JP6603034B2 - Endoscope apparatus and measuring method of three-dimensional shape of subject surface - Google Patents

Description

  The present invention relates to an endoscope apparatus and a method for measuring a three-dimensional shape of a subject surface, and in particular, an endoscope apparatus capable of measuring a three-dimensional shape of a subject surface and a method for measuring a three-dimensional shape of a subject surface. About.

Conventionally, in order to inspect a subject, an endoscope having a long insertion portion and having an imaging unit such as an optical system and an imaging device at the distal end of the insertion portion is used.
In an endoscope apparatus using such an endoscope, a plurality of fringe images obtained by projecting interference fringes on a subject are acquired while shifting the phase of light of the interference fringes, and the obtained plurality of fringes are obtained. An apparatus that calculates a three-dimensional shape of the surface of a subject by a known phase shift method using an image is known.

  Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 2012-228459, there is also proposed an endoscope apparatus in which a projection window for projecting interference fringes is combined into one and the insertion portion of the endoscope is reduced in diameter. According to the proposal, the interference fringes projected on the subject may be not only the bright and dark pattern of parallel lines but also a concentric bright and dark pattern.

JP 2012-228459 A

  However, in the above proposal, there is a description that the interference fringes projected onto the subject may be a concentric light and dark pattern, but how is the absolute value distance or absolute value in the three-dimensional space of the subject surface? It is not disclosed whether to measure the shape.

  Therefore, the present invention provides an endoscope apparatus capable of projecting a closed interference fringe pattern such as a concentric circle and measuring the absolute value shape in the three-dimensional space of the surface of the subject, and the three-dimensional shape of the subject surface. An object is to provide a measurement method.

  According to one aspect of the present invention, an interference fringe projection unit for projecting an interference fringe, which is provided in the insertion part and includes a center and a closed line, onto the subject, and the interference fringe projection An imaging unit that images the subject to obtain a subject image including the interference fringes projected on the subject through an observation window disposed at a position different from the unit; and light that generates the interference fringes A phase shift unit for shifting the phase, and a point on the surface of the subject corresponding to the center obtained by calculating from the position of the center of the interference fringes in the subject image obtained by the imaging unit Of the surface of the subject obtained by calculation by the phase shift method based on the distance information up to and a plurality of subject images including the interference fringes obtained by changing the phase of the light by the phase shift unit. From the 3D shape information, in real space Serial it is possible to provide an endoscope apparatus having a three-dimensional shape information calculating unit that calculates shape information of the subject surface.

According to one aspect of the present invention, an interference fringe having a center and a closed line is projected onto a subject (excluding a human body) , and the subject is projected from a position different from the position where the interference fringe is emitted. The subject corresponding to the center obtained by imaging the subject to obtain the projected subject image including the interference fringe and calculating from the position of the center of the interference fringe in the subject image. Obtained by calculating by the phase shift method based on a plurality of object images including the interference fringes obtained by changing the distance information to the point on the surface of the specimen and the phase of the light causing the interference fringes It is possible to provide a method for measuring the three-dimensional shape of the subject surface, which calculates the shape information of the subject surface in real space from the three-dimensional shape information of the subject surface.

  According to the present invention, an endoscope apparatus capable of projecting a closed interference fringe pattern such as a concentric circle and measuring the absolute value shape in the three-dimensional space of the surface of the subject, and the three-dimensional shape of the subject surface A measurement method can be realized.

1 is a configuration diagram showing a configuration of an endoscope apparatus 1 according to an embodiment of the present invention. It is a figure for demonstrating the structure of the front-end | tip part 21 of the insertion part 11 which concerns on embodiment of this invention, and the projection principle which projects a circular interference fringe pattern. It is a figure for demonstrating the polarization direction of the light which passes each optical element based on embodiment of this invention. It is a flowchart which shows the flow of the absolute value shape measurement process in the main body apparatus 4 based on embodiment of this invention. It is a figure for demonstrating the method of distance measurement to the center C based on embodiment of this invention. It is sectional drawing which shows the structure of the front-end | tip part of the insertion part of the endoscope apparatus which concerns on the modification 1 of embodiment of this invention. It is a block diagram of the optical member which has two half mirrors and a piezoelectric element which concern on the modification 2 of embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram showing a configuration of an endoscope apparatus 1 according to the present embodiment. As shown in FIG. 1, an endoscope apparatus 1 according to the present embodiment is an endoscope apparatus for measurement, and an electronic endoscope (hereinafter referred to as an endoscope) 2 and the endoscope 2 are connected to each other. A light source device 3, a main body device 4 including a camera control unit (hereinafter referred to as CCU), a laser light source 5, and a monitor 6.

The endoscope 2 includes an elongated insertion portion 11, an operation portion 12 connected to the proximal end of the insertion portion 11, and a universal cable 13 extending from the operation portion 12.
A connector 14 provided at the distal end of the universal cable 13 extended from the operation unit 12 can be detachably attached to the light source device 3. Two signal cables 15 and 16 extend from the connector 14. A connector 17 provided at the end of the signal cable 15 can be detachably attached to the main unit 4. A connector 18 provided at an end of the signal cable 16 can be detachably attached to the laser light source 5.

  The insertion portion 11 of the endoscope 2 has a hard distal end portion 21 formed at the distal end thereof, a bendable bending portion 22 formed adjacent to the distal end portion 21, and further on the proximal end side of the bending portion 22. A long flexible part 23 is formed. The user of the endoscope apparatus 1 can bend the bending portion 22 by operating the bending knob 24 provided on the operation portion 12.

  The light source device 3 is incident on the proximal end surface of the optical fiber 46 (FIG. 2) inserted into the universal cable 13 and the insertion portion 11, and generates illumination light that is emitted from the distal end of the insertion portion 11 and illuminates the subject. Including a light source such as a lamp.

  In addition to the CCU, the main body device 4 includes a control unit for controlling the entire endoscope device 1. The main unit 4 includes a central processing unit (hereinafter referred to as a CPU) 4a, a ROM, a RAM (not shown), and the like, and a user can perform various operations on an operation panel (not shown). The main device 4 executes a program corresponding to the function in order to realize a function corresponding to the operation. The main body device 4 outputs an image signal of an endoscopic image that is a subject image generated in the CCU to the monitor 6, and the endoscopic image is displayed on the monitor 6.

As will be described later, the CPU 4a of the main unit 4 generates three-dimensional shape information on the surface of the subject by calculation or the like.
The laser light source 5 is a device for generating light for interference fringes for obtaining three-dimensional shape information.

FIG. 2 is a diagram for explaining the configuration of the distal end portion 21 of the insertion portion 11 according to the present embodiment and the projection principle for projecting a circular interference fringe pattern.
A projection window 25, an observation window 26, and an illumination window 27 are provided on the distal end surface of the distal end portion 21 of the insertion portion 11.

  The projection window 25 is provided with a concave lens 31 constituting a projection optical system. Inside the distal end portion 21, behind the concave lens 31, a polarizing plate 32, a birefringent element 33, and the distal end surface of the optical fiber 34 are disposed.

  The optical fiber 34 is a polarization-maintaining fiber inserted into the insertion portion 11, and the base end portion of the optical fiber 34 is connected to the phase shifter 35 of the laser light source 5. Laser light having a predetermined wavelength from the laser diode 36 is incident on the phase shifter 35, and the light that has passed through the phase shifter 35 is incident on the base end face of the optical fiber 34. The phase shifter 35 and the laser diode 36 are provided in the laser light source 5.

  The observation window 26 is provided with a concave lens 41 constituting an objective optical system. Inside the distal end portion 21, behind the concave lens 41, a lens group 42 that constitutes the objective optical system, like the concave lens 41, a diaphragm 43, and an image sensor 44 are disposed.

  The light incident on the concave lens 41 passes through the lens group 42 and the diaphragm 43 and is irradiated on the imaging surface of the imaging device 44. The imaging element 44 is a CCD or the like, and photoelectrically converts an optical image formed on the imaging surface and outputs an imaging signal to the CCU in the main body device 4. The main body device 4 generates a display signal for displaying an endoscopic image on the monitor 6 from the input imaging signal and outputs the display signal to the monitor 6.

  The optical axis OL1 of the projection optical system of the projection window 25 and the optical axis OL2 of the observation optical system of the observation window 26 are substantially parallel and separated by a predetermined distance d so that the projection optical system of the projection window 25 and the observation window are separated. 26 observation optical systems are arranged.

  The illumination window 27 is provided with a concave lens 45 constituting an illumination optical system. The concave lens 45 receives illumination light from the light source device 3 from the optical fiber 46 and emits it to the subject along the optical axis OL3 of the concave lens 45 of the illumination window 27.

A circular interference fringe pattern IP, which will be described later, is irradiated to the subject so as to spread from the projection window 25 by the concave lens 31 of the projection window 25.
The polarizing plate 32 disposed behind the concave lens 31 of the projection window 25 has a polarization axis that is inclined by 45 degrees with respect to the optical axis of the birefringent element 33. That is, the polarizing plate 32 is an optical element for extracting each 45 degree component that becomes a coherent wave from the light of two polarization components orthogonal to each other from the birefringent element 33.

  The birefringent element 33 is a birefringent plate made of a rutile crystal, crystal, or the like, and the crystal axis of the birefringent element 33 is orthogonal to the optical axis OL1 of the projection optical system. The birefringent element 33 is an optical element that separates light of two polarization components orthogonal to each other from incident light. The two lights emitted from the birefringent element 33 are as if emitted from two points P1 and P2 at different positions on the optical axis OL1.

The optical fiber 34 is a panda fiber that is a polarization-maintaining fiber.
The phase shifter 35 is an element that shifts the phase of incident light from the laser diode 36 that is polarized in one direction. The phase shifter 35 is a device that shifts the phase of light by electrical control, and shifts the phase of one of two lights that are orthogonal to each other according to an electrical input signal (for example, a voltage signal). The electro-optical device.

  Here, although the phase shifter 35 is an electro-optical device, for example, a quarter wave plate (λ / 4 wave plate) is rotated as shown in the embodiment of Japanese Patent Laid-Open No. 5-87543. Thus, it may have a structure for performing phase shift by changing the phase of transmitted light.

FIG. 3 is a diagram for explaining the polarization direction of light passing through each optical element. It is assumed that the light emitted from the laser diode 36 is light polarized in the direction indicated by the arrow A1.
Light emitted from the laser diode 36 enters the phase shifter 35. The light emitted from the phase shifter 35 is emitted from the front end surface of the optical fiber 34 through the optical fiber 34 while maintaining the plane of polarization. The light emitted from the optical fiber 34 that is a polarization-maintaining fiber is light that is polarized in the direction of the polarization plane of the polarization-maintaining fiber indicated by the arrow A2 or A3. In FIG. 3, arrows A2 and A3 indicate the x-axis and y-axis directions, respectively.

  The light emitted from the distal end surface of the optical fiber 34 passes through the birefringent element 33, is separated into two light beams whose polarization directions are orthogonal to each other, and is emitted from the birefringent element 33. The direction of the crystal axis of the birefringent element 33 coincides with the direction of the arrow A2 or A3.

  Two light beams emitted from the birefringent element 33 are transmitted through the polarizing plate 32. The two light beams whose incident polarization directions are orthogonal to each other become two coherent lights having the same polarization direction as that of the polarization plate 32 by the polarization plate 32. If the polarization direction of the polarizing plate 32 is the direction indicated by the arrow A1, the two lights are light polarized in the direction indicated by the arrow A1. As a result, the two light beams emitted from the two points P1 and P2 having different phases emitted from the birefringent element 33 become interference light, and a circular interference fringe pattern IP is formed on the surface of the subject. Appears.

  As shown in FIG. 2, here, the interference fringe pattern IP is a circular multiple ring having a center C. The center C of the interference fringe is on the optical axis OL1 of the projection optical system. The interference fringe pattern IP has a plurality of ring-shaped stripes R2 and R3 around a circular center stripe R1. The center of the central circular fringe R1 is indicated by C.

  The position of each interference fringe R1, R2, R3 from the center C is changed on the surface of the subject by controlling the input signal to the phase shifter 35 and shifting the phase of one of the two lights with respect to the other. be able to. In other words, the phase shifter 35 is a phase shift unit that shifts the phase of light that generates interference fringes, and the size of each interference fringe can be changed by controlling the phase shifter 35. In other words, the brightness of each interference fringe can be changed continuously.

A subject image including the interference fringe pattern IP projected from the projection window 25 onto the surface of the subject is formed on the imaging surface 44a of the imaging element 44 by an objective optical system such as the concave lens 41.
As described above, the concave lens 31, the polarizing plate 32, the birefringent element 33 and the like disposed in the projection window 25 constitute an interference fringe projection unit provided in the insertion unit. The interference fringe projection unit projects an interference fringe having a center C and consisting of a closed line (here, a ring-shaped line) onto the subject.

  The objective optical system such as the concave lens 41 provided in the observation window 26 and the image pickup device 44 constitute an image pickup unit. In other words, the observation window 26 and the image sensor 44 pass through the subject to obtain the subject image including the interference fringes projected on the subject through the observation window 26 arranged at a position different from the above-described interference fringe projection unit. An imaging unit for imaging is configured.

The optical axis OL1 of the projection optical system of the interference fringe projection unit and the optical axis OL2 of the imaging optical system of the imaging unit are substantially parallel and separated by a predetermined distance d. In other words, the interference fringe projection unit and the imaging unit are provided at the distal end portion 21 of the insertion unit 11 and have parallax.
(Function)
Next, the operation of the main device 4 will be described. The user of the endoscope apparatus 1 can instruct the CPU 4a of the main body apparatus 4 to execute absolute value shape measurement processing by performing a predetermined operation on an operation panel (not shown) of the main body apparatus 4. The main body device 4 operates the laser light source 5 when receiving an instruction to execute the absolute value shape measurement process. As a result, the interference fringe pattern IP as described above is projected onto the surface of the subject.

FIG. 4 is a flowchart showing the flow of absolute value shape measurement processing in the main device 4. FIG. 5 is a diagram for explaining a method of measuring the distance to the center C.
First, the CPU 4a of the main unit 4 calculates the distance from the endoscopic image obtained by imaging with the imaging device 44 to the center C of the interference fringe pattern IP (step (hereinafter abbreviated as S) 1). As shown in FIG. 5, the position of the center C of the interference fringe pattern IP changes on the optical axis OL1 in the three-dimensional space according to the position of the surface of the subject, but the distance d is fixed. Of the light from the subject that has passed through the objective optical system including the concave lens 41 and the lens group 42, the position of the center C is unambiguous on the imaging surface 44 a of the imaging element 44 according to the distance to the subject. Is determined. For example, in FIG. 5, the light from the position of the center C at the distance z1 from the distal end surface of the distal end portion 21 travels along the optical path L1 and becomes a point P1 on the imaging surface 44a. Further, the light from the position of the center C at the distance z2 from the distal end surface of the distal end portion 21 travels along the optical path L2, and becomes a point P2 on the imaging surface 44a.

  Therefore, the CPU 4a of the main body device 4 is centered from the distal end surface of the distal end portion 21 in the three-dimensional space based on the position of the center C on the imaging surface 44a (that is, on the endoscopic image) based on the principle of so-called triangulation. The distance to C can be calculated.

  As shown in FIG. 2, the center C does not appear as a point in the endoscopic image, but is the center of the circular interference fringe R1, so that the circular interference fringe on the endoscopic image is obtained by image processing. The center C of R1 can be obtained.

Next, the CPU 4a of the main unit 4 measures the three-dimensional shape of the surface of the subject by the phase shift method (S2).
Specifically, the CPU 4a of the main body device 4 drives the phase shifter 35 to shift one phase of the two lights with respect to the other, so that each interference fringe R1, R2, R3 of the interference fringe pattern IP is changed. The position is changed on the surface of the subject, and a plurality of projection images of the interference fringe pattern IP having different phases are acquired. The CPU 4a of the main unit 4 can obtain and obtain information about the three-dimensional shape of the surface of the subject from the acquired projection images of the plurality of interference fringe patterns IP by, for example, a known phase shift method using a 4-bucket method. it can. That is, by extracting only phase component information from a plurality of projection images, it is possible to calculate and obtain relative position information on the surface of the subject, that is, unevenness information.

  Then, the CPU 4a of the main device 4 calculates the absolute distance in the three-dimensional space of the surface of the subject from the absolute distance information to the center C and the relative position information of the subject surface obtained by the phase shift method. To measure (S3).

  That is, the absolute position information of each point on the surface of the subject is calculated from the absolute distance information of the center C obtained in S1 and the relative position information of each point on the surface of the subject obtained by the phase shift method. Thus, an absolute value shape in the three-dimensional space on the surface of the subject can be obtained.

  That is, the main body device 4 including the CPU 4a has the surface of the subject corresponding to the center C obtained by calculating from the position of the center C of the interference fringes in the subject image obtained by the imaging element 44 constituting the imaging unit. Obtained by calculating by the phase shift method based on the distance information to the upper point and a plurality of object images including interference fringes obtained by changing the phase of light by the phase shifter 35 constituting the phase shift unit A three-dimensional shape information calculation unit that calculates the shape information of the surface of the subject in real space from the three-dimensional shape information of the surface of the subject is configured.

  As described above, according to the above-described embodiment, an endoscope apparatus capable of measuring the absolute value shape in the three-dimensional space of the surface of the subject by projecting a concentric closed interference fringe pattern is realized. can do.

Even if a part of the endoscopic image obtained through the observation window 26 includes a dark part region, if the center C is included in the endoscopic image, the absolute position of each point on the surface other than the dark part is obtained. Information can be obtained.
(Modification 1)
The embodiment described above relates to an endoscope apparatus that can obtain information on the absolute position of each point on the surface of the subject by bringing the distal end surface of the insertion portion 11 closer to the surface of the subject. However, the first modification relates to an endoscope apparatus that can measure the absolute shape of the inner peripheral surface of a subject such as a pipe.

FIG. 6 is a cross-sectional view illustrating the configuration of the distal end portion of the insertion portion of the endoscope apparatus according to the first modification.
The endoscope apparatus according to the first modification has the same configuration as that of the endoscope apparatus 1 according to the embodiment shown in FIG. 1 and includes a light source device 3, a main body device 4, and a monitor 6. However, the endoscope apparatus according to the first modification does not include the laser light source 5 as shown in FIG. 1, and a laser light source is provided at the distal end of the insertion portion. Furthermore, the present modification 1 is different from the endoscope apparatus of the embodiment in the configuration of the distal end portion of the insertion unit 11, and the interference fringe projection unit and the imaging unit are opposed to each other, and the projection of the interference fringe pattern The projection direction of light by the optical system is opposite to the imaging direction by the imaging optical system.

  The insertion unit 11 of the endoscope apparatus according to the first modification is inserted into a pipe 51 that is a subject. The distal end portion 21A of the insertion portion 11 of the endoscope apparatus has casings 61A and 61B having cylindrical shapes. The casing 61A is provided at the distal end portion of the insertion portion 11, and has a shape in which the distal end side is closed. A plurality of centering devices 62 are fixed to the outer peripheral surfaces of the casings 61A and 61B.

  When the distal end portion 21A of the insertion portion 11 is inserted into the pipe 51, the plurality of centering devices 62 are arranged so that the central axes of the cylindrical casings 61A and 61B substantially coincide with the central axis of the pipe 51. A plurality of the casings 61A and 61B on the distal end side of the distal end portion 21A are provided along the circumferential direction.

  Each centering device 62 has a spring member 62A and a wheel 62B, and the spring member 62A has outer peripheral portions of the casings 61A and 61B in the pipe 51 so as to press the wheel 62B against the inner wall 52 of the pipe 51. Is provided. Each wheel 62B is provided on the spring member 62A so as to be rotatable when the distal end portion 21A moves in the pipe 51 along the axial direction of the pipe 51.

  Transparent pipes 63 and 64 are provided between the casings 61A and 61B. The transparent pipes 63 and 64 are, for example, sapphire glass pipes. The transparent pipes 63 and 64 are connected via a connection member 65.

  A diverging optical system 66 is fixed inside the transparent pipe 63. The diverging optical system 66 constitutes a light diverging portion having conical portions 66A and 66B whose surfaces are mirror surfaces on the distal end side and the proximal end side of the distal end portion 21A, respectively. As shown in FIG. 6, the diverging optical system 66 has a shape in which the bottom surfaces of the conical portions 66A and 66B are in close contact with each other.

  On the inner peripheral surface of the transparent pipe 64, a plurality of light emitting diodes (hereinafter referred to as LEDs) 67 arranged in a plurality along the axial direction of the transparent pipe 64 and also along the circumferential direction are fixed. A signal cable 67 a extending from the LED 67 passes through the insertion portion 11 and is connected to the main body device 4.

  Inside the transparent pipe 64, an objective optical system 68 and an image sensor 69 constituting an image pickup unit are provided and fixed by a fixing member (not shown). The objective optical system 68 includes a concave lens 68a and a lens group 68b, and a diaphragm member 70 is disposed on the way. The concave lens 68a constitutes an observation window. The image sensor 69 is an image sensor such as a CCD. A signal cable 69 a extending from the image sensor 69 passes through the insertion portion 11 and is connected to the main body device 4.

  A diverging lens 71, a polarizing plate 72, a birefringence element 73, a phase modulation element 74, a laser diode 75, and a controller 76 are provided and fixed inside the casing 61A. The diverging lens 71 and the like constitute an interference fringe projection unit, and the diverging lens 71 constitutes a projection window. The controller 76 includes a battery 77.

  The two transparent pipes 63 and 64 are members that protect the diverging optical system that projects the interference fringe pattern and the imaging optical system.

The controller 76 supplies power to the phase modulation element 74 and the laser diode 75 and controls the phase modulation element 74 to change the phase at a predetermined interval.
The inner wall 52 of the pipe 51 is illuminated by a plurality of LEDs 67 arranged along the circumferential direction.

  The light emitted from the laser diode 75 passes through the phase modulation element 74, the birefringence element 73, and the polarizing plate 72, is diverged by the diverging lens 71, and is irradiated onto the conical portion 66A of the diverging optical system 66.

  The light reflected by the conical portion 66A is projected on the inner wall of the pipe 51 as a plurality of circular stripe patterns extending along the circumferential direction. That is, interference light that generates a circular stripe pattern extending in the circumferential direction is emitted in the outer diameter direction.

  The light reflected by the diverging optical system 66 and passing through the objective optical system 68 is applied to the imaging surface of the imaging element 69 which is an imaging unit. An image obtained by the image sensor 69 is an endoscopic image including a circular interference fringe pattern similar to the above-described interference fringe pattern IP.

  As described above, the endoscope apparatus according to the first modification has the light divergence unit disposed between the interference fringe projection unit and the imaging unit, and the interference fringe projection unit and the imaging unit are included in the interference fringe projection unit. The projection window and the observation window of the imaging unit are arranged to face each other, and the light of the interference fringe from the interference fringe projection unit is directed in a direction of a predetermined angle with respect to the axis of the insertion unit 11 by the light divergence unit It is emitted to the subject. The imaging unit receives light from the subject reflected by the light divergence unit.

Therefore, the imaging unit and the interference fringe projection unit are fixed apart from each other by a predetermined distance in the distal end portion 21A, and by acquiring the plurality of images by changing the phase of the ring-shaped fringe pattern by the phase shift method, Since the unevenness information of the inner wall 52 of the pipe 51 can be obtained, the endoscope apparatus of the first modification also has the same effect as the endoscope apparatus of the above-described embodiment.
(Modification 2)
In the embodiment and the first modification described above, a circular interference fringe pattern is generated using a birefringent element, and the phase is shifted by the phase shifter 35 for the phase shift method. However, a circular interference fringe pattern is generated. In order to shift the phase, two half mirrors and a piezoelectric element may be used.

  FIG. 7 is a configuration diagram of an optical member having two half mirrors and a piezoelectric element according to the second modification. The optical member 81 has glass plates 84 and 85 having half mirrors 82 and 83, respectively. The two glass plates 84 and 85 are fixed by connecting members 86 and 87 so that the light transmission surfaces are parallel to each other.

  The connecting members 86 and 87 have piezoelectric elements 86a and 87a, respectively. The piezoelectric elements 86a and 87a are provided on the connecting members 86 and 87, respectively, so that when a voltage is applied to the piezoelectric elements 86a and 87a, the distance d1 between the two half mirrors 82 and 83 changes according to the applied voltage. It has been.

One side of the glass plate 85 is a light incident side to the optical member 81. On the incident side of the light to the optical member 81, the tip of the optical fiber 34 that is a polarization-maintaining fiber is located.
The light from the laser diode 36 is emitted from the front end surface of the optical fiber 34 that is a polarization plane holding fiber, and passes through the glass plate 85 and the half mirror 83. The optical fiber 34 emits linearly polarized light from the laser diode 36 to the glass plate 85 while maintaining the polarization direction of the linearly polarized light.

  The light transmitted through the glass plate 85 is transmitted through the half mirror 83 as linearly polarized light. The light from the half mirror 83 enters the glass plate 84 and is reflected by the surface of the half mirror 82, but the light reflected by the half mirror 82 is reflected again by the surface of the half mirror 83.

The light reflected by the half mirror 83 passes through the glass plate 84 and the half mirror 82 and is emitted from the optical member 81.
As a result, the light emitted through the two glass plates 84 and 85 and the light reflected and emitted from the half mirrors 82 and 83 become light emitted from different points P3 and P4, respectively, and interfere with each other. Thus, a ring-shaped stripe pattern can be projected. Further, by changing the voltage applied to the piezoelectric elements 86a and 87a, the optical path difference between the light transmitted through the two glass plates 84 and 85 and the light reflected and emitted from the half mirrors 82 and 83 is obtained. To change the phase of the light that produces the interference fringe pattern IP.

  Therefore, the two half mirrors 82 and 83 arranged in parallel constitute an interference fringe projection unit. The piezoelectric elements 86a and 87a are interval changing units for changing the interval between the two half mirrors, and constitute a phase shift unit.

  In the above-described embodiment and each modification, the shape of each interference fringe formed of a closed line to be projected is an annular shape, but has a center such as an ellipse or a rectangle, and is a closed stripe. But you can.

In the case of an ellipse, the center of the line connecting the two focal points is the center. In the case of a rectangle, the intersection of two diagonal lines is the center.
Furthermore, as long as the center of the closed line can be determined, a part of the circle, ellipse, or rectangle may be cut off.

  As described above, according to the embodiment and each modification described above, it is possible to measure the absolute value shape in the three-dimensional space of the surface of the subject by projecting a closed interference fringe pattern such as a concentric circle. An endoscope apparatus and a method for measuring a three-dimensional shape of a subject surface can be provided.

  The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Endoscope apparatus, 2 Endoscope, 3 Light source apparatus, 4 Main body apparatus, 4a CPU, 5 Laser light source, 6 Monitor, 11 Insertion part, 12 Operation part, 13 Universal cable, 14 Connector, 15, 16 Signal cable, 17, 18 Connector, 21, 21A Tip portion, 22 Curved portion, 23 Soft portion, 24 Curved knob, 25 Projection window, 26 Observation window, 27 Illumination window, 31 Concave lens, 32 Polarizing plate, 33 Birefringence element, 34 Optical fiber , 35 phase shifter, 36 laser diode, 41 concave lens, 42 lens group, 44 imaging element, 44a imaging surface, 45 concave lens, 46 optical fiber, 51 pipe, 52 inner wall, 61A, 61B housing, 62 centering device, 62A spring member , 62B Wheel, 63, 64 Transparent pipe, 65 Connection member, 66 Divergence optical system, 66A, 66B Conical part, 67a Signal cable, 68 Objective optical system, 68a Concave lens, 68b Lens group, 69 Imaging element, 69a Signal cable, 70 Diaphragm member, 71 Diverging lens, 72 Polarizing plate, 73 Birefringence element, 74 Phase modulation element, 75 Laser diode, 76 Controller, 77 Battery, 81 Optical member, 82, 83 Half mirror, 84, 85, Glass plate, 86 Connecting member, 86a, 87a Piezoelectric element.

Claims (12)

An insertion part;
An interference fringe projecting unit for projecting an interference fringe having a center and a closed line on the subject, provided in the insertion unit;
An imaging unit that images the subject to obtain a subject image including the interference fringes projected on the subject through an observation window arranged at a position different from the interference fringe projection unit;
A phase shift unit that shifts the phase of light that causes the interference fringes;
Distance information to a point on the surface of the subject corresponding to the center obtained by calculating from the position of the center of the interference fringes in the subject image obtained by the imaging unit, and the phase shift From the three-dimensional shape information of the surface of the subject obtained by calculation by the phase shift method based on a plurality of subject images including the interference fringes obtained by changing the phase of the light by the unit, real space A three-dimensional shape information calculation unit for calculating shape information of the surface of the subject in the body,
An endoscope apparatus characterized by comprising:   The endoscope apparatus according to claim 1, wherein the interference fringes are circular, elliptical, or rectangular.   The endoscope apparatus according to claim 1, wherein the interference fringe projection unit and the imaging unit are provided at a distal end portion of the insertion unit and have a parallax.   The first optical axis of the projection optical system of the interference fringe projection unit and the second optical axis of the imaging optical system of the imaging unit are parallel and separated by a predetermined distance. The endoscope apparatus according to 3.   The endoscope apparatus according to claim 1, wherein the phase shift unit is a device that shifts the phase of the light by electrical control.   The endoscope apparatus according to any one of claims 1 to 5, wherein the interference fringe projection unit includes a concave lens and a birefringent element. A light divergence unit disposed between the interference fringe projection unit and the imaging unit;
The interference fringe projection unit and the imaging unit are arranged such that a projection window of the interference fringe projection unit and an observation window of the imaging unit are opposed to each other,
The light of the interference fringes from the interference fringe projection unit is emitted by the light divergence unit toward the subject in a direction of a predetermined angle with respect to the axis of the insertion unit,
The endoscope apparatus according to claim 1, wherein the imaging unit receives light from the subject reflected by the light divergence unit.   The endoscope apparatus according to claim 1, wherein the interference fringe projection unit includes two half mirrors arranged in parallel to each other.   The endoscope apparatus according to claim 8, wherein the phase shift unit includes an interval changing unit for changing an interval between the two half mirrors.   The endoscope apparatus according to claim 9, wherein the interval changing unit includes a piezoelectric element. Project an interference fringe with a center and a closed line onto the subject (excluding the human body)
Imaging the subject to obtain a subject image including the interference fringes projected on the subject from a position different from the position where the interference fringes are emitted;
Distance information to a point on the surface of the subject corresponding to the center obtained by calculation from the position of the center of the interference fringe in the subject image, and a phase of light causing the interference fringe From the three-dimensional shape information of the surface of the subject obtained by the phase shift method based on a plurality of subject images including the interference fringes obtained by changing the surface of the subject in real space A method for measuring the three-dimensional shape of the surface of a subject characterized by calculating shape information of the subject. The subject image is an image obtained by imaging with an imaging unit provided in an insertion unit of an endoscope apparatus,
The method for measuring a three-dimensional shape of a subject surface according to claim 11, wherein the interference fringes are projected from a projection unit provided in the insertion unit.

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