Imaging device and control method thereof

Abstract

To excellently image a subject moving between a long distance and a short distance, even when two optical systems are not driven.SOLUTION: An imaging apparatus 30e includes an imaging element 301c for imaging a subject image formed by each of two optical systems 10c and 20d arranged in parallel, image generation means 302c for generating two stereoscopically viewable images by using a signal from the imaging element, acquisition means 302c for acquiring a subject distance, and control means 302c for controlling imaging. The image generation means generates two images by using the signals of two segmentation areas in two image circles formed on the imaging element by two optical systems. The control means moves at least one of two segmentation areas in the image circle, to change the center interval of the two segmentation areas, according to the subject distance.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an imaging device that captures an image capable of stereoscopic vision.

Background Art

[0002] Imaging devices that capture left and right parallax images capable of stereoscopic vision, which are used in Virtual Reality (VR), Augmented Reality (AR), Mixed Reality (MR), etc., are disclosed in Patent Documents 1 to 3. When the subject moves suddenly to the near distance side while the subject is being imaged with a narrow angle of view on the telephoto side in these imaging devices, the subject will fall out of the angle of view unless the convergence points of the left and right optical systems are quickly moved to the near distance side.

[0003] Patent Document 1 discloses an imaging device that changes the position of the convergence point by driving an eccentric group, which is a part of the optical system, eccentrically (shift) according to a change in the subject distance. Patent Document 2 discloses an imaging device that calculates an overlapping region that overlaps each other among the angles of view of the left and right optical systems according to the subject distance, focuses on the overlapping region, or rotates and drives the left and right optical systems according to the position of the overlapping region to move the convergence point. Patent Document 3 discloses an imaging device that corrects the optical axis deviation due to manufacturing errors of the left and right optical systems by changing the image cutout region on the imaging element.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] However, as described in Patent Document 1, significantly shifting the eccentric group to move the convergence point from the far-field to the near-field may degrade optical performance. Furthermore, it is difficult to incorporate a configuration that enables large shifts of the eccentric group into an imaging device where miniaturization is required. Additionally, as described in Patent Document 2, driving the left and right optical systems to move the convergence point requires a certain amount of time, making it difficult to move the convergence point in response to the rapid movement of the subject between the far-field and near-field. Moreover, Patent Document 3 does not mention moving the convergence point in response to the movement of the subject between the far-field and near-field.

[0006] The present invention provides an imaging device that can capture images of a subject moving between long and short distances without having to drive two optical systems. [Means for solving the problem]

[0007] An imaging device as one aspect of the present invention includes an image sensor that captures an image of a subject formed by each of two parallel-arranged optical systems, Two cropped regions in the two image circles formed on the image sensor by the two optical systems. Using the signal from the image sensor 、 Image generation means for generating two stereoscopically viewable images, and acquisition means for acquiring the distance to the subject. , covered Depending on the distance to the subject, at least one of the two cropped areas is moved within the image circle to change the distance between the centers of the two cropped areas. It has a control means. When Z is the distance between the centers of the lens surfaces closest to the object in each of the two optical systems in a direction perpendicular to the optical axis of the two optical systems, and Dout is the distance between the centers of the lens surfaces closest to the image in each of the two optical systems, 2.43 ≤ Z / Dout ≤ 5.00 The conditions are met It is characterized by the following:

[0008] Another aspect of the present invention, the control method, is applied to an imaging device having an image sensor that captures a subject image formed by each of two parallel-arranged optical systems. The control method is: Two cropped regions in the two image circles formed on the image sensor by the two optical systems. Using the signal from the image sensor 、 The steps include generating two stereoscopic images and obtaining the subject distance. , coveredMove at least one of the two cutout areas within the image circle according to the subject distance to change the center distance between the two cutout areas The control step is as follows: When Z is the distance between the centers of the lens surfaces closest to the object in each of the two optical systems in a direction perpendicular to the optical axis of the two optical systems, and Dout is the distance between the centers of the lens surfaces closest to the image in each of the two optical systems, 2.43 ≤ Z / Dout ≤ 5.00 The conditions are met It is characterized by this. Note that a program for causing a computer to execute processing according to the above control method also constitutes another aspect of the present invention.

Effect of the Invention

[0009] According to the present invention, even without driving two optical systems, by moving the image cutout areas within the two image circles according to the subject distance, it is possible to satisfactorily image a subject moving between a long distance and a short distance.

Brief Description of the Drawings

[0010] [Figure 1] A diagram showing the schematic configuration of the imaging device of Example 1 and the image circle [Figure 2] A diagram showing the schematic configuration of the imaging device of Example 2 and the image circle [Figure 3] A block diagram showing the detailed configuration of the imaging device of Example 1 [Figure 4] A block diagram showing the detailed configuration of the imaging device of Example 2 [Figure 5] A block diagram showing the detailed configuration of the imaging device which is a modification of Example 1 [Figure 6] A diagram showing the relationship between the movement amount of the focus lens and the subject distance [Figure 7] A diagram showing the positions of the subject and the subject images formed by the left and right optical systems [Figure 8] A diagram showing the movement amount of the subject image according to the subject distance [Figure 9] A flowchart showing the processing performed in Example 1 [Figure 10] A diagram showing the subject distance and the cutout area within the image circle in Example 1 [Figure 11] A flowchart showing the processing performed in Example 2 [Figure 12] A diagram showing the subject distance and the cropping area within the image circle in Example 2. [Figure 13] Another diagram showing the subject distance and the cropping area within the image circle in Example 2. [Figure 14] A diagram showing the subject distance and the cropping area within the image circle in Example 3. [Figure 15] A flowchart illustrating the process performed in Example 3. [Figure 16] A diagram showing the subject distance and the cropping area within the image circle in Example 3. [Figure 17] Top cross-sectional view of the left and right optical systems in numerical example 1. [Figure 18] A side cross-sectional view of one of the optical systems in numerical example 1. [Figure 19] Aberration diagram at the wide-angle end for numerical example 1. [Figure 20] Aberration diagram at the intermediate zoom position for numerical example 1. [Figure 21] Aberration diagram at the telephoto end of numerical example 1. [Figure 22] Top cross-sectional view of the left and right optical systems in numerical example 2. [Figure 23] A side cross-sectional view of one of the optical systems in numerical example 2. [Figure 24] Aberration diagram at the wide-angle end for numerical example 2. [Figure 25] Aberration diagram at the intermediate zoom position for numerical example 2. [Figure 26] Aberration diagram at the telephoto end of numerical example 2. [Figure 27] Top cross-sectional view of the left and right optical systems in numerical example 3. [Figure 28] A side cross-sectional view of one of the optical systems in numerical example 3. [Figure 29] Aberration diagram for numerical example 3. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] The left side of Figure 1 shows a schematic configuration of a digital camera 200 as an imaging device, which is Embodiment 1 of the present invention. The digital camera 200 has a camera body bb having one image sensor ib and a lens unit Lb. The image sensor ib is a photoelectric conversion element such as a CCD sensor or a CMOS sensor. The camera body bb is further equipped with a shutter button shb. The lens unit Lb may be provided integrally with the camera body bb or may be provided detachably from the camera body bb. Note that the imaging device in this embodiment is not limited to the digital camera 200, but includes various imaging devices such as broadcast cameras and surveillance cameras. This is also true for Embodiment 2, which will be described later.

[0013] The lens unit Lb has two optical systems, LbL and LbR, arranged in parallel on the left and right sides. Both optical systems LbL and LbR have two reflective surfaces R1 and R2 that bend the optical path, and have the same configuration as each other except for the orientation of these reflective surfaces R1 and R2. The image sensor ib is positioned at the image plane (paraxial imaging position) of the two optical systems LbL and LbR.

[0014] The image circle formed by the two optical systems LbL and LbR is set so that at least a portion of the outer edge where peripheral light intensity is 0% is contained within the imaging surface (imaging area) of the image sensor ib. The two optical systems LbL and LbR are arranged at a predetermined distance (baseline length) from each other in a direction perpendicular to their optical axes. Therefore, it is possible to acquire two images (moving data) with parallax from each other using a single image sensor ib.

[0015] In the upper right corner (201) of Figure 1, the image circles ibwL and ibwR are shown, which are formed side by side on the image sensor ib with a horizontal size of hb by the left and right optical systems LbL and LbR at the wide-angle end. In this embodiment, the image circle refers to a region whose outer edge is the radial position (image height) where the peripheral light intensity is 0%. In general optical systems, the image height at which the peripheral light intensity is 0% is often designed to be outside the imaging plane of the image sensor, but in this embodiment, the image height at which the peripheral light intensity is 0% is included within the imaging plane. Furthermore, in this embodiment, the left and right image circles ibwL and ibwR are formed side by side on the imaging plane of a single image sensor ib so as not to overlap each other.

[0016] The figure also shows the radii rbwL and rbwR of the image circles ibwL and ibwR, the cropped regions sbwL and sbwR within the image circles ibwL and ibwR, and the radii ybwL and ybwR2 of these cropped regions sbwL and sbwR. It is possible to generate an image by reading signals from all pixels within the image circles ibwL and ibwR of the image sensor ib. However, in this embodiment, only the signals read from the pixels within the cropped regions sbwL and sbwR are used to generate left and right images for display on a head-mounted display, PC monitor, or the rear monitor of the camera body bb, or for recording on a recording medium. The shaded areas in the figure are the regions from the outer edges of the cropped regions sbwL and sbwR to the outer edges of the image circles ibwL and ibwR, and are regions from which signals for display or recording are not read.

[0017] The lower right corner (202) of Figure 1 shows the image circles ibtL and ibtR formed on the image sensor ib at the telephoto end. The figure also shows the radii rbtL and rbtR of the image circles ibtL and ibtR, the cropped regions sbtL and sbtR, and the radii ybtL and ybtR2 of these cropped regions sbtL and sbtR.

[0018] The left side of Figure 2 shows a schematic configuration of a digital camera 100 as an imaging device, which is Embodiment 2 of the present invention. The digital camera 100 has a camera body ba having two image sensors iaL and iaR, and a lens unit La. The image sensors iaL and iaR are photoelectric conversion elements such as a CCD sensor or a CMOS sensor a. The camera body ba is further equipped with a shutter button sha. The lens unit La may be integrally provided with the camera body ba, or it may be detachably provided with respect to the camera body ba.

[0019] The lens unit La has two optical systems, LaL and LaR, arranged in parallel on the left and right sides. The two optical systems, LbL and LbR, have identical configurations. Image sensors iaL and iaR are positioned at the image planes (paraxial imaging positions) of the two optical systems, LaL and LaR.

[0020] The image circles formed by the two optical systems, LaL and LaR, are set so that at least a portion of the outer edge where peripheral light intensity is 0% is contained within the imaging planes of the image sensors iaL and iaR. The two optical systems, LaL and LaR, are positioned with a predetermined baseline length between them, perpendicular to their optical axes. Therefore, the two image sensors iaL and iaR can acquire two images (moving data) with parallax between them.

[0021] In the upper right corner (101) of Figure 2, the image circles iawL and iawR are shown formed on the image sensors iaL and iaR, with horizontal sizes haL and haR respectively, by the left and right optical systems LaL and LaR at the wide-angle end. The image circles in this embodiment also represent the region whose outer edge is the image height at which the peripheral light intensity is 0%. In this embodiment as well, the image height at which the peripheral light intensity is 0% is included within the imaging plane.

[0022] The figure also shows the radii rawL and rawR of the image circles iawL and iawR, the cropped regions sawL and sawR within the image circles iawL and iawR, and the radii yawL and ybaR2 of these cropped regions sawL and sawR.

[0023] The lower right corner (102) of Figure 2 shows the image circles iatL and iatR formed on the image sensor elements iaL and iaR at the telephoto end. The figure also shows the radii ratL and ratR of the image circles iatL and iatR, the cropped regions satL and satR, and the radii yatL and yatR2 of these cropped regions satL and satR.

[0024] Figure 17 shows a specific configuration example (numerical example 1) of the lens unit of Embodiment 1. The lens unit 400 has two optical systems 401 and 402 arranged left and right (top and bottom in the figure) when viewed from above. IP is the image plane. One image sensor is placed on the image plane IP. Two optical images (image circles) are formed on the image sensor by the optical systems 401 and 402. Since these optical systems 401 and 402 have the same configuration as each other except for the orientation of the reflective surface which will be described later, only the configuration of optical system 401 will be described below.

[0025] The optical system 401 includes a reflective member 403. The reflective member 403 has two reflective surfaces Rf1 and Rf2 for bending the optical path. In this example, two reflective surfaces are provided on a single reflective member, but two reflective members, each having a reflective surface, may also be used.

[0026] Figure 18 shows the side view configuration of the optical system 401. The optical system 401 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, an aperture SP, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with positive refractive power, arranged in order from the object side to the image side.

[0027] In a zoom lens, a lens group is a collection of one or more lenses that move together during zooming between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming. A lens group may include an aperture diaphragm. The wide-angle and telephoto ends represent the zoom states at the maximum angle of view (shortest focal length) and minimum angle of view (longest focal length), respectively, when the lens group moving during zooming is positioned at both ends of the range that is mechanically or controllly movable along the optical axis.

[0028] In optical system 401, when zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the object in a concave trajectory, the second lens group L2 moves toward the image side, and the third lens group L3 moves toward the object side. In addition, the fourth lens group L4 and the fifth lens group L5 move toward the object side, and the sixth lens group L6 moves toward the object in a convex trajectory. At this time, the distance between the first lens group L1 and the second lens group L2 narrows and then widens, the distance between the second lens group L2 and the third lens group L3 narrows, and the distance between the third lens group L3 and the fourth lens group L4 narrows. In addition, the distance between the fourth lens group L4 and the fifth lens group L5 widens, and the distance between the fifth lens group L5 and the sixth lens group L6 widens. When zooming from the wide-angle end to the telephoto end, the first lens group L1, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move toward the object, and the second lens group L2 moves toward the image, thereby shortening the overall optical length at the wide-angle end.

[0029] The optical systems 401 and 402 in this numerical example are zoom lenses with a magnification ratio of 35.71 and an aperture ratio of approximately 4.00 to 7.00. At the wide-angle end of optical systems 401 and 402, the image height at which peripheral illumination is 0% is 6.5 mm, the image height at the outer edge of the cropped area (hereinafter referred to as the cropped image height) is 6.14 mm, the image height at which peripheral illumination is 0% at the telephoto end is 7.3 mm, and the cropped image height is 3.88 mm. The cropped image height is set to an image height that ensures sufficient light within the cropped area.

[0030] If optimization is performed across the entire zoom range while maintaining the cropped image height at the wide-angle end, the overall optical length at the telephoto end will increase proportionally to the image height. However, by setting the cropped image height at the telephoto end lower than at the wide-angle end, the overall optical length at the telephoto end can be shortened. This reduces the amount of movement of the first lens group L1, allowing the optical system 401 to be miniaturized.

[0031] The aperture SP is located between the second lens group L2 and the third lens group L3, closer to the third lens group L3. 、 During zooming, it moves independently of each lens group. This reduces the distance between the object-side surface of the first lens group L1 and the aperture SP at the wide-angle end, thereby reducing the diameter of the first lens group L1.

[0032] Furthermore, by moving the first lens group L1 towards the object when zooming from the wide-angle end to the telephoto end, the overall optical length at the wide-angle end is shortened while achieving a large magnification ratio.

[0033] Furthermore, the diameter of the frontmost surface (closest to the object) of the first lens group L1 is determined by the off-axis rays at the wide-angle end, and the diameter of the frontmost surface increases as the angle of view widens, making miniaturization difficult. For this reason, the overall optical length at the wide-angle end is shortened, the position of the first lens group L1 and the aperture SP are brought closer together, and the zoom magnification at the telephoto end is secured by moving the first lens group L1 toward the object during zooming, thereby reducing the diameter of the first lens group L1.

[0034] Furthermore, by constructing the first lens group L1 with two cemented lenses and two positive lenses, chromatic aberration is corrected, as is spherical aberration at the ultra-focal length end of the telephoto range.

[0035] Furthermore, by moving the second lens group L2 so that it is positioned closer to the image at the telephoto end compared to the wide-angle end, and the distance between the first lens group L1 and the second lens group L2 widens, the magnification effect is ensured.

[0036] Furthermore, by moving the third lens group L3 so that it is positioned closer to the object at the telephoto end compared to the wide-angle end, and the distance between the second lens group L2 and the third lens group L3 is narrowed, fluctuations in field curvature during zooming are suppressed.

[0037] Furthermore, by moving the fourth lens group L4 so that it is positioned closer to the object at the telephoto end compared to the wide-angle end, and the distance between the third lens group L3 and the fourth lens group L4 is narrowed, the zoom-magnification effect is increased and the fluctuation of field curvature is suppressed.

[0038] Furthermore, by moving the fifth lens group L5 so that it is positioned closer to the object at the telephoto end compared to the wide-angle end, and thus changing the distance between the fourth lens group L4 and the fifth lens group L5, fluctuations in field curvature during zooming are suppressed.

[0039] Furthermore, by moving the sixth lens group L6 in a convex trajectory toward the object when zooming from the wide-angle end to the telephoto end, fluctuations in field curvature during zooming are suppressed.

[0040] Furthermore, in this numerical example, focusing is performed by moving the sixth lens group L6. The solid curve fa and the dotted curve fb shown below the sixth lens group L6 in the figure represent the movement trajectories used to correct image plane fluctuations associated with zooming when focusing on an object at infinity and a nearby object, respectively. When focusing from an object at infinity to a nearby object at the telephoto end, the sixth lens group L6 moves toward the object as shown by arrow fc.

[0041] In order to move the sixth lens group L6 toward the object during focusing, a gap is provided between the fifth lens group L5 and the sixth lens group L6 to avoid mutual interference during focusing. Furthermore, in order to effectively correct image plane fluctuations during zooming, the sixth lens group L6 moves along a different trajectory than the other lens groups.

[0042] Furthermore, when the digital camera is powered off and the lens unit retracts relative to the camera body, it is possible to shorten the overall optical length by reducing the air gap between the second lens group L2 and the third lens group L3.

[0043] In this numerical example, in order to form two optical images side-by-side on a single image sensor while ensuring the baseline length of the left and right optical systems 401 and 402, a reflective member 403 having two reflective surfaces Rf1 and Rf2 is positioned on the image side of the sixth lens group L6. By positioning the reflective member 403 on the image side of the sixth lens group L6, each lens group can be moved during zooming, and the degree of freedom of the lens group to be moved can be ensured. This makes zooming possible while shortening the overall optical length.

[0044] Furthermore, the diameter of the reflective element 403 is reduced in order to perform two reflections between the sixth lens group L6 and the image sensor. In order to reduce the diameter of the reflective element 403, it is necessary to weaken the refractive power of the third lens group L3. If the refractive power of the third lens group L3 is strong, off-axis rays will be bent significantly by the third lens group L3, and the diameter of the lens group on the image side will become larger than that of the third lens group L3. Even if the refractive power of the lens groups from the third lens group L3 onward is increased in order to allow the light rays to pass through the reflective element 403, it is difficult to reduce the effective diameter of the reflective element 403, and the reflective element 403 will become larger. For this reason, the refractive power of the third lens group L3 is set to be weak.

[0045] Furthermore, by arranging the reflective surfaces Rf1 and Rf2 at a 45° angle to the optical axes of the first to sixth lens groups L1 to L6, the first to sixth lens groups L1 to L6 can be arranged efficiently. The higher the refractive index of the prism used as the reflective element 403, the longer the optical path length can be secured, so a higher refractive index of the prism is preferable.

[0046] Furthermore, when arranging identical optical systems side by side, the length of the reflective member 403 must be appropriately set to prevent the largest first lens group L1 of the left and right optical systems from interfering with each other. Specifically, the back focus is appropriately set based on the horizontal size of the image sensor, the diameter of the first lens group L1, and the refractive index of the prism.

[0047] Figures 19, 20, and 21 show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the optical system of Numerical Example 1 at the wide-angle end, intermediate zoom position, and telephoto end, respectively. In the spherical aberration diagram, Fno indicates the F number, d indicates the spherical aberration with respect to the d line (wavelength 587.6 nm), and g indicates the spherical aberration with respect to the g line (wavelength 435.8 nm). In the astigmatism diagram, S indicates the sagittal image plane and M indicates the meridional image plane. The distortion diagram shows the distortion with respect to the d line. The chromatic aberration diagram shows the lateral chromatic aberration at the g line. ω is the half-angle of view (°).

[0048] Figure 22 shows a specific configuration example (numerical example 2) of the lens unit of Embodiment 2. The lens unit 500 has two optical systems 501 and 502 arranged left and right (top and bottom in the figure) when viewed from above. IP is the image plane. An image sensor is placed on the image plane IP of each of the left and right optical systems 501 and 502. Optical images (image circles) are formed on the two image sensors by each of the optical systems 501 and 502. Since these optical systems 501 and 502 have the same configuration, only the configuration of optical system 501 will be described below.

[0049] Figure 23 shows the side view configuration of the optical system 501. The optical system 501 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, an aperture SP, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a concave trajectory toward the object side, the second lens group L2 moves toward the image side, and the third lens group L3 moves toward the object side. In addition, the fourth lens group L4 moves toward the object side, and the fifth lens group L5 moves in a convex trajectory toward the object side. At this time, the distance between the first lens group L1 and the second lens group L2 narrows and then widens, the distance between the second lens group L2 and the third lens group L3 narrows, and the distance between the third lens group L3 and the fourth lens group L4 narrows. Furthermore, the distance between the fourth lens group L4 and the fifth lens group L5 is increased. When zooming from the wide-angle end to the telephoto end, the first lens group L1, the third lens group L3, and the fourth lens group L4 move towards the object, and the second lens group L2 moves towards the image, thereby shortening the overall optical length at the wide-angle end.

[0050] The optical systems 501 and 502 in this numerical example are rim lenses with a magnification ratio of 33.52 and an aperture ratio of approximately 4.00 to 8.00. At the wide-angle end of optical systems 501 and 502, the image height at which peripheral illumination is 0% is 7.9 mm, and the cropped image height is 7.5 mm. At the telephoto end, the image height at which peripheral illumination is 0% is 6.3 mm, and the cropped image height is 3.88 mm. The cropped image height is set to ensure sufficient light within the cropped area.

[0051] If optimization is performed across the entire zoom range while maintaining the cropped image height at the wide-angle end, the overall optical length at the telephoto end will increase proportionally to the image height. However, by setting the cropped image height at the telephoto end lower than at the wide-angle end, the overall optical length at the telephoto end can be shortened. This reduces the amount of movement of the first lens group L1, allowing the optical system 501 to be miniaturized.

[0052] The aperture SP is positioned between the second lens group L2 and the third lens group L3, and moves independently of each lens group during zooming. This reduces the distance between the aperture SP and the object-facing surface of the first lens group L1 at the wide-angle end, thereby reducing the diameter of the first lens group L1.

[0053] Furthermore, by moving the first lens group L1 towards the object when zooming from the wide-angle end to the telephoto end, the overall optical length at the wide-angle end is shortened while achieving a large magnification ratio.

[0054] Furthermore, the diameter of the frontmost surface (closest to the object) of the first lens group L1 is determined by the off-axis rays at the wide-angle end, and the diameter of the frontmost surface increases as the angle of view widens, making miniaturization difficult. For this reason, the overall optical length at the wide-angle end is shortened, the position of the first lens group L1 and the aperture SP are brought closer together, and the zoom magnification at the telephoto end is secured by moving the first lens group L1 toward the object during zooming, thereby reducing the diameter of the first lens group L1.

[0055] Furthermore, by constructing the first lens group L1 with two cemented lenses and two positive lenses, chromatic aberration is corrected, as is spherical aberration at the ultra-focal length end of the telephoto range.

[0056] Furthermore, by moving the second lens group L2 so that it is positioned closer to the image at the telephoto end compared to the wide-angle end, and the distance between the first lens group L1 and the second lens group L2 widens, the magnification effect is ensured.

[0057] Furthermore, by moving the third lens group L3 so that it is positioned closer to the object at the telephoto end compared to the wide-angle end, and the distance between the second lens group L2 and the third lens group L3 is narrowed, fluctuations in field curvature during zooming are suppressed.

[0058] Furthermore, by moving the fourth lens group L4 so that it is positioned closer to the object at the telephoto end compared to the wide-angle end, and the distance between the third lens group L3 and the fourth lens group L4 is narrowed, the zoom-magnification effect is increased and the fluctuation of field curvature is suppressed.

[0059] Furthermore, by moving the fifth lens group L5 in a convex trajectory toward the object when zooming from the wide-angle end to the telephoto end, fluctuations in field curvature during zooming are suppressed.

[0060] In this numerical example, focusing is performed by moving the fifth lens group L5. The solid curve fa and the dotted curve fb shown below the fifth lens group L5 in the figure represent the movement trajectories used to correct image plane fluctuations associated with zooming when focusing on an object at infinity and a nearby object, respectively. When focusing from an object at infinity to a nearby object at the telephoto end, the fifth lens group L5 moves towards the object as shown by arrow fc.

[0061] In order to move the fifth lens group L5 toward the object during focusing, a gap is provided between the fourth lens group L4 and the fifth lens group L5 to avoid mutual interference during focusing. Furthermore, in order to effectively correct image plane fluctuations during zooming, the fifth lens group L5 moves along a different trajectory than the other lens groups.

[0062] Furthermore, when the digital camera is powered off and the lens unit retracts relative to the camera body, it is possible to shorten the overall optical length by reducing the air gap between the second lens group L2 and the third lens group L3.

[0063] Figures 24, 25, and 26 show the longitudinal aberrations of the optical system in numerical example 2 at the wide-angle end, intermediate zoom position, and telephoto end, respectively.

[0064] Figure 27 shows a specific configuration example (numerical example 3) of the lens unit of Embodiment 3. The lens unit 600 has two optical systems 601 and 602 arranged left and right (top and bottom in the figure) when viewed from above. IP is the image plane. One image sensor is placed on the image plane IP of the left and right optical systems 601 and 602. Two optical images (image circles) are formed on the image sensor by the optical systems 601 and 602. Since these optical systems 601 and 602 have the same configuration as each other except for the orientation of the reflective surface which will be described later, only the configuration of optical system 601 will be described below.

[0065] The optical system 601 has two reflective members 603 and 604 that bend the optical path. Reflective member 603 has a reflective surface Rf1, and reflective member 604 has a reflective surface Rf2. Although two reflective members 603 and 604 are provided in this numerical example, a single reflective member having reflective surfaces Rf1 and Rf2 may be used, as in numerical example 1.

[0066] Figure 28 shows a side view of the optical system 601. The optical system 601 is composed of a front group L1 with positive refractive power, reflective members 603 and 604, and a rear group L2 with positive refractive index, arranged in order from the object side to the image side. The focal length is extended by optimizing the focal lengths of the front group L1 and the rear group L2. The optical system 601 is a telephoto type single-focus optical system.

[0067] In this numerical example, the image height at which peripheral illumination is 0% in optical systems 601 and 602 is 7.2 mm, and the cropped image height is 3.88 mm. The cropped image height is set to an image height that ensures sufficient light within the cropped area. Furthermore, by setting a low cropped image height of 3.88 mm, the overall optical length is shortened.

[0068] Furthermore, by shifting the overall L0 of the optical system 601 to the object-side fc relative to the image plane IP, focusing is performed from an object at infinity to an object at close range.

[0069] In this numerical example, in order to ensure the baseline length of the left and right optical systems 601 and 602 while forming two optical images side by side on a single image sensor, reflective members 603 and 604, each having two reflective surfaces Rf1 and Rf2, are placed between the front group L1 and the rear group L2. A wide gap is required between the front group L1 and the rear group L2 to realize a telephoto type single-focus optical system, and reflective members 603 and 604 are placed within this gap.

[0070] Figure 29 shows the longitudinal aberrations of the optical system in numerical example 3 at the wide-angle end, intermediate zoom position, and telephoto end.

[0071] Figure 3 shows an example of the internal configuration of the imaging device of Embodiment 1. 10c and 20d are the right and left lens units, respectively, which include optical systems with the same configuration. 30c is the camera body. 40c is a convergence angle changing mechanism that changes the orientation of the optical axis of the right lens unit 10c.

[0072] In the right lens unit 10c, 101c is a lens group that moves during zooming and is driven by the zoom lens drive unit 103c. The zoom lens drive unit 103c drives the lens group 101c by being controlled by the drive control unit 110c in response to the user's operation of the zoom operation unit 107c. The zoom operation unit 107c is configured to allow operation of a zoom lever, zoom ring, etc. The position of the lens group 101c is detected by the drive control unit 110c via the position sensor 105c.

[0073] 102c is a lens group that moves during focusing and is driven by the focus drive unit 104c. The focus drive unit 104c drives the lens group 102c by being controlled by the drive control unit 110c in response to the user's operation of the focus operation unit 108c. The focus operation unit 108c is configured to allow operation of the shutter button (half-press) and the focus ring, etc. The position of the lens group 102c is detected by the drive control unit 110c via the position sensor 106c.

[0074] The optical system shown in Figure 17 (hereinafter referred to as the right optical system) is constructed by multiple lens groups, including lens groups 101c and 102c, and an aperture (not shown). The aperture is also controlled by the drive control unit 110c. Information on the zoom state for each position of lens group 101c and the subject distance at which each position of lens group 102c is in focus in the right optical system is recorded in memory 109c.

[0075] The left lens unit 20d has a left optical system with the same configuration as the right optical system described above. The left optical system includes lens groups 101d and 102d, which are driven by a zoom lens drive unit 103d and a focus drive unit 104d, respectively, controlled by a drive control unit 110d, and an aperture (not shown) controlled by the drive control unit 110d.

[0076] Information regarding the zoom state for each position of lens group 101d and the subject distance at which each position of lens group 102d is in focus in the left optical system is recorded in memory 109d. Using the information recorded in memories 109c and 109d, the drive control unit 110d controls the positions of lens groups 101d and 102d so that the zoom state and focus state are the same as those of the right optical system.

[0077] The camera body 30c has one image sensor 301c, an image capture control unit 302c, and a display unit 303c. The image capture control unit 302c, which acts as an image generation, acquisition, and control means, reads the charge (signal) accumulated by the image sensor 301c to generate video data. At this time, the image capture control unit 302c calculates the subject distance from the position (focus position) information of the lens groups 102c and 102d acquired from the drive control units 110c and 110d. Then, it generates video data of a cropped area corresponding to the subject distance from the image circles of the right and left optical systems on the image sensor 301c. The left and right images corresponding to the left and right video data thus generated, which have parallax with respect to each other, are displayed in the left and right display areas of the display unit 303a, such as a rear monitor. The left and right video data for recording are recorded in the memory 304c.

[0078] The convergence angle changing mechanism 40c is configured to change the orientation (angle) of all or part of the right lens unit 10c. During the manufacturing of the imaging device, the angle of the optical axis of the right lens unit 10c is adjusted so that the optical axes of the right lens unit 10c and the left lens unit 20d intersect (converge) at a reference subject distance, and this angle is stored in the memory 203c as the reference angle. When the user operates the convergence angle operation unit 201c, the right lens unit 10c rotates and the angle of its optical axis is changed. At this time, the amount of angle change from the reference angle is detected by the position sensor 202c. The amount of angle change is transmitted to the imaging control unit 302c and used by the imaging control unit 302c to determine the cropping area.

[0079] In Figure 3, the convergence angle changing mechanism 40c is shown as changing only the angle of the optical axis of the right lens unit 10c. However, it is also possible to change only the angle of the optical axis of the left lens unit 20d, or to change the angles of the optical axes of both the right and left lens units 10c and 20d.

[0080] Figure 4 shows an example of the internal configuration of the imaging device of Embodiment 2. 10a and 20b are the right and left lens units, respectively, which include optical systems with the same configuration. 30a is the camera body. 40a is a convergence angle changing mechanism that changes the orientation of the optical axis of the right lens unit 10a.

[0081] In the right lens unit 10a, 101a is a lens group that moves during zooming and is driven by the zoom lens drive unit 103a. The zoom lens drive unit 103a drives the lens group 101a by being controlled by the drive control unit 110a in response to the user's operation of the zoom operation unit 107a. The zoom operation unit 107a is configured to allow operation of a zoom lever, zoom ring, etc. The position of the lens group 101a is detected by the drive control unit 110a via the position sensor 105a.

[0082] 102a is a lens group that moves during focusing and is driven by the focus drive unit 104a. The focus drive unit 104a drives the lens group 102a by being controlled by the drive control unit 110a in response to the user's operation of the focus operation unit 108a. The focus operation unit 108a is configured to allow operation of the shutter button (half-press) and the focus ring, etc. The position of the lens group 102a is detected by the drive control unit 110a via the position sensor 106a.

[0083] The optical system shown in Figure 22 (hereinafter referred to as the right optical system) is constructed by multiple lens groups, including lens groups 101a and 102a, and an aperture (not shown). The aperture is also controlled by the drive control unit 110a. Information on the zoom state for each position of lens group 101a and the subject distance at which each position of lens group 102a is in focus in the right optical system is recorded in memory 109a.

[0084] The left lens unit 20b has a left optical system with the same configuration as the right optical system described above. The left optical system includes lens groups 101b and 102b, which are driven by a zoom lens drive unit 103b and a focus drive unit 104b, respectively, controlled by a drive control unit 110b, and an aperture (not shown) controlled by the drive control unit 110b.

[0085] Information regarding the zoom state for each position of lens group 101b and the subject distance at which each position of lens group 102b in the left optical system is focused is recorded in memory 109b. Using the information recorded in memories 109a and 109b, the drive control unit 110b controls the positions of lens groups 101b and 102b so that the zoom state and focus state are the same as those of the right optical system.

[0086] The camera body 30a includes an image sensor 301a for the right optical system, an image sensor 301b for the left optical system, an image control unit 302a for image sensor 301a, an image control unit 302b for image sensor 301b, and a display unit 303c. The image control units 302a and 302b each read the charge (signal) accumulated by the image sensors 301a and 301b to generate video data. At this time, the image control units 302a and 301b each calculate the subject distance from the position (focus position) information of the lens groups 102a and 102b obtained from the drive control units 110a and 110b. Then, they generate video data of the image circle of the right optical system on image sensor 301a and the image circle of the left optical system on image sensor 301b, with the data cropped according to the subject distance. The left and right video data thus generated, which have parallax with respect to each other, are displayed on the display unit 303a, such as a rear monitor, either overlapping each other or in different areas. The left and right video data for recording are stored in memory 304a and 304b, respectively.

[0087] The convergence angle changing mechanism 40a is configured to change the orientation (angle) of all or part of the right lens unit 10a. During the manufacturing of the imaging device, the angle of the optical axis of the right lens unit 10a is adjusted so that the optical axes of the right lens unit 10a and the left lens unit 20b intersect (converge) at a reference subject distance, and this angle is stored in the memory 203a as the reference angle. When the user operates the convergence angle operation unit 201a, the right lens unit 10a is rotated and the angle of its optical axis is changed. At this time, the amount of angle change from the reference angle is detected by the position sensor 202a. The amount of angle change is transmitted to the imaging control unit 302a and used by the imaging control units 302a and 302b to determine the cropping area.

[0088] In Figure 4, the convergence angle changing mechanism 40a is shown as changing only the angle of the optical axis of the right lens unit 10a. However, it is also possible to change only the angle of the optical axis of the left lens unit 20b, or to change the angles of the optical axes of both the right and left lens units 10a and 20b.

[0089] Figure 5 shows an example of the internal configuration of an imaging device, which is a modified example of Embodiment 1. The lens unit 10e has a right optical system and a left optical system with identical configurations. 30e is the camera body. 40e is a convergence angle changing mechanism that changes the direction of the optical axis of the left optical system.

[0090] 101e consists of left and right lens groups that move during zooming and are driven collectively by the zoom lens drive unit 103e. The zoom lens drive unit 103e drives the left and right lens groups 101e by being controlled by the drive control unit 110e in response to the user's operation of the zoom operation unit 107e. The zoom operation unit 107e is configured to allow operation of a zoom lever, zoom ring, etc. The positions of the left and right lens groups 101e are detected by the drive control unit 110e via the position sensor 105e.

[0091] 102e are the left and right lens groups that move during focusing and are driven by the focus drive unit 104e. The focus drive unit 104e is controlled by the drive control unit 110e in response to the user's operation of the focus operation unit 108e, thereby driving the left and right lens groups 102e as a single unit. The focus operation unit 108e is configured to allow half-pressing of the shutter button and operation of the focus ring, etc. The position of the left and right lens groups 102e is detected by the drive control unit 110e via the position sensor 106e.

[0092] The left and right optical systems are composed of multiple left and right lens groups, including the left and right lens groups 101e and 102e, and left and right apertures (not shown). The apertures are also controlled by the drive control unit 110e. Information on the zoom state for each position of the left and right lens group 101e and the subject distance at which the left and right lens group 102e is in focus is recorded in the memory 109e.

[0093] The camera body 30e has one image sensor 301e, an image processing unit 302e, and a display unit 303e. The image processing unit 302e reads the charge (signal) accumulated by the image sensor 301e and generates video data. At this time, the image processing unit 302e calculates the subject distance from the position (focus position) information of the lens group 102e obtained from the drive control unit 110e. Then, it generates video data of a cropped area corresponding to the subject distance from the image circles of the right and left optical systems on the image sensor 301e. The left and right video data thus generated, which have parallax with respect to each other, are displayed on the display unit 303e, such as a rear monitor, either overlapping each other or in different areas. The left and right video data for recording are recorded in memory 304e.

[0094] The convergence angle changing device 40e is configured to change the direction (angle) of the optical axis of the left optical system by shifting a part of the left optical system (the lens 111e closest to the object). During the manufacturing of the imaging device, the angle of the optical axis of the left optical system is adjusted so that the optical axes of the right optical system and the left optical system intersect (converge) at a reference subject distance, and this angle is stored in the memory 203a as the reference angle. When the user operates the convergence angle operation unit 201a, the lens 111e is shifted and the angle of the optical axis of the left optical system is changed. At this time, the amount of angle change from the reference angle is detected by the position sensor 202e. The amount of angle change is transmitted to the imaging control unit 302e and used by the imaging control unit 302e to determine the cropping area.

[0095] In Figure 5, the convergence angle changing mechanism 40e shows the case where only the angle of the optical axis of the left optical system is changed. However, the angle of the optical axis of the right optical system may be changed only, or the angles of the optical axes of both the right and left optical systems may be changed.

[0096] The upper part of Figure 6 (300) shows the relationship between the amount of movement (position) of the focus group, which is the lens group that moves during focusing in a single-focus optical system like the one described in Example 3 above, and the distance to the subject. The amount of movement of the focus group shown on the vertical axis and the distance to the subject shown on the horizontal axis have the relationship shown by curve line 1 in the figure, and the amount of movement of the focus group increases as the subject is closer.

[0097] The lower part of Figure 6 (301) shows the relationship between the amount of focus group movement and focal length for different subject distances in the zoom optical systems described in Examples 1 and 2 above. Curve line 2 in the figure shows the amount of focus group movement for each focal length for close-range subjects, curve line 4 shows the amount of focus group movement for each focal length for distant subjects, and curve line 3 shows the amount of focus group movement for each focal length for intermediate-range subjects.

[0098] Generally, for the same subject distance, the longer the focal length, the greater the amount of movement of the focus group. Data like lines 2-4 can be calculated from the paraxial value in optical design. The relationship between the amount of movement of the focus group and the subject distance is adjusted according to the amount of spherical aberration due to zooming and focusing of each optical system and the variation in spherical aberration due to manufacturing errors, and recorded as adjustment data. For example, the adjustment data for the right optical system and the left optical system in Figure 3 are recorded as ROM information in memories 109c and 109d, respectively. The drive control unit 110c determines (acquires) the subject distance using the recorded information in memory 109c and the actual amount of movement of the focus group and focal length detected through position sensors 105c and 106c. The drive control unit 110d uses the subject distance determination result of the drive control unit 110c, the recorded information in memory 109d, and the amount of movement of the focus group and focal length detected through position sensors 105d and 106d to control the left optical system so that its focal length and focusing distance are equal to those of the right eye optical system.

[0099] Here, we have explained how to obtain the subject distance from the focal length and the amount of movement of the focus group, but any method that can obtain the distance to the subject is acceptable. For example, the subject distance can be obtained using contrast detection or phase difference detection, or the distance to the subject can be measured directly.

[0100] Next, we will explain the alignment of the optical axes of the right and left optical systems. We will explain the change in the position of the subject image on the image plane in response to a change in the subject distance, starting from a state in which the optical axes of the right and left optical systems are aligned to a certain subject distance (reference state). Figure 7 shows the case in which a subject O located at a subject distance Lo, which is different from the reference distance of infinity, is imaged through the right optical system R and the left optical system L.

[0101] The right optical system R and the left optical system L both have a focal length f and are positioned apart from each other by a baseline length Z. The right optical system R and the left optical system L are adjusted during the manufacturing of the imaging device so that the centers of their left and right fields of view coincide when the subject is at infinity. The angle between the optical axis of the right optical system R and the optical axis of the left optical system L, which is directed toward the subject O, i.e., the convergence angle is 2θо. The convergence angle is defined with respect to the center of the optical system, which is the intersection point of the optical axis and the front principal point.

[0102] When an infinity-far subject is imaged at the center of the field of view of the left and right optical systems L and R, and a subject O located at subject distance Lo lies on the perpendicular bisector of the line connecting the right optical system R and the left optical system L, the amount of displacement of the subject image from the center of the image plane (image circle) of the left optical system L is: xi = Z × f / 2L It is expressed as follows.

[0103] The same amount of image shift occurs in the right optical system R as in the left optical system L. Therefore, the sum of the image shifts of the left and right subject images from the center of the image circles of the left and right optical systems L and R is: Z×f / Lo This is the result.

[0104] Figure 8 shows the case where a subject j located at an arbitrary distance is imaged. With the convergence angle adjusted so that subject j is imaged at the center of the field of view of the right optical system R and the left optical system L, the amount of displacement of the center of the subject image from the center of the image circle (hereinafter referred to as the center displacement) when a subject k, which is closer than subject j, is imaged is calculated.

[0105] Assume that subjects j and k are located on the perpendicular bisectors of the right optical system R and the left optical system L, respectively. Let Lj and Lk be the distances from the right optical system R and the left optical system L to subjects j and k, respectively. Let 2θj and 2θk be the convergence angles when the optical axes of the right optical system R and the left optical system L are aligned with subjects j and k, respectively. Let Z be the baseline length of the right optical system R and the left optical system L. In this case, the amount of center displacement xik of the image of subject k from the center of the image circle of the left optical system Lb is: xik=Z×f×(Lj×cosθj-Lk×cosθk) / 2×Lj×Lk It is expressed as follows.

[0106] At telephoto focal lengths, very close subject distances are magnified too much. Therefore, if we assume the closest subject distance is around 2m, cosθj and cosθk approximate 1, and thus xik is... xik = Z × f × (Lj - Lk) / 2 × Lj × Lk It is expressed as follows.

[0107] The right optical system R also experiences the same amount of central displacement of the subject image as the left optical system L. Therefore, the sum of the central displacement amounts of the left and right subject images from the center of the image circles of the left and right optical systems L and R is: Z × f × (Lj - Lk) / Lj × Lk This is the result.

[0108] The flowchart in Figure 9 shows the process performed in the imaging device of Example 1 (Figure 3). The imaging control unit 302c, acting as a computer, executes this process according to the computer program. This process can also be performed in the imaging devices of Example 2 (Figure 4) and Example 3 (Figure 5).

[0109] In step 1000 (hereinafter abbreviated as S), various drive information is stored in the memory area of ​​the imaging control unit 302c during the manufacturing of the imaging device. This information includes the size of the image sensor 301c, the baseline lengths of the right lens unit 10c and the left lens unit 20d, the image height at which peripheral light intensity becomes 0% for each zoom state (image circle diameter), the focus position for each subject distance to be in focus, the cropping area of ​​the video data (cropped image height), and the subject distance that serves as the reference for the convergence angle (convergence angle reference distance). In this step, the zoom state and focus state of the right lens unit 10c and the left lens unit 20d are adjusted to be the same.

[0110] In S100, the imaging control unit 302c starts processing. In S101, the imaging control unit 302c sets the zoom positions of the right lens unit 10c and the left lens unit 20d to the zoom positions corresponding to the zoom operation by the zoom operation unit 107a.

[0111] In S102, the imaging control unit 302c selects either the right lens unit 10c or the left lens unit 20d as the reference lens unit. Here, we will describe the case where the left lens unit 20d is selected as the reference lens unit. The imaging control unit 302c positions the subject image in the center of the image circle of the left lens unit 20d (i.e., the left display area of ​​the display unit 303c). Then, it performs autofocus to focus on the subject in response to the half-press operation of the shutter button on the focus operation unit 108a. At this time, the user positions the subject near the center of the image displayed in the left display area of ​​the display unit 303c and performs the half-press operation of the shutter button. When the left lens unit 20d is in focus, the right lens unit 10c also becomes in focus on the same subject.

[0112] In S103, the imaging control unit 302c calculates the distance from the focus position to the subject. In S104, the imaging control unit 302c calculates the amount of center displacement of the subject image corresponding to the right lens unit 10c from the subject distance.

[0113] In S105, the imaging control unit 302c changes the position of the cropping area in the image circle of the right lens unit 10c by the amount of the center shift.

[0114] In S106, the imaging control unit 302c terminates this process. Subsequently, if the subject moves (S107), S108 determines whether or not to change the zoom position. If it is changed, the process returns to S101; otherwise, it returns to S102.

[0115] Figure 10 shows the image circle and cropped area (SS100-SS102) on the image sensor for each positional relationship (ST100-ST102) between the imaging device and the subject. Note that while the figure shows the case where the imaging device has one image sensor, the same applies when there are two image sensors (left and right).

[0116] In ST100 to ST102, the far position from the imaging device is denoted as F, the near position is denoted as N, and the intermediate position between the far position F and the near position N is denoted as M. A is the subject (bird).

[0117] In ST100, the optical axes (convergence points) of the left and right optical systems L and R, where the zoom position is at the telephoto end, are aligned with subject A at a distant position F. SS100 shows the left and right image circles ibtL and ibtR and the left and right cropped regions stbL and stbR on the image sensor in the ST100 state. The left and right subject images imAL and imAR are located at the centers of the left and right image circles ibtL and ibtR. Therefore, the left and right cropped regions stbL and stbR are set so that their centers are located at the centers of the left and right image circles ibtL and ibtR.

[0118] In ST101, because subject A has moved to a nearby position N, the imaging device has been moved to the right so that the subject image imAL is positioned at the center of the left image circle ibtL (left cropping region stbL), as shown in SS101. The right subject image imAR is positioned to the right of the center of the right image circle ibtR, and a portion of it is outside the right cropping region stbR. At this time, when focusing on subject A, the amount of center displacement xa of the right subject image imAR is: xa = Z × f × (Lj - Lk) / Lj × Lk Therefore, the amount of center displacement xa is smaller than the radius of the right-cut region sbtR.

[0119] In SS102, by shifting the center of the right cropping region stbR to the right by xa in the state of ST101, the right subject image imAR is positioned at the center of the cropping region stbR. This makes it possible to capture / display subject images imAL and imAR, which are located at the centers of the left and right cropping regions stbL and stbR, respectively.

[0120] The cropping area is moved automatically and quickly so that the user can check whether subject A is in the center of the left and right images while recording video. In scenes where a moving subject such as a bird is being tracked, the autofocus setting should be set to focus on the center of the left optical system L's field of view. As a result, even if the zoom position is changed, the image on the right side of the display will automatically continue to show the subject centered, while the user tracks the subject while looking at the image on the left side of the display.

[0121] The flowchart in Figure 11 shows a modified version of the process shown in Figure 9. Steps S2000, S201-S204, S212, and S213 are the same as S1000, S101-104, S107, and S108 in Figure 9, respectively.

[0122] In S204, the imaging control unit 302c calculates the amount of central displacement of the subject image corresponding to the right lens unit 10c according to the subject distance. In S205, it determines whether the amount of central displacement can be corrected by moving only the cropping area in one of the right image circles. If correction is possible, the process proceeds to S206; otherwise, it proceeds to S208.

[0123] In S206, the imaging control unit 302c changes the position of the cropping area in the image circle of the right lens unit 10c by the amount of the center shift. Then, in S207, this process is completed. After that, the process returns to S201 or S202 via S212 and S213.

[0124] On the other hand, if the imaging control unit 302c determines in S205 that the amount of center misalignment cannot be corrected by moving only one of the cropped regions, it determines in S208 whether the amount of center misalignment can be corrected by moving the cropped regions in both the left and right image circles. If correction is possible, it proceeds to S209; otherwise, it proceeds to S211. In S211, the imaging control unit 302c displays on the display unit 211 that image correction is not possible.

[0125] In S209, the imaging control unit 302c changes the position of the cropping region in the image circle of the left and right lens units 20d and 10c by the sum of the center displacement amounts. At this time, the amount of movement of the cropping region in the right image circle may be set to the maximum possible movement amount within the right image circle, and the amount of movement of the cropping region in the left image circle may be set to the remaining amount as the required movement amount. Alternatively, the amount of movement of the left and right cropping regions may be set to be the same. Then, in S210, this process is completed. After that, the process returns to S201 or S202 via S212 and S213.

[0126] Figure 12 shows the image circle and cropped area (SS200-SS202) on the image sensor for each positional relationship between the imaging device and the subject (ST200-ST203). Note that while the figure shows the case where the imaging device has one image sensor, the same applies when there are two image sensors (left and right).

[0127] In ST200~ST203, the far position from the imaging device is denoted as F, the near position is denoted as N, and the intermediate position between the far position F and the near position N is denoted as M. A is the subject (bird).

[0128] In ST200, the optical axes (convergence points) of the left and right optical systems L and R, where the zoom position is at the telephoto end, are aligned with subject A at the far position F. SS200 shows the left and right image circles ibtL and ibtR and the left and right cropped regions stbL and stbR on the image sensor in the ST200 state. The left and right subject images imAL and imAR are located at the centers of the left and right image circles ibtL and ibtR. Therefore, the left and right cropped regions stbL and stbR are set so that their centers are located at the centers of the left and right image circles ibtL and ibtR.

[0129] In ST201, because subject A has moved to a nearby position N, the imaging device has been moved to the right so that the left subject image imAL is centered in the left image circle ibtL (left cropping region stbL), as shown in SS201. The right subject image imAR is located significantly to the right of the center of the right image circle ibtR, and the entire image is outside the right cropping region stbR. At this time, when focusing on subject A, the amount of center displacement xa of the right subject image imAR is: xa = Z × f × (Lj - Lk) / Lj × Lk Therefore, the amount of center displacement xa is greater than the radius of the right-cut region sbtR.

[0130] In this case, as in SS202, the cropped area sbtR is moved to the right by a movement amount xc corresponding to the maximum possible movement amount using the right image circle ibtR, while the cropped area stbL is moved by a movement amount xb corresponding to the maximum possible movement amount using the left image circle ibtL. The sum of the movement amounts xc and xb corresponds to the amount of center displacement of the subject image imAR.

[0131] However, even with the left image circle ibtL, moving the left cropping area stbL causes a portion of the subject image imAL, located at the center of the left image circle ibtL, to fall outside the cropping area stbL. Therefore, in SS203, the imaging device is moved to the left to position the left subject image imAL at the center of the cropping area stbL. This allows the subject images imAL and imAR, located at the centers of the left and right cropping areas stbL and stbR, to be captured and displayed. If, even after moving the imaging device, the left and right subject images imAL and imAR cannot be positioned within the left and right cropping areas stbL and stbR respectively, S211 displays a message indicating that image correction is not possible.

[0132] As shown in Figures 10 and 12, when the optical axes of the left and right optical systems L and R at the telephoto end are aligned with the subject A at a far position F, and the subject A moves to a near position N, the left and right cropping regions stbL and stbR move such that the distance between their centers (center spacing) widens. If the far position F is sufficiently far away, the left and right cropping regions stbL and stbR will not move in a way that narrows the distance between their centers. Therefore, within each image circle, the direction in which the cropping region moves from its center becomes unidirectional, and the maximum possible movement of the cropping region becomes small.

[0133] Therefore, as shown in ST300 in Figure 13, it is best to align the optical axes of the left and right optical systems L and R at the telephoto end with the subject A at an intermediate distance M. In this case, as shown in ST301, when subject A moves to a far position F, the left and right cropping regions stbL and stbR are moved so that the distance between their centers becomes narrower compared to SS300, as shown in SS301. Also, as shown in ST302, when subject A moves to a near position N, the left and right cropping regions stbL and stbR are moved so that the distance between their centers widens, as shown in SS302. In this way, there are two directions in which the cropping region can be moved from its center within each image circle, and the maximum amount of movement of the cropping region can be increased. That is, the cropping region can be moved using the image circle to the maximum extent possible.

[0134] The subject distance for aligning the optical axes of the left and right optical systems (L and R) may be set as the adjustment distance during the manufacturing of the imaging device, or it may be adjusted using the convergence angle adjustment mechanism for the left and right optical systems (L and R) if such a mechanism is available.

[0135] As shown in ST301, when subject A is located at the far position F, in SS301, the subject images imAL and imAR are located at the center of the cropped regions stbL and stbR, which are moved so that the distance between them is minimized within the left and right image circles ibtL and ibtR. At this time, the amount of center displacement xa is as shown above. xa = Z × f × (Lj - Lk) / Lj × Lk In SS301, the movement of the left cropping region stbL is shown as xf (=xa), and the movement of the right cropping region stbR is shown as xg (=xa).

[0136] Furthermore, as shown in ST302, when subject A is located at a nearby position N, in SS302 the cropped region stbL is moved so that the distance between them is maximized within the left and right image circles ibtL and ibtR, and the subject images imAL and imAR are located at the center of stbR. In SS301, the amount of movement of the left cropped region stbL is shown as xd (=xa), and the amount of movement of the right cropped region stbR is shown as xe (=xa).

[0137] As described above, by appropriately setting the subject distance to align the optical axes of the left and right optical systems (L and R), it becomes possible to distribute the direction of movement of the left and right cropping regions (stbL and stbR) to the left and right (the direction in which the distance between them narrows and the direction in which it widens). In other words, the range within the left and right image circles can be effectively utilized.

[0138] Figure 14 shows the image circle and cropped area (SS400-SS403) on the image sensor for each positional relationship between the imaging device and the subject (ST400-ST403). Note that while the figure shows the case where the imaging device has one image sensor, the same applies when there are two image sensors (left and right).

[0139] In ST400 to ST403, the far position from the imaging device is denoted as F, the near position is denoted as N, and the intermediate position between the far position F and the near position N is denoted as M. A is the subject (bird).

[0140] The ST400, like the ST300 in Figure 13, shows the left and right optical systems L and R at the telephoto end aligned with subject A at an intermediate distance M.

[0141] ST401 shows the state where the imaging device has been moved to the left so that the left subject image imAL is centered in the left image circle ibtL (left cropped region stbL) because subject A has moved to a distant position F. Part of the right subject image imAR is outside the right image circle ibtL. The amount of center displacement xa of the right subject image imAR at this time is: xa = Z × f × (Lj - Lk) / Lj × Lk Therefore, the amount of center displacement xa is greater than the radius of the right-cut region sbtR.

[0142] In SS402, the left and right cropping regions stbL and sbtR are moved within the left and right image circles ibtL and ibtR so that the gap between them is minimized. As a result, a portion of the left subject image imAL is moved outside the left cropping region stbL. Therefore, by moving the imaging device to the right as shown in ST403, the left and right subject images imAL and imAR can be positioned at the center of the left and right cropping regions stbL and sbtR, respectively. In S208 of Figure 11, if the left and right subject images imAL and imAR cannot be positioned within the left and right cropping regions stbL and sbtR, respectively, even after moving the imaging device, a message indicating that image correction is not possible is displayed in S211.

[0143] The flowchart in Figure 15 shows a modified version of the process shown in Figure 11. Steps S3000, S301-S310, S312, and S313 are the same as S2000, S201-S210, S212, and S213 in Figure 11, respectively.

[0144] In this modified example, if the left and right subject images cannot be positioned within the left and right cropping areas even when the left and right cropping areas are moved to their maximum extent within the left and right image circles, the convergence angle of the left and right optical systems is corrected. Specifically, if the imaging control unit 302c determines in S308 that the amount of center misalignment cannot be corrected by moving the cropping areas in both the left and right image circles, the process proceeds to S311. In S311, the imaging control unit 302c displays a message on the display unit 303c indicating that the convergence angle will be corrected, and the convergence angle is changed by rotating the right lens unit 10c with the convergence angle changing mechanism 40c. In the imaging device shown in Figure 5, the convergence angle is changed by shifting the lens group 111e of the left optical system with the convergence angle changing mechanism 40e. Such convergence angle correction is effective for macro imaging, which captures subjects at extremely close range.

[0145] Furthermore, since correcting the convergence angle in S311 changes the convergence angle reference distance, the imaging control unit 302c changes the convergence angle reference distance in S3000.

[0146] Figure 16 shows the image circle and cropped area (SS500-SS502) on the image sensor for each positional relationship between the imaging device and the subject (ST500-ST502). Note that while the figure shows the case where the imaging device has one image sensor, the same applies when there are two image sensors (left and right).

[0147] In ST500 to ST502, the far position from the imaging device is denoted as F, the near position is denoted as N, and the intermediate position between the far position F and the near position N is denoted as M. A is the subject (bird).

[0148] The ST500, like the ST300 in Figure 13, shows the left and right optical systems L and R at the telephoto end aligned with subject A at an intermediate distance M.

[0149] ST501 indicates that the right subject image imAR is significantly out of the right image circle ibtR because subject A has moved to a nearby position N. The amount of center displacement xa of the right subject image imAR at this time is: xa = Z × f × (Lj - Lk) / Lj × Lk The amount of center displacement xa is greater than the radius of the right image circle ibtR. The convergence angle is corrected when this amount of center displacement is greater than the sum of the left and right image circles ibtL, the left and right cropping regions stbL within ibtR, and the maximum movable range of sbtR.

[0150] ST502 shows a state in which the left and right subject images imAL and imAR are positioned at the center of the left and right image circles ibtL and ibtR (stbL, sbtR) due to a change in the angle of the optical axis of the right optical system R. The change in the convergence angle by the convergence angle changing mechanism 40c (40e) may be done by an actuator such as a motor, or it may be done manually by the user.

[0151] If the convergence angle is corrected, a new convergence angle reference distance is stored in S3000 of Figure 15. After this, the imaging control unit 302c calculates the amount of center misalignment using the new convergence angle reference distance. By setting the subject reference distance to the final distance N, it becomes possible to align the optical axis to even closer distances.

[0152] Next, we will describe the conditions that are preferable to satisfy in an imaging device having left and right optical systems, in order to appropriately set the cropping area on the image circle for stereoscopic observation using an observation device such as a head-mounted display. In particular, we will describe the conditions that are preferable to satisfy in order to quickly move the left and right cropping areas relative to the subject.

[0153] Let r be the radius of the image circle, h be the horizontal size of the imaging area (imaging plane) on the image sensor, y be the radius of the image cropping region within the image circle, f be the focal length of each optical system, Z be the distance between the centers of the left and right optical systems closest to the object (baseline length), and L be the distance to the subject. The horizontal size h is the width in the direction of arrangement of the left and right optical systems (i.e., the left-right direction). Let Lj be the reference subject distance (convergence angle reference distance), which is the distance to the subject j where the optical axes (convergence points) of the left and right optical systems align, Lk be the distance to the subject k, dbmax be the maximum value of the distance between the centers of the left and right cropping regions, and dbmin be the minimum value of this distance. Let Dout be the distance between the centers of the left and right optical systems closest to the image (final surface), yw be the radius of each cropping region at the wide-angle end, yt be the radius of each cropping region at the telephoto end, rw be the radius of the image circle at the wide-angle end, and rt be the radius of the image circle at the telephoto end. When the imaging device has two image sensors, one for the left and one for the right optical system, the maximum distance between the centers of the left and right cropped regions is defined as dbmax2, and the minimum distance is defined as dbmin2. Furthermore, in each optical system as a zoom lens, the focal length of the first lens group closest to the object is defined as f1, and the focal length of the second lens group second from the object side is defined as f2. In this case, it is preferable that the imaging device of each embodiment satisfies at least one of the following conditions (1) to (13). 0.12 ≤ r / h ≤ 0.70 (1) 0.30 ≤ y / r < ​​1.00 (2) 0.01 ≤ Z × f / L ≤ r ≤ 0.70 (3) 0.00 <Z×f×(Lj-Lk) / Lj×Lk×y≦0.35 (4) 1.0 <dbmax / dbmin≦5.0 (5) 1.00 ≤ Z / Dout ≤ 5.00 (6) 1.50 ≤ Z / dbmax ≤ 5.00 (7) 2.00 ≤ Z / dbmin ≤ 10.00 (8) 1.20 ≤ yw / yt ≤ 3.00 (9) 0.50 ≤ rw / rt ≤ 1.50 (10) 0.80 ≤ Z / dbmax2 ≤ 3.00 (11) 1.00 ≤ Z / dbmin2 ≤ 10.00 (12) -10.0 ≤ f1 / f2 ≤ -5.0 (13) Equation (1) shows the conditions relating the radius r of the image circle where peripheral light intensity is 0% and the horizontal size h of the image-capable area of ​​the image sensor. When the image circle becomes larger such that r / h exceeds the upper limit of equation (1), it is advantageous for moving the cropping area significantly, but it is undesirable because the optical system becomes larger. Also, it is undesirable because a large portion of the image circle falls outside the image-capable area. When the image circle becomes smaller such that r / h falls below the lower limit of equation (1), it is advantageous for miniaturizing the optical system, but it is undesirable because the amount of movement of the cropping area becomes smaller.

[0154] Equation (2) shows the conditions relating the radius r of the image circle to the radius (image light) y of the cropping area. If the cropping area becomes large enough so that y / r exceeds the upper limit of equation (2), the amount of movement of the cropping area becomes small, which is undesirable. If the cropping area becomes small enough so that y / r falls below the lower limit of equation (2), sufficient movement of the cropping area is ensured, but the image acquired from the cropping area becomes too small, resulting in black areas where there is no image around the displayed image, which is undesirable.

[0155] Equation (3) shows the conditions relating the sum of the center displacement amounts of the left and right subject images relative to infinity, when the subject distance Lo is 5m, to the radius r of each image circle. Lo = 5m is the distance at which the left and right subject images are to be positioned within the left and right cropping regions by moving the cropping region without changing the convergence angle of the optical axes of the left and right optical systems. If Z × f / Lo × r exceeds the upper limit of equation (3), it becomes necessary to correct the convergence angle or reduce the size of the cropping region, which is undesirable because the image that can be observed by the viewer without moving their head when observing with a head-mounted display becomes too small. If Z × f / Lo × r falls below the lower limit of equation (3), it is undesirable because the amount of movement of the cropping region becomes too small.

[0156] Equation (4) shows the conditions relating the sum of the center displacement amounts of the left and right subject images at a reference subject distance Lj, ​​where the reference subject distance Lj is 10m and the subject distance Lk is 5m, to the diameter of each cropped region. Lk = 5m is the distance at which the left and right subject images are to be positioned within the left and right cropped regions by moving the cropped region alone, without changing the convergence angle of the optical axes of the left and right optical systems. If the value of equation (4) exceeds the upper limit, it becomes necessary to correct the convergence angle or reduce the size of the cropped region, which is undesirable because the image that can be observed by the viewer without moving their head when observing with a head-mounted display becomes too small. If the value of equation (4) falls below the lower limit, it is undesirable because the amount of movement of the cropped region becomes too small.

[0157] Equation (5) shows the conditions relating the maximum center distance dbmax and the minimum center distance dbmin of the left and right cropping regions. If dbmax / dbmin exceeds the upper limit of equation (5), the cropping region becomes too small relative to the image circle, which is undesirable. If dbmax / dbmin falls below the lower limit of equation (5), the movable amount of each cropping region becomes too small, which is also undesirable.

[0158] Equation (6) shows the conditions relating the baseline length Z of the left and right optical systems to the center distance Dout of the image-side surface (final surface). If the baseline length increases so that Z / Dout exceeds the upper limit of equation (6), it is advantageous for ensuring parallax between the left and right parallax images at the telephoto end, but it is undesirable because the imaging device becomes larger in the lateral direction. If the baseline length decreases so that Z / Dout falls below the lower limit of equation (6), it is advantageous for miniaturizing the imaging device, but it is undesirable because it becomes difficult to ensure parallax between the left and right parallax images at the telephoto end.

[0159] Equation (7) shows the conditions relating the baseline length Z of the left and right optical systems to the maximum center distance dbmax of the left and right cropped regions. When the baseline length increases so that Z / dbmax exceeds the upper limit of equation (7), it is advantageous for ensuring parallax between the left and right disparity images at the telephoto end, but it is undesirable because the amount of movement of each cropped region becomes too small. When the baseline length decreases so that Z / dbmax falls below the lower limit of equation (7), it is advantageous for miniaturizing the imaging device and increasing the amount of movement of the cropped regions, but it is undesirable because it becomes difficult to ensure parallax between the left and right disparity images at the telephoto end.

[0160] Equation (8) shows the conditions relating the baseline length Z of the left and right optical systems to the minimum center distance dbmin of the left and right cropped regions. When the baseline length increases so that Z / dbmin exceeds the upper limit of equation (8), the amount of movement of each cropped region increases, but this is undesirable because the image circle becomes larger and the imaging device becomes larger. When the baseline length decreases so that Z / dbmin falls below the lower limit of equation (8), the amount of movement of each cropped region decreases, and it becomes difficult to ensure parallax between the left and right parallax images at the telephoto end, which is also undesirable.

[0161] Equation (9) shows the conditions relating the radius yw of each cropped region at the wide-angle end to the radius yt of each cropped region at the telephoto end. When the radius of the cropped region at the telephoto end decreases so that yw / yt exceeds the upper limit of equation (9), the overall length of each optical system at the telephoto end is shortened, which is advantageous for miniaturizing the imaging device. However, this is undesirable because the image that the viewer can observe without moving their head on a head-mounted display becomes too small. Also, this is undesirable because the number of display pixels may become insufficient for the required number. When the radius of the cropped region at the telephoto end increases so that yw / yt falls below the lower limit of equation (9), the overall length of each optical system at the telephoto end increases, which is undesirable.

[0162] Equation (10) shows the conditions relating the radius rw of the image circle at the wide-angle end to the radius rt of the image circle at the telephoto end. When the radius of the image circle at the telephoto end decreases so that rw / rt exceeds the upper limit of equation (10), the overall length of each optical system at the telephoto end is shortened, which is advantageous for miniaturizing the imaging device. However, this is undesirable because the amount of movement of each cropping region becomes too small. When the radius of the image circle at the telephoto end increases so that rw / rt falls below the lower limit of equation (10), the overall optical length at the telephoto end increases, which is undesirable.

[0163] Equation (11) shows the conditions relating the baseline length of the left and right optical systems and the maximum center distance dbmax2 of the left and right cropped regions when the imaging device has two image sensors, one for the left and one for the right optical system. If the baseline length increases so that Z / dbmax2 exceeds the upper limit of equation (11), it is advantageous for ensuring the parallax of the left and right disparity images at the telephoto end, but it is undesirable because the amount of movement of each cropped region becomes too small. If the baseline length decreases so that Z / dbmax2 falls below the lower limit of equation (11), it is advantageous for miniaturizing the imaging device and ensuring the amount of movement of each cropped region, but it is undesirable because it becomes difficult to ensure the parallax of the left and right disparity images at the telephoto end.

[0164] Equation (12) shows the conditions relating the baseline length of the left and right optical systems and the minimum center distance dbmin2 of the left and right cropped regions when the imaging device has two image sensors, one for the left and one for the right optical system. When the baseline length increases so that Z / dbmin2 exceeds the upper limit of equation (12), it is advantageous to ensure parallax between the left and right disparity images at the telephoto end and to ensure the amount of movement of each cropped region. However, this is undesirable because the image circle becomes larger and the imaging device becomes larger. When the baseline length decreases so that Z / dbmin2 falls below the lower limit of equation (12), the amount of movement of each cropped region becomes too small, and it becomes difficult to ensure parallax between the left and right disparity images at the telephoto end, which is undesirable.

[0165] Equation (13) shows the conditions relating the focal length f1 of the first lens group and the focal length f2 of the second lens group when the left and right optical systems are zoom lenses. If the focal length of the first lens group is increased so that f1 / f2 exceeds the upper limit of equation (13), it is advantageous for improving the performance of each optical system, but it is undesirable because the amount of movement of the first and second lens groups becomes large, making it difficult to control their simultaneous movement. If the focal length of the first lens group is shortened so that f1 / f2 falls below the lower limit of equation (13), the amount of movement of the first and second lens groups becomes small, which is advantageous for miniaturization, but it is undesirable because it becomes difficult to correct spherical aberration and field curvature during zooming.

[0166] It is preferable to set the numerical ranges for equations (1) to (13) as follows. 0.15 ≤ r / h ≤ 0.65 (1a) 0.40 ≤ y / r ≤ 0.97 (2a) 0.012≦Z×f / Lо×r≦0.650 (3a) 0.003≦Z×f×(Lj-Lk) / Lj×Lk×y≦0.320 (4a) 1.01≦dbmax / dbmin≦3.50 (5a) 1.00 ≤ Z / Dout ≤ 4.50 (6a) 2.00 ≤ Z / dbmax ≤ 4.00 (7a) 3.00 ≤ Z / dbmin ≤ 7.00 (8a) 1.30 ≤ yw / yt ≤ 2.50 (9a) 0.60 ≤ rw / rt ≤ 1.35 (10a) 0.90 ≤ Z / dbmax2 ≤ 2.90 (11a) 1.00 ≤ Z / dbmin2 ≤ 8.00 (12a) -9.50 ≤ f1 / f2 ≤ -6.00 (13a) It is even preferable to set the numerical ranges for equations (1) to (13) as follows. 0.18 ≤ r / h ≤ 0.60 (1b) 0.50 ≤ y / r ≤ 0.95 (2b) 0.013≦Z×f / Lо×r≦0.600 (3b) 0.005≦Z×f×(Lj-Lk) / Lj×Lk×y≦0.300 (4b) 1.02≦dbmax / dbmin≦2.70 (5b) 1.00 ≤ Z / Dout ≤ 4.00 (6b) 2.30 ≤ Z / dbmax ≤ 3.50 (7b) 3.40 ≤ Z / dbmin ≤ 5.50 (8b) 1.50 ≤ yw / yt ≤ 2.00 (9b) 0.75 ≤ rw / rt ≤ 1.20 (10b) 0.92 ≤ Z / dbmax2 ≤ 2.80 (11b) 1.00 ≤ Z / dbmin2 ≤ 7.10 (12b) -9.00 ≤ f1 / f2 ≤ -6.50 (13b) Numerical examples 1-3 are shown below. Surface number i indicates the order of the surfaces when counted from the object side. r is the radius of curvature (mm) of the i-th surface from the object side, d is the lens thickness or air gap (mm) between the i-th and (i+1)-th surfaces, and nd is the refractive index of the optical material at the d-line between the i-th and (i+1)-th surfaces. νd is the Abbe number based on the d-line of the optical material between the i-th and (i+1)-th surfaces. BF represents the back focus (mm). Back focus is the distance along the optical axis from the final surface of the optical system (the lens surface closest to the image) to the paraxial image plane, expressed in terms of air-equivalent length. The total lens length is the distance along the optical axis from the frontmost surface of the optical system (the lens surface closest to the object) to the final surface plus the back focus.

[0167] The Abbe number νd is expressed as νd = (Nd-1) / (NF-NC), where Nd, NF, and NC are the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm).

[0168] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where x is the displacement from the surface vertex in the direction of the optical axis, h is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, K is the cone constant, and A4, A6, A8, A10, A12 are aspherical coefficients. x=( h 2 / R) / [1+{1-(1+K)(h / R) 2} 1 / 2 ]+A4h 4 +A6h 6 +A8h 8 The aspherical coefficient "ex" is multiplied by 10. -x It means...

[0169] Figures 19 and 24 show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end of the optical systems in numerical examples 1 and 2. Figures 20 and 25 show the longitudinal aberrations at the intermediate zoom position of numerical examples 1 and 2. Figure 29 shows the longitudinal aberrations at the wide-angle end of the optical system in numerical example 3. In the spherical aberration diagram, Fno indicates the F number and shows the spherical aberration with respect to the d line (wavelength 587.6 nm) and the g line (wavelength 435.8 nm). In the astigmatism diagram, S indicates the sagittal image plane and M indicates the meridional image plane. The distortion aberration diagram shows the distortion aberration with respect to the d line. The chromatic aberration diagram shows the lateral chromatic aberration at the g line. ω is the half-angle of view (°).

[0170] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd Effective diameter 1 250.000 1.45 1.91082 35.3 47.54 2 57.764 5.96 1.49700 81.5 43.61 3 -475.675 0.05 42.65 4 63.151 4.56 1.59410 60.5 43.20 5 710.617 0.05 42.99 6 81.595 3.14 1.59410 60.5 42.32 7 413.402 (Variable) 42.00 8 157.816 0.60 1.88300 40.8 25.96 9 18.950 5.60 21.69 10 -36.349 0.50 1.83481 42.7 20.99 11 19.317 0.16 19.97 12 20.113 2.79 1.98612 16.5 20.00 13 71.869 (Variable) 19.79 14 (aperture) ∞ (variable) 9.30 15* 13.110 2.26 1.77047 29.7 9.43 16* -36.732 0.20 9.15 17 -27.101 0.60 1.83400 37.3 9.07 18 15.718 (Variable) 8.75 19 108.649 0.60 1.80450 39.6 9.77 20 26.869 1.92 1.49700 81.5 9.79 21 -25.364 (variable) 9.90 22 103.224 1.59 1.49700 81.5 9.90 23 -22.125 0.50 1.85883 30.0 9.88 24 -42.059 (variable) 9.93 25 84.352 1.76 1.49700 81.5 10.52 26 -20.273 0.50 1.78590 43.9 10.60 27 -35.010 (variable) 10.73 28 ∞ 10.50 2.00100 29.1 10.82 29 ∞ 21.00 2.00100 29.1 11.06 (prism reflection surface) 30 ∞ 10.50 2.00100 29.1 11.54 (prism reflection surface) 31 ∞ (variable) 11.78 Image plane ∞ Aspherical data Page 15 K = 2.84841e-001 A 4=-2.53821e-005 A 6=-4.85031e-007 A 8= 4.50616e-009 Page 16 K =-3.53308e+001 A 4=-1.01064e-004 A 6= 5.15231e-007 Various data Zoom ratio 35.71 Wide-angle, Medium, Telephoto Focal length 8.40 14.17 300.00 F-number 4.00 4.99 7.00 Half-angle (°): 40.7 15.7 0.74 Cutout image height 6.14 3.88 3.88 Light intensity 0% image height 6.50 7.10 6.50 Lens length: 138.99, 132.68, 188.99 BF 35.97 44.12 36.30 d 7 0.45 1.26 60.71 d13 50.06 18.55 0.80 d14 2.44 13.04 -0.60 d18 9.11 8.24 1.00 d21 2.46 1.01 2.64 d24 3.72 11.67 53.35 d27 1.50 9.65 1.83 d31 13.48 13.48 13.48 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 82.86 15.21 6.65 -2.96 2 8 -12.59 9.65 2.71 -4.43 3 14 ∞ 0.00 0.00 -0.00 4 15 356.78 3.06 -40.74 -38.18 5 19 63.95 2.52 1.79 0.17 6 22 112.08 2.09 1.11 -0.23 7 25 71.00 2.26 1.14 -0.33 8 28 ∞ 42.00 10.49 -10.49 Single lens data Lens starting plane, focal length 1 1 -82.77 2 2 104.03 3 4 116.36 4 6 170.51 5 8 -24.44 6 10 -15.05 7 12 27.58 8 15 12.79 9 17 -11.85 10 19 -44.52 11 20 26.58 12 22 36.81 13 23 -54.99 14 25 33.07 15 26 -62.21 16 28 0.00 17 29 0.00 18 30 0.00 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd Effective diameter 1 142.550 1.45 1.88300 40.8 40.00 2 66.794 3.74 1.43875 94.7 39.49 3 935.558 0.05 39.46 4 70.567 3.44 1.43875 94.7 39.40 5 642.715 0.00 39.22 6 111.958 1.92 1.59410 60.5 38.87 7 345.572 (variable) 38.65 8* 126.028 0.60 1.75500 52.3 22.38 9* 10.327 6.15 16.90 10 -29.055 0.00 1.88300 40.8 16.37 11 -29.055 0.50 1.88300 40.8 16.37 12 40.959 0.10 16.33 13 24.349 2.77 1.85896 22.7 16.58 14 -78.697 (variable) 16.44 15 (aperture) ∞ (variable) 7.08 16* 11.060 2.83 1.74400 44.8 8.61 17* -39.247 0.77 8.54 18 389.972 0.60 1.69895 30.1 8.33 19 6.621 2.13 1.49700 81.5 8.07 20 15.492 (Variable) 8.15 21 16.175 0.50 1.96300 24.1 10.53 22 8.000 1.76 1.95906 17.5 10.30 23 12.137 (Variable) 10.15 24 21.869 5.15 1.49700 81.5 14.12 25 -12.207 0.50 1.76200 40.1 14.40 26 -20.370 (variable) 14.90 27 ∞ 0.80 1.51633 64.1 20.00 28 ∞ (Variable) 20.00 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4=-2.12982e-05 A 6= 5.62507e-08 A 8= 4.76749e-11 9th page K = 0.00000e+00 A 4=-3.68061e-05 A 6=-5.71106e-08 A 8=-4.14334e-09 Page 16 K = 6.46931e-01 A 4=-1.03133e-04 A 6=-9.71941e-07 A 8=-1.60550e-08 Page 17 K = 0.00000e+00 A 4= 6.69019e-05 A 6=-6.08186e-07 Various data Zoom ratio 33.52 Wide-angle, Medium, Telephoto Focal length 8.95 16.65 300.00 F-number 4.00 4.99 8.00 Half-angle (°): 39.96 13.10 0.74 Cutout image height 7.50 3.88 3.88 Light intensity 0% image height 7.90 6.30 6.10 Lens length: 99.27 x 108.25 x 179.73 BF 14.73 23.08 7.52 d 7 0.75 22.47 99.98 d14 25.18 12.26 0.30 d15 11.58 7.92 0.01 d20 6.09 1.67 5.15 d23 5.99 5.88 31.82 d26 13.44 21.79 6.23 d28 0.76 0.76 0.76 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 122.24 10.60 3.60 -3.44 2 8 -13.84 10.12 0.42 -8.11 3 15 ∞ 0.00 0.00 -0.00 4 16 25.87 6.33 -4.73 -7.55 5 21 -68.60 2.26 6.26 4.68 6 24 26.90 5.65 1.76 -2.12 Single lens data Lens starting plane, focal length 1 1 -143.63 2 2 163.73 3 4 180.34 4 6 277.91 5 8 -14.93 6 10 0.00 7 11 -19.19 8 13 21.92 9 16 11.88 10 18 -9.64 11 19 21.55 12 21 -16.95 13 22 20 25 14 24 16.60 15 25 -41.07 16 27 0.00 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd Effective diameter 1 47.841 2.76 1.95375 32.3 18.33 2 -79.697 1.71 17.97 3 -63.932 1.10 1.89286 20.4 16.62 4 111.773 25.65 16.11 5 (aperture) ∞ 3.00 9.50 6 ∞ 6.00 1.56883 56.4 11.00 7 ∞ 6.00 1.56883 56.4 11.00 (Prism reflecting surface) 8 ∞ 9.50 11.00 9 ∞ 6.00 1.56883 56.4 11.00 10 ∞ 18.00 1.56883 56.4 11.00 (Prism reflecting surface) 11 ∞ 3.69 11.00 12 -14.605 0.50 1.72151 29.2 11.23 13 17.357 0.20 12.36 14 19.323 3.60 1.95375 32.3 12.62 15 -20.877 12.98 13.08 Image plane ∞ Various data Focal length 85.01 F-number 5.50 Half angle of view (°) 2.61 Cut-out image height 7.30 Image height at 0% light quantity 3.88 Overall lens length 100.69 BF 12.98 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 85.01 87.71 67.12 -72.03 Single lens data Lens Starting surface Focal length 1 1 31.68 2 3 -45.42 3 6 0.00 4 7 0.00 5 9 0.00 6 10 0.00 7 12 -10.92 8 14 11.00 Table 1 summarizes the values ​​of equations (1) to (13) in the following Examples 1-1 to 3-3. Examples 1-1 and 1-2 show the values ​​of equations (1) to (13) at the wide-angle and telephoto ends of an imaging device having one image sensor with an aspect ratio of 3:2 and a horizontal size of 36.0 mm, and the left and right optical systems of Numerical Example 1, respectively.

[0171] Examples 2-1 and 2-2 show the values ​​of equations (1) to (13) at the wide-angle and telephoto ends of an imaging device having two image sensors with an aspect ratio of 3:2 and a horizontal size of 23.33 mm, and the left and right optical systems of numerical example 1, respectively.

[0172] Examples 2-3 and 2-4 show the values ​​of equations (1) to (13) at the wide-angle and telephoto ends of an imaging device having two image sensors with an aspect ratio of 3:2 and a horizontal size of 23.33 mm, and the left and right optical systems of numerical example 2, respectively.

[0173] Example 3-1 shows the numerical values ​​of equations (1) to (13) for an imaging device having one image sensor with an aspect ratio of 3:2 and a horizontal size of 36.0 mm, and the left and right optical systems of numerical example 3.

[0174] Example 3-2 shows the values ​​of equations (1) to (13) at the wide-angle and telephoto ends of an imaging device having two image sensors with an aspect ratio of 3:2 and a horizontal size of 23.33 mm, and the left and right optical systems of numerical example 3.

[0175] Example 3-3 shows the values ​​of equations (1) to (13) at the wide-angle and telephoto ends of an imaging device having two image sensors with an aspect ratio of 3:2 and a horizontal size of 13.13 mm, and the left and right optical systems of numerical example 3.

[0176] [Table 1]

[0177] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0178] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of Symbols]

[0179] LbL Left Lens Unit LbR Right Lens Unit ib image sensor 302c Imaging Control Unit ibtL, ibtR Image Circle sbtL, sbtR Extraction Area

Claims

1. An image sensor that captures the subject image formed by each of two parallel-arranged optical systems, Image generation means that generates two stereoscopic images using signals from the image sensor in two cropped regions in two image circles formed on the image sensor by the two optical systems, A means for obtaining the subject distance, The system includes a control means that moves at least one of the two cropped regions within the image circle according to the subject distance to change the distance between the centers of the two cropped regions, When Z is the distance between the centers of the lens surfaces closest to the object in each of the two optical systems in a direction perpendicular to the optical axis of the two optical systems, and D is the distance between the centers of the lens surfaces closest to the image in each of the two optical systems, 2.43 ≤ Z / Dout ≤ 5.00 An imaging device characterized by satisfying the following conditions.

2. The imaging apparatus according to claim 1, characterized in that the control means widens the center spacing as the subject distance decreases.

3. The imaging apparatus according to claim 1 or 2, characterized in that the control means, starting from a state where the centers of the two cropped regions, each containing the subject image of a subject located at an intermediate distance between a long distance and a short distance, are located at the centers of the two image circles, narrows the distance between the centers as the subject distance moves from the intermediate distance towards the long distance, and widens the distance between the centers as the subject distance moves towards the short distance.

4. When the image circle is defined as the region on the imaging area of ​​the image sensor whose outer edge is the image height at which the peripheral light intensity is 0%, and the radius of the image circle is r, and the size of the imaging area in the direction in which the two optical systems are arranged is h, 0.12 ≤ r / h ≤ 0.70 An imaging device according to any one of claims 1 to 3, characterized in that it satisfies the following conditions.

5. Let y be the radius of each of the two cut-out regions. 0.30≦y / r<1.00 The imaging apparatus according to claim 4, characterized in that it satisfies the following conditions.

6. The imaging apparatus according to any one of claims 1 to 5, characterized in that the control means uses the distance at which the optical axes of the two optical systems converge as a reference distance, the focal length of each of the two optical systems as f, and the subject distance as Lo, calculates the amount of displacement of the subject image from the center of the image circle according to Z × f / Lo, corresponding to the difference between the reference distance and the subject distance, and moves at least one of the cropped regions according to the amount of displacement.

7. When the radius of each of the two image circles is r and the subject distance Lo is 5m, 0.01 ≤ Z × f / Lo × r ≤ 0.70 The imaging device according to claim 6, characterized in that it satisfies the following conditions.

8. The imaging apparatus according to any one of claims 1 to 5, characterized in that the control means uses the distance Lj at which the optical axes of the two optical systems converge as a reference distance, the focal length of each of the two optical systems as f, and the subject distance as Lk, calculates the amount of displacement of the subject image from the center of the image circle according to Z × f × (Lj - Lk) / Lj × Lk, corresponding to the difference between the reference distance and the subject distance, and moves at least one of the cropping regions according to the amount of displacement.

9. When the radius of each of the two image circles is r, the reference distance Lj is 10 m, and the subject distance Lk is 5 m, 0.00<Z×f×(Lj-Lk) / Lj×Lk×r≦0.35 The imaging apparatus according to claim 8, characterized in that it satisfies the following conditions.

10. When the maximum value of the center distance is dbmax and the minimum value is dbmin, 1.0<dbmax / dbmin≦5.0 An imaging device according to any one of claims 1 to 9, characterized in that it satisfies the following conditions.

11. When the maximum value of the aforementioned center distance is denoted as dbmax, 1.50 ≤ Z / dbmax ≤ 5.00 An imaging apparatus according to any one of claims 1 to 10, characterized in that it satisfies the following conditions.

12. When the minimum value of the center distance is denoted as dbmin, 2.00 ≤ Z / dbmin ≤ 10.00 An imaging apparatus according to any one of claims 1 to 11, characterized in that it satisfies the following conditions.

13. The two optical systems described above are capable of zooming between the wide-angle end and the telephoto end, When the radius at the wide-angle end and the radius at the telephoto end of the two cropped regions are denoted as yw and yt respectively, 1.20 ≤ yw / yt ≤ 3.00 An imaging device according to any one of claims 1 to 12, characterized in that it satisfies the following conditions.

14. The two optical systems described above are capable of zooming between the wide-angle end and the telephoto end, The image circle is defined as the region on the imaging area of ​​the image sensor whose outer edge is the image height at which the peripheral light intensity is 0%, and the radius of the image circle at the wide-angle end is rw, and the radius at the telephoto end is rt. 0.50 ≤ rw / rt ≤ 1.50 An imaging device according to any one of claims 1 to 13, characterized in that it satisfies the following conditions.

15. The image sensor comprises two image sensors: one on which one of the two image circles is formed and another on which the other image circle is formed, and when the maximum value of the center distance is dbmax2, 0.80 ≤ Z / dbmax² ≤ 3.00 An imaging device according to any one of claims 1 to 14, characterized in that it satisfies the following conditions.

16. The image sensor comprises two image sensors: one on which one of the two image circles is formed and another on which the other image circle is formed, and the minimum value of the center distance is dbmin2. 1.00 ≤ Z / dbmin2 ≤ 10.00 An imaging apparatus according to any one of claims 1 to 15, characterized in that it satisfies the following conditions.

17. The two optical systems described above are each capable of zooming between the wide-angle end and the telephoto end, and have a first lens group with positive refractive power and a second lens group with negative refractive power arranged sequentially from the object side to the image side. When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, -10.0 ≤ f1 / f2 ≤ -5.0 An imaging device according to any one of claims 1 to 16, characterized in that it satisfies the following conditions.

18. A control method for an imaging device having an image sensor that captures an image of a subject formed by each of two parallel-arranged optical systems, The steps include generating two stereoscopic images using signals from the image sensor in two cropped regions within two image circles formed by the two optical systems on the image sensor, Steps to obtain the subject distance, The control step includes moving at least one of the two cropped regions within the image circle according to the subject distance to change the distance between the centers of the two cropped regions, When Z is the distance between the centers of the lens surfaces closest to the object in each of the two optical systems in a direction perpendicular to the optical axis of the two optical systems, and D is the distance between the centers of the lens surfaces closest to the image in each of the two optical systems, 2.43 ≤ Z / Dout ≤ 5.00 A control method characterized by satisfying the following conditions.

19. A program characterized by causing a computer to execute a process according to the control method described in claim 18.

Images