Stereoscopic imaging device for dental treatment and stereoscopic observation system for dental treatment

Abstract

A stereoscopic imaging device is provided that can suitably capture an image of the inside of a narrow hole in a subject as a stereoscopically visible image. [Solution] The stereoscopic imaging device 2A comprises an imaging unit 21 having an imaging area divided into left and right, a convergence angle setting unit 10 that sets the convergence angle between the left and right imaging areas and the subject, and a display control unit 31A that controls the image captured by the imaging unit 21, and the convergence angle setting unit 10 sets the convergence angle with respect to the subject to be greater than 0° and not more than 5°.

Description

[Technical Field]

[0001] The present invention relates to a technique for capturing an image of a subject in a manner that allows it to be viewed stereoscopically. [Background technology]

[0002] As a technique for capturing images of a subject that can be viewed stereoscopically, Patent Document 1 describes a stereo photography device in which a stereo adapter is attached to a lens-shutter camera. The stereo adapter is equipped with a first reflecting mirror and a second reflecting mirror. Sunlight from the subject is reflected by the first reflecting mirror and then the second reflecting mirror, and enters the lens-shutter camera. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-064216 Summary of the Invention [Problem to be solved by the invention]

[0004] In this stereo photography device, the convergence angle of the subject can be set by changing the orientation of the first reflecting mirror, which is located outward to the left and right of the second reflecting mirror. However, with this stereo photography device, the convergence angle becomes large when the distance to the subject is short, and the range in which stereoscopic vision is possible is narrow.

[0005] Furthermore, in conventional stereo microscopes, the convergence angle is set to about 12°. For example, when stereoscopically viewing the inside of a tooth root canal during dental treatment, it is difficult to obtain a stereoscopic view of the deep inside of the root canal using a stereo microscope with such a convergence angle.

[0006] The present invention has been made in view of the above points, and provides a method for suitably capturing an image of the inside of a narrow hole in a subject as a stereoscopic image. For dental treatment Stereoscopic imaging device and For dental treatmentThe object is to provide a stereoscopic observation system. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, For dental treatment The stereoscopic imaging device includes an imaging unit having imaging regions divided into left and right halves, a convergence angle setting unit that sets a convergence angle between the left and right imaging regions and a subject, and a display control unit that controls an image captured by the imaging unit, wherein the convergence angle setting unit: Located at a distance of 300mm to 1000mm from the convergence angle setting unit The convergence angle is set to be greater than 0° and equal to or less than 5° with respect to the subject. [Effects of the Invention]

[0008] According to the present invention, the convergence angle can be set small, and it is possible to suitably capture an image of the inside of a narrow hole in a subject, such as the inside of a root canal of a tooth, as a stereoscopic image. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram schematically showing a stereoscopic observation system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view schematically showing a convergence angle setting unit. [Figure 3] 10A and 10B are diagrams for explaining an example of an image rearrangement method by a rearrangement unit, in which (a) is a diagram schematically showing an image when a subject is imaged at a focal length, (b) is a diagram schematically showing an image when a subject is imaged at a distance farther than the focal length, and (c) is a diagram schematically showing an image when the area and subject are aligned in the case of (b). [Figure 4] 10A and 10B are diagrams for explaining an example of an image rearrangement method by a rearrangement unit, in which (a) is a diagram schematically showing an image when a subject is imaged at a focal length, (b) is a diagram schematically showing an image when a subject is imaged closer than the focal length, and (c) is a diagram schematically showing an image when the area and subject are aligned in the case of (b). [Figure 5]10A and 10B are schematic diagrams for explaining examples of the offset amount between the center of the subject and the center of the imaging area. [Figure 6] 10A and 10B are diagrams for explaining an example of changing the magnification of an image by a magnification change unit, in which (a) is a diagram schematically showing the image and display range when the magnification is relatively small (before changing the magnification), and (b) is a diagram schematically showing the image after changing the magnification. [Figure 7] 1A and 1B are diagrams showing examples of stereoscopic display devices, where FIG. 1A is a diagram showing a single device that displays left and right images, and FIG. 1B is a diagram showing two devices that display left and right images, respectively. [Figure 8] 4 is a flowchart for explaining an example of the operation of the stereoscopic observation system according to the first embodiment of the present invention. [Figure 9] FIG. 10 is a block diagram schematically showing a stereoscopic observation system according to a second embodiment of the present invention. [Figure 10] 10 is a flowchart for explaining an example of the operation of the stereoscopic observation system according to the second embodiment of the present invention. [Figure 11] FIG. 10 is a block diagram schematically showing a stereoscopic observation system according to a third embodiment of the present invention. [Figure 12] FIG. 2 is a plan view schematically showing a convergence angle setting unit. [Figure 13] 10 is a flowchart for explaining an example of the operation of the stereoscopic observation system according to the third embodiment of the present invention. [Figure 14] FIG. 10 is a block diagram schematically showing a stereoscopic observation system according to a fourth embodiment of the present invention. [Figure 15] 10 is a flowchart for explaining an example of the operation of the stereoscopic observation system according to the fourth embodiment of the present invention. [Figure 16] FIG. 10 is a plan view schematically showing a stereoscopic display device of a stereoscopic observation system according to a fifth embodiment of the present invention. [Figure 17] FIG. 10 is a plan view schematically showing a stereoscopic display device of a stereoscopic observation system according to a fifth embodiment of the present invention, and is a diagram for explaining the convergence angle of a displayed virtual image. [Figure 18]FIG. 10 is a plan view schematically showing a stereoscopic display device of a stereoscopic observation system according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same elements are given the same reference numerals, and duplicated explanations will be omitted. Directional expressions in the drawings indicate the corresponding relationships between the drawings.

[0011] First Embodiment As shown in Fig. 1, a stereoscopic observation system 1A according to a first embodiment of the present invention is a system (more specifically, a stereoscopic observation system for dental treatment) that captures an image of the inside of a root canal of a tooth (see Fig. 2) as a narrow hole 4a of a subject 4 and displays the image in a stereoscopic manner. The stereoscopic observation system 1A comprises a stereoscopic imaging device 2A and a stereoscopic display device 3.

[0012] <Stereoscopic imaging device> The stereoscopic imaging device 2A includes a convergence angle setting unit 10, an imaging device 20A, and a control unit 30A. The stereoscopic imaging device 2A is a device (more specifically, a stereoscopic imaging device for dental examination) that generates a pair of left and right images (stereo images) that allow a stereoscopic view of the subject 4 by capturing images of the subject 4 from different angles using one imaging device 20A. The stereoscopic imaging device 2A is, for example, a stereoscopic microscope.

[0013] <Convergence angle setting unit> 2, the convergence angle setting unit 10 sets the convergence angle θ between the imaging areas 20L and 20R divided into left and right and the subject 4. In this embodiment, the convergence angle θ is the angle between the subject 4 and the optical components of the convergence angle setting unit that are arranged closest to the subject 4 (in this embodiment, mirrors 12L and 12R, which will be described later).

[0014] The convergence angle setting unit 10 includes a left optical system 11L and a right optical system 11R as the optical system 11. The optical system 11 includes mirrors 12 (12L, 12R) and prisms 13 (13L, 13R) as optical components of the left optical system 11L and the right optical system 11R, respectively. The optical system 11 includes a prism 14 as an optical component common to the left optical system 11L and the right optical system 11R. The convergence angle setting unit 10 realizes the optical system using the mirror 12, the prism 13, and the prism 14, thereby enabling the subject 4 to be photographed at a short distance. Furthermore, the mirror 12 of the convergence angle setting unit 10 can also realize variability in the convergence angle θ, as in third and fourth embodiments described below.

[0015] The mirror 12 is disposed between the subject 4 and the prism 14 in the optical axis direction of the imaging device 20A. The mirror 12 has a reflecting surface 12a. The reflecting surface 12a is a first reflecting surface that reflects light 5 from the subject 4 outward in the left-right direction. In the left optical system 11L, the reflecting surface 12a of the mirror 12L reflects light 5L from the subject 4 to the left. In the right optical system 11R, the reflecting surface 12a of the mirror 12R reflects light 5R from the subject 4 to the right. Note that in Figures 2 and 12, the line drawn as light 5 is the optical axis of light 5.

[0016] Prism 13 is disposed outward in the left-right direction from mirror 12 and prism 14. Prism 13 includes incident / exit surface 13a, reflecting surface 13b, and reflecting surface 13c. Reflecting surface 13b is a second reflecting surface that reflects light 5 incident from reflecting surface 12a through incident / exit surface 13a toward imaging device 20A in the optical axis direction. In left optical system 11L, prism 13L is disposed to the left of mirror 12L and prism 14. Reflecting surface 13b of prism 13L reflects light 5L reflected by reflecting surface 12a of mirror 12L toward reflecting surface 13c. In right optical system 11R, prism 13R is disposed to the right of mirror 12R and prism 14. Reflecting surface 13b of prism 13R reflects light 5R reflected by reflecting surface 12a of mirror 12R toward reflecting surface 13c.

[0017] Reflecting surface 13c is a third reflecting surface that reflects light 5L reflected by reflecting surface 13b inward to the left and right. In left optical system 11L, reflecting surface 13c of prism 13L reflects light 5L reflected by reflecting surface 13b of prism 13L in the right direction. In right optical system 11R, reflecting surface 13c of prism 13R reflects light 5R reflected by reflecting surface 13b of prism 13R in the left direction.

[0018] Prism 14 is disposed between mirror 12 and imaging device 20A in the optical axis direction of imaging device 20A. Prism 14 includes reflecting surface 14a belonging to left optical system 11L and reflecting surface 14b belonging to right optical system 11R. Reflecting surface 14a is a fourth reflecting surface that reflects light 5L from reflecting surface 13c of prism 13L toward imaging device 20A in the optical axis direction, causing the light to enter left imaging region 20L of imaging unit 21. Reflecting surface 14b is a fourth reflecting surface that reflects light 5R from reflecting surface 13c of prism 13R toward imaging device 20A in the optical axis direction, causing the light to enter right imaging region 20R of imaging unit 21.

[0019] In this way, light 5L from the subject 4 is reflected by the left optical system 11L, i.e., by the reflective surface 12a of the mirror 12L, the reflective surfaces 13b and 13c of the prism 13L, and the reflective surface 14a of the prism 14, and then enters the left imaging region 20L of the imaging device 20A. Meanwhile, light 5R from the subject 4 is reflected by the right optical system 11R, i.e., by the reflective surface 12a of the mirror 12R, the reflective surfaces 13b and 13c of the prism 13R, and the reflective surface 14b of the prism 14, and then enters the right imaging region 20R of the imaging device 20A.

[0020] In this embodiment, the convergence angle setting unit 10 sets the convergence angle θ by the attitude of the fixed mirrors 12L and 12R. Furthermore, because the mirrors 12L and 12R are arranged so as to be narrower in the left-right direction than the reflecting surfaces 13c of the prisms 13L and 13R, the convergence angle setting unit 10 can set the convergence angle θ to a small value even when the distance to the subject 4 is short.

[0021] The convergence angle setting unit 10 desirably sets the convergence angle θ to greater than 0° and equal to or less than 5° at a working distance L. Here, the working distance L is the distance in the optical axis direction of the imaging device 20A between the point at which light 5 is reflected by the reflecting surface 12a of the mirror 12 and the subject 4. When the subject 4 is a tooth requiring root canal treatment, the working distance L is preferably in the relatively short range of 300 mm to 1000 mm, more preferably 300 mm to 500 mm. Note that the convergence angle setting unit 10 may be configured to set the convergence angle θ to greater than 0° and equal to or less than 5° for a subject 4 whose working distance L is greater than 1000 mm.

[0022] Here, we will explain the convergence angle θ when the distance W between the points where light 5 from the subject 4 is reflected on the reflective surfaces 12a of the left and right mirrors 12, i.e., the distance W between the point where the optical axis of light 5L is reflected on the reflective surface 12a of mirror 12L and the point where the optical axis of light 5R is reflected on the reflective surface 12a of mirror 12R, is set to 20.0 mm. When the working distance L is 300 mm, the convergence angle θ is approximately 3.78°, and when the working distance L is 400 mm, the convergence angle θ is approximately 2.86°. When the working distance L is 500 mm, the convergence angle θ is approximately 2.29°, and when the working distance L is 1000 mm, the convergence angle θ is approximately 1.15°. In this way, by setting the distance W between the reflecting surfaces 12a of the left and right mirrors 12 narrow (approximately 20.0 mm), the convergence angle θ can be set to be greater than 0° and equal to or less than 5° within the above-mentioned range of working distance L, allowing the inside of the root canal of the tooth, which is the hole 4a of the subject 4, to be suitably imaged and a stereoscopic image to be generated. Furthermore, by setting the convergence angle θ even smaller, the displacement m between the subject 4, which is the tooth, and the viewpoint from the front side of the tooth to the back of the root canal, which is the hole 4a, becomes approximately constant (the difference between the displacement m between the subject 4 and the viewpoint on the front side of the tooth and the displacement m between the subject 4 and the viewpoint at the back of the root canal is very small), allowing suitably stereoscopic viewing from the front side of the tooth to the back of the root canal. Here, the displacement m between the subject 4 and the viewpoint is the offset amount between the centers of the left and right imaging areas, i.e., the centers of the left and right display areas 3L and 3R, and the centers of the left and right subjects 4 imaged in those imaging areas. 2 and 12, which will be described later, depict the deviation m corresponding to one (left optical system 11L) of the left and right optical systems 11. The distance W can be set based on the distance to the front side of the subject 4 and the convergence angle θ at which the hole 4a of the subject 4 can be suitably imaged.

[0023] A root canal of a tooth, which is an example of the subject 4, is a hole with a diameter of 1 mm or less (approximately 0.5 mm). To observe the depths of a root canal with a diameter of 1 mm and a depth of 12 mm, the convergence angle θ must be set to approximately 4.8° or less. To observe the depths of a root canal with a diameter of 0.5 mm and a depth of 12 mm, the convergence angle θ must be set to approximately 2.4° or less. Note that a conventional stereomicroscope with a convergence angle of 12° can only observe a root canal with a diameter of 0.5 mm to a depth of 2.38 mm. Therefore, it is desirable for the convergence angle setting unit 10 to set the convergence angle θ to 5° or less, and more desirably to set the convergence angle θ to 3° or less.

[0024] That is, the convergence angle setting unit 10 includes a left optical system 11L and a right optical system 11R. The distance W between the points where the optical axis of light 5 from the subject 4 is reflected on the reflecting surface 12a of the left optical system 11L or the right optical system 11R, which is closest to the subject 4, is set to 20.0 mm. This allows the convergence angle setting unit 10 to set the convergence angle θ to be greater than 0° and equal to or less than 5° with a simple configuration when the working distance L is in the range of 300 mm to 1000 mm. Note that the number, angle, etc. of reflecting surfaces other than the reflecting surface 12a can be changed as appropriate as long as the light 5 from the subject 4 can be captured in the left and right imaging regions of the imaging device 20A via the reflecting surface 12a.

[0025] Here, we will explain the working distance L when imaging the inside of a root canal of a tooth, which is the hole 4a of the subject 4, during dental treatment. From the perspective of placing hands, treatment instruments, etc., inside the patient's oral cavity, it is preferable to ensure a space of 300 mm or more between the stereoscopic microscope serving as the stereoscopic imaging device 2A and the patient's mouth. Furthermore, from the perspective of operability of treatment instruments, etc., inside the oral cavity, it is preferable that the distance between the stereoscopic microscope serving as the stereoscopic imaging device 2A and the patient's mouth be set to preferably 1000 mm or less, more preferably 500 mm or less.

[0026] <Imaging device> As shown in FIG. 1, the imaging device 20A includes an imaging section 21 and an imaging control section 22A.

[0027] <Image capture unit> The imaging unit 21 includes a control board 21a, an imaging element 21b, an optical system 21c, and an optical system driving unit 21d.

[0028] <Control board> The control board 21a includes an electronic circuit having a plurality of electronic components mounted on the board. The control board 21a is electrically connected to the image sensor 21b, the optical system driving unit 21d, and the imaging control unit 22A. The control board 21a outputs an electrical signal from the image sensor 21b to the imaging control unit 22A. The control board 21a also controls the optical system driving unit 21d based on a control signal from the imaging control unit 22A.

[0029] <Image sensor> The imaging element 21b forms an image of light from the subject 4, converts the formed light into an electrical signal (digital signal), and outputs the converted electrical signal to the control board 21a. The imaging element 21b has an imaging area divided into left and right halves. Here, the "imaging area divided into left and right halves" refers to the planar imaging element 21b being partitioned at the center in the left-right direction and divided into a left imaging area and a right imaging area, and does not refer to two planar imaging elements arranged side by side and spaced apart from each other. The left and right imaging areas are set to correspond to the left and right optical systems 11 of the convergence angle setting unit 10, respectively.

[0030] ≪Optical system≫ The optical system 21c is a group of optical components (lenses, etc.) arranged in front of the imaging element 21b.

[0031] <Optical system drive unit> The optical system driving unit 21d is configured with a motor or the like, and changes the focal position by driving the optical system 21c. The optical system driving unit 21d outputs a focus position value, which is position information of the optical components of the optical system 21c, to the distance measurement unit 22b as a value related to the focal position.

[0032] <Imaging control unit> The imaging control unit 22A is configured with a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), an input / output circuit, etc. The imaging control unit 22A includes, as functional units, a focus changing unit 22a and a distance measuring unit 22b.

[0033] <<Focus change section>> The focus changing unit 22a controls the optical system driving unit 21d via the control board 21a to drive the optical system 21c and change the focal position (focus function).

[0034] <Distance measurement section> Distance measurement unit 22b measures the distance from image sensor 21b to subject 4 and / or the distance from mirror 12 to subject 4, and outputs the measured distance to control unit 30A. Distance measurement unit 22b measures the length of the optical path of light 5 reflected by convergence angle setting unit 10 as the distance from image sensor 21b or a distance sensor serving as distance measurement unit 22b to subject 4.

[0035] <Control unit> The control unit 30A is configured with a CPU, a ROM, a RAM, an input / output circuit, etc. The control unit 30A includes a display control unit 31A as a functional unit.

[0036] <Display control section> The display control unit 31A controls the display content of the image of the subject 4 captured by the imaging unit 21 on the stereoscopic display device 3, and includes a rearrangement unit 31a and a magnification change unit 31b.

[0037] <Relocation part> The rearrangement unit 31a moves the display ranges 6L, 6R based on the measurement results of the distance measurement unit 22b and a preset convergence angle θ, and rearranges (aligns) the image of the subject 4 to the center of the display areas 3L, 3R. In the convergence angle setting unit 10 of this embodiment, the convergence angle θ is fixed to a preset angle, so a shift m occurs between the subject 4 and the viewpoint as the distance to the subject 4 changes. In response to this, the rearrangement unit 31a eliminates the shift m between the subject 4 and the viewpoint by suitably moving the display ranges 6L, 6R, and can generate an image of the subject 4 that is suitable for stereoscopic viewing.

[0038] For example, consider a case where the distance between the subject 4 and the stereoscopic imaging device 2A increases from the state shown in Fig. 3(a) where the image of the subject 4 is located at the center of the display ranges 6L and 6R. In this case, the change in the distance to the subject 4 causes a deviation m between the subject 4 and the viewpoint, and the subject 4 moves away from each other in the imaging areas 20L and 20R, as shown in Fig. 3(b). In response to this, the rearrangement unit 31a moves the left and right display ranges 6L and 6R to follow the image of the subject 4, as shown in Fig. 3(c), thereby displaying the image of the subject 4 at the center of the display areas 3L and 3R.

[0039] Next, a case will be described in which the distance between the subject 4 and the stereoscopic imaging device 2A decreases from the state in which the image of the subject 4 is positioned at the center of the display ranges 6L and 6R shown in Fig. 4(a). In this case, the change in the distance to the subject 4 causes a deviation m between the subject 4 and the viewpoint, and as shown in Fig. 4(b), the subject 4 moves closer to each other in the imaging areas 20L and 20R. In response to this, the rearrangement unit 31a moves the left and right display ranges 6L and 6R to follow the image of the subject 4, as shown in Fig. 4(c), thereby displaying the image of the subject 4 at the center of the display areas 3L and 3R.

[0040] <Relocation Method 1> Here, a first control method by the rearrangement unit 31a will be described. First, the distance measurement unit 22b measures the distance to the subject 4. Next, the rearrangement unit 31a calculates the displacement m [mm] between the subject 4 and the viewpoint and the magnification ratio based on the measured distance. Next, the rearrangement unit 31a calculates the offset amount [pixels] between the center of the image of the subject 4 and the centers of the display areas 3L, 3R based on the displacement m between the subject 4 and the viewpoint, the magnification ratio, and the number of pixels in the horizontal direction of the display areas 3L, 3R. Next, the rearrangement unit 31a moves the display ranges 6L, 6R based on the calculated offset amount, thereby aligning the center of the image of the subject 4 with the centers of the display areas 3L, 3R.

[0041] <Relocation Method 2> Next, a second control method by the rearrangement unit 31a will be described. First, based on experiments, a database containing the relationship between the imaging distance and the offset amount between the center of the image of the subject 4 and the center of the display areas 3L and 3R, and / or a relational expression (approximation) between the imaging distance and the offset amount [pixel] based on the database is generated in advance. Next, the distance measurement unit 22b measures the distance to the subject 4. Next, the rearrangement unit 31a calculates the offset amount based on the measured distance and the database or the relational expression. Next, the rearrangement unit 31a moves the display ranges 6L and 6R based on the calculated offset amount, thereby aligning the center of the image of the subject 4 with the center of the display areas 3L and 3R.

[0042] As shown in FIG. 5, the offset amount is the amount of deviation in the image width direction (i.e., the above-mentioned deviation m) between the display center at which the image of subject 4 (4L, 4R) should be displayed and the center of the image of subject 4 (4L, 4R) in each of the left display area 3L where the image of subject 4L captured in the left imaging area 20L is displayed and the right display area 3R where the image of subject 4R captured in the right imaging area 20R is displayed. Offset amount [mm] = Center position of subject image - Center of display Offset amount [pixel] = Offset amount [mm] x Number of pixels in image width / Image width [mm]

[0043] <Magnification change section> 1, magnification change unit 31b changes the magnification of the image of subject 4. For example, magnification change unit 31b can display the image of subject 4 larger by reducing the display range (increasing the magnification) (FIG. 6(a) → FIG. 6(b)), or can display the image of subject 4 smaller by expanding the display range (reducing the magnification).

[0044] The magnification change unit 31b may be configured to set the magnification of the subject 4 based on the pixel size of the stereoscopic display device 3. For example, when the stereoscopic display device 3 has a relatively low resolution (i.e., when the pixel size of the stereoscopic display device 3 is large), the magnification change unit 31b can prevent the subject 4 from being displayed too large by setting the magnification to a small value. Also, when the stereoscopic display device 3 has a relatively high resolution (i.e., when the pixel size of the stereoscopic display device 3 is small), the magnification change unit 31b can prevent the subject 4 from being displayed too small by setting the magnification to a large value.

[0045] <Stereoscopic display device> The stereoscopic display device 3 is a device (more specifically, a stereoscopic display device for dental treatment) that displays left and right images of a subject 4 based on output from a display control unit 31A, allowing an observer to see the displayed left and right images in a stereoscopic manner. As shown in FIG. 7(a), a display device 3X that constitutes a part of the stereoscopic display device 3 is configured with a liquid crystal monitor or the like, and displays images of subjects 4L and 4R as the left and right imaging results on one display device 3X. As a stereoscopic display device 3 that includes such a display device 3X, stereoscopic display devices 3E and 3F, which will be described later, can be used.

[0046] 7(b), a stereoscopic display device 3Y as an example of the stereoscopic display device 3 displays images of subjects 4L and 4R as left and right imaging results on left and right stereoscopic display devices 3YL and 3YR, respectively. A 3D monitor, 3D glasses, a VR headset, VR goggles, etc. can be used as the stereoscopic display device 3Y.

[0047] ≪Relocation operation example≫ As shown in the flowchart of FIG. 8, the focus changing unit 22a controls the optical system driving unit 21d to execute the autofocus function, thereby adjusting the focal position on the subject 4 (step S11). Subsequently, the optical system driving unit 21d outputs a focus position value to the distance measuring unit 22b (step S12). Here, the focus position value is a value related to the position of the optical components of the optical system 21c associated with the autofocus function. Subsequently, the distance measuring unit 22b calculates the distance to the subject 4 based on the focus position value (step S13). Here, the distance measuring unit 22b can calculate the distance to the subject 4 based on the relationship between the focus position value and the distance to the subject 4 that is stored in advance. Subsequently, the rearrangement unit 31a aligns the center of the image of the subject 4 with the display ranges 6L and 6R using the rearrangement method described above (step S14).

[0048] Here, the relationship between the working distance L and the focus position value is determined in advance by experiment, and an approximation formula for the approximation curve is generated from an approximation curve of a graph of this relationship. The distance measurement unit 22b can calculate the distance to the subject 4 from the focus position value based on this approximation formula.

[0049] A stereoscopic imaging device 2A according to a first embodiment of the present invention comprises an imaging unit 21 having imaging areas 20L and 20R divided into left and right, a convergence angle setting unit 10 that sets the convergence angle θ between the left and right imaging areas 20L and 20R and a subject 4, and a display control unit 31A that controls the image captured by the imaging unit 21, and the convergence angle setting unit 10 sets the convergence angle θ with respect to the subject to be greater than 0° and not greater than 5°. Therefore, the stereoscopic imaging device 2A can widen the range of stereoscopic vision within the distance to the subject 4, and can suitably capture images of the inside of a narrow hole 4a of a small subject 4, such as the inside of a tooth root canal. Furthermore, the stereoscopic imaging device 2A can generate images that can reduce eye fatigue of the viewer.

[0050] The convergence angle setting unit 10 sets the convergence angle θ to a value greater than 0° and equal to or less than 5° for the subject 4 located at a distance (working distance L) from the convergence angle setting unit 10 of 300 mm to 1000 mm. Therefore, the stereoscopic imaging device 2A can more suitably capture images of the inside of a narrow hole 4a of a small subject 4, such as the inside of a root canal of a tooth.

[0051] The convergence angle setting unit 10 is an optical system 11 (11L, 11R) that uses at least one of a mirror 12 and prisms 13 and 14. Therefore, the stereoscopic imaging device 2A can implement the convergence angle setting section 10 using simple optical components.

[0052] The stereoscopic imaging device 2A includes a distance measurement unit 22b that measures the distance to the subject 4, and the display control unit 31A arranges the left and right images based on the distance and the convergence angle θ. Therefore, the stereoscopic imaging device 2A can appropriately generate a stereoscopic image in response to a displacement m between the subject 4 and the viewpoint caused by a change in the distance to the subject 4.

[0053] The display control unit 31A outputs the arranged left and right images to one display device 3X. Therefore, the stereoscopic imaging device 2A can suitably display stereoscopic images on a general-purpose display device.

[0054] The display control unit 31A outputs the arranged left and right images to the left and right display devices (stereoscopic display devices 3YL, 3YR) corresponding to the left and right images, respectively. Therefore, the stereoscopic imaging device 2A can suitably display stereoscopic images on a display device dedicated to stereoscopic viewing.

[0055] The distance measurement unit 22b measures the distance using an autofocus function. Therefore, the stereoscopic imaging device 2A can suitably measure the distance to the subject 4 using the functions of a general-purpose imaging device.

[0056] The display control unit 31A can change the display magnification of the left and right images. Therefore, the stereoscopic imaging device 2A can preferably display an image of a part of the subject 4 that should be focused on by enlarging it, or can preferably display an image of the entire subject 4 by reducing it.

[0057] The convergence angle setting unit 10 includes, on each of the left and right sides, a first reflecting surface (reflecting surface 12a) that reflects light 5 from the subject 4 outward to the left and right, a second reflecting surface (reflecting surface 13b) that reflects the light 5 reflected by the first reflecting surface toward the imaging unit 21 in the optical axis direction, a third reflecting surface (reflecting surface 13c) that reflects the light reflected by the second reflecting surface inward to the left and right, and a fourth reflecting surface (reflecting surfaces 14a, 14b) that reflects the light reflected by the third reflecting surface toward the optical axis direction and makes it incident on the imaging unit 21. Therefore, the stereoscopic imaging device 2A can achieve the desired distance to the subject 4 and the desired convergence angle θ with fewer reflecting surfaces.

[0058] Moreover, the stereoscopic observation system 1A according to the first embodiment of the present invention comprises a stereoscopic imaging device 2A and a stereoscopic display device 3 that displays images captured by the stereoscopic imaging device 2A. Therefore, the stereoscopic observation system 1A can suitably capture an image of the subject 4 as a stereoscopically viewable image and suitably display the image as a stereoscopically viewable image. Furthermore, the stereoscopic observation system 1A can reduce eye fatigue of the observer.

[0059] Second Embodiment Next, a stereoscopic observation system according to a second embodiment of the present invention will be described, focusing on the differences from the stereoscopic observation system 1A according to the first embodiment. As shown in Fig. 9, the stereoscopic observation system 1B according to the second embodiment of the present invention includes a stereoscopic imaging device 2B instead of the stereoscopic imaging device 2A.

[0060] Stereoscopic imaging device 2B includes imaging device 20B instead of imaging device 20A, and also includes distance measurement unit 40. Imaging device 20B includes imaging control unit 22B instead of imaging control unit 22A. Imaging control unit 22B does not include distance measurement unit 22b.

[0061] <Distance measurement section> The distance measurement unit 40 is configured separately from the imaging control unit 22B and is a distance sensor (such as an infrared sensor) that detects the distance to the subject 4 and outputs the detection result to the control unit 30A. The distance measurement unit 40 measures the length of the optical path along which the light 5 is reflected by the convergence angle setting unit 10 as the distance from the imaging element 21b or the distance sensor serving as the distance measurement unit 22b to the subject 4.

[0062] ≪Relocation operation example≫ In this operation example, the distance measurement unit 40 is a distance sensor that measures the distance to the subject 4. As shown in the flowchart of FIG. 10, the distance measurement unit 40 measures the distance to the subject 4 (step S21). Next, the focus change unit 22a controls the optical system drive unit 21d to adjust the focal position to the measured distance (step S22). Next, the rearrangement unit 31a uses the above-mentioned rearrangement method to align the center of the image of the subject 4 with the display ranges 6L and 6R (step S23).

[0063] In a stereoscopic imaging device 2B according to the second embodiment of the present invention, a distance measurement unit 40 is a distance sensor that measures the distance to the subject 4. Therefore, the stereoscopic imaging device 2B can suitably measure the distance to the subject 4 using, for example, an infrared sensor.

[0064] <Third embodiment> Next, a stereoscopic observation system according to a third embodiment of the present invention will be described, focusing on the differences from the stereoscopic observation system 1A according to the first embodiment. As shown in FIG. 11, a stereoscopic observation system 1C according to the third embodiment of the present invention includes a stereoscopic imaging device 2C instead of the stereoscopic imaging device 2A. The stereoscopic imaging device 2C includes a convergence angle setting section 10 similar to that of the first embodiment. However, in this embodiment, the convergence angle setting section 10 is configured to vary the convergence angle θ, for example, within a range greater than 0° and equal to or less than 5°. Furthermore, the stereoscopic imaging device 2C includes a convergence angle changing section 50, and a control section 30C instead of the control section 30A.

[0065] <Convergence angle change unit> The convergence angle change unit 50 is composed of a motor, a transmission mechanism that transmits the power of the motor to the mirror 12, etc., and changes the posture of the mirror 12 (12L, 12R) to change the convergence angle θ (see Figure 12).

[0066] <Control unit> The control unit 30C includes a display control unit 31C as a functional unit instead of the display control unit 31A. The display control unit 31C does not include the rearrangement unit 31a. The control unit 30C also includes a convergence angle control unit 32 as a functional unit. That is, by including the convergence angle control unit 32, the control unit 30C has a configuration in which the rearrangement unit 31a is omitted.

[0067] <Convergence angle control unit> The convergence angle control unit 32 controls the convergence angle changing unit 50 based on the distance to the subject 4 measured by the distance measurement unit 22b. That is, the convergence angle control unit 32 changes the convergence angle θ by changing the attitude of the mirror 12 based on the distance to the subject 4, and aligns the center of the image of the subject 4 with the centers of the display areas 3L and 3R, thereby generating an image of the subject 4 that is suitable for stereoscopic viewing.

[0068] ≪Relocation operation example≫ 13, focus change unit 22a controls optical system driver 21d to execute the autofocus function, thereby adjusting the focal position on subject 4 (step S11). Subsequently, optical system driver 21d outputs the focus position value to distance measurement unit 22b (step S12). Subsequently, distance measurement unit 22b calculates the distance to subject 4 based on the focus position value (step S13). Subsequently, convergence angle control unit 32 sets the convergence angle θ by controlling convergence angle change unit 50 based on the calculated distance, and aligns the center of the image of subject 4 with display areas 3L and 3R (step S15).

[0069] A stereoscopic imaging device 2C according to a third embodiment of the present invention includes a distance measurement unit 22b that measures the distance to the subject 4, a convergence angle change unit 50 that changes the convergence angle θ set by the convergence angle setting unit 10, and a convergence angle control unit 32 that controls the convergence angle change unit 40, and the convergence angle control unit 32 controls the convergence angle change unit 50 to set the convergence angle θ based on the distance. Therefore, the stereoscopic imaging device 2B can appropriately respond to changes in the distance to the subject 4 and appropriately generate images for stereoscopic viewing.

[0070] <Fourth embodiment> Next, a stereoscopic observation system according to a fourth embodiment of the present invention will be described, focusing on the differences from the stereoscopic observation system 1C according to the third embodiment. As shown in Fig. 14, the stereoscopic observation system 1D according to the fourth embodiment of the present invention includes a stereoscopic imaging device 2D instead of the stereoscopic imaging device 2C.

[0071] Stereoscopic imaging device 2D includes imaging device 20B instead of imaging device 20A, and also includes distance measurement unit 40. Imaging device 20B includes imaging control unit 22B instead of imaging control unit 22A. Imaging control unit 22B does not include distance measurement unit 22b.

[0072] <Distance measurement section> The distance measurement unit 40 is configured separately from the imaging control unit 22B and is a distance sensor (such as an infrared sensor) that detects the distance to the subject 4 and outputs the detection result to the control unit 30A. The distance measurement unit 40 measures the length of the optical path along which the light 5 is reflected by the convergence angle setting unit 10 as the distance from the imaging element 21b or the distance measurement unit 40 to the subject 4.

[0073] ≪Relocation operation example≫ In this operation example, the distance measurement unit 40 is a distance sensor that measures the distance to the subject 4. As shown in the flowchart of FIG. 15, the distance measurement unit 40 measures the distance to the subject 4 (step S21). Next, the focus change unit 22a controls the optical system drive unit 21d to adjust the focal position to the measured distance (step S22). Next, the convergence angle control unit 32 sets the convergence angle θ by controlling the convergence angle change unit 50 based on the measured distance, and aligns the center of the image of the subject 4 with the display areas 3L and 3R (step S24).

[0074] In a stereoscopic imaging device 2D according to the fourth embodiment of the present invention, the distance measurement unit 40 is a distance sensor that measures the distance to the subject 4. Therefore, the stereoscopic imaging device 2D can suitably measure the distance to the subject 4 using, for example, an infrared sensor.

[0075] <Fifth embodiment> Next, a stereoscopic observation system according to a fifth embodiment of the present invention will be described, focusing on the differences from the stereoscopic observation systems 1A, 1B, 1C, and 1D according to the first to fourth embodiments. As shown in Fig. 16, a stereoscopic observation system 1E according to the fifth embodiment includes left and right first gaze guide units 51 (51L, 51R). In this embodiment, the display device 3X and the left and right first gaze guide units 51 constitute a stereoscopic display device 3E that allows a viewer to stereoscopically view an object 4 imaged by the stereoscopic imaging devices 2A to 2D.

[0076] <First line of sight guidance section> The first line-of-sight guidance unit 51 is a convex lens that is interposed between the viewer's eye and the display device 3X and guides light from the viewer's eye side to the display center (center in the horizontal direction) of each of the left and right images on the display device 3X. L (see FIG. 17) and the left display area 3L of the display device 3X, and L The right first line-of-sight guidance unit 51R guides the viewer's line of sight to the center of the image of the subject 4 in the left display region 3L of the display device 3X. R (see FIG. 17) and the right display area 3R of the display device 3X, and R The first gaze guide unit 51 guides the left and right gazes of observers with any eye width to the display centers of the left and right images by using the light-collecting properties of the convex lens.

[0077] 17, the convergence angle θ1 of the virtual image 4X of the subject 4 displayed on the display device 3X observed by the viewer through the first line-of-sight guidance unit 51 is equal to the convergence angle θ set by the convergence angle setting unit 10. Furthermore, the display control unit 31A (see FIG. 1) or the display control unit 31C (see FIG. 14) can cause the display device 3X to display the left and right images based on the convergence angle θ set by the convergence angle setting unit 10 so that the convergence angle θ1 of the virtual image 4X of the image of the subject 4 to be displayed is equal to the convergence angle θ.

[0078] For example, when the convergence angle θ set by the convergence angle setting unit 10 is 2.86°, the distance between the centers of the left and right first gaze guidance units 51 is set to 65 mm, which is the average interpupillary distance. In this case, the distance b between the first gaze guidance unit 51 and the virtual image 4X (virtual image distance) is 1302 mm. When the first gaze guidance unit 51 is a convex lens with a focal length f=90 mm, the distance a between the first gaze guidance unit 51 and the display device 3X (monitor distance) is set to 84.2 mm in order to achieve the virtual image distance b. 1 / f=1 / a-1 / b a=bf / (b+f)≒84.2 When the monitor distance a is set to 84.2 mm, the viewpoint on the display device 3X is located 30.4 mm to the left and right of the center of the display device 3X. The display control units 31A and 31C align the center of the image of the subject 4 with the respective viewpoint positions in the left display region 3L and right display region 3R of the display device 3X. Because the widthwise distance between the center of the display device 3X and the viewpoints is approximately half the interpupillary distance, the viewer can view the virtual image 4X while looking straight ahead into the distance. Therefore, the stereoscopic viewing system 1E can reduce viewer fatigue caused by long-term viewing.

[0079] Furthermore, when a 5.5-inch monitor is used as the display device 3X, the centers of the left and right images on the display device 3X are located 30.36 mm from the center of the display device 3X. The difference between this distance and half of the average interpupillary distance of 65 mm is 2.14 mm. When the convergence angle θ set by the convergence angle setting unit 10 is 2.86°, if the centers of the left display region 3L and the right display region 3R of the display device 3X are aligned with the left and right viewpoints of the viewer on the display device 3X, respectively, the distance a between the left and right first gaze guidance units 51 and the display device 3X is 85.7 mm. When the first gaze guidance unit 51 is a convex lens with a focal length f = 90 mm, the distance b (virtual image distance) between the first gaze guidance unit 51 and the virtual image 4X of the image of the subject 4 displayed on the display device 3X is 1794 mm. Therefore, the stereoscopic observation system 1E uses the display control units 31A and 31C to display the images of the left and right subjects 4 so that their centers are aligned with the centers of the left display area 3L and the right display area 3R of the display device 3X, respectively, thereby allowing the observer to view the images of the subject 4 in a stereoscopic manner.

[0080] In a stereoscopic observation system 1E according to a fifth embodiment of the present invention, the stereoscopic display device 3E includes a display device 3X that displays the left and right images corresponding to the left and right imaging areas output by the display control units 31A and 31C in left and right display areas, respectively, and left and right first gaze guidance units 51L and 51R that are provided corresponding to the centers of the left and right display areas in the display device 3X and can focus light onto the centers of the left and right display areas. Therefore, the stereoscopic viewing system 1E allows the viewer to view the image of the subject 4 in a suitable stereoscopic view even if the viewer's left and right eyes are different in width.

[0081] The convergence angle θ1 of the images displayed by the stereoscopic display device 3E is equal to the convergence angle θ set by the convergence angle setting unit 10. Therefore, the stereoscopic observation system 1E allows the observer to view the image of the subject 4 in a suitable stereoscopic view.

[0082] Sixth Embodiment Next, a stereoscopic observation system according to a sixth embodiment of the present invention will be described, focusing on the differences from the stereoscopic observation system 1E according to the fifth embodiment. As shown in Fig. 18, a stereoscopic observation system 1F according to the sixth embodiment of the present invention includes left and right second gaze guide units 52 (52L, 52R). In this embodiment, the display device 3X, the left and right first gaze guide units 51, and the left and right second gaze guide units 52 constitute a stereoscopic display device 3F that allows a viewer to stereoscopically view a subject 4 imaged by the stereoscopic imaging devices 2A to 2D.

[0083] <Second line of sight guide section> The second line-of-sight guidance unit 52 is a wedge prism (wedge lens) that is interposed between the first line-of-sight guidance unit 51 and the display device 3X and guides the light collected by the first line-of-sight guidance unit 51 to the display centers (left-right centers) of the left and right images on the display device 3X. The left second line-of-sight guidance unit 52L is interposed between the left first line-of-sight guidance unit 51L and the left display area 3L of the display device 3X and guides the light toward the left eye E of the viewer. L The right second line-of-sight guidance section 52R is interposed between the right first line-of-sight guidance section 51R and the right display region 3R of the display device 3X, and guides the line of sight of the viewer's right eye E to the center of the left image displayed in the left display region 3L of the display device 3X. R The line of sight is guided to the center of the right image displayed in the right display region 3R of the display device 3X.

[0084] For example, if a 7-inch monitor is used as the display device 3X, the centers of the left and right images of the stereoscopic display device 3X will be located 38.675 mm from the center of the display device 3X. This distance is significantly different from half the average interpupillary distance of 65 mm. In contrast, the stereoscopic observation system 1F can guide the viewer's gaze to the centers of the images displayed in the left display region 3L and the right display region 3R using the second line-of-sight guidance unit 52. Therefore, the stereoscopic observation system 1F can provide the viewer with a suitable stereoscopic view of the image of the subject 4 by using the display control units 31A and 31C to display the images so that the centers of the left and right images of the subject 4 are aligned with the centers of the left display region 3L and the right display region 3R of the display device 3X.

[0085] In a stereoscopic observation system 1F according to a sixth embodiment of the present invention, the stereoscopic display device 3F is provided with second gaze guidance units 52L and 52R that are arranged between the left and right first gaze guidance units 51L and 51R and the left and right display areas of the display device 3X and can guide the light focused by the left and right first gaze guidance units 51L and 51R toward the centers of the left and right display areas, respectively. Therefore, the stereoscopic observation system 1F can allow the observer to view the image of the subject 4 stereoscopically in a suitable manner by using the second line-of-sight guidance sections 52L and 52R according to the size (horizontal dimension) of the stereoscopic display device 3X.

[0086] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the present invention. For example, the first line-of-sight guidance section 51 and the second line-of-sight guidance section 52 of the stereoscopic observation systems 1E and 1F according to the fifth and sixth embodiments can also be applied to the stereoscopic observation systems 1C and 1D according to the third and fourth embodiments. [Explanation of symbols]

[0087] 1A, 1B, 1C, 1D, 1E, 1F Stereoscopic Observation System 2A,2B,2C,2D Stereoscopic imaging device 3,3Y,3E,3F Stereoscopic display device 3X display device 10. Convergence angle setting unit 20 Imaging device 20L, 20R imaging area 22b Distance measurement section 31A, 31B Display control unit 32 Convergence angle control unit 40 Distance measurement unit 50 Convergence angle change unit 51,51L,51R First line of sight guidance section 52,52L,52R Second line of sight guidance section

Claims

1. an imaging unit having imaging regions divided into left and right; a convergence angle setting unit that sets a convergence angle between the left and right imaging areas and a subject; a display control unit that controls the image captured by the imaging unit; Equipped with The convergence angle setting unit sets the convergence angle to be greater than 0° and equal to or less than 5° for the subject located at a distance of 300 mm to 1000 mm from the convergence angle setting unit. A stereoscopic imaging device for dental examination characterized by:

2. The subject is a root canal of a tooth.

2. The stereoscopic imaging apparatus for dental examination according to claim 1.

3. The convergence angle setting unit is an optical system using at least one of a mirror and a prism.

2. The stereoscopic imaging apparatus for dental examination according to claim 1.

4. a distance measurement unit for measuring the distance to the subject, The display control unit arranges the left and right images based on the distance and the convergence angle.

2. The stereoscopic imaging apparatus for dental examination according to claim 1.

5. The display control unit outputs the arranged left and right images to one display device.

4. The stereoscopic imaging apparatus for dental examination according to claim 3.

6. The display control unit outputs the arranged left and right images to left and right display devices corresponding to the left and right images, respectively.

4. The stereoscopic imaging apparatus for dental examination according to claim 3.

7. a distance measurement unit for measuring the distance to the subject; a convergence angle changing unit that changes the convergence angle set by the convergence angle setting unit; a convergence angle control unit that controls the convergence angle change unit; Equipped with The convergence angle control unit controls the convergence angle change unit to set the convergence angle based on the distance.

2. The stereoscopic imaging apparatus for dental examination according to claim 1.

8. The distance measurement unit measures the distance using an autofocus function.

8. The stereoscopic imaging apparatus for dental examination according to claim 4 or 7.

9. The distance measurement unit is a distance sensor that measures the distance to the subject.

8. The stereoscopic imaging apparatus for dental examination according to claim 4 or 7.

10. The display control unit is capable of changing the display magnification of the left and right images.

2. The stereoscopic imaging apparatus for dental examination according to claim 1.

11. The convergence angle setting unit is provided on each of the left and right sides. a first reflecting surface that reflects light from the subject outward to the left and right; a second reflecting surface that reflects the light reflected by the first reflecting surface toward the imaging unit in the optical axis direction; a third reflecting surface that reflects the light reflected by the second reflecting surface inwardly to the left and right; a fourth reflecting surface that reflects the light reflected by the third reflecting surface in the optical axis direction and causes the light to be incident on the imaging unit; 2. The stereoscopic imaging device for dental examination according to claim 1, further comprising:

12. The stereoscopic imaging device for dental examination according to claim 1 or 2; a stereoscopic display device for dental examination that displays images captured by the stereoscopic imaging device for dental examination; A stereoscopic observation system for dental examination, comprising:

13. The stereoscopic display device for dental examination comprises: a display device that displays the left and right images corresponding to the left and right imaging areas output by the display control unit in left and right display areas, respectively; left and right first gaze guide units provided corresponding to centers of the left and right display areas of the display device and capable of converging light onto the centers of the left and right display areas; 13. The stereoscopic observation system for dental examination according to claim 12, further comprising:

14. The stereoscopic display device for dental examination comprises: and second gaze guide units that are provided between the left and right first gaze guide units and the left and right display areas of the display device and that can guide the light collected by the left and right first gaze guide units to the centers of the left and right display areas, respectively.

14. The stereoscopic observation system for dental examination according to claim 13.

15. The convergence angle of the image displayed by the dental examination stereoscopic display device is equal to the convergence angle set by the convergence angle setting unit.

13. The stereoscopic observation system for dental examination according to claim 12.

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