB value corresponding to a Macbeth chart image photographed by a three-plate color camera (see Equation 1).

  For example, color correction can be performed using RGB values corresponding to two types of Macbeth chart images obtained by this calculation. That is, the RGB values obtained by correcting the RGB values of each of the 24 colors of the Macbeth chart of the single-plate color camera of the present embodiment obtained by the above calculation with the color correction coefficient are the general three-plate type for broadcasting obtained by the above calculation. A color correction coefficient is calculated so as to approach each RGB value of the color camera. For example, when performing color correction with a linear matrix, the RGB values of each of the 24 colors of the Macbeth chart of the single-plate color camera of the present embodiment are closest to the respective RGB values of a general 3-plate color camera for broadcasting. The correction coefficient of the linear matrix is obtained by the least square method.

  In the linear matrix correction, adjustment is performed by changing the RGB mixing ratio with the following primary conversion matrix of RGB three primary colors.

Here, R ₁ , G ₁ , B ₁ are RGB values corresponding to the image of the Macbeth chart photographed with the single-plate color camera of this embodiment, and R ₂ , G ₂ , B ₂ are Macbeth photographed with the three-plate color camera. RGB values corresponding to the chart image.

  The correction matrix LM is

で算出する。実際には最小二乗法により最も近い行列を求める。具体的には例えば、いくつかの色票（例えばマクベスチャートの２４色）を選定し、補正処理後のＲＧＢ値をＲ_２’，Ｇ_２’，Ｂ_２’とすると、補正ターゲット（Ｒ_２，Ｇ_２，Ｂ_２）との差の二乗平均を、

Calculate with Actually, the nearest matrix is obtained by the least square method. Specifically, for example, when several color charts (for example, 24 colors of Macbeth chart) are selected and the RGB values after correction processing are R ₂ ′, G ₂ ′, B ₂ ′, correction targets (R ₂ , G ₂ , B ₂ )

, And find the LM with the smallest value for all colors. At this time, an arbitrary color chart may be selected, or weighted averaging may be performed with emphasis on a specific color (for example, skin color).

  The color correction coefficient calculation circuit 114 outputs the color correction coefficient calculated in this way (linear matrix coefficient when linear matrix correction is performed).

  Using the color correction coefficient obtained by the color correction coefficient calculation circuit 114, color correction (in the case of linear matrix correction, linear matrix color correction processing) is performed in the color correction circuit 112 of the single-panel color camera (imaging device) of this embodiment. ), The color reproduction characteristics of the image pickup apparatus (single-plate color camera) of this embodiment can be brought close to the color reproduction characteristics of the three-plate color camera.

  In this embodiment, when the flip-up mirror is lowered (when not shooting), the color correction coefficient is calculated for the light source of the subject, and the flip-up mirror is used by using the color correction coefficient. When the image is raised (when shooting the subject), color correction of the subject image is performed. When the flip-up mirror is lowered (when not shooting), it passes through the same optical lens as the actual shooting, so the color correction coefficient can be calculated with high accuracy, and the color correction coefficient can be used to jump. Since color correction is performed when the raising mirror is raised (when shooting), color correction accuracy can be improved.

  In addition, when the flip-up mirror is raised (when taking a picture), light from an external light source around the camera is incident on the spectrometer 113 through the opening 106. It is also possible to calculate a color correction coefficient for an external light source around the camera during shooting and use the color correction coefficient to correct the color of the subject image. When the flip-up mirror is raised, the achromatic standard reflection chart is not used, but the ground glass 104 scatters the incident light from the aperture 106 and the spectral characteristics are measured by the scattered light. Measurements similar to those using an achromatic standard reflection chart when the mirror is lowered can be made. Of course, it is necessary for the light source of the subject and the light source around the camera to match, but in this case, color correction can be performed in real time during shooting. As a specific example, the optimum color correction can always be continued even when the weather is clear or cloudy when shooting in daylight. In addition, when the camera moves from outdoor to indoor in a relay program, etc., and the light source changes from outside light to room light (for example, a fluorescent lamp), color correction that matches the indoor direction (automatically) To be able to). On the other hand, the disadvantage is that it is measured not by the subject's light but by the ambient light of the camera. Therefore, when the light source is different only for the subject (for example, when the subject is exposed to tungsten light under an indoor fluorescent lamp), the subject's light source and camera This method cannot be used because the surrounding light source is different. Even if the subject and the light source around the camera are the same, the true color correction coefficient taking into account the transmittance of the lens and the like may not be obtained, and the accuracy may be somewhat reduced. When such a point becomes a problem, as described above, the color correction coefficient is calculated when the flip-up type mirror is lowered (when not shooting), and the color correction coefficient is used to jump. When the raising mirror is raised (when the subject is photographed), color correction of the subject image may be performed.

  An image pickup apparatus according to a second embodiment using the present invention will be described with reference to FIGS.

  2 and FIG. 3 show a single-plate color image pickup device that incorporates a shutter (rotating mirror) 121 that realizes a semicircle (shutter opening angle 180 degrees) or an arbitrary shutter opening angle and rotates in synchronization with the operation of the image pickup device. The camera for a model is shown typically. In a movie camera or the like, a mechanism incorporating such a rotating shutter (rotating mirror) 121 is generally used (for example, Patent Document 3 and others), and the basic rotating shutter mechanism and operation are the same as those. In this embodiment, the lens mechanism and the image pickup mechanism are arranged below the rotary shutter mechanism.

  In FIG. 2, the optical image is reflected by the rotating mirror 121 (hereinafter sometimes referred to as “mirror 121”) in a state where the lower half of the rotating mirror 121 is a reflecting surface (described by a solid line), and the upper part of the mirror structure. The focal distance from the photographic lens 101 is imaged on the ground glass 104 installed at a distance equal to the image sensor 110. The image on the frosted glass 104 is further divided into two by a half mirror 105 (beam splitter) installed on the top thereof, and one of the images is incident on a spectrometer 113 installed in the horizontal direction of the half mirror 105. At this time, there is an imaging lens of the rotating mirror 121 and a surface opposite to the imaging surface side between the half mirror 105 and the spectrometer 113, and only from the half mirror during the period of the opening (denoted by a dotted line) of the rotating mirror. The optical image is incident on the spectrometer 113. Another image transmitted through the half mirror 105 can be observed from an opening 106 serving as a viewfinder port disposed above the half mirror 105. If a viewfinder is not required, the half mirror 105 may be a total reflection mirror and the viewfinder port may not be installed. Thus, when the lower half of the rotating mirror 121 is a reflecting surface, the spectral characteristics of the subject being photographed through the photographing lens 101 can be measured by the spectrometer 113.

  In FIG. 3, the optical image from the photographic lens 101 is formed on the surface of the image sensor 110 through the rotating mirror mechanism in a state where the lower half of the rotating mirror 121 is a transmission surface (described by a dotted line). The image sensor 110 converts an optical image into an electrical signal by the image sensor drive circuit 111, becomes a camera video signal by the drive camera process circuit 111, and is output through the color correction circuit 112.

  At the same time, the upper half of the rotating mirror 121 is a reflecting surface (shown by a solid line) in FIG. 3, and light from the external light intake opening 123 installed together with the diffusion plate 122 below the camera is a cylindrical light guide tube. 124 reaches the upper reflecting surface of the rotating mirror 121, is reflected, and enters the spectrometer 113. Thus, when the upper half of the rotating mirror 121 is a reflection surface, the spectral characteristics of the external light incident from the external light intake opening 123 at the bottom of the camera can be measured by the spectrometer 113. Yes. On the other hand, when the upper half of the rotary mirror 121 is a transmission surface as shown in FIG. 2, the light from the light guide tube 124 from outside light passes through the rotary mirror mechanism part and is a dark part or dark curtain inside the camera housing 102. Absorbed at 125 mag. The external light intake opening 123 may be installed in the upper part of the camera or in an arbitrary place. A combination of a suitable light guide tube and a reflection mirror, or a light guide tube such as an optical fiber in some cases, may be used. Light may be guided to the reflecting surface of the rotating mirror.

  The spectrometer 113 performs measurement in synchronization with the opening (shown by a dotted line) of the rotating mirror 121. For example, as shown in FIG. 2, the spectral characteristics of the subject photographed through the photographing lens 101 can be measured by performing the measurement only during the period when only the upper part of the rotating mirror 121 is open. Further, as shown in FIG. 3, when the measurement is performed while the upper part of the rotating mirror 121 is a reflecting surface (shown by a solid line), the spectral characteristics of the external light around the camera can be measured. For example, a spectroradiometer sold by Edmund Optics Japan Co., Ltd. can set the measurement start trigger, the measurement time, and the number of measurements. By setting these appropriately, It is also possible to repeatedly measure light incidence for a target period to improve measurement sensitivity and noise characteristics.

  The configurations and operations of the spectrometer 113, the color correction coefficient calculation circuit 114, and the color correction circuit 112 are the same as those in the first embodiment.

  In this embodiment, when the upper part of the rotating mirror 121 is open as shown in FIG. 2 (when no image is taken), a color correction coefficient is calculated for the light source of the subject, and the color correction coefficient is used. Thus, when the upper part of the rotating mirror 121 is a reflecting surface (shown by a solid line) as shown in FIG. 3 (when the subject is photographed), color correction of the subject image is performed. When the upper part of the rotating mirror 121 is open as shown in FIG. 2 (when not photographing), the color correction coefficient can be calculated with high accuracy because the same optical lens as that actually photographed is passed. Using the correction coefficient, color correction is performed when the upper part of the rotating mirror 121 is a reflecting surface (shown by a solid line) as shown in FIG. 3 (when photographing), so that the color correction accuracy is improved. Can do.

  When the upper part of the rotating mirror 121 is a reflecting surface (shown by a solid line) as shown in FIG. 3 (when photographing), light from an external light source around the camera is split through the opening 123. Since the light is incident on the total 113, it is also possible to calculate a color correction coefficient with respect to an external light source around the camera during shooting, and use the color correction coefficient to correct the color of the subject image. Of course, it is necessary for the light source of the subject and the light source around the camera to match, but in this case, color correction can be performed in real time during shooting. As a specific example, the optimum color correction can always be continued even when the weather is clear or cloudy when shooting in daylight. In addition, when the camera moves from outdoor to indoor in a relay program, etc., and the light source changes from outside light to room light (for example, a fluorescent lamp), color correction that matches the indoor direction (automatically) To be able to). On the other hand, the disadvantage is that it is measured not by the subject's light but by the ambient light of the camera. Therefore, when the light source is different only for the subject (for example, when the subject is exposed to tungsten light under an indoor fluorescent lamp), the subject's light source and camera This method cannot be used because the surrounding light source is different. Even if the subject and the light source around the camera are the same, the true color correction coefficient taking into account the transmittance of the lens and the like may not be obtained, and the accuracy may be somewhat reduced. When such a point becomes a problem, as described above, the color correction coefficient is calculated when the upper part of the rotating mirror 121 is open as shown in FIG. Using the correction coefficient, color correction of the subject image may be performed when the upper part of the rotating mirror 121 is a reflecting surface (when the subject is photographed).

  In each of the embodiments described above, a computer and a program may be used instead of the circuit.

  As described above, each embodiment of the present invention has been described in detail. However, the image pickup apparatus according to the embodiment of the present invention has a photographing lens, an image sensor that photographs a subject through the photographing lens, and a spectral characteristic of the subject through the photographing lens. What is necessary is just to provide the spectrometer for a measurement in the inside of the same camera housing | casing.

  The image pickup apparatus according to the embodiment of the present invention calculates a color correction coefficient based on the spectral characteristics measured by the spectrometer, and performs color correction processing using the color correction coefficient for an image shot by the image pickup device. It may be what performs.

  The image pickup apparatus according to the embodiment of the present invention includes a flip-up mirror and a frosted glass. While the flip-up mirror is lowered, an image from the photographing lens is reflected by the flip-up mirror. An image is formed on the ground glass, and the image is incident on the spectrometer. While the flip-up mirror is raised, an image from the photographing lens is incident on the image sensor. There may be something.

  In addition, the imaging apparatus according to the embodiment of the present invention includes a half mirror and an opening serving as a viewfinder port and an outside light intake port, and while the flip-up mirror is lowered, an image from the photographing lens is Reflected by the flip-up mirror and formed on the ground glass, the image can be observed from the viewfinder port through the half mirror, and the image reflected by the half mirror is the spectrometer. While the flip-up mirror is raised, the image from the photographing lens is incident on the image sensor, while outside light incident from the opening passes through the half mirror and the ground glass. And part of the light is scattered on the ground glass, and the light transmitted through the ground glass is reflected by the flip-up mirror. Then, it is incident again on the ground glass and further scattered, and the scattered light is reflected by the half mirror and incident on the spectrometer. The spectrometer has a structure in which the flip-up mirror is lowered. Spectral characteristics of a subject may be measured through a photographing lens, and spectral characteristics of external light incident from the opening may be measured while the flip-up mirror is flipped up.

  In addition, the imaging apparatus according to the embodiment of the present invention includes a rotating mirror having a structure in which a part of the rotating mirror is opened and the other part is a mirror surface and rotates, and a ground glass, and the upper part of the rotating mirror is an opening. In the meantime, the image from the photographic lens is reflected by the mirror surface below the rotating mirror and imaged on the ground glass, and the image is incident on the spectrometer. In this case, the image from the lens may pass through the opening under the rotating mirror and enter the image sensor.

  In addition, the imaging apparatus according to the embodiment of the present invention includes a half mirror or a total reflection mirror, an opening serving as a viewfinder opening or an outside light intake opening, and the upper portion of the rotating mirror is an opening. The image from the photographic lens is reflected by the mirror surface below the rotating mirror and forms an image on the ground glass. The image can be observed from the viewfinder port through the half mirror, and the image reflected by the half mirror can be observed. A structure that is transmitted through the opening of the rotating mirror and incident on the spectrometer, or an image of the ground glass that is reflected by the total reflection mirror and transmitted through the opening of the rotating mirror and incident on the spectrometer. At the same time, the light from the outside light intake opening is transmitted through the opening above the rotating mirror and absorbed by the dark curtain. On the other hand, while the lower part of the rotating mirror is an opening part, the image from the lens is transmitted through the opening part of the lower part of the rotating mirror and is incident on the image sensor, and outside light from the outside light intake opening part is received. The structure is such that it is reflected by the mirror surface above the rotating mirror and is incident on the spectrometer, and the spectrometer measures the spectral characteristics of the subject through the photographing lens while the upper part of the rotating mirror is an opening. The spectral characteristics of the external light from the external light intake opening may be measured while the lower part of the rotating mirror is an opening. The measurement by the spectrometer may be performed in synchronization with the rotation of the rotating mirror.

  In the imaging apparatus according to the embodiment of the present invention, the imaging element is a single-plate color imaging element, the spectral characteristics measured by the spectrometer, the spectral characteristics of the imaging apparatus measured in advance, and the spectral characteristics of a three-plate color camera. From the characteristics, a color correction coefficient calculating means for calculating a color correction coefficient that brings the color reproducibility of the imaging apparatus closer to the color reproduction characteristics of a three-plate color camera, and the color correction coefficient calculated by the color correction coefficient calculating means And color correction means for correcting the color of the video signal from the single-plate color imaging device.

  As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

DESCRIPTION OF SYMBOLS 101 ... Shooting lens, 102 ... Camera housing, 103 ... Flip-up mirror, 104 ... Ground glass, 105 ... Half mirror, 106 ... Opening, 107 ... Eyepiece hood (or light shielding hood), 108 ... Rotating light shielding lid, 109 DESCRIPTION OF SYMBOLS ... Dark curtain, 110 ... Image sensor, 111 ... Image sensor drive circuit / camera process circuit, 112 ... Color correction circuit, 113 ... Spectrometer, 114 ... Color correction coefficient calculation circuit, 121 ... Rotating shutter (rotating mirror), 122 ... Diffusion Plate 123: Opening opening for external light 124: Light guide tube 125, 126 ... Dark curtain

Claims (8)

In an imaging device for photographing a subject,
An imaging apparatus comprising: a photographing lens; an imaging element that photographs a subject through the photographing lens; and a spectrometer for measuring spectral characteristics of the subject through the photographing lens. The imaging device according to claim 1,
An image pickup apparatus, wherein a color correction coefficient is calculated based on spectral characteristics measured by the spectrometer, and color correction processing is performed using the color correction coefficient on an image photographed by the image pickup device. The imaging device according to claim 1 or 2,
It has a flip-up mirror and ground glass,
While the flip-up mirror is lowered, the image from the photographing lens is reflected by the flip-up mirror and forms an image on the ground glass, and the image is incident on the spectrometer.
An image pickup apparatus having a structure in which an image from the photographing lens is incident on the image pickup element while the flip-up mirror is raised. The imaging device according to claim 3.
It has a half mirror and an opening that serves as a viewfinder and external light intake.
While the flip-up mirror is lowered, the image from the taking lens is reflected by the flip-up mirror and forms an image on the ground glass, and the image can be observed from the viewfinder port through the half mirror. The structure is such that an image reflected by the half mirror is incident on the spectrometer,
While the flip-up mirror is flipped up, an image from the photographing lens is incident on the image sensor, while external light incident from the opening is incident on the ground glass through the half mirror, and a part thereof Light scattered on the ground glass and transmitted through the ground glass is reflected by the flip-up mirror, is incident on the ground glass again, and is further scattered, and the scattered light is reflected by the half mirror to the spectrometer. The incident structure,
The spectrometer measures the spectral characteristics of the subject through the photographing lens while the flip-up mirror is lowered, and the spectral characteristics of external light incident from the opening while the flip-up mirror is raised. An imaging device characterized by measuring. The imaging device according to claim 1 or 2,
It is equipped with a rotating mirror that is partly open and the other part is made of a mirror surface and rotates, and frosted glass.
While the upper part of the rotating mirror is an opening, the image from the photographing lens is reflected by the mirror surface below the rotating mirror and forms an image on the ground glass, and the image is incident on the spectrometer. Structure,
On the other hand, while the lower part of the rotating mirror is an opening, the image pickup apparatus has a structure in which an image from the lens passes through the opening of the lower part of the rotating mirror and enters the imaging element. The imaging apparatus according to claim 5,
It has a half mirror or total reflection mirror and an opening that becomes the viewfinder mouth or an outside light intake opening.
While the upper part of the rotating mirror is an opening, an image from the photographing lens is reflected by the mirror surface below the rotating mirror and forms an image on the ground glass, and the image is passed through the half mirror and the viewfinder. A structure in which an image that can be observed from the mouth and reflected by the half mirror passes through the opening of the rotating mirror and enters the spectrometer, or an image of the ground glass is reflected by the total reflection mirror, and the opening of the rotating mirror A structure in which the light is transmitted through the part and incident on the spectrometer, and at the same time, the light from the external light intake opening is transmitted through the opening part above the rotating mirror and absorbed by the dark curtain,
On the other hand, while the lower part of the rotating mirror is an opening part, the image from the lens is transmitted through the opening part of the lower part of the rotating mirror and is incident on the image sensor, and outside light from the outside light intake opening part is received. It is a structure that is reflected by the mirror surface above the rotating mirror and incident on the spectrometer,
The spectrometer measures the spectral characteristics of the subject through the photographing lens while the upper part of the rotating mirror is an opening, and the outside light intake opening while the lower part of the rotating mirror is an opening. An image pickup apparatus that measures spectral characteristics of external light from a unit. In the imaging device according to claim 5 or 6,
The imaging apparatus, wherein the measurement of the spectrometer is performed in synchronization with the rotation of the rotating mirror. The imaging device according to any one of claims 2 to 7,
The image sensor is a single plate color image sensor,
A color that brings the color reproducibility of the imaging device closer to the color reproduction properties of a three-plate color camera from the spectral characteristics measured by the spectrometer, and the spectral characteristics of the imaging device measured in advance and the spectral characteristics of a three-plate color camera. Color correction coefficient calculating means for calculating a correction coefficient;
Color correction means for performing color correction of a video signal from the single-plate color imaging device by the color correction coefficient calculated by the color correction coefficient calculation means;
A single-plate color imaging device comprising:

Images