JP5213998B2 - Stereoscopic photographing apparatus and electronic apparatus equipped with the same - Google Patents

Description

  The present invention relates to a polarization-combining stereo camera capable of taking still images or moving images in stereo, and in particular, a polarization-combining stereo camera that can combine two polarized images of the same subject and obtain two polarized images again through an optical system. About.

  As a method of displaying a subject on a display in three dimensions, it has been proposed to take a subject image from two different directions and generate a stereo image. Further, as one method for measuring the distance to the subject, a stereo image of the subject is generated, and the distance to the subject is measured from the deviation of the subject using the principle of triangulation.

There are the following general methods for taking a stereo image.
(1) One that uses two cameras.
(2) A camera that shoots with the imaging element of the camera divided in half using a pair of reflecting means on the left and right.

  In the method of using two cameras of (1), two cameras having exactly the same characteristics are required. In particular, it is necessary to attach the two cameras, that is, to perform optical axis alignment with high accuracy. Also, a mechanism for capturing video in synchronization with an external signal is required for the two cameras. For example, in the one described in Patent Document 1, the left and right cameras are each provided with a positioning device arranged on a jig, and using a reference point and a reference horizontal line provided on a white plate arranged in parallel with the jig, The camera's optical axis and horizontal angle are adjusted.

  Further, as a method of using (2) a pair of reflecting means on the left and right sides and dividing the camera's imaging element in half and using the left and right imaging elements, for example, two subject light incident windows are used. A stereo adapter is attached to a camera capable of taking a stereo image, and a stereo format screen is divided into two to expose the right-eye and left-eye photos side by side (see Patent Document 2), or the camera's image sensor is arranged horizontally (horizontal). (Direction) When the image is divided in half, the left and right fields of view are narrowed. Therefore, the optical path of the two left and right imaging lenses is compressed in the left and right direction using a rotating mirror and a curved (convex) mirror. There is known a stereo adapter and a stereo image imaging device (see Patent Document 3) in which the aspect ratio is the same as when the image is expanded by processing and imaged using the entire imaging device.

  However, if the image sensor is divided into left and right in this way, the left and right optical axes for capturing the same subject (subject) are different (physically separated), so the lens distortion is eliminated. In addition to the need to correct the captured left and right images, the field of view in the left and right direction of the captured image is narrowed. To avoid this, for example, complicated correction means as described in Patent Document 3 Is required. In addition, since the left and right images are picked up by half of the image pickup device, there is a problem that the images become rough as compared with the case of picking up using the whole pixels.

  In addition, as Patent Document 4, it is conceivable that the right-eye image is a P-polarized image, the left-eye image is an S-polarized image, and the S-polarized light is easily reflected. When the glass window is projected, the reflected light is well reflected and the reflected light is not easily reflected in the P-polarized light. Therefore, even if the same image is captured in the P-polarized image and the S-polarized image, the left and right images are different. Even if two images are combined, it is difficult to recognize as a stereoscopic image.

Japanese Patent Laid-Open No. 7-229736 Japanese Unexamined Patent Publication No. 7-77747 JP 2003-140280 A JP-A 64-54438

  The present invention has been made to solve the problems of the conventional method for capturing a stereo image, and its purpose is to capture an image once divided into left and right by a stereo adapter with the entire imaging pixels of the camera. By forming a single image, the problem of dividing the conventional imaging pixel into left and right is solved, and by allowing the left and right images to be easily divided from there, the conventional optical system This is to make it possible to easily obtain a stereo image free from blurring and distortion without requiring correction or correction of a captured image.

In order to solve this problem, the stereoscopic imaging apparatus of the present invention takes out polarized image light beams having different parallaxes from the same subject image, and uses the same optical axis by the first prism provided with a polarization separation film that separates different polarization components. The combined image beam is formed by a polarization combining unit that forms a combined image beam, a camera optical system that forms an image of the combined image beam formed by the polarized beam combining unit on a plurality of imaging elements described later, and a second prism. after separating the polarized image light to different optical axis directions possess a polarization separation section for imaging the plurality of imaging elements, a,
The polarization combining unit includes two lenses for forming an image, a first prism formed with a polarization separation film that reflects one polarized light and transmits the other polarized light, and one reflected polarized light. Λ / 4 film disposed on a plane orthogonal to the λ / 4 film and a reflecting surface disposed in parallel with the λ / 4 film.

According to the above configuration, a stereoscopic image with no parallax can be obtained with one camera, and no distortion occurs in the left and right captured images. do not need. In addition, a thin and compact polarizing composition unit can be obtained.

  In the stereoscopic imaging device of the present invention, polarized image light beams having different parallaxes extracted from the same subject image are set as the same polarization component.

  According to the above configuration, the difference in the appearance of the image due to the difference in polarization can be eliminated, and a good stereoscopic image can be obtained using the two images.

  Further, the stereoscopic imaging apparatus of the present invention is provided with means for shifting the phase by 1 / 2λ in an optical path until polarized image light beams of different parallax extracted from the same subject image exit from the first prism. Yes.

  According to the above configuration, polarized image light beams having different parallaxes extracted from the same subject image can be set as the same polarization component.

  The stereoscopic imaging apparatus of the present invention is characterized in that polarized image light beams having different parallax extracted from the same subject image are polarized light of an S-polarized component.

  According to the above configuration, a captured image reflecting the influence of reflection is obtained.

  In the stereoscopic imaging device of the present invention, the polarization combining unit has the same optical path length for different images from the light incident unit to the light emitting unit to the camera optical system unit.

  According to the above configuration, a captured image without distortion can be obtained with a simple configuration.

  In addition, the polarization beam combining unit of the present invention includes a polarization sheet for transmitting a specific polarization component on the incident side or the emission side of the two lenses.

  According to the above configuration, a stereoscopic image without a sense of incongruity can be obtained.

  In the stereoscopic image pickup apparatus according to the present invention, the polarization combining unit may include a zoom optical system in which the camera optical system unit can change an image forming magnification.

  According to the above configuration, a stereoscopic imaging device capable of zooming is obtained.

  The polarization beam combining unit of the present invention includes a polarization correction sheet for correcting polarization polarization.

  By arranging the phase difference sheet, an image with a bias due to polarization can be made a natural image without a bias. The arrangement position of the phase difference sheet may be in the previous stage of the polarization combining unit of the first prism.

  In the stereoscopic imaging device of the present invention, the polarization separation unit separates one polarization image and the other polarization image, forms the separated one polarization image on a corresponding image sensor, and separates the other polarization image. It is composed of a prism that forms an image of a polarized image on the other corresponding image sensor.

  In the stereoscopic imaging device of the present invention, a polarizing sheet for reducing crosstalk at the time of polarization separation is arranged between the second prism and the plurality of imaging elements.

  According to the above configuration, crosstalk at the time of polarization separation can be reduced.

  In addition, an electronic apparatus equipped with the stereoscopic imaging apparatus of the present invention can obtain a stereoscopic image having a parallax without blurring with a single camera.

  In addition, the stereoscopic imaging apparatus of the present invention has a distance measuring unit that calculates the distance to the subject based on the two separated images, so that the calculation processing for each small area divided on the image based on the principle of triangulation By performing the above, the distance to the object included in the small area can be obtained.

  According to the present invention, since a stereoscopic image having a parallax without blurring can be obtained with one camera, two cameras having exactly the same characteristics as in the case of using two cameras as in the past are used. There is no need to prepare a stand, and there is no need for adjustment work such as mounting of two cameras, that is, alignment of the optical axes, and a synchronization mechanism of the two cameras.

  In addition, since distortion does not occur in the left and right captured images, an apparatus for correcting distortion and image processing are not required. Therefore, according to the present invention, not only the cost but also the equipment and processing burden for obtaining a stereo image can be greatly reduced.

  Also, according to the present invention, different polarizations can be obtained by shifting the image light of the same polarization of the same subject having the parallax according to the distance between the two light incident portions by shifting the phase of the image light of one parallax by λ / 2. Since the combined image light is separated into image light beams of different polarization by a polarization separation element and imaged on the corresponding image sensor, the difference in the appearance of the image due to the difference in polarization It can be eliminated, and a good stereoscopic image can be obtained using two images.

1 is a schematic diagram of a stereoscopic imaging apparatus according to an embodiment of the present invention. It is a top view explaining the three-dimensional imaging device which concerns on embodiment of this invention. It is a perspective view explaining the three-dimensional imaging device which concerns on embodiment of this invention. It is a perspective view of the other three-dimensional imaging device of this invention. It is a figure of the other polarization separation part of this invention. It is a figure of the other polarization separation part of this invention. It is a figure of the other polarization separation part of this invention. It is the schematic of the three-dimensional imaging device which concerns on the 2nd Embodiment of this invention. It is a figure of the other polarization composition part of the present invention. It is a figure of the other polarization composition part of the present invention. It is a figure of the other polarization composition part of the present invention. It is a figure of the other polarization composition part of the present invention. It is a block diagram explaining the structure of an image processing apparatus. It is the Example which mounted the stereoscopic imaging device which concerns on embodiment of this invention in the electronic device.

<Embodiment 1>
An embodiment of the present invention will be described with reference to the drawings. The stereoscopic imaging apparatus according to the present embodiment shifts the phase of an image beam of the same subject having the same parallax with the parallax corresponding to the difference in distance between the two incident surfaces by λ / 2. , Synthesized as image light beams with different polarizations, photographed with one camera optical system, separated again into two image light beams due to the difference in polarization, and imaged on the corresponding image sensors to form two images on the left and right Is. The configuration will be specifically described below.

  FIG. 1 is a conceptual diagram schematically showing a polarization combining type stereoscopic photographing apparatus according to an embodiment of the present invention. That is, the polarization-combining stereoscopic imaging apparatus roughly includes two light incident portions 10 and 12 that capture an image of the subject 0 as light rays α1 and α2 with different parallaxes, and an image incident from the light incident portion 10. The phase of the S-polarized component of the light beam α1 and the S-polarized component of the image light beam α2 incident from the light incident portion 12 are shifted by λ / 2 to form P-polarized light, and the optical axes of the light beam α1 and the light beam α2 coincide. The polarization combining unit 2 that guides the camera optical system 3 to the camera optical system 3, the camera optical system 3 that emits an image formed so that the combined and incident image light beam forms an image on the image sensor at a desired magnification, and camera optics The formed image emitted from the system 3 is imaged (photoelectrically converted) after being separated from the polarization separation unit 4 that separates the formed image in the direction of the two imaging sensors (elements) 5 and 6 according to the difference in polarization, and then A / D converted. Image processing apparatus for forming an image from obtained digital image data It is made up of 7.

  In the above embodiment, in consideration of the influence of the reflected light, the phase of the S-polarized component of the image beam α1 incident from the light incident unit 10 and the S-polarized component of the image beam α2 incident from the light incident unit 12 is λ / When the influence of the reflected light is suppressed, the P-polarized component of the image beam α1 incident from the light incident unit 10 and the P-polarized component of the image beam α2 incident from the light incident unit 12 are combined. May be combined as an S-polarized component with a phase shift of λ / 2. In that case, the first polarization separation film 13 ′ positioned in the polarization beam combiner 2 shown in FIG. 2 reflects the P-polarized light and transmits the S-polarized light.

  2A and 2B are diagrams schematically showing a specific embodiment of the polarization combining type stereoscopic photographing apparatus 1, in which FIG. 2A shows a plan view and FIG. 2B shows a perspective view. The polarization beam combining unit 2 includes lenses 10 and 12 that are light incident portions and a first prism 13 when viewed from the light incident side.

  The first prism 13 bends and propagates the image incident from the lens, and reflects the first polarized light and transmits the other polarized light (for example, reflects the S polarized light and transmits the P polarized light). The polarization separation film 13 ′. Further, a λ / 4 film (λ / 4 sheet, λ / 4 phase difference sheet) 17 (λ is a visible wavelength region, λ = 450 nm to 700 nm) and an image are formed on the opposite side of the side facing the camera optical system unit 3. A reflecting mirror 18 is disposed as a reflecting surface for reflection.

  Next, the image rays α1 and α2 will be described with reference to FIG. The image ray α1 is indicated by a solid line, and α2 is indicated by a broken line. Light rays α1 and α2 incident on the lenses 10 and 12 from the Z direction are reflected in the direction of the first polarization separation film 13 ′ by the prism portion below. Here, a case where the first polarization separation film 13 ′ is a polarization separation film that reflects S-polarized light and transmits P-polarized light will be described. Of the light α1 incident on the first polarization separation film 13 ′ from the lens 10 side, the polarized image light beam composed of the S-polarized component is reflected and travels in the direction of the camera optical system unit 3 in the −Y direction. On the other hand, the polarized image light beam composed of the P-polarized component in the light beam α2 is transmitted through the first polarization separation film 13 ′ and does not move toward the camera optical system unit 3 and does not contribute to image formation. In other words, the light ray α1 shown by the solid line is composed of P-polarized light and S-polarized light from the lens 10 to the polarization separation film 13 ′, but the light ray α1 is transmitted from the polarization separation film 13 ′ to the camera optical system unit 3 only from S-polarization. Become.

  Also, the polarized image light beam composed of the S-polarized component of the light beam α2 incident on the first polarization separation film 13 ′ from the lens 12 side is reflected in the Y direction and transmitted through the λ / 4 sheet 17, for example, to the right The light is converted into circularly polarized light and further reflected by the reflecting mirror 18 to become counterclockwise circularly polarized light, and again transmitted through the λ / 4 sheet 17 to become P polarized light. The polarized image light beam that has become P-polarized light passes through the first polarization separation film 13 ′ and is emitted in the direction of the camera optical system unit 3.

  Of the image light incident on the first polarization separation film 13 ′ from the lens 12 side, the polarization image light composed of the P-polarized component is transmitted through the first polarization separation film 13 ′ and directed toward the camera optical system unit 3. It does not contribute to image formation. That is, the light ray α2 indicated by the broken line is composed of P-polarized light and S-polarized light from the lens 12 to the polarization separation film 13 ′, and the S-polarized light reflected by the polarization separation film 13 ′ is transmitted through the λ / 4 sheet 17 and reflected. Reflected by the mirror 18 and again transmitted through the λ / 4 sheet 17, it becomes P-polarized light, and is transmitted through the polarization separation film 13 ′. From the polarization separation film 13 ′, the light α 2 is P-polarized light. Consist only of.

  Further, in terms of optical characteristics, it is desirable that the optical path lengths of the image light beam emitted from the lens 10 side in the direction of the camera optical system unit 3 and the image light beam emitted from the lens 12 side in the direction of the camera optical system unit 3 are the same. The prism length on the lens 10 side is made longer than that on the lens 12 side, and the optical path length is made uniform. That is, the S-polarized light of the image light beam α2 incident from the lens 12 side is reflected by the polarization separation film 13 ′, and then passes through the reflection separation film 13 ′ through the λ / 4 sheet 17 and the reflection mirror 18 to become P-polarization. The prism length on the lens 10 side is lengthened by the amount of the optical path length until this time.

  2A has a configuration in which a λ / 4 sheet 17 and a reflection mirror 18 are provided on the lens 12 side in order to change the S-polarized light of the image light α2 to P-polarized light. As another configuration, the polarization separation film 13 ′ reflects P-polarized light and transmits S-polarized light, and a λ / 2 sheet having the S-polarized light of the image light α 1 on the lens 10 side as P-polarized light is the polarization separation film 13. The polarized image light beam that has become P-polarized light of the image light beam α1 is reflected by the polarization separation film 13 ′ and directed toward the camera optical system unit 3, while the image light beam α2 on the lens 12 side is reflected by the reflection mirror 18. The light is incident on the camera optical system unit 3 from the direction of the light, the P-polarized light is reflected by the polarization separation film 13 ′ and is directed in a direction different from the direction of the camera optical system unit 3, and the S-polarized light is directed to the camera optical system unit 3. It does not matter.

  The relationship between the P-polarized light and the S-polarized light described so far may be reversed for the P-polarized light and the S-polarized light including the configuration of the polarization separation film 13 ′ and the like. In addition, the lenses 10 and 12 in the light incident portion can easily obtain optical characteristics of the camera optical system portion 3 described later, or can reduce the diameter of the light beam propagating through the polarization combining portion 2, but the assembling property is improved. In addition, it is possible to eliminate the lenses 10 and 12 as the light incident portions in order to reduce the cost by reducing the number of parts and reduce the thickness of the apparatus.

  With the above method, two images captured from the lens 10 side and the lens 12 side can be combined on one optical axis and emitted to the camera optical system unit 3. In addition, although the difference between P-polarized light and S-polarized light is used for image synthesis, all the captured images are S-polarized images, and the phase of one of the S-polarized images is shifted by 1 / 2λ inside the apparatus. Because it is only converted to P-polarized light, for example, the difference in polarization between the two images, such as the water surface, the reflected light of the glass, and the liquid crystal display screen, does not occur, and a stereoscopic image described later is generated. If you do this, you will get an image without any sense of incongruity.

  As the characteristics of the first polarization separation film 13 ′, the visible light wavelength band λ (450 nm to 700 nm) is used, and the P-polarized light transmittance 80 is in the range of 45 ± 10 degrees incident on the first polarization separation film 13 ′. % Or more and S-polarized reflectance of 80% or more are desirable.

  Further, in order to further remove the P-polarized light emitted to the camera optical system unit 3, a polarizing sheet 9 may be disposed on either side of the lenses 10 and 12 as shown in FIG. 3A shows that the polarizing sheet 9 is arranged in front of the lenses 10 and 12, and FIG. 3B shows that the polarizing sheet 9 is arranged after the lenses 10 and 12. In FIG. As a result, the P-polarized image can be removed and the ratio of the S-polarized image can be increased at the stage of incidence on the first prism 13, so that a difference in image due to the difference in polarization does not occur, and a three-dimensional image is generated. If this is the case, an image without a sense of discomfort can be obtained. In addition, when the polarizing sheet 9 is disposed after the lenses 10 and 12, the light rays are collected by the lens, and the incident angle of the light rays to the polarizing sheet 9 can be narrowed. Therefore, the performance of the polarizing sheet 9 is further exhibited. More effective.

  Furthermore, a polarization correction sheet 11 may be disposed before and after the lenses 10 and 12 of the subject image capturing unit. The polarization correction sheet 11 converts the phase of the linearly polarized light component including the polarization component of the S-polarized light component or the P-polarized light component (especially, water surface, reflected light of glass, liquid crystal display screen, etc.) to a circularly polarized light component by shifting it by λ / 4. And has a function of correcting a difference in appearance due to polarization deviation. Further, a polarizing sheet 9 that transmits only the S-polarized light may be added behind it in order to reduce crosstalk during polarization synthesis. As a result, even if the changed separation characteristics of the polarization separation film 13 ′ in the subsequent stage are not sufficient, the light from α1 is mixed as P-polarized light and the light from α2 is mixed as S-polarized light at the time of polarization synthesis, thereby degrading the 3D image as crosstalk. Can be prevented.

  In addition, in order to suppress stray light that degrades the 3D image, it is also possible to perform sanitization or frosted glass processing on the surface of the first prism 13 excluding a portion through which the light rays α1 and α2 pass. When stray light generated by scattering on the edge of the lens or on the reflection surface is emitted to the camera optical system unit 3 and formed on the imaging sensors 5 and 6, the 3D image is degraded. Stray light other than the light rays α1 and α2 can be suppressed. In addition, by increasing the distance in the X direction between the lenses 10 and 12 and the camera optical system unit 3, stray light entering the camera optical system unit 3 through the lens can be suppressed.

  Next, the camera optical system unit 3 is composed of a plurality of lens groups 8, and is a zoom optical system that can change the focal length by driving some of these lens groups 8. For this reason, the two types of input polarized images are simultaneously zoomed and focused by this set of zoom lens units, and the influence of the aberration of the optical system acts on the two images in the same way. The difference between the images does not occur, and the cost of the imaging system is the highest, and the effect of cost reduction and size minimization is great for the camera optical system part that is affected by the size increase.

  Two types of polarized image light beams emitted from the camera optical system unit 3 enter the polarization separation unit 4, and the original P-polarized image and S-polarized image are output by the second prism 4 ′ (for example, PBS polarizing beam splitter Polarizing Beam Splitter). And imaged on the image sensor 5. At this time, the characteristic of the second prism 4 ′ is that the visible light wavelength band λ (450 nm to 700 nm), the P polarization transmittance is 80% or more in the range of the incident angle 45 ± 10 degrees to the second polarization separation film 4 ″, S The polarization reflectance is preferably 80% or more. Further, by arranging the polarizing sheet 9 between the second polarization separation film 4 ″ and the imaging sensors 5 and 6, crosstalk at the time of polarization separation can be reduced.

  In FIG. 4, a polarizing sheet 9 is disposed between the second polarization separation film 4 ″ and the imaging sensors 5 and 6 in order to reduce crosstalk during polarization separation. For example, the polarization separation film 4 ″. The stray light is blocked by disposing a polarizing sheet 9 that transmits S-polarized light between the image sensor 5 and the imaging sensor 5 and a polarizing sheet 9 that transmits P-polarized light between the polarization separation film 4 ″ and the image sensor 6. The light rays incident from the lenses 10 and 13 can be neatly subdivided and imaged on each sensor.

  FIGS. 5A to 5E show other examples of the polarized light separation unit 4 having a layout in which the interval between the image sensors 5 is widened to facilitate the arrangement. 5 (a) to 5 (c), the shape of the second prism 4 'is changed to a different shape, and the incident angle of the light to the second polarization separation film 4 "is made smaller than 45 degrees so that the interval between the image sensors 5 is increased. 5D, the second prism 4 ′ in FIG. 5D has a second polarization separation film 4 ″ that reflects S-polarized light and transmits P-polarized light, and λ / 4 on the side facing the direction of the camera optical system unit 3. The sheet 17 and the reflection mirror 18 are disposed. Of the image incident from the direction of the camera optical system unit 3, the S-polarized component is reflected by the second polarization separation film 4 "and directed to the image sensor 5, and the P-polarized component is transmitted through the second polarization separation film 4". By passing through the λ / 4 sheet, it is converted into, for example, clockwise circularly polarized light, and further reflected by the reflecting mirror 18 to become counterclockwise circularly polarized light, and again through the λ / 4 sheet, it becomes S polarized light. The S-polarized image reflects off the polarization separation film 4 ″ and enters the image sensor 6. In addition, it is desirable that the optical path lengths of the images incident on the image sensors 5 and 6 are the same because of optical characteristics. The second prism 4 'on the sensor 5 side is lengthened to make the optical path length uniform.

  The second prism 4 ′ in FIG. 5E includes a second polarization separation film 4 ″ that reflects S-polarized light and transmits P-polarized light, a λ / 4 sheet 17 and a reflecting mirror 18 on the side perpendicular to the direction of the camera optical system 3. Of the image incident from the direction of the camera optical system 3, the P-polarized light component passes through the second polarization separation film 4 ″ and travels toward the image sensor 6, and the S-polarized light component is the second polarization separation film. By reflecting 4 ″ and transmitting through the λ / 4 sheet, for example, it is converted into clockwise circularly polarized light, and further reflected by the reflecting mirror 18 to become counterclockwise circularly polarized light, and again transmitted through the λ / 4 sheet. The P-polarized image passes through the second polarization separation film 4 ″ and enters the image sensor 5. In addition, in view of optical characteristics, it is desirable that the optical path lengths of the images incident on the imaging sensors 5 and 6 are the same, and the second prism 4 ′ on the imaging sensor 6 side is lengthened to make the optical path lengths uniform.

  As another example of the polarization separation unit 4, as shown in FIG. 6, a polarization element 20 for transmitting P-polarized light and a changing element for transmitting S-polarized light are alternately arranged at positions corresponding to the respective pixels 21 of the imaging sensor 6. The polarizing plate 22 is configured to separate the P and S polarized light from the camera optical system unit 3. As a result, it is not necessary to use only one image sensor 6, the assembling property is improved, the cost can be reduced, a large optical element such as a prism is not required, and the apparatus can be miniaturized. The optical performance is improved.

  The imaging sensors 5 and 6 include, for example, an imaging element (sensor) such as a CCD image sensor or a CMOS image sensor, a sample hold circuit, an A / D converter, and the like, and imaging based on the P-polarized and S-polarized separated images. Image data is generated based on the output of the element. In addition, the camera device has a built-in memory that records information related to the image taken by itself, and performs image processing using a general-purpose interface capable of transferring images at high speed, such as a bidirectional parallel interface or a SCSI interface, or USB (Universal Series Bus). It is connected to the computer of the device 7.

<Embodiment 2>
Next, a second embodiment related to the stereoscopic photographing apparatus of the present invention will be described with reference to FIGS. In the first embodiment, the configuration using the λ / 4 sheet and the reflection mirror as means for converting one S-polarized image of the S-polarized images into P-polarized light by the polarization combining unit has been described. In the second embodiment, the λ / 4 sheet and the reflection mirror are not used. Since other configurations are the same as those in the first embodiment, the same reference numerals are given and detailed descriptions thereof are omitted.

  FIG. 7 shows another embodiment of the polarization beam combiner 2. The polarization beam combiner 2 includes lenses 10 and 12 that are light incident portions when viewed from the image incident side, and a first prism 13. Here, a description will be given assuming that the polarization correction sheet 11 is not provided.

  The first prism 13 is composed of a prism portion that bends and propagates an image incident from the lenses 10 and 12, and a first polarization separation film 13 ′ that reflects one polarized light and transmits the other polarized light. . Hereinafter, a case where the first polarization separation film 13 ′ reflects S-polarized light and transmits P-polarized light will be described. The S-polarized light of the image beam α1 on the lens 10 side is reflected by the polarization separation film 13 ′ and travels to the camera optical system unit 3, and the P-polarized light is transmitted through the polarization separation film 13 ′ and differs from the direction of the camera optical system unit 3. Head for. On the other hand, the image light beam α2 on the lens 12 side is incident on the first prism 13 from the direction facing the camera optical system unit 3, and the S-polarized light is reflected by the polarization separation film 13 ′ and is different from the direction of the camera optical system unit 3. The P-polarized light is directed to the camera optical system unit 3 while moving in the direction. That is, the polarization combining unit 2 here is guided to the camera optical system unit 3 so that the optical axes of the S-polarized light of the image light α1 and the P-polarized light of the image light α2 coincide.

  The relationship between the P-polarized light and the S-polarized light described so far may be reversed for the P-polarized light and the S-polarized light including the configuration of the polarization separation film 13 ′ and the like. In addition, the lenses 10 and 12 in the light incident portion can easily obtain optical characteristics of the camera optical system portion 3 described later, or can reduce the diameter of the light beam propagating through the polarization combining portion 2, but the assembling property is improved. In addition, it is possible to eliminate the lenses 10 and 12 as the light incident portions in order to reduce the cost by reducing the number of parts and reduce the thickness of the apparatus.

  Next, a case where a polarization correction sheet (λ / 4 phase difference sheet) 11 is provided in front of the lenses 10 and 12 in order to reduce crosstalk during polarization synthesis will be described. The polarization correction sheet 11 may be provided in any polarization synthesis unit 2 up to the polarization separation film 13 ′. At this time, the images incident from the lenses 10 and 12 are polarized by the polarization correction sheet 11 (λ / 4 retardation sheet), and the polarization component of the S-polarization component or the P-polarization component (especially water surface, reflected light of glass, liquid crystal display screen, etc.) Is converted into a circularly polarized light component, and a uniform image with corrected polarization deviation is obtained. The polarization correction sheet 11 is not limited to the λ / 4 phase difference sheet, and the λ / 2 phase difference sheet rotates the 45-degree polarized light with respect to the polarization direction of the P-polarized light or S-polarized light of the polarization separation film 13 ′. In this case, the polarization direction of the light, which was the S-polarized component at the time of light incidence, is rotated by 45 degrees with respect to the polarization-separating film surface of the polarization separating film 13 ′, so that the P-polarized component is 50%, S Similarly, the light that was the P-polarized component at the time of incident light is converted into 50% P-polarized component and 50% S-polarized component by rotating 45 degrees. As a result, the S-polarized light reflected by the polarization separation film surface of the polarization separation film 13 'is composed of 50% of the light that was S-polarized at the time of light incidence and 50% of the light that was P-polarized at the time of light incidence. It is possible to capture without bias (only P-polarized light or only S-polarized light). The polarization correction sheet 11 may be omitted for cost reduction when the polarization deviation of the subject is not a concern.

  Next, the uniform polarization-corrected image is bent and propagated by the prism unit that propagates the image incident from the lenses 10 and 12, the optical axis is bent by 90 degrees, one polarized light is transmitted, and the other polarized light is reflected. Is incident on a prism portion (for example, PBS polarizing beam splitter Polarizing Beam Splitter, hereinafter referred to as PBS). PBS has a visible light wavelength band λ (450 nm to 700 nm), a P-polarized light transmittance of 80% or more, and an S-polarized light reflectance of 80% or more in a range of an incident angle of 45 ± 10 degrees to the first polarization separation film 13 ′. Is desirable.

  Further, in order to reduce crosstalk during polarization synthesis, the polarizing sheet 9 may be disposed between the λ / 4 phase difference sheet 11 and the first polarization separation film 13 ′. At this time, the S-polarized component of the image from the lens 10 side is reflected by the first prism 13 and proceeds in the direction of the camera optical system unit 3, and the image from the lens 12 side is the S-polarized component by the λ / 4 phase difference sheet. Alternatively, the polarization component of the P-polarized component (particularly the water surface, the reflected light of the glass, the liquid crystal display screen, etc.) is converted into a circularly polarized component, and the P-polarized component of the image obtained by correcting the polarization polarization is uniform. Through the prism 13 and proceed in the direction of the camera optical system 3. As a result, the S-polarized image from the lens 10 side and the P-polarized image from the lens 12 side are synthesized by the polarization synthesizing unit 2 and input to the camera optical system unit 3 with the optical axes coincident.

  As another embodiment of the polarization combiner 2, when configured as shown in FIGS. 8A and 8B, the lenses 10 and 12 are aligned in the X direction of the drawing, and the combined polarization light is emitted in the −Y direction. Therefore, it is possible to reduce the size without creating a useless space. Further, when the layouts as shown in FIGS. 8C to 8F are taken, the distance (base line length) between the lenses 10 and 12 can be increased, and when a stereoscopic image is generated, a more stereoscopic image can be created. Can do. Further, in the case of the layouts as shown in FIGS. 8D to 8F, since the camera optical unit can also be arranged in the X direction, an apparatus that can further reduce the length in the Y direction can be realized.

  FIG. 9 shows a structure in which the first prism 13 of the polarization beam combiner 2 is divided. As a result, the base line length can be increased, and when a stereoscopic image is generated, an image with a more stereoscopic effect can be created. Further, as shown in FIG. 9B, the stereoscopic effect of the generated stereoscopic image can be adjusted by adding the function of the tilt to the divided lens-side prism. The factor that determines the stereoscopic effect is the convergence angle θ formed by the intersection of the optical axes of the two light rays α1 and α2, and the convergence angle θ decreases as the subject 0 is far, and increases when the subject 0 is close. As described above, since the stereoscopic effect of the subject 0 can be adjusted by the size of the convergence angle θ, the stereoscopic effect of the stereoscopic image can be adjusted by adjusting the convergence angle θ by adding a tilt to the divided prism. The device can be realized. Moreover, you may add the polarizing sheet 9 to the clearance gap which divided | segmented and was vacant.

  Furthermore, a configuration as shown in FIG. 10 is also possible as an embodiment in which the size of the prism is made as small as possible while keeping the base line length long. In FIG. 10, an image incident on the lenses 10 and 12 from the Z direction has a circular component of the S-polarized component or P-polarized component (particularly water surface, reflected light of glass, liquid crystal display screen, etc.) by the λ / 4 retardation sheet 11. It is converted into a polarization component, the polarization deviation is corrected, and reflected by the prism 14 below in the prism direction. At this time, the prism has a cross prism structure formed of a polarizing film 15 that reflects S-polarized light and transmits P-polarized light and a polarizing film 16 that transmits and reflects S-polarized light. As a result, of the image incident on the prism from the lens 10 side, the S-polarized light component is transmitted through the polarizing film 16 and reflected by the polarizing film 15 toward the camera optical system in the -Y direction, and from the lens 12 side to the prism. Of the incident image, the P-polarized light component passes through the polarizing film 15 and is reflected by the polarizing film 16 and travels in the −Y direction toward the camera optical system. With such a configuration, a more compact stereoscopic imaging device can be provided.

  11A and 11B, the prism shape is made different, and the incident angle of the image to the polarizing film 15 is made smaller than 45 degrees, so that the size of the prism is made relatively small, and the distance between the lenses 10 and 12 is reduced. And the base line length that is the interval can be increased.

<Embodiment 3>
Next, an electronic apparatus equipped with the stereoscopic imaging apparatus of the present invention will be described with reference to FIGS. Since the configuration of the stereoscopic imaging apparatus is the same as that of the first embodiment or the second embodiment, the same reference numerals are given and the detailed description and drawings are omitted. FIG. 12 is a block diagram illustrating the structure of the image processing device 7.

  The image processing apparatus 7 includes a CPU 71 having a function of executing arithmetic processing and outputting an instruction, a ROM 72 storing a program for causing the CPU 71 to execute a procedure for image processing, and the processing operation of the CPU. Therefore, the above-mentioned program read from the ROM 72, the computer 70 composed of the RAM 73 for temporarily storing data necessary for the processing of the CPU, the input unit 74 for inputting data, commands, etc. A display unit 75 for displaying the output of the CPU and storage means (not shown) for storing image data as necessary are provided.

  In the above configuration, the incident images α1 and α2 that have passed through each of the light incident units 10 and 12 pass through the polarization combining unit 2, the camera optical system unit 3, and the polarization separation unit 4, respectively, on the image sensor, respectively with P-polarized light and S An image separated into polarized light is formed. The P and S polarized images are slightly shifted from each other according to the parallax of the light incident portions 10 and 12.

  The image is converted into an electrical signal by the image sensor, A / D converted, then entered into a built-in image signal processing circuit, subjected to processing such as shading correction and γ correction, and then recorded in the built-in memory. The image data recorded in the built-in memory is input to the image processing device 7 in response to an image data request from the image processing device 3. The image data input to the image processing device 7 is formed into two stereo images by the computer 70. The computer 70 of the image processing device 7 can also calculate, for example, the distance to the subject from the two images obtained in this way, and output it to an output device (not shown).

  FIG. 13 shows an embodiment when the polarization combining type stereoscopic photographing apparatus 1 of the present invention is incorporated in a casing of an electronic device such as a mobile phone, a pocket movie, or a digital camera. In the electronic apparatus of FIG. 13A, the light incident units 10 and 12 are arranged on a plane composed of the polarization combining unit 2, the camera optical system unit 3, and the polarization separation unit 4, as in the stereoscopic imaging apparatus of the embodiment of FIG. 6. FIG. 13B shows an example of mounting when arranged on the orthogonal side, and the electronic apparatus of FIG. 13B includes a light combining unit 10 and a polarization combining unit 2 and a camera optical system as shown in FIG. 4 shows an example of mounting in the case where the unit 3 and the polarization separation unit 4 are arranged in a plane direction.

  In addition, the stereoscopic imaging apparatus of the present invention can make the distance measurement possible by further providing a configuration necessary for distance measurement and mounting the structure on an electronic apparatus. The distance measurement by the polarization combining type stereo camera is performed based on the already known triangulation principle. By performing arithmetic processing based on the principle of triangulation for each small area divided on the image, the distance to the object included in the small area can be obtained.

  The stereoscopic photographing apparatus according to the present invention can be widely applied to all photographing apparatuses such as a digital still camera. In addition, the present invention can be applied to a small photographing device suitable for carrying. Specifically, it is mounted on a portable information terminal or a mobile phone.

DESCRIPTION OF SYMBOLS 1 Polarization composition type | formula three-dimensional imaging device 2 Polarization composition part 3 Camera optical system part 4 Polarization separation part 4 '2nd prism 4''Polarization separation films 5 and 6 Image sensor 7 Image processing apparatus 9 Polarization sheet 70 Computer 71 CPU
72 ROM
73 RAM
74 Input unit 75 Display unit 10, 12 Light incident unit 11 Polarization correction sheet 13 First prism 13 ′ Polarization separation film

Claims (12)

A polarized light combining unit that extracts polarized image light beams having different parallax from the same subject image and forms a combined image light beam on the same optical axis by the first prism, and a combined image light beam formed by the polarized light combining unit is formed. possess a camera optical system unit, and a polarization separating part which separates the polarized image light is imaged on a plurality of image pickup elements in a different optical axis from the composite image light beam by the second prism,
The polarization combining unit includes two lenses for forming an image and forming an image, a first prism on which a polarization separation film that reflects one polarized light and transmits the other polarized light is formed, A stereoscopic photographing apparatus comprising: a λ / 4 film disposed on a surface orthogonal to one of the reflected polarized light; and a reflective surface disposed in parallel to the λ / 4 film . 2. The stereoscopic photographing apparatus according to claim 1, wherein the polarized image light beams having different parallaxes extracted from the same subject image have the same polarization component. 2. A means for shifting a phase by λ / 2 is provided in an optical path until polarized image light beams having different parallaxes extracted from the same subject image are emitted from the first prism. Stereoscopic camera. 2. The stereoscopic photographing apparatus according to claim 1, wherein the polarized image light beams having different parallaxes extracted from the same subject image are polarized light of an S polarization component. The three-dimensional imaging device according to claim 1, wherein the optical path lengths of different images from the light incident part of the polarization beam combining part to the light emitting part to the camera optical system part are the same. The polarization combining section, the stereoscopic imaging apparatus according to claim 1, characterized in that it comprises two lenses polarizing sheet for transmitting a specific polarized light component on the incident side or exit side of the. The camera optics unit, three-dimensional imaging apparatus of claim 1 to claim 4, wherein the consisting of zoom optical system that can change the imaging magnification of the image. The stereoscopic imaging apparatus according to claim 1, wherein the polarization beam combining unit includes a polarization correction sheet for correcting polarization polarization. The polarization separation unit separates one polarization image from the other polarization image, forms the separated one polarization image on a corresponding image sensor, and forms the separated other polarization image on the other corresponding image sensor. It is composed of a prism for imaging stereoscopic imaging apparatus according to claim 1 to claim 5 wherein. Wherein between the second prism and the plurality of imaging devices, solid imaging of claims 1 to 5, wherein the polarizing sheet to reduce crosstalk during polarization separation is located apparatus. Claim 1 to an electronic apparatus, characterized in that mounting the stereoscopic imaging apparatus according to claim 5, wherein. In the stereoscopic imaging apparatus according to claim 1 to claim 5, wherein the three-dimensional imaging apparatus characterized by having a distance measuring means for calculating the distance to the object based on the two images separated.