JP2006222637A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus that can light up a photographic scene at different color temperatures by parts, using a simple and inexpensive constitution and can obtain a photographed image with proper white balance. <P>SOLUTION: The imaging apparatus has an imaging element 23; an imaging optical system 22 which forms the image of a subject on the imaging element 23; a light source 2 which emits a light beam for lighting subjects 14a and 14b, spatial modulating elements 8R, 8G, and 8B having a plurality of modulation regions, capable of varying at least the color temperature of the light beam from the light source 2 for each part; a projection optical system 13 which forms images of the spatial modulating elements 8R, 8G, and 8B at subject positions; a lighting parameter setting section 39, which sets lighting parameters including color temperatures by the parts when actual photography is performed, while the subjects is lit by the light source 2, on the basis of imaging data obtained from the imaging element 23 through test photographing of the subjects; and a control section 40, which controls modulation of the light beam from the light source 2 in the respective modulation regions of the spatial modulating elements 8R, 8G, and 8B on the basis of the lighting parameters set by the lighting parameter setting section 39. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus that illuminates and shoots a subject.

  Conventionally, as a strobe device used for an image pickup device (camera or the like), for example, a liquid crystal filter is disposed in front of the strobe, and the density of the liquid crystal filter is determined based on the color temperature of reflected light from the subject and the color temperature of ambient light. It is known that the color temperature of illumination light by a strobe is changed by controlling so as to reduce the white balance error in a photographed image (see, for example, Patent Document 1).

There is also known a multi-flash photographing system that uses a plurality of flashes and adjusts the color temperature of each flash to illuminate a photographing scene with a different color temperature for each location (for example, see Patent Document 2).
JP-A-7-131797 JP-A-8-201885

  However, in the strobe device disclosed in Patent Document 1, since the overall color temperature of the strobe light that illuminates the subject is adjusted, good white balance cannot be obtained depending on the photographing scene such as the subject and its background. There is a case.

  On the other hand, in the photographing system disclosed in Patent Document 2, a photographing scene can be illuminated with a different color temperature for each place, so that a good white balance can be obtained. However, in this photographing system, it is necessary to use a plurality of flashes and adjust their color temperatures independently, and more flashes are required to obtain a better white balance. There is a concern that the system configuration is complicated and expensive.

  Accordingly, an object of the present invention made in view of such circumstances is to provide an imaging device that can illuminate a scene with different color temperatures for each part and obtain a captured image with good white balance with a simple and inexpensive configuration. There is.

The invention of an imaging apparatus according to claim 1 that achieves the above object is as follows:
An image sensor;
An imaging optical system for forming an image of a subject on the imaging element;
A light source that emits light for illuminating the subject;
A spatial modulation element having a plurality of modulation regions capable of changing at least the color temperature of the light beam from the light source for each part;
A projection optical system that forms an image of the spatial modulation element at a subject position;
An illumination parameter setting unit that sets illumination parameters including color temperature for each part when the subject is illuminated with the light source and is actually captured, based on imaging data obtained from the imaging element by test imaging of the subject;
A control unit that controls modulation of light from the light source in each modulation region of the spatial modulation element based on the illumination parameter set by the illumination parameter setting unit;
It is characterized by having.

The invention according to claim 2 is the imaging apparatus according to claim 1,
The object distance of the imaging optical system and the object distance of the projection optical system are configured to be the same.

The invention according to claim 3 is the imaging apparatus according to claim 1 or 2,
The imaging field angle of the imaging optical system and the projection field angle of the projection optical system are configured to be the same.

The invention according to claim 4 is the imaging device according to claim 1, 2, or 3,
The illumination unit having the light source, the spatial modulation element, and the projection optical system, and the camera unit having the imaging element, the imaging optical system, the illumination parameter setting unit, and the control unit are configured to be separable. It is what.

The invention according to claim 5 is the imaging apparatus according to any one of claims 1 to 4,
A motion detector that detects the movement of the subject based on temporal changes in imaging data obtained from the imaging device;
The modulation region of the spatial modulation element corresponding to the illumination parameter set by the illumination parameter setting unit is configured to follow the motion detected by the motion detection unit.

The invention according to claim 6 is the imaging apparatus according to any one of claims 1 to 5,
The image sensor is configured to capture the subject at a lower resolution during the test photographing than at the time of the main photographing.

  According to the present invention, the color temperature of the illumination light is partially reduced with a simple and inexpensive configuration in which a spatial modulation element capable of modulating the light from the light source is provided for each part and the image is formed at the subject position by the projection optical system. Since it can be controlled in detail every time, a captured image with good white balance can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of an imaging apparatus according to the first embodiment of the present invention. This imaging apparatus has an illumination unit 1 and a camera unit 21 that are integrally or separably coupled. In the illumination unit 1, white light from a light source 2 formed of a white discharge lamp such as an ultrahigh pressure mercury lamp is incident on a dichroic mirror 6 through a fly-eye lens 3, a PS conversion element 4 and an illumination optical system 5. A transmissive LCD that reflects red (R) light, transmits other light, separates the R light, reflects the separated R light by the mirror 7, and then modulates the intensity of the light for each part The modulated R light is incident on the dichroic prism 9 through the spatial modulation element 8R.

  The light transmitted through the dichroic mirror 6 is incident on the dichroic mirror 10 to reflect green (G) light and transmit blue (B) light to separate G light and B light, and the separated G light. Is transmitted through a spatial modulation element 8G formed of a transmissive LCD similar to the spatial modulation element 8R, and the modulated G light is incident on the dichroic prism 9.

  Further, the B light separated by the dichroic mirror 10 is sequentially reflected by the mirrors 11 and 12, and then transmitted through the spatial modulation element 8B formed of a transmissive LCD similar to the spatial modulation elements 8R and 8G, and is modulated. The B light is incident on the dichroic prism 9.

  The dichroic prism 9 reflects the modulated and incident R light and B light, transmits the G light, synthesizes the R, G, and B light, and combines the combined light by the projection optical system 13 with the spatial modulation elements 8R, 8G. , 8B is irradiated so that the combined image is formed at the subject position, and the subjects 14a and 14b are illuminated.

  In this way, the projection optical system 13 forms a composite image of the spatial modulation elements 8R, 8G, and 8B at the subject position, thereby combining the light beams formed on the spatial modulation elements 8R, 8G, and 8B at the subject position. An image corresponding to the image can be formed. Accordingly, the illumination color and illumination intensity at the subject position are set for each part, for example, as shown in FIG. 2, the color temperature of the combined modulated image at the position 14a ′ on the spatial modulation elements 8R, 8G, and 8B corresponding to the subject 14a is 3000K. And the color temperature of the combined modulated image at the position 14b ′ on the spatial modulation elements 8R, 8G, and 8B corresponding to the subject 14b can be controlled in detail so as to be 6000K.

  Note that the number of divisions (number of pixels) of each of the spatial modulation elements 8R, 8G, and 8B may be determined depending on how finely the illumination area is controlled, such as increasing the number of pixels when the illumination area is finely controlled. Good.

  On the other hand, in the camera unit 21, the images of the subjects 14 a and 14 b are formed on the image pickup device 23 made of, for example, a CCD by the image pickup optical system 22. Further, the camera unit 21 is provided with a distance measuring sensor 24 for measuring the object distance at the time of photographing, thereby measuring the object distance to the subject 14a or 14b, and focusing the imaging optical system 22 based on the distance measurement data. Perform adjustment (focus control).

  In the present embodiment, the optical characteristics of the imaging optical system 22 and the optical characteristics of the projection optical system 13 of the illumination unit 1 are made the same, and the focus adjustment of the imaging optical system 22 is performed based on the distance measurement data from the distance sensor 24. And the focus adjustment of the projection optical system 13 are performed to make the object distances of the imaging optical system 22 and the projection optical system 13 the same.

  Note that the imaging optical system 22 and the projection optical system 13 are preferably configured so that both have the same angle of view, and in the case of having a zoom function, the two cooperate with each other.

  FIG. 3 is a block diagram illustrating a circuit configuration of the imaging apparatus according to the present embodiment. The image pickup apparatus according to the present embodiment includes a light emitting circuit 31 that turns on the light source 2, a drive circuit 32 that drives the spatial modulation elements 8R, 8G, and 8B, a projection optical system control circuit 33 that adjusts the projection optical system 13, and an image pickup element. 23, a memory 35 for storing image data, an image pickup optical system control circuit 36 for adjusting the focus of the image pickup optical system 22, a white balance calculation unit 37, a motion detection unit 38 for detecting the movement of the subject, color temperature distribution and illumination of the subject An illumination parameter setting unit 39 that sets illumination parameters such as an intensity distribution, and a control circuit 40 that inputs distance measurement data from the distance measurement sensor 24 and image pickup data from the image sensor 23 and controls the overall operation. . Although not shown, the illumination parameter setting unit 39 has an image display unit that displays captured images.

  Further, in the present embodiment, a light beam shutter 41 that is driven and controlled by the projection optical system control circuit 33 and selectively illuminates a subject only at the time of photographing is provided on the illumination unit 1 side. Is provided with a light beam shutter 42 that is driven and controlled by the imaging optical system control circuit 36 to make it difficult for imaging data to flow with respect to high-speed movement of a subject during imaging. When the illumination unit 1 and the camera unit 21 are configured to be separable, for example, the light emitting circuit 31, the drive circuit 32, and the projection optical system control circuit 33 are provided on the illumination unit 1 side, and the memory 35 and the imaging optical system are provided. The control circuit 36, the white balance calculation unit 37, the motion detection unit 38, the illumination parameter setting unit 39, and the control circuit 40 can be provided on the camera unit 21 side.

  The schematic operation of the imaging apparatus according to the present embodiment will be described below with reference to the flowchart shown in FIG.

  First, test photographing of the subjects 14a and 14b is performed (step S1). In this test photographing, the projection optical system 13 is adjusted by the projection optical system control circuit 33 via the control circuit 40 based on the distance measurement data from the distance measurement sensor 24, and the imaging optical system control circuit 36 is used for imaging optical. The focus of the system 22 is adjusted, the object distances of the imaging optical system 22 and the projection optical system 13 are adjusted to be the same, the subjects 14a and 14b are photographed in this state, and the test imaging data is stored in the memory 35.

  In this test imaging, the illumination unit 1 does not have to illuminate the subjects 14a and 14b. However, when illuminating, the light source 2 is turned on by the light emitting circuit 31, and the light from the light source 2 is The subjects 14a and 14b are illuminated by being modulated by the spatial modulation elements 8R, 8G, and 8B based on preset illumination parameters so as to obtain a uniform color temperature distribution and illumination intensity distribution.

  Thereafter, the white balance calculation unit 37 calculates white balance (RGB gain) based on the test imaging data stored in the memory 35. When the subjects 14a and 14b are illuminated by the illumination unit 1 during test shooting, white balance is calculated using the preset illumination parameters at that time as correction data.

  When the white balance of the test imaging data is calculated, the test imaging data is adjusted based on the white balance, and the test image is displayed on the image display unit of the illumination parameter setting unit 39.

  Next, the illumination parameter setting unit 39 refers to the test image displayed on the image display unit by the photographer, and changes the color temperature for each part or changes the light intensity for each part, that is, for each part at the time of the actual photographing. It is determined whether or not the exposure condition needs to be changed due to excessive light amount or insufficient light amount. When changing the exposure condition, the illumination color temperature and illumination light intensity for each part are set (step S2). Here, as one aspect of changing the light intensity for each part, the intensity of the illumination light is set high in the dark part and low in the bright part so as to eliminate the brightness unevenness based on the intensity distribution of the test image.

  When the setting of the illumination parameter at the time of the main photographing is completed, the white balance is calculated again by the white balance calculation unit 37 using the illumination parameter as the correction data.

  After that, the control circuit 40 creates output images of the spatial modulation elements 8R, 8G, and 8B based on the set illumination parameters (step S3), and the output circuits correspond to the spatial modulation elements corresponding to the drive circuit 32. In the state displayed on 8R, 8G, and 8B, the light source 2 is turned on by the light emitting circuit 31 (step S4), and the main photographing of the subjects 14a and 14b is performed in synchronization with the lighting of the light source 2 (step S5).

  The imaging data obtained by the actual photographing is adjusted based on the white balance finally obtained by the white balance calculating unit 37 and stored in the memory 35.

  The motion detection unit 38 detects motion by comparing images before and after continuously captured data particularly in continuous shooting and moving image capturing, and the motion detection unit 38 detects the motion of the subject. If it is, the illumination parameter for each part set by the illumination parameter setting unit 39 is followed in real time according to the movement.

  According to the present embodiment, the illumination unit 1 is provided with the spatial modulation elements 8R, 8G, and 8B capable of modulating the light from the light source 2 for each part, and the combined image is placed at the subject position by the projection optical system 13. An image corresponding to the combined modulation image of the light beam formed on the spatial modulation elements 8R, 8G, and 8B can be formed at the subject position with a simple and inexpensive configuration. Since it can be controlled in detail for each portion, a captured image with good white balance can be obtained. In addition, since the focus adjustment of the imaging optical system 22 and the projection optical system 13 is performed based on the distance measurement data from the distance sensor 24, the adjustment can be easily performed.

(Second Embodiment)
FIG. 5 shows a schematic configuration of a main part of an imaging apparatus according to the second embodiment of the present invention.
In this embodiment, instead of the three spatial modulation elements 8R, 8G, and 8B of the illumination unit 1 in the first embodiment, a single-plate spatial modulation element 8 made of an RGB color transmission type LCD is used. The light from the light source 2 is modulated and transmitted by the spatial modulation element 8 through the fly-eye lens 3, the PS conversion element 4 and the illumination optical system 5, and the modulated light is imaged by the projection optical system 13. Is illuminated so that an image is formed at the subject position to illuminate the subject. Other configurations and operational effects are the same as those of the first embodiment, and thus the description thereof is omitted.

  In the case of the present embodiment, since the spatial modulation element 8 is colored by forming an RGB color filter in each pixel, the unit region for color temperature control is equivalent to three RGB pixels, but the first embodiment Compared with the case where the three-plate spatial modulation elements of R, G, and B are used as described above, there are advantages that the illumination unit 1 can be made simpler and cheaper and the color temperature can be easily controlled.

  In addition, this invention is not limited to the said embodiment, Many deformation | transformation or a change is possible. For example, the test imaging can be performed with the image sensor 23 having a lower resolution than the actual imaging. In this way, the burden of image processing can be reduced and the processing speed can be improved. The present invention can also be applied effectively when a color image is captured by the frame sequential method. Further, the spatial modulation element is not limited to a transmissive LCD, and a reflective LCD (LCOS) or DMD can also be used. In addition, the control of the color temperature is not limited to the three colors RGB, and can be performed using four or more primary colors.

1 is a diagram illustrating a schematic configuration of an imaging apparatus according to a first embodiment of the present invention. It is a figure which shows the relationship between the to-be-photographed object position by the projection optical system of FIG. 1, and a spatial modulation element. FIG. 2 is a block diagram illustrating a circuit configuration of the imaging apparatus in FIG. 1. Similarly, it is a flowchart which shows schematic operation | movement of the imaging device of FIG. It is a figure which shows schematic structure of the principal part of the imaging device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination part 2 Light source 3 Fly eye lens 4 PS conversion element 5 Illumination optical system 6,10 Dichroic mirror 7, 11, 12 Mirror 8R, 8G, 8B, 8 Spatial modulation element 9 Dichroic prism 13 Projection optical system 14a, 14b Subject 21 Camera unit 22 Imaging optical system 23 Imaging element 24 Distance sensor 31 Light emitting circuit 32 Drive circuit 33 Projection optical system control circuit 35 Memory 36 Imaging optical system control circuit 37 White balance calculation unit 38 Motion detection unit 39 Illumination parameter setting unit 40 Control circuit 41, 42 Ray shutter

Claims (6)

An image sensor;
An imaging optical system for forming an image of a subject on the imaging element;
A light source that emits light for illuminating the subject;
A spatial modulation element having a plurality of modulation regions capable of changing at least the color temperature of the light beam from the light source for each part;
A projection optical system that forms an image of the spatial modulation element at a subject position;
An illumination parameter setting unit that sets illumination parameters including color temperature for each part when the subject is illuminated with the light source and is actually captured, based on imaging data obtained from the imaging element by test imaging of the subject;
A control unit that controls modulation of light from the light source in each modulation region of the spatial modulation element based on the illumination parameter set by the illumination parameter setting unit;
An imaging device comprising:   The imaging apparatus according to claim 1, wherein the object distance of the imaging optical system and the object distance of the projection optical system are configured to be the same.   The imaging apparatus according to claim 1 or 2, wherein an imaging field angle of the imaging optical system and a projection field angle of the projection optical system are configured to be the same.   The illumination unit having the light source, the spatial modulation element, and the projection optical system, and the camera unit having the imaging element, the imaging optical system, the illumination parameter setting unit, and the control unit are configured to be separable. The imaging apparatus according to claim 1, 2, or 3. A motion detector that detects the movement of the subject based on temporal changes in imaging data obtained from the imaging device;
5. The structure according to claim 1, wherein the modulation region of the spatial modulation element corresponding to the illumination parameter set by the illumination parameter setting unit is configured to follow the motion detected by the motion detection unit. The imaging device according to claim 1. The imaging device according to any one of claims 1 to 5, wherein the imaging device is configured to capture the subject at a lower resolution at the time of the test photographing than at the time of the main photographing.

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