JP2009168995A - Range-finding device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a range-finding device capable of performing focus detection nearly all over the area of a photographic image plane. <P>SOLUTION: The range-finding device includes: first and second polarization elements 11 (11a and 11b) arranged at different positions from each other on a plane conjugate to the pupil of an optical system 1 and having different polarization characteristic from each other; a polarized light splitting element 2 splitting first luminous flux from the first polarization element 11 (11a) and second luminous flux from the second polarization element 11 (11b) out of luminous flux passing through the optical system 1; a plurality of imaging means 3 and 4 arranged on a scheduled imaging surface of the optical system 1 and picking up a first image formed by the first luminous flux and a second image formed by the second luminous flux respectively independently; and a focus detection means 5 detecting the focusing state of the optical system 1 based on relative image shift between the first and second images. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a distance measuring device and an imaging device.

  Conventionally, an optical apparatus that performs focus detection of an imaging optical system by a pupil division method is known (see, for example, Patent Document 1).

  In the above-described apparatus, an electro-optical element combining a diffraction grating and liquid crystal is inserted into the pupil plane of the imaging optical system, and light that has passed through different regions in the exit pupil is deflected in different directions. Then, the respective light fluxes are formed on different regions of the image pickup device for picking up an image of the image forming optical system, and phase difference AF is performed based on the image pickup data.

JP 2006-106435 A

  However, in the conventional apparatus described above, focus detection information can be obtained only in a part of the image plane of the imaging optical system.

A distance measuring device according to a first aspect of the present invention includes first and second polarizing elements that are arranged at different positions on a plane conjugate with a pupil of an optical system and have different polarization characteristics, and a light beam that passes through the optical system. A polarization separation element that separates the first light flux from the first polarization element and the second light flux from the second polarization element, and the first light flux by the first light flux is disposed on the planned imaging plane of the optical system. And a plurality of imaging means for independently capturing the second image and the second image by the second light beam, and detecting the focus adjustment state of the optical system based on the relative displacement between the first and second images And a focus detection means.
According to a second aspect of the present invention, in the distance measuring device according to the first aspect, an aperture stop is provided in the vicinity of the pupil of the optical system and restricts the first and second light beams, respectively.
According to a third aspect of the present invention, in the distance measuring device according to the second aspect, the aperture stop has a plurality of apertures having different distances from the optical axis of the optical system, and selects any one of the plurality of apertures. It is characterized by comprising selection means arranged in the vicinity of the pupil.
According to a fourth aspect of the present invention, in the distance measuring device according to the first aspect, a re-imaging optical system that re-images the image by the first light beam and the image by the second light beam is provided. The polarizing element is arranged on a surface optically equivalent to the pupil of the optical system.
According to a fifth aspect of the present invention, in the distance measuring apparatus according to any one of the first to fourth aspects, the plurality of imaging means includes a first imaging element that captures a first image, and a first imaging element. And a second imaging element that has a larger imaging area and captures the second image.
An imaging device according to a sixth aspect of the present invention is photographed using the distance measuring device according to any one of the first to fifth aspects and at least one of the first image imaging data and the second image imaging data. An image generation means for generating an image is provided.
According to a seventh aspect of the present invention, in the imaging apparatus according to the sixth aspect, the first and second polarization elements are provided with moving means for moving the first and second polarization elements so as to advance and retreat relative to the optical path of the optical system. A captured image is generated based on imaging data of the first and second images captured in a state where the element is moved to a position retracted from the optical path of the optical system.
According to an eighth aspect of the present invention, in the imaging apparatus according to the seventh aspect, the captured image is generated by adding the captured image data of the captured first and second images.
According to a ninth aspect of the present invention, in the imaging device according to the sixth aspect, the imaging data corresponding to each other of the imaging data of the first and second images is based on the relative image shift between the first and second images. A photographed image is generated by adding the two to each other.
A tenth aspect of the present invention is the imaging apparatus according to any one of the sixth to ninth aspects, wherein the first display image based on the first image imaging data and the second image based on the second image imaging data. A display device that displays each display image is provided.
According to an eleventh aspect of the present invention, there is provided an image pickup apparatus that uses the image pickup data of one of the first and second image pickup elements in accordance with the distance measuring device according to the fifth aspect and the focal length of the optical system. And an image generation means for generating.

  According to the present invention, focus detection can be performed for almost the entire region of the shooting screen.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a diagram showing a first embodiment of a distance measuring device according to the present invention, and shows a basic configuration of the distance measuring device. The distance measuring device includes an objective optical system 1, a polarization separation element 2, a first image sensor 3, a second image sensor 4, an image processing circuit 5, an AF control circuit 6, an AF drive mechanism 7, and an image memory 8. Yes. Note that the distance measuring device according to the present embodiment can also generate an image for photographing based on the image data of the imaging elements 3 and 4.

  The objective optical system 1 is provided with a polarizing element 11 disposed in the vicinity of the pupil position. The polarizing element 11 is divided into two regions 11a and 11b around the optical axis, and the polarization axis of the region 11a and the polarization axis of the region 11b are orthogonal to each other. Since the polarizing element 11 is disposed in the vicinity of the pupil position, the pupil region is divided into two partial pupil regions corresponding to the regions 11a and 11b.

  The light beam incident on the objective optical system 1 is converted into two polarized light beams orthogonal to each other by the polarizing element 11. The polarized light emitted from the region 11 a passes through the polarization separation surface of the polarization separation element (polarization beam splitter) 2 disposed between the polarization element 11 and the imaging element 3 and forms an image on the imaging element 3. The On the other hand, the polarized light emitted from the region 11 b is reflected by the polarization separation surface of the polarization separation element 2, and forms an image on the image sensor 4 disposed below the polarization separation element 2. The image sensor 4 is disposed at an optically equivalent position to the image sensor 3, and when an image in focus is formed on the image sensor 3, an image in focus is also formed on the image sensor 4. The As the image pickup elements 3 and 4, area sensors in which light receiving elements are arranged two-dimensionally are used.

  The outputs of the image pickup device 3 and the image pickup device 4 are respectively sent to the image processing circuit 5, where image processing such as A / D conversion and color processing is performed. Further, the image processing circuit 5 performs calculations related to focus detection based on image data obtained from the outputs of the image sensor 3 and the image sensor 4. The AF control circuit 6 controls the driving of the AF drive mechanism 7 based on the focus detection calculation value calculated by the image processing circuit 5 and performs the focus adjustment of the objective optical system 1. The image data obtained by the image processing circuit 5 is recorded in the image memory 8.

  FIG. 2 is a diagram for explaining the principle of the focus detection method in the present embodiment. Reference numeral 20 denotes an object plane, and 21 denotes an imaging plane of the imaging elements 3 and 4. In FIG. 1, a plurality of objective lenses are shown in the objective optical system 1, but in FIG. As described above, the image pickup surfaces of the image pickup devices 3 and 4 constitute optically equivalent surfaces, and therefore are represented by the same image pickup surface 21 in FIG.

  Light beams 22 a and 22 b emitted from the object plane 20 are imaged by the objective lens 12 of the objective optical system 1. When the light beam 22a is incident on the region 11a of the polarizing element 11 through the objective lens 12, only the polarization component that passes through the region 11a is emitted from the region 11a and forms an image near the imaging surface 21 of the imaging device 3. On the other hand, when the light beam 22 b enters the region 11 b of the polarizing element 11 through the objective lens 12, only the polarization component that passes through the region 11 b is emitted from the region 11 b and forms an image near the imaging surface 21 of the imaging device 4.

  FIG. 2A shows an in-focus state, and an image by the light beam 22 a and an image by the light beam 22 b are formed on the imaging surface 21 and projected on the same position on the imaging surface 21. That is, when the captured image of the image sensor 3 and the captured image of the image sensor 4 are overlapped, the imaging positions coincide. FIG. 2B shows a state defocused to the front side. Since the image formation position is behind the image pickup surface 21, the image on the image pickup surface 21 is blurred, and a deviation C occurs in the position of the image by the light beams 22a and 22b. The image 23a by the light beam 22a is shifted from the optical axis on the upper side in the drawing, and the image 23b by the light beam 22b is shifted from the lower side with respect to the optical axis. On the contrary, in the state defocused to the rear side shown in FIG. 2C, the image 23a by the light beam 22a is shifted downward with respect to the optical axis, and the image 23b by the light beam 22b is shifted with respect to the optical axis. The image is shifted to the upper side.

  In this manner, the polarization components from the regions 11a and 11b are separated by the polarization separation element 2 and formed on the two independent image pickup devices 3 and 4, thereby obtaining images of the respective polarization components, and the two images. By comparing the phase differences of the images in the image, the defocus amount can be calculated in the same manner as the normal phase difference AF. Note that a pupil mask 24 for limiting the transmission region of the pupil as shown in FIG. 2D may be inserted so that the image shift C can be detected more clearly. By inserting a pupil mask 24 having a pair of transmission parts, light in the vicinity of the optical axis is shielded, and only a light beam having a large F value is used, so that the parallax becomes large and the light beam is narrowed down, so that the images 23a and 23b by defocusing are used. The blur becomes smaller. As a result, the image shift C can be detected more clearly.

  2A to 2C show that the image shift states of the images 23a and 23b are different depending on the photographing distance with respect to one point of the object plane 20. FIG. On the other hand, when the entire screen areas of the images picked up by the image pickup devices 3 and 4 are compared, since the shooting distance is different if the subject area is different, the image shift state is different for each subject area. Therefore, if each image shift is detected and the defocus amount is calculated, distance measurement data regarding the entire screen area can be acquired by one imaging.

  For example, consider a case where there are only two subjects with different shooting distances on the screen. FIG. 3A schematically shows an image pickup signal of an image A picked up by the image pickup device 3, the horizontal axis represents the position of the light receiving element on the image pickup surface 21, and the vertical axis represents the light receiving element. The level of the imaging signal output from is shown. In the image A, a signal 30A and a signal 31A appear corresponding to each subject.

  FIG. 3B is an image obtained by superimposing the image of the image sensor 4 on the image A of the image sensor 3. The solid line indicates the image signal distribution of the image A, and the broken line indicates the image signal distribution of the image B. . FIG. 3A shows an ideal signal in which no noise component or the like appears. Actually, the influence of noise increase due to a decrease in shutter speed or an increase in sensitivity is shown in FIG. 3B. Included. The signal 30B and the signal 30A are signals corresponding to the same subject, and the signal 31A and the signal 31B are signals corresponding to other same subjects. In correspondence with the images 23a and 23b in FIG. 2, the signals 30A and 31A correspond to the image 23a, and the signals 30B and 31B correspond to the image 23b.

  Although the signal 30B in FIG. 3B is shifted by x1 with respect to the signal 30A, this image shift amount can be obtained by the same method as in the image shift amount calculation in the phase difference AF. For example, regarding the partial region image including the signals 30A and 30B, when the absolute value of the difference between the image B signal shifted by one light receiving element and the image A signal is taken and the difference is minimized. The shift amount is defined as an image shift amount x1.

  As shown in FIG. 3C, when the shift amount of the image B becomes x1, the signal 30A and the signal 30B cancel each other, and the absolute value of the difference becomes the minimum. FIG. 3D shows a case where the same processing is performed on the images corresponding to the signals 31A and 31B. When the shift amount of the image B is x2, the signal 31A and the signal 31B cancel each other, and the difference The absolute value of is minimal. By performing such processing for the entire screen area, distance information for each subject in the entire screen area can be obtained.

  In the present embodiment, since the light beam is separated by the polarizing element 2, the light incident on one imaging element is halved, and the above-described effects such as an increase in noise due to a decrease in shutter speed and an increase in sensitivity occur. . Therefore, when an image for photographing is generated from the image data of the image sensors 3 and 4, the outputs of the two image sensors 3 and 4 are added as follows to increase sensitivity and reduce noise. Can do. In this case, the imaging signals in the area where the absolute value of the difference is minimized as shown in FIG. 4A are added (averaged), and this is newly added as an image (signals 30 and 31) as shown in FIG. 4B. Output as. Although the image shift amount varies depending on the region, this process is performed for all regions. This addition processing makes it possible to increase sensitivity and reduce noise, and the conditions are almost the same as those in a conventional optical system that does not perform polarization separation.

  FIG. 5 is a diagram showing a division form of the polarizing element 11. FIG. 5A is the same as that shown in FIG. 1 and is divided symmetrically about the optical axis. In this case, since the image shift occurs only in the left-right direction, the image shift cannot be detected for the subject having only the horizontal stripe pattern. Of course, if it is divided symmetrically, it becomes impossible to detect a subject that has only a vertical stripe pattern. Therefore, as shown in FIG. 5B, when the dividing line is inclined 45, the image displacement direction is also inclined 45 degrees (upper right and lower left directions), so that the image displacement amount is detected for both the vertical stripes and the horizontal stripe patterns. Can reduce the number of subjects that are not good at focus detection.

  FIG. 6 is a diagram for explaining the pupil mask 24 shown in FIG. The pupil mask 24 includes a light shielding unit 240 and a transmission unit 241 and needs to be optimally selected depending on the F value of the objective optical system 1. Here, as shown in FIG. 6A, three types of pupil masks 24a to 24c are selected and used according to the F value. When the F value is small (bright), the distance measurement accuracy is maintained by using a pupil region farthest from the optical axis as in the pupil mask 24a.

  As the F value becomes larger (darker), the light flux is limited from the peripheral portion. Therefore, the pupil mask is switched in the order of 24a → 24b → 24c so that the transmitting portion 241 is brought closer to the optical axis in order. These are selected according to the open F value, and when the F value changes depending on the focal length, it is possible to always perform optimum detection by switching according to the focal length. FIG. 6B is a diagram showing an arrangement example of the pupil masks 24a to 24c, and the pupil masks 24a to 24c are fixed to a disc 242 that can rotate around the optical axis. A circle 243 indicated by a thick line indicates an optical path portion of the objective optical system 1, and the disc 242 is rotated to position a desired one from the pupil masks 24a to 24c on the optical path portion 243. That is, the pupil mask can be easily switched by rotating the disk 242.

  FIG. 7 shows an example in which the pupil mask and the shutter are integrated. A disc 242 provided so as to be rotatable around the optical axis is provided with a pupil mask 24, a light shielding part 242a, and a transmission part 242b. The size of the transmission part 242b is set to be approximately the same as the size of the optical path part 243 of the objective optical system 1. By rotating the circular plate 242, the distance measuring state, the light shielding state, and the exposure state are switched.

  In the configuration shown in FIG. 1, since the light of the subject is separated by the polarizing element 11, the amount of light incident on each of the image pickup devices 3 and 4 is half of the light incident on the objective optical system 1, and as described above, the shutter. Effects such as increased noise due to reduced speed and increased sensitivity appear. In addition, since the light of the polarization component is imaged, an undesirable polarization effect may occur depending on the subject.

  Therefore, in the case of the configuration shown in FIG. 7, the polarizing element 11 is configured to rotate integrally with the pupil mask 24 without leaving the polarizing element 11 arranged in the optical path portion 243 as shown in FIG. 1. . For example, the polarizing element 11 is provided in the transmission part 241 of the pupil mask 24, and the polarization separation element 2 is retracted outside the optical path during exposure. As a result, a non-polarized light beam is incident only on the image sensor 3 during exposure.

  First, at the time of distance measurement, the disc 242 is rotated as shown in FIG. 7A to position the pupil mask 24 in the optical path portion 243. Next, as shown in FIG. 7B, the light shielding portion 242a is positioned on the optical path portion 243 to close the shutter, and the image sensors 3 and 4 are reset. At the time of exposure, the transmission part 242b is positioned on the optical path part 243 as shown in FIG. Next, as shown in FIG. 7D, the light shielding unit 242a is positioned on the optical path unit 243 to close the shutter, and the image sensor is read.

  In the example shown in FIG. 7, the pupil mask 24, the light shielding part 242a, and the transmission part 242b are switched by rotating the disk 242. However, as shown in FIG. Also good. In FIG. 8, a slide mechanism 80 is disposed in the vicinity of the pupil position of the objective optical system 1. A transmissive portion 80a of the slide mechanism 80 is provided, and the transmissive portion 80a is disposed so that the transmissive portion 80a is positioned in the optical path portion.

  The slide mechanism 80 is provided with a light-shielding shutter 800 and the polarizing element 11 shown in FIG. 1 so as to be slidable in a direction perpendicular to the optical axis. As the polarization separation element 2, a plate-shaped element is provided in place of the cubic polarization separation element (polarization beam splitter) 2 shown in FIG. As shown in FIGS. 8A to 8C, the polarization separation element 2 is configured to be retracted out of the optical path of the light beam incident on the imaging element 3.

  FIG. 8A shows a state at the time of distance measurement, and the polarizing element 11 is positioned on the transmission part 80 a of the slide mechanism 80. Therefore, the polarization component transmitted through the region 11 a of the polarization element 11 is transmitted through the polarization separation element 2 and enters the imaging element 3. On the other hand, the other polarization component transmitted through the region 11 b of the polarization element 11 is reflected by the polarization separation element 2 and enters the other imaging element 4. Then, distance information (ranging data) of the entire screen area is calculated based on the image data of the imaging elements 3 and 4.

  In FIG. 8B, the polarizing element 11 is retracted from the transmission unit 80a and the light-shielding shutter 800 is slid to the transmission unit 80a in response to a release signal that instructs photographing. As a result, the subject light flux is shielded by the light shielding shutter 800 and the shutter is closed. At the same time, the polarization separation element 2 is also moved to the retracted position, and the accumulated charge of the image pickup element 3 is reset in the shutter closed state to prepare for exposure.

  FIG. 8C shows a state at the time of exposure. After the image sensor reset is completed, the light-shielding shutter 800 is opened and slid out of the light path (downward in the drawing) from the transmission part 80a to be exposed. Since the transmission part 80a is in an open state, not the polarization component but the entire light beam is incident on the image sensor 3, and only the image sensor 3 is imaged. As a result, a normal image having no polarization effect is obtained. The polarization separation element 2 is in a retracted state at the same position as in FIG.

  After the exposure is completed, the procedure shown in FIGS. 8A to 8C is followed in reverse. That is, the charge of the image sensors 3 and 4 is read and reset in parallel with the movement of the light blocking shutter 800 to the transmission unit 80a and the polarization separation element 2 being inserted into the optical path of the image sensor 3. Thereafter, the light-shielding shutter 800 is retracted from the transmission unit 80a and the polarizing element 11 is moved to the transmission unit 80a so that distance measurement is possible.

  In the above-described example, since only the image sensor 3 is imaged to obtain an image, the polarization separation element 2 is retracted as shown in FIGS. 8B and 8C. When a captured image is generated using both of the image data, it is not necessary to save. That is, as shown in FIG. 8C, if the transmission unit 80a transmits the entire light flux, no image shift occurs, and thus each image based on the polarization component imaged by the imaging elements 3 and 4 is simply added. Thus, the effects of the polarization effect and the decrease in the amount of light can be offset.

  By the way, in the peripheral part of the image pickup devices 3 and 4, when an image shift occurs, the image may protrude from the image pickup region of the image pickup devices 3 and 4. In such a case, it becomes difficult to perform distance measurement by detecting image shift. FIGS. 9A and 9B are diagrams for explaining the protrusion of an image from the image sensor, and FIG. 9C is a diagram showing an example of countermeasures for solving the problem.

  In FIG. 9A, an image 23 a is formed on the image sensor 3, and an image 23 b is formed on the image sensor 4. However, the center position of the image 23a protrudes outside the imaging range of the image sensor 3 by the amount of protrusion E. Note that the direction of image shift is reversed depending on whether front defocusing or rear defocusing is performed as shown in FIGS. 2B and 2C. In FIGS. 9A and 9B, rear defocusing is performed. Shows the case. Further, since the configuration of the polarizing element 11 shown in FIG. 1 is used, the image 23a is shifted to the right and the image 23b is shifted to the left.

  In general, the subject near the left and right ends often has a distant view than the subject at the center, and therefore the images 23a and 23b are displaced as shown in FIGS. 9A and 9B. FIG. 9B shows images 23a and 23b projected on the left ends of the image sensors 3 and 4, and the positions of the image sensors 3 and 4 are the same. Since a part of the image 23b protrudes to the left from the image sensor 4, it is difficult to perform distance measurement in this left end region.

  Therefore, as shown in FIG. 9C, the size of the image sensor 4 is set larger than that of the image sensor 3, so that the image 23b can also be captured. With such a configuration, distance information can be acquired in the entire region of the imaging range of the smaller imaging device 3. The captured image is captured by the smaller image sensor 3. In addition, when a captured image is generated based on the imaging data of both the image sensors 3 and 4, the imaging range of the smaller image sensor 3 is the range of the captured image. By adopting such a configuration, distance information of the entire screen can be acquired for the range captured by the smaller image sensor 3, which is wasteful compared to the case where a large image sensor is used with two large image sensors. There is no.

  In the telephoto lens, the amount of defocus increases and the possibility of capturing the subject full of the screen increases. Further, in order to narrow the angle of view and enhance the telephoto effect, it is better that the imaging size is small. Therefore, when the focal length becomes longer, the distance measurement is performed by the two image sensors 3 and 4, and the smaller image sensor 3 is mainly photographed.

  On the other hand, with a wide-angle lens, the amount of image shift is small, and it is unlikely that the subject will occupy the corners of the screen. In order to increase the angle of view or increase the number of shooting pixels, it is better to increase the imaging size. Therefore, when the focal length is shortened, the distance measurement is performed by the two imaging elements 3 and 4, and the larger imaging cord 4 is mainly imaged.

-Second Embodiment-
FIG. 10 is a diagram showing a second embodiment of the present invention. In the present embodiment, the distance measuring device shown in the first embodiment is applied to the re-imaging phase difference AF. In a conventional re-imaging type phase difference distance measuring device, a light beam is separated by a fixed pupil mask to obtain an image shift. However, since the pupil mask is fixed, distance measurement cannot be performed with a lens having an F value equal to or higher than the mask transmitted light.

  FIG. 10A is a diagram illustrating a basic configuration of the distance measuring apparatus according to the second embodiment, and a surface optically equivalent (conjugate) to the pupil position of the objective lens 100 in the re-imaging optical system. The polarizing element 11 and the pupil mask 24 are disposed. In FIG. 10A, the polarizing element 11 and the disc 242 including the three pupil masks 24a to 23c shown in FIG. 6B are arranged between the re-imaging lenses 100a and 100b. . In this case, the same pupil division effect as that obtained by inserting the polarizing element 11 at the pupil position of the objective lens 100 is obtained.

  FIG. 10B shows a case where the distance measuring device shown in FIG. 10A is built in a single-lens reflex digital camera. The subject luminous flux from the objective lens 100 is reflected below the camera body by the sub mirror 121 provided behind the main mirror 120 and passes through the pupil mask 24 and the polarizing element 11 in this order. The light beam emitted from the polarizing element 11 is bent by 90 degrees by the mirror 123, passes through the re-imaging lens 100 b, and then enters the polarization separating element 2. The polarization components separated by the polarization separation element 2 are incident on the imaging elements 3 and 4, respectively. Imaging is performed by a dedicated image sensor 122.

  By rotating the disc 242, the pupil masks 24 a to 24 c can be easily switched, and distance measurement in accordance with the F value of the objective lens 100 becomes possible. In addition, since the entire area to be re-imaged can be set as the distance measurement range, there is no restriction on the arrangement of the distance measurement areas unlike phase difference AF using a line sensor.

-Third embodiment-
FIG. 11 is a diagram showing the third embodiment, and is configured to display images picked up by the image pickup devices 3 and 4 on the display devices 300a and 300b, respectively. The observer observes the image of the display element 300a with the right eye through one eyepiece lens 301a, and observes the image of the display element 300b with the left eye through the other eyepiece lens 301b, thereby obtaining a monocular optical system. A three-dimensional image can be observed. As in the first embodiment, autofocusing can be performed by a distance measuring operation based on image data of the image sensors 3 and 4.

  In addition, since distance information is obtained for the entire screen, if you want to focus on a certain subject, you can emphasize or change the sense of distance by performing playback processing that blurs other areas. You can also. Further, by adopting a configuration in which the pupil mask and the polarization filter can be switched, it is possible to adjust the stereoscopic effect and to perform simple binocular observation without the stereoscopic effect (left-right parallax). For example, the stereoscopic effect is adjusted by changing the F value of the pupil mask, and the stereoscopic effect is lost by retracting the polarizing element 11 out of the optical path.

  FIG. 12 is a diagram showing a configuration when the basic configuration shown in FIG. 11 is applied as a binocular observation device. 12A is a plan view of the apparatus, and FIG. 12B is a view seen from the eyepiece lens direction. Here, the display area of one display element 300 is divided into two, and the images of the imaging elements 3 and 4 are displayed in the respective areas. The light beam of the right-eye image emitted from the display element 300 is reflected in the right direction in the figure by the dividing mirror 330 and then reflected in the direction of the eyepiece lens 301a by the bending mirror 332a. On the other hand, the light beam of the image for the left eye emitted from the display element 300 is reflected by the split mirror 330 in the left direction in the figure, and then reflected by the bending mirror 332b in the direction of the eyepiece lens 301b. As with a normal digital camera, the data can be saved in the image memory 310 by operating the save button 320, so that a stereoscopic image can be saved and reproduced.

  FIG. 13 is a diagram showing a modification of the above-described third embodiment. In the binocular observation device of FIG. 12, the pupil polarization division is performed outside (front side) of the objective optical system 1. The casing 400 is provided with openings serving as left and right pupils at predetermined intervals, and polarizing elements 411a and 411b are provided in the openings. As the polarizing element 411a, the same polarizing element as that constituting the region 11a of the polarizing element 11 shown in FIG. 1 is used, and the same polarizing element as that constituting the region 11b of the polarizing element 11 is used as the polarizing element 411b. It is used. That is, the polarization axes of the polarizing elements 411a and 411b are orthogonal to each other.

  The light incident from the left and right openings is bent in the optical path by the plurality of mirrors M1 to M3, and is synthesized on the same optical axis by the half mirror M4. This is separated by the polarization separation element 2 in the vicinity of the imaging surface and is incident on the two imaging elements 3 and 4 respectively. Here, the polarizing elements 411a and 411b are provided in the left and right openings. However, by replacing the half mirror M4 with the polarization separating element, the polarizing element is not used and the light quantity attenuation by the half mirror can be avoided. .

  Such a configuration is difficult to achieve with an objective optical system with a wide angle of view, because the left and right optical paths interfere with each other. However, if the objective optical system has a sufficiently narrow angle of view and the incident light beam is nearly parallel, interference is not possible. It is possible to avoid the configuration. By providing an aperture that restricts the pupil outside the objective optical system, the distance (baseline length) between the left and right pupils can be taken regardless of the specifications of the objective optical system. It is possible to take a strong image.

As described above, according to the above-described embodiment, distance information in the entire screen area can be acquired simultaneously with shooting with a single lens and one shot.
In other words, since phase difference AF is performed using the image received on the imaging surface, there is no area that cannot be measured within the screen, and full-screen phase difference AF is possible. Also, the number of AF areas is arbitrary in the number of pixels of the image sensor. Can be set to
In addition, since the conventional distance measuring sensor and the image sensor are composed of the same image sensor, in principle, the detection limit and the required accuracy of imaging coincide with each other, and highly accurate distance measurement can be performed. Furthermore, since the imaging objective optical system also serves as the distance measuring optical system, there is no problem of inability to perform distance measurement or insufficient accuracy due to insufficient matching between the objective optical system and the distance measuring optical system as in the prior art.
Further, stereoscopic imaging can be performed without using a plurality of lenses, and the size and weight can be reduced as compared with the conventional stereoscopic imaging apparatus, and the cost can be reduced.
In addition, the above description is an example to the last, and this invention is not limited to the said embodiment at all unless the characteristic of this invention is impaired.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the ranging device by this invention, and shows the basic composition of a ranging device. It is a figure explaining the principle of a focus detection system. It is a figure explaining acquisition of ranging data. It is a figure explaining image composition. It is a figure explaining the area | region division of a pupil. It is a figure explaining the pupil mask 24 The example which integrated the pupil mask and the shutter is shown. It is a figure explaining the slide mechanism. It is a figure explaining the protrusion of the image from an image sensor. It is a figure explaining 2nd Embodiment. It is a figure which shows 3rd Embodiment. It is a figure which shows the structure at the time of applying the basic structure shown in FIG. 11 as a binocular observation apparatus. It is a figure which shows the modification of 3rd Embodiment.

Explanation of symbols

  1: objective optical system, 2: polarization separation element, 3, 4: imaging element, 5: image processing circuit, 6: AF control circuit, 7: AF drive mechanism, 8: image memory, 11: polarization element, 11a, 11b : Area, 24, 24a to 24c: Pupil mask, 80: Slide mechanism, 242: Disc, 242a: Light shielding part, 242b: Transmission part

Claims (11)

First and second polarizing elements disposed at different positions on a plane conjugate with the pupil of the optical system and having different polarization characteristics;
A polarization separation element that separates a first light flux from the first polarization element and a second light flux from the second polarization element among the light fluxes passing through the optical system;
A plurality of imaging means arranged on a predetermined imaging plane of the optical system and independently imaging a first image by the first light beam and a second image by the second light beam;
A distance measuring apparatus comprising: a focus detection unit configured to detect a focus adjustment state of the optical system based on a relative shift between the first and second images. The distance measuring device according to claim 1,
A distance measuring apparatus comprising an aperture stop disposed near a pupil of the optical system and configured to limit the first and second light beams, respectively. The distance measuring device according to claim 2,
The aperture stop has a plurality of apertures with different distances from the optical axis of the optical system,
A distance measuring apparatus comprising: a selection unit that selectively arranges any one of the plurality of openings in the vicinity of the pupil. The distance measuring device according to claim 1,
A re-imaging optical system that re-images the image by the first light beam and the image by the second light beam;
A distance measuring device, wherein the first and second polarizing elements are arranged in a plane optically equivalent to a pupil of the optical system. In the distance measuring device according to any one of claims 1 to 4,
The plurality of image pickup means includes a first image pickup device that picks up the first image, and a second image pickup device that picks up the second image having an image pickup area larger than that of the first image pickup device. A distance measuring device comprising: A distance measuring device according to any one of claims 1 to 5,
An image pickup apparatus comprising: an image generation unit configured to generate a captured image using at least one of the image data of the first image and the image data of the second image. The imaging device according to claim 6,
Moving means for moving the first and second polarizing elements so as to advance and retreat with respect to the optical path of the optical system;
The image generating means is based on imaging data of the first and second images captured in a state where the first and second polarizing elements are moved to positions retracted from the optical path of the optical system. An imaging device that generates a captured image. The imaging apparatus according to claim 7,
The image generation unit generates the captured image by adding image data of the captured first and second images. The imaging device according to claim 6,
The image generation means adds the imaging data corresponding to each other of the imaging data of the first and second images based on a relative image shift between the first and second images, thereby obtaining the imaging An imaging device that generates an image. In the imaging device according to any one of claims 6 to 9,
An imaging apparatus comprising: a display device configured to display a first display image based on imaging data of the first image and a second display image based on imaging data of the second image. A distance measuring device according to claim 5;
An image pickup apparatus comprising: an image generation unit configured to generate a photographed image using image data of one of the first and second image sensors in accordance with a focal length of the optical system.

Images