JP4812418B2 - Endoscope device - Google Patents

Description

  The present invention relates to an endoscope apparatus. For example, the present invention relates to an endoscope apparatus that can stably capture an image centered at a substantially constant position in a subject even when subjected to disturbance.

2. Description of the Related Art Conventionally, an endoscope apparatus includes a bending drive mechanism that bends the distal end side of an endoscope insertion portion, and changes the amount of the bending to thereby change the direction of an imaging optical system provided at the distal end of the endoscope insertion portion. And an image of a subject at a desired position can be acquired. For example, when the relative position between the imaging optical system and the subject is shifted due to movement or disturbance of the endoscope insertion portion for inspection, the bending amount is adjusted by the bending drive mechanism, and the imaging optical system and the subject are adjusted. There is known an apparatus which corrects the relative position between the two.
For example, Patent Document 1 describes an endoscope apparatus that detects a deviation amount as a vector and corrects the bending angle of a bending portion so as to correct the deviation amount when the subject image is shifted during enlarged display. .
Patent Document 2 is an endoscope apparatus that is inserted into a tube, and includes a plurality of photoelectric elements that detect the brightness distribution of a subject image, and controls the amount of curvature according to the deviation of the detection output to provide a tip configuration. An endoscope is described in which a portion is directed toward the substantial center of the peripheral wall of the system to be observed.
In Patent Document 3, a subject image is divided into a plurality of areas, brightness information of the divided areas is detected, and the bending amount of the bending drive means is controlled using fuzzy reasoning means based on the brightness information. An endoscopic device is described.
JP 2001-046331 A (FIGS. 4, 17, and 18) Japanese Examined Patent Publication No. 61-37927 (Fig. 1-5) Japanese Patent No. 2948833 (FIGS. 1 and 5)

However, the conventional endoscope apparatus as described above has the following problems.
In the technique described in Patent Document 1, the movement direction and the amount of movement are detected based on a change in the subject image, and the amount of curvature is corrected. Therefore, the movement when the subject image is within the imaging range can be followed, but from the imaging range. When the subject jumps out, it takes time and effort to return to a low magnification, place the subject in the imaging range, correct the amount of curvature, and then restore the original magnification. For this reason, there is a problem in that stable observation cannot be performed efficiently when the subject is subject to a large disturbance such as jumping out of the shooting range, or when the subject is magnified and observed at a high magnification within a narrow viewing angle.
In the technique described in Patent Document 2, since the deviation of the brightness distribution is detected and the amount of bending is controlled, the bending is performed only when the brightness distribution has a specific distribution as in the case of observing the center in the tube. The amount can be stably controlled. Therefore, there is a problem that the amount of bending cannot be controlled correctly when it is difficult to extract a deviation that makes the brightness substantially uniform within the imaging range, or when specific patterns are arranged in the same pattern.
In the technique described in Patent Document 3, brightness distribution is detected, and the amount of bending is controlled using fuzzy inference. Therefore, although the curvature can be controlled even when the brightness distribution of the subject is somewhat varied, in order to set the fuzzy inference rule, the brightness distribution of the subject and the background must have some characteristics. Therefore, there is a problem similar to that of Patent Document 2 even if the degree is different.

  The present invention has been made in view of the above-described problems. For example, even when the imaging position is shifted due to disturbance or the like and the subject jumps out of the imaging range, the subject is positioned at the substantially center position of the imaging range. It is an object of the present invention to provide an endoscope apparatus that can quickly capture and perform stable observation.

In order to solve the above-described problem, according to the first aspect of the present invention, there is provided an endoscope apparatus having a bending portion on a distal end side of an endoscope insertion portion to be inserted into a subject, and having a distal end than the bending portion. An imaging unit provided with an imaging optical system on the side , a bending drive mechanism for bending the bending unit, a bending unit position / posture detection unit for detecting the posture of the bending unit, and an imaging center position of the subject by the imaging unit The capturing operation setting means for starting or canceling the capturing operation of the subject to be kept substantially constant, and the subject from the detection output of the bending portion position / orientation detecting means when the capturing operation start is instructed by the capturing operation setting means The image pickup center position is calculated, and the bending drive mechanism is driven and controlled so that the optical axis of the image pickup optical system faces the image pickup center position according to the detection output of the bending portion position / posture detection means. Conversion A structure comprising a stage, a.
According to the present invention, when the start of the subject capturing operation is set by the capturing operation setting means, the detection output of the bending portion position / orientation detecting means is acquired by the imaging position stabilizing means, and the subject is imaged at that time. A center position (hereinafter referred to as an initial imaging center position) is calculated. Then, the bending drive mechanism is driven so that the optical axis of the imaging optical system faces the initial imaging center position according to the detection output of the bending portion position / posture detection means.
Therefore, even when the subject is out of the imaging range after the subject capturing operation starts, the subject can be quickly and easily captured at the initial imaging center position without changing the magnification.

According to a second aspect of the present invention, in the endoscope apparatus according to the first aspect, the distance measuring unit includes a stereo measuring unit that images a subject from a plurality of viewpoints, and at least a part of the distance measuring unit is the imaging unit. It is set as the structure which serves as.
According to the present invention, the distance measuring means is constituted by the stereo measuring means for imaging the subject at a plurality of fulcrums, and at least a part of the distance measuring means also serves as the imaging means, so that a simple configuration can be achieved.
In addition, since a stereoscopic image of the subject can be captured by the stereo measurement means, the initial imaging center position can be accurately positioned with reference to the uneven shape of the subject.
When all of the stereo measurement means are imaging means, the imaging optical system is a multifocal optical system. In this specification, the optical axis of the imaging optical system in this case is a multifocal light unless otherwise specified. It shall refer to the axis of symmetry with respect to the axis.

According to a third aspect of the present invention, in the endoscope apparatus according to the first or second aspect, the bending portion position / orientation detection means includes a plurality of acceleration detection means provided respectively at a distal end and a proximal end of the bending portion. It is set as the structure which is.
According to the present invention, since the bending portion position / orientation detection means is an acceleration detection means, it can respond at high speed to a displacement due to a disturbance or the like, and can be detected together with the displacement and direction at the installation position with a small sensor. Therefore, it can be easily installed inside the endoscope insertion portion.

According to a fourth aspect of the present invention, in the endoscope apparatus according to any one of the first to third aspects, a deviation amount of the imaging center position of the subject is detected from image data of the subject imaged by the imaging means. An image shift detection unit configured to detect a shift amount of the imaging center position detected by the image shift detection unit when the capture operation start instruction is issued by the subject capture operation setting unit. Accordingly, the bending drive mechanism can be driven and controlled.
According to this aspect of the invention, since the image deviation detecting means for detecting the deviation amount of the imaging center position of the subject from the image data of the subject imaged by the imaging means is provided, the imaging center position of the subject is directly determined by the subject image data. Therefore, the accuracy of the subject capturing operation can be improved.

According to a fifth aspect of the present invention, in the endoscope apparatus according to any one of the first to fourth aspects, the image shift detecting means extracts the contrast information of the image of the subject as the image data, and A shift amount of the imaging center position of the subject is detected by a change in contrast information.
According to the present invention, the image shift detection unit detects the shift amount of the imaging center position of the subject based on the change in the contrast information of the image of the subject. Therefore, the amount of image data used for the detection can be compressed. A subject capturing operation can be performed.

In the invention according to claim 6, in the endoscope apparatus according to claim 4 or 5, the imaging position stabilization means includes:
A first subject capturing operation is performed by driving the bending drive mechanism in accordance with a detection output of the bending portion position / orientation detecting unit, and the first subject capturing operation is completed. The second subject capturing operation is performed by driving the bending drive mechanism according to the detection output.
According to the present invention, the first subject capturing operation using the detection output of the bending portion position / orientation detection means is performed, and after completion thereof, the second subject capturing operation using the detection output of the image shift detection means is performed. Therefore, even when a detection error or the like occurs in the bending portion position / posture detection means, the second subject capturing operation for detecting the shift amount of the imaging center position of the subject is performed, so that the capture target is captured reliably and with high accuracy. be able to.

  According to the endoscope apparatus of the present invention, when the capturing operation start is instructed by the subject capturing operation setting unit, the imaging position stabilizing unit performs the bending drive mechanism according to the detection output of the bending portion position / posture detection unit. , And the optical axis of the imaging optical system can be directed to the imaging center position of the subject at the start of the capture operation.For example, even when the subject jumps out of the imaging range due to disturbance, the magnification can be changed. Thus, it is possible to quickly capture the subject at a substantially central position within the imaging range without causing any trouble, and it is possible to perform stable observation.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An endoscope apparatus according to a first embodiment of the present invention will be described.
FIG. 1 is an explanatory diagram schematically illustrating a schematic configuration of the endoscope apparatus according to the first embodiment of the present invention.

The endoscope apparatus 50 according to the present embodiment can capture a subject under observation at a substantially central position in an imaging range even when subjected to disturbance such as external force or vibration. The type of subject is not particularly limited, and can be used for appropriate purposes such as medical use, industrial use, and measurement use.
As shown in FIG. 1, the schematic configuration of the endoscope apparatus 50 includes an insertion section 1 (endoscope insertion section), an apparatus main body section 51, and a monitor 13.

The insertion unit 1 is a mechanism formed in an elongated shape as a whole in order to insert into the subject and acquire a subject image in the subject from the tip, and on the tip side, the curved tip 3 (of the bending portion). A distal end), a bending portion 2, and a bending proximal end portion 8 (a proximal end of the bending portion). The proximal end side portion of the insertion portion 1 connected to the curved proximal end portion 8 has flexibility and is connected to the apparatus main body portion 51.
The curved tip portion 3 is a disc-shaped or columnar hard portion having substantially the same outer diameter as the curved portion 2.
An entrance (not shown) that guides incident light to the inside is formed in the distal end surface 3a of the curved distal end portion 3, and a binocular lens 4A (imaging optical system) and an image sensor 4B are disposed on the distal end surface 3a side. Imaging means 4 arranged in this order are provided.
The binocular lens 4A is an imaging optical system in which objective lenses 4a and 4b having the same focal length and angle of view are arranged with their optical axes separated by a predetermined distance d. Therefore, an image formed by incident light from the tip surface 3a can be formed as a parallax image having parallax d on an imaging plane aligned on the same plane.
Thus, although the binocular lens 4A is a multifocal optical system, for the sake of convenience, the axis of symmetry of the optical axes of the objective lenses 4a and 4b is hereinafter referred to as the optical axis of the binocular lens 4A.
The optical axis of the binocular lens 4A is directed in the axial direction of the curved distal end portion 3, that is, the normal direction of the distal end surface 3a.
Although not shown in particular, the curved distal end portion 3 is provided with an illumination system that emits illumination light from the distal end surface 3a to the outside.

The image sensor 4B is for photoelectrically converting a subject image formed by the binocular lens 4A, and is composed of a solid-state image sensor such as a CCD.
Two imaging elements 4B may be provided corresponding to each of the objective lenses 4a and 4b, or only one imaging element 4B may be provided to capture an image corresponding to the objective lenses 4a and 4b on one imaging surface. You may do it. In any case, the image signal 300 that is the output of the image sensor 4B can be appropriately separated into two parallax images 301 for the same subject and processed by a camera control unit (hereinafter abbreviated as CCU) 104 described later. It can be done.
The image signal 300 captured by the image sensor 4B is sent to the apparatus main body 51 through the signal cable 7 in the insertion unit 1.
Thus, the imaging unit 4 also serves as a stereo measurement unit that acquires the parallax image 301.

  In the vicinity of the imaging means 4, an acceleration sensor 5 </ b> A (acceleration detection) that detects three-dimensional displacement information by detecting a change in acceleration in three axial directions and acquires direction information based on a difference from the gravitational acceleration. Means) is fixed. Therefore, the displacement and posture of the curved tip 3 can be detected by the output of the acceleration sensor 5A. The detection output of the acceleration sensor 5 </ b> A is sent to the apparatus main body 51 through a signal cable 5 a that passes through the insertion portion 1.

The bending portion 2 includes a bendable tubular member provided between the bending distal end portion 3 and the bending proximal end portion 8, and wires 10 </ b> A and 10 </ b> B that transmit bending driving force are provided therein from the bending distal end portion 3. A power line (not shown) for supplying a necessary current to the extended signal cables 5a and 7 and the members in the curved distal end portion 3 is inserted.
The tubular member can adopt an appropriate structure as long as it can be bent. For example, a plurality of plate-like bending pieces having insertion holes through which the wires 10A, 10B, the signal cables 5a, 7 and the like are inserted are shafts. It is arranged at an equal pitch at the center position, and the distance from the adjacent bending pieces at the peripheral portion is varied according to the balance of the pulling force of the wires 10A and 10B, and each bending piece is bent as a whole so as to bend as a whole. Can be adopted.

The wire 10 </ b> A is disposed in a state where both ends thereof are opposed to each other with the central axis of the insertion portion 1 in the vicinity of the outer peripheral portion of the insertion portion 1, and is fixed to the proximal end side of the curved distal end portion 3. And the intermediate part is wound around the pulley 11A of the bending drive mechanism 52 mentioned later.
In addition, the wire 10B is fixed to the proximal end side of the bending distal end portion 3 and the intermediate portion is wound around the pulley 11B of the bending drive mechanism 52 in the same manner as the wire 10A. However, the fixing position of each end of the wire 10B is shifted by 90 ° with respect to the fixing position of each end of the wire 10A. For example, in the vicinity of the curved distal end portion 3, the opposing wire pair in the wire 10 </ b> A is disposed in the paper surface of FIG. 1, and the opposing wire pair in the wire 10 </ b> B is disposed in the paper surface vertical surface in FIG.
Therefore, for example, when the pulley 11A that drives the motor 9A of the bending drive mechanism 52 and winds the wire 10A rotates in one direction, one of the end portions is pulled and the other is loosened in the drawing. When the pulley 9B that winds the wire 10B by driving the motor 9B of the bending drive mechanism 52 rotates in one direction, one of the end portions is pulled and the other is loosened on the plane perpendicular to the paper surface. In this way, by controlling the independent motors 9A and 9B and appropriately setting the rotation angles of the pulleys 11A and 11B, the direction of the curved distal end portion 3 at a distance can be freely changed.

The curved proximal end portion 8 is a hard portion that connects the curved portion 2 to the flexible tube on the proximal end side of the insertion portion 1, and constitutes the reference end of the curved portion 2. And the acceleration sensor 5B (acceleration detection means) which has the structure similar to the acceleration sensor 5A is incorporated. The detection output of the acceleration sensor 5B is sent to the apparatus main body 51 through the signal cable 5b inserted into the flexible tube on the rear end side of the insertion section 1.
The acceleration sensors 5 </ b> A and 5 </ b> B constitute bending portion position / posture detection means for detecting the position and posture of the distal end and the base end of the bending portion 2.

As shown in FIG. 1, the schematic configuration of the apparatus main body 51 includes a bending drive mechanism 52, a tension detection unit 54, an operation unit 14, and a control unit 53.
The bending drive mechanism 52 winds intermediate portions of the wires 10A and 10B (hereinafter sometimes simply referred to as the wire 10) around the pulleys 11A and 11B, respectively, and the bending distal end portion 3 and the bending proximal end portion 8 Is a mechanism for changing the amount of bending of the bending portion 2 by changing the lengths of the wires 10A and 10B stretched between the pulleys 11A and 11B for winding the wires 10A and 10B, and making them freely reversible It consists of motors 9A and 9B that are rotationally driven (hereinafter may be simply referred to as motors 9).
As long as each motor 9 can control the rotation angle, an appropriate motor can be adopted. For example, a DC servo motor that performs rotation angle control using rotation angle detection means such as a rotary encoder can be employed.
According to the bending drive mechanism 52, the direction of the bending distal end portion 3 can be freely changed as described above.

The tension detection unit 54 is for detecting the tension of each wire 10, and includes four strain gauges 12 attached to each wire 10. FIG. 1 illustrates strain gauges 12A and 12B attached to the wires 10A and 10B.
Each detection output of the strain gauge 12 is sent to the control unit 53.
The breaking limit value of each wire 10, that is, the pulling amount limit value by the bending drive mechanism 52 is set in advance in the memory 101 described later.

The operation unit 14 is for performing operation input of the endoscope apparatus 50. At least the bending operation mechanism 15 that operates the bending amount of the bending unit 2 in the biaxial direction and the subject imaged by the imaging unit 4 are operated. A lock button 16a (capture operation setting means) for instructing the start of an object capture operation that keeps the imaging center position substantially constant, and a lock release button 16b (capture operation setting means) for instructing the release of the capture operation are provided. The bending operation mechanism 15 can employ a mechanism such as a joystick or an angle switch, for example.
When the lock release button 16b is pressed, an interrupt signal for the control unit 100 described later is generated, the operation of the bending drive mechanism 52 is stopped, and a capture servo ON flag described later is reset. Thereby, even during the execution of the subject capturing operation, the subject capturing operation can be forcibly terminated and the bending by the manual operation using the bending operation mechanism 15 can be performed.
Each input signal input by operating the operation unit 14 is sent to the control unit 53.

The schematic configuration of the control unit 53 includes a control unit 100, a memory 101 (storage means), a motor driver 102, and a CCU 104.
The control unit 100 is electrically connected to the operation unit 14, the memory 101, the motor driver 102, the CCU 104, and the monitor 13. Input signals from the operation unit 14, acceleration sensors 5 </ b> A and 5 </ b> B, and detection outputs of the tension detection unit 54. In accordance with the parallax image 301 transmitted from the CCU 104, various control operations and processing operations relating to the control of the entire apparatus and the control of the bending drive mechanism 52 are performed. And the imaging position stabilization means is comprised. The information processed by the control unit 100 can be converted into appropriate image data 303 composed of characters, images, etc., and displayed on the monitor 13.
The control unit 100 may be configured by using hardware having an appropriate control circuit group, but in the present embodiment, is configured by a CPU and an input / output interface (not shown). Then, a group of programs for performing each control operation and processing operation to be described later is loaded into the memory 101 and executed by the CPU, thereby realizing each control operation and processing operation corresponding to each program.

The motor driver 102 controls the rotation angle of each motor 9 according to a control signal sent from the control unit 100.
The CCU 104 performs an appropriate image processing such as brightness correction, sharpness correction, and stereo image data processing on the image signal 300 captured by the image sensor 4B as necessary, and displays an image on the monitor 13 Data 302 is generated and transmitted to the monitor 13, and two parallax images 301 for performing stereo measurement are generated and transmitted to the control unit 100.

Next, the operation of the endoscope apparatus 50 will be described.
First, the bending detection operation of the bending portion 2 in the present embodiment will be described.
FIG. 2 is an explanatory perspective view illustrating the positional relationship between the distal end and the proximal end in the bending state of the bending portion of the endoscope apparatus according to the first embodiment of the present invention.

In order to perform the bending operation, the control unit 100 instructs the bending amount in the biaxial direction from the bending operation mechanism 15 of the operation unit 14 or the like. As a result, a control signal for appropriately winding each wire 10 is sent from the control unit 100 to the motor driver 102, and each motor 9 is rotated by the motor driver 102. As a result, for example, as shown in FIG. 2, the curved portion 2 extending in the direction along the vector B direction deviates from the vector B direction, and the normal line of the distal end surface 3 a of the curved distal end portion 3 is in the vector A direction. Suppose that a curve that faces the direction is caused.
The purpose of bending the bending portion 2 in the endoscope apparatus 50 is to move the bending distal end portion 3 and image a desired subject by the imaging means 4 built in the bending distal end portion 3. Therefore, the bending shape of the bending portion 2 is sufficient if the relative positional relationship between the bending distal end portion 3 and the bending proximal end portion 8 can be described.
In the present embodiment, the positions of the curved distal end portion 3 and the curved proximal end portion 8 are determined based on the accelerations in the triaxial directions detected by the acceleration sensors 5A and 5B provided at the curved distal end portion 3 and the curved proximal end portion 8, respectively. Detect posture.
The position information is acquired as a three-dimensional displacement amount from the initially arranged reference position by integrating the acceleration variation detected by the acceleration sensors 5A and 5B.
The posture information is detected three-dimensionally as a difference with respect to the gravitational acceleration component detected by the acceleration sensors 5A and 5B.
Since the acceleration sensors 5A and 5B are fixed at predetermined positions of the curved distal end portion 3 and the curved proximal end portion 8, these positional information and posture information form a rigid portion and can be regarded as a rigid body. 3. The curved base end portion 8 can be easily converted into position information and posture information at an arbitrary position inside each.

For this reason, the rigid body motion of the curved distal end portion 3 and the curved proximal end portion 8 can be described by a vector in an appropriate XYZ orthogonal coordinate system based on the position information and posture information detected by the acceleration sensors 5A and 5B.
For example, the unit direction vectors A and B shown in FIG. 2 represent the postures of the curved distal end portion 3 and the curved proximal end portion 8, respectively.
A = (A _x , A _y , A _z ) (1)
B = (B _x , B _y , B _z ) (2)
The bending angle of the bending distal end portion 3 with respect to the bending proximal end portion 8 when the bending portion 2 is bent is defined as an angle θ formed by these unit direction vectors A and B as follows.
θ = cos ⁻¹ {(A * B) / (| A | · | B |)} (3)
Here, the symbols *,... Represent vector inner product and scalar multiplication, respectively. Also, | A | = | B | = 1.
Further, the bending direction is expressed as a direction vector W defined as a difference between unit direction vectors A and B.
W = A-B
_{= (A x -B x, A} y -B y, A z -B z) ··· (4)

The endoscope apparatus 50 of the present embodiment can keep the imaging center position of the subject substantially constant, and the following description will focus on the subject capturing operation.
FIG. 3 is a flowchart for explaining the operation of the endoscope apparatus according to the first embodiment of the present invention. FIG. 4A is an operation explanatory diagram for explaining the principle of the subject image capturing operation of the endoscope apparatus according to the first embodiment of the present invention. FIG. 4B is a vector diagram for explaining the displacement vector of FIG. FIGS. 5A and 5B are auxiliary explanatory diagrams showing a geometric relationship for calculating a bending angle and a bending direction in the capturing operation of FIG. 4A. FIG. 6 is a principle explanatory diagram for explaining distance measurement using a parallax image.

The operator operates the bending operation mechanism 15 of the operation unit 14 to bend the bending unit 2 in an appropriate direction, thereby changing the optical axis direction of the binocular lens 4A and imaging the subject 20 from various directions. Can be observed.
Then, by pressing the lock button 16a at a desired timing, it is possible to execute a subject capturing operation for keeping the imaging center position of the subject 20 imaged at that time substantially constant. That is, when the lock button 16a is pressed, the operation flow shown in FIG. 3 is started.

  In step S1, the servo command signal generated by the lock button 16a is sent to the control unit 100. The control unit 100 sets a capture servo ON flag in the memory 101.

In step S2, the detection outputs of the acceleration sensors 5A and 5B are taken into the control unit 100, and the positions and postures of the curved distal end portion 3 and the curved proximal end portion 8 at the start of the capturing operation are acquired.
For example, as shown by a broken line in FIG. 4 (a), it shall be captured by the image sensor 4B away object image around p (initial imaging center position) in the normal direction by the optical path length h ₁ of the object 20.
For simplicity, the acceleration sensor 5A as the position information of the curved distal portion 3, and detects the position of a ₀ point of the center of the imaging surface of the imaging element 4B. The acceleration sensor 5B detects the position of the point b ₀ in the curved proximal end portion 8, and the points a ₀ and b ₀ are on the optical axis of the binocular lens 4A. The distance between the points a ₀ and b ₀ is L.
In this case, the position sensors of the points a ₀ and b ₀ are detected by the acceleration sensors 5A and 5B, and the unit direction vectors A ₀ and B ₀ are detected as the posture information.
In this case, in Equation (3), by setting A = A ₀ and B = B ₀ , the bending angle θ ₀ = 0 can be obtained.
Further, the direction vector W ₀ = A ₀ −B ₀ = (0, 0, 0) is obtained as the bending direction.

In step S3, the position information of the points a ₀ and b ₀ and the posture information of the curved distal end portion 3 and the curved proximal end portion 8 in this state are stored in the memory 101.

In step S4, the parallax image 301 sent from CCU104, to measure the distance _{h 1} to the object image center p of the object 20.
This measurement principle is a known technique described in, for example, Japanese Patent Publication No. 8-12332. However, it will be briefly described with reference to FIG.
As shown in FIG. 6, it is assumed that images of the subject 20 are captured as images I ₁ and I ₂ by objective lenses 4a and 4b arranged to have parallax d, respectively. Here, O ₁ and O ₂ in the figure are the center positions of the objective lenses 4a and 4b, respectively, and f represents the focal length of each lens.
Subject image center p is an objective lens 4a, the 4b, on the images _I 1, _{I 2,} are imaged point _p a, the position of the _{p b.} When image pickup center position of the image _I 2, _{I 1} is superimposed so as to coincide, the point _{p a} corresponds to _{q a} point shifted on the image _{I 2} by a distance _{d i.}
Therefore, the following equation is established from the similar relationship between ΔO ₁ pO ₂ and Δq _a O ₂ p _b .
h = f · d / d _i (5)
h ₁ = h + f (6)
Here, h represents the distance from the center position of the objective lenses 4a and 4b to the subject image center p.
Therefore, for example, the distance h ₁ can be accurately calculated by extracting the positions of the points p _a and p _{b in} the two parallax images 301 by image processing and calculating the amount of positional deviation on these images. it can. Also, by performing these calculations at each image position, it is possible to generate a stereoscopic image from the images I ₁ and I ₂ , and a stereoscopic measurement on the subject 20 is possible.

In step S5, and stores the distance _{h 1} calculated in step S4 in the memory 101.
In step S6, the same measurement as in step S2 is performed, and the result is stored in the work area of the memory 101. Thereby, information at the present time is acquired.
For example, it is assumed that the insertion unit 1 has been moved due to disturbance until the present time, and is in a state indicated by a two-dot chain line in FIG. For the sake of simplicity, it is assumed that the movement and rotation occur within the illustrated paper plane that coincides with the ZX plane.
That is, the image sensor 4B moves to the point a ₁ and the acceleration sensor 5B moves to the point b ₁ , and the position vector and unit direction vectors A ₁ and B ₁ are detected accordingly, and the direction vector W ₁ = A _1. -B ₁ , the bending angle θ = α is obtained and stored in the work area of the memory.
At this time, as shown in FIG. 4 (a), the distance to the point q on the optical axis 22 is a distance h _3. The distance h ₂ is the distance in the Z axis direction between the imaging position and the acceleration sensor 5A before disturbed.

In step S7, the bending angle and the bending direction based on the position and posture information of the points a ₀ and b ₀ stored in the memory 101 are compared with the distance h ₁ and the values measured in steps S5 and S6. If this occurs, a curvature target value for correcting the deviation is calculated.
In this embodiment, control is performed so that the optical axis of the imaging optical system faces the initial imaging center position. Therefore, as shown by a solid line in FIG. 4A, the bending amount for correcting the deviation is represented by a bending angle γ that causes the bending portion 2 to bend so that the optical axis 24 after bending passes through the subject image center p. .
The concept of this calculation process will be briefly described.
As shown in FIG. 4B, displacement due to disturbance is represented by displacement vectors Δa and Δb.
Δa = a ₁ −a ₀
= (Δa _x , Δa _y , Δa _z ) (7)
Δb = b ₁ −b ₀
= (Δb _x , Δb _y .Δb _z ) (8)
First, the following equation is obtained from the geometric relationship shown in FIG.
α = sin ⁻¹ {(Δa _x −Δb _x ) / L} (9)
As shown in FIG. 4A, when the bending portion 2 is rotated by an angle α around the point b ₁ , the point a ₁ moves to the point a ₂ and the bending portion 2 is parallel by Δb. This corresponds to the moved state.

In this case, a geometrical relationship as shown in FIG. 5B is established between each component of Δb and the distances h ₁ and h ₂ .
The angle β ₁ in the figure is a case where the curved tip 3 rotates around the point b ₁ , and the angle β ₂ is a case where the curved tip 3 rotates around the point a ₂ . These are extreme cases, and the rotational movement of the bending tip portion 3 due to actual bending has a center of rotation at an intermediate portion of the bending portion 2. Therefore, the angle β takes a value between the angles β ₁ and β ₂ . The angle β is a value determined depending on the bending characteristics of the bending mechanism of the bending portion 2.
Therefore, the following equation holds.
h ₂ = h ₁ + Δb _z (10)
β = tan ⁻¹ {Δb _x / (h ₂ + δ · L · cos α)} (11)
Here, δ (where 0 <δ <1) is a correction coefficient that takes into account the movement of the rotation center due to the bending characteristics of the bending mechanism of the bending portion 2, and depending on the structure of the bending portion 2, for example, through experiments It can be set appropriately. In this embodiment, δ = 0.6.
From the equations (9) and (11), the bending angle γ of the bending target value is obtained as the following equation.
γ = α + β (12)

In the above, in order to explain the calculation method for introducing the correction coefficient δ in an easy-to-understand manner, an example of simplified geometric calculation has been described. However, in the internal calculation performed by the control unit 100, the bending angle calculated from the direction vector is described. By using three-dimensional vector calculation using θ, a direction vector W that defines the bending direction, and a correction coefficient that corrects the rotation center of the bending tip 3, the bending angle and the bending direction of the bending portion 2 that are the bending target values are obtained. It is determined. These values are stored in the memory 101.
In this case, the initial state of bending need not be a straight state as described above.

In step S8, it is determined whether or not the curvature target value calculated in step S7 is equal to or less than the lower limit threshold value of curvature set in the memory 101 in advance.
If the bending target value is less than or equal to the lower limit threshold for bending, the curve cannot be captured with higher accuracy due to bending, and the process proceeds to step S11 without performing the bending operation.
If the curve target value is greater than the curve lower limit threshold, step S9 is executed.
The lower limit threshold for bending is set to a value as necessary in consideration of the minimum bending amount of the bending portion 2 and bending control accuracy.

In step S <b> 9, it is determined whether or not the curvature target value calculated in step S <b> 7 is equal to or greater than a curvature upper limit threshold set in advance in the memory 101.
If the curve target value is equal to or greater than the curve upper limit threshold, step S12 is executed to display a warning. For example, the image data 303 containing a message warning that the capture operation cannot be performed because it tried to bend beyond the limit is sent to the monitor 13 and the capture servo ON flag in the memory 101 is reset to end the capture servo. . Then, the process proceeds to step S11.
By performing the determination as in step S9, an attempt is made to perform bending beyond the bendable limit, and the tension applied to each wire 10 and the driving load of each motor 9 become excessive, and the wire 10 breaks. The motor 9 can be prevented from being damaged.
When the bending target value is smaller than the upper limit threshold for bending, step S10 is executed.
The upper limit threshold for bending is set to a value as necessary in consideration of the bending degree of freedom and rigidity of the bending portion 2.

In step S10, the bending operation of the bending portion 2 is performed according to the bending target value calculated in step S7. This bending operation will be described with reference to FIG.
FIG. 7 is a flowchart for explaining details of the bending operation.

In step S20, the current (current time) bending angle and bending direction are measured in the same manner as in step S6 of FIG.
In step S21, the values of the bending angle and the bending direction measured in step S20 are compared with the bending target value calculated in step S7 of FIG.
If it matches the curve target value, the process proceeds to step S24.
If it does not match the curve target value, the process proceeds to step S22.

In step S24, a control signal is sent to the motor driver 102, and the operation of the bending drive mechanism 52 is stopped. In the present embodiment, each motor 9 is stopped at the current position.
Then, the bending operation is terminated, and the process proceeds to step S11 in FIG.

In step S <b> 22, the detection output of each strain gauge 12 is acquired from the tension detection unit 54, and converted into the tension value of the wire 10 corresponding to each.
In step S23, it is determined whether or not the tension value converted in step S22 is greater than or equal to the tension threshold value stored in advance in the memory 101.
If there is more than the tension threshold, the process proceeds to step S25.
If all the tension values are smaller than the tension limit threshold value, the process proceeds to step S26.

In step S25, the image data 303 containing a message warning that the bending operation cannot be performed because the tension of the wire 10 exceeds the limit value is sent to the monitor 13, and the capture of the memory 101 is terminated in order to end the capture servo. Reset the servo ON flag. Then, the process proceeds to step S24.
For this reason, it is possible to prevent the wire 10 from breaking.

In step S26, the bending drive mechanism 52 is driven by sending a control signal to the motor driver 102 in accordance with the deviation between the bending target value and the bending state of the current position. And it returns to step S20 and repeats said process.
Therefore, unless an abnormality in the tension of the wire 10 is detected, step S26 is executed, and when the bending state matches the bending target value, step S24 is executed, and the bending operation ends.
Thereafter, the process proceeds to step S11 in FIG.

In step S11, the memory 101 is referenced to determine whether there is a capture servo ON flag.
If the capture servo ON flag is set, the process returns to step S6 and the above process is repeated. Therefore, even if a disturbance is received during the execution of these steps, for example, a target curve value for correcting the disturbance is set every time steps S6 to S7 are executed, and the capture servo loop functions effectively.
When the capture servo ON flag is reset, the capture operation is terminated.

As described above, for example, even when the insertion portion 1 moves due to disturbance or the like, the position or direction of the curved distal end portion 3 changes, and the center of the imaging position deviates from the subject image center p by the imaging means 4, the acceleration sensor 5A. 5B, based on the position and orientation detection output by 5B and the measurement result of the distance to the subject image center p by stereo measurement, the curved tip 3 is bent and moved, and the subject image center p before receiving the disturbance is within the imaging range. Can be captured at substantially the same position.
Therefore, every time a disturbance occurs, the subject image can be observed stably without taking the trouble of finely adjusting the direction of the optical axis by manual operation or searching for the subject.

In such subject capturing operation, the distance of the initial imaging center position is measured with reference to the image data of the subject 20 for distance measurement, but thereafter, the capturing operation is performed without using the image of the subject image center p. Therefore, even if the position of the subject image center p is outside the imaging range due to disturbance or the like, for example, there is an advantage that it can be easily captured as long as it is within the bendable range. Therefore, a wide capture range is provided according to the bendable range.
In addition, the amount of bending for capturing the subject image center p is calculated with a small number of parameters such as the detection output of the acceleration sensors 5A and 5B and distance information by stereo measurement. For example, the image data in the imaging range is processed. As compared with the case where image processing is performed, there is an advantage that high-speed computation can be performed and quick capturing operation can be performed.

  Further, the position, posture, and bending state of the bending portion 2 are detected by the acceleration sensors 5A and 5B built in the bending distal end portion 3 and the bending proximal end portion 8, and the capture servo is applied based on the detection outputs thereof. Therefore, compared to the case where the capture operation is performed by the open loop control depending on the drive accuracy of the bending drive mechanism 52, the capture operation with higher accuracy can be performed even if the drive accuracy of the bending drive mechanism 52 is the same. Therefore, there is an advantage that an inexpensive device can be configured.

[Second Embodiment]
Next, an endoscope apparatus according to a second embodiment of the present invention will be described.
FIG. 8 is an explanatory diagram schematically illustrating the schematic configuration of the endoscope apparatus according to the second embodiment of the present invention.

  As shown in FIG. 8, the endoscope apparatus 70 of the present embodiment replaces the bending drive mechanism 52 that drives the wire 10 using the motor 9 of the first embodiment with a fluid pressure such as an air pressure drive. The difference is that a bending drive mechanism 72 that performs a bending operation by driving is used. Accordingly, instead of the tension detection unit 54, the control unit 53, and the two wires 10 of the endoscope apparatus 50, the pressure detection unit 74, the control unit 73, and the four supply tubes 36 and the bending tube 37, respectively. Is provided. Hereinafter, a description will be given focusing on differences from the first embodiment.

The schematic configuration of the bending drive mechanism 72 includes an air cylinder 30, a regulator 31, a pressure sensor 32, a tube joint 29, and electromagnetic valves 33 and 34.
The air cylinder 30 is an air supply source containing compressed air.
The regulator 31 is a unit that adjusts the compressed air in the air cylinder 30 to a constant pressure in accordance with a control signal from a control unit 105 (imaging position stabilization unit), which will be described later, and supplies the compressed air to the tube joint 29. The tube is connected to the air cylinder 30 and the tube joint 29.
The air pressure supplied from the regulator 31 is detected by the pressure sensor 32 and monitored by the control unit 105 in order to prevent a malfunction of bending due to abnormal pressure or sudden pressure fluctuation.

The tube joint 29 distributes and supplies the constant pressure air supplied from the regulator 31 to the four supply tubes 36.
The four supply tubes 36 are made of a hard tube that has flexibility but hardly expands or contracts due to air pressure within a range of supplied air pressure, and is provided in the bending drive mechanism 72 and the proximal end of the insertion portion 1. It is piped in the range of the flexible tube in which the curved base end part 8 is provided from the part.
In the insertion portion 1, each supply tube 36 passes through a position that divides the outer peripheral direction into four equal parts in the vicinity of the outer peripheral portion of the insertion portion 1, as in the wire 10 of the first embodiment. They are arranged symmetrically.
FIG. 8 shows two supply tubes 36A and 36B that are opposed to each other.

Connected to the distal end side of each supply tube 36 is a soft curved tube 37 that can be expanded and contracted in the pipeline direction by the internal pressure of the supplied air through a pipe joint (not shown) provided at the curved base end portion 8. Has been.
The bending tube 37 is piped into the bending portion 2 while maintaining the same positional relationship as the supply tube 36, and the distal end of the bending tube 37 extends to the bending distal end 3, and the distal end of the bending tube 37 is closed. It is fixed to the end face on the end side.

In the bending drive mechanism 72, electromagnetic valves 33 and 34 are arranged in this order from the tube joint 29 side on the pipe line of each supply tube 36.
The electromagnetic valve 33 is a three-way electromagnetic valve that is operated by a solenoid that is driven in accordance with a control signal from the control unit 105. That is, when the solenoid is ON, the illustrated ports P and A are opened and the ports A and E are closed. When the solenoid is OFF, the illustrated ports A and E are opened and the ports P and A are closed. It is what
The solenoid valve 34 is a two-way solenoid valve that is operated by a solenoid that is driven in accordance with a control signal from the control unit 105. That is, when the solenoid is ON, the illustrated ports P and A are opened, and when the solenoid is OFF, the illustrated ports P and A are closed.
Therefore, by appropriately opening and closing the electromagnetic valves 33 and 44, it is possible to control the increase / decrease in the amount of air into the supply tube 36 and the bending tube 37 on the downstream side of each electromagnetic valve 34. Yes.

The pressure detection unit 74 is for preventing the bending tube 37 from rupturing due to an abnormal air pressure and making the bending operation difficult, and is disposed on each supply tube 36 on the downstream side of the electromagnetic valve 34. It consists of two pressure sensors 35.
The pressure sensor 35 detects the air pressure on the downstream side of the electromagnetic valve 34 and sends the detected output to the control unit 105 in order to prevent the bending tube 37 from bursting.

The control unit 73 includes a control unit 105 instead of the control unit 100 of the control unit 53 of the first embodiment.
The control unit 105 has the same configuration as that of the control unit 100 except that a part of the control target is changed from the bending drive mechanism 52 to the bending drive mechanism 72, and a part of the control method is changed. Can be adopted.
However, the tension limit threshold value stored in advance in the control unit 100 is replaced with an internal pressure limit threshold value for preventing the bending tube 37 from bursting.
Here, what is measured by the pressure sensor 35 is the air pressure in the supply tube 36, but the internal pressures of the curved tube 37 and the supply tube 36 connected to each other are the same. If the internal pressure is such that the curved tube 37 does not rupture, the supply tube 36 naturally does not rupture.

According to such a configuration, the air supplied from the air cylinder 30 and adjusted to a constant pressure by the regulator 31 is supplied to the four supply tubes 36 via the tube joint 29.
The control unit 105 sends a control signal to the electromagnetic valves 33 and 34 based on the instruction input from the operation unit 14 and the bending target value obtained as a result of the operations in steps S1 to S7 in FIG. The amount of air in the bending tube 37 is varied. That is, air is supplied by opening the ports P and A of the electromagnetic valves 33 and 34. Further, the amount of air is maintained by closing between the ports P and A of the electromagnetic valve 34.
And by opening and closing between the ports P and A of the electromagnetic valve 34 in a state where the ports A and E of the electromagnetic valve 33 are opened, an appropriate amount of air in the pipeline is exhausted.
Since each bending tube 37 expands and contracts in the pipe line direction according to the internal pressure by the supplied air, the bending portion 2 can be bent in the biaxial direction according to the balance of the expansion and contraction amounts. ing.

Next, the capturing operation of the endoscope apparatus 70 of the present embodiment will be described.
The endoscope apparatus 70 is capable of capturing a subject image similarly to the endoscope apparatus 50 of the first embodiment, and only the operation in step S10 in FIG. 3 is different. Therefore, the bending operation corresponding to step S10 will be described.
FIG. 9 is a flowchart for explaining details of the bending operation of the endoscope apparatus according to the second embodiment of the present invention.

As shown in FIG. 9, the bending operation of this embodiment includes steps S30 to S34 corresponding to steps S20 to S24 of FIG.
In step S30, the bending angle and the bending direction at the current position are measured in the same manner as in step S6 in FIG.
In step S31, the values of the bending angle and the bending direction measured in step S30 are compared with the bending target value calculated in step S7 in FIG.
If it matches the curve target value, the process proceeds to step S34.
If it does not match the curve target value, the process proceeds to step S32.

In step S34, a control signal is sent to the electromagnetic valves 33, 34, the electromagnetic valves 33, 34 are closed to seal the air, and the operation of the bending drive mechanism 72 is stopped.
Then, the bending operation is terminated, and the process proceeds to step S11 in FIG.

In step S <b> 32, the internal pressure values of the pressure detector 74, the supply tube 36 and the bending tube 37 detected by each pressure sensor 35 are acquired.
In step S33, it is determined whether any of the internal pressure values acquired in step S32 is greater than or equal to the limit threshold value of the internal pressure of the bending tube 37 stored in advance in the memory 101.
If there is an internal pressure exceeding the limit threshold, the process proceeds to step S35.
If all the internal pressure values are smaller than the limit threshold of internal pressure, the process proceeds to step S36.

In step S35, image data 303 containing a message warning that the bending operation cannot be performed because the internal pressure of the bending tube 37 has exceeded the limit value is sent to the monitor 13, and the capture of the memory 101 is terminated in order to end the capture servo. Reset the servo ON flag. Then, control goes to a step S34.
For this reason, it is possible to prevent the bending tube 37 (supply tube 36) from rupturing.

In step S36, a control signal is sent to each electromagnetic valve 33, 34 in accordance with the deviation between the bending target value and the bending state at the current position, and the bending operation is performed by controlling the internal pressure in each bending tube 37.
And it returns to step S30 and repeats said process.
Therefore, in the bending operation, unless an abnormality in the internal pressure of the bending tube 37 (supply tube 36) is detected, step S36 is executed, and when the bending state matches the bending target value, step S34 is executed, and the bending operation ends. To do.
Thereafter, the process proceeds to step S11 in FIG.

  Thus, the endoscope apparatus 70 of this embodiment is an example in which the bending driving mechanism of the endoscope apparatus 50 is replaced with a fluid pressure driving means. It can be seen that the subject capturing operation of the present embodiment can be performed essentially in the same manner as in the case of the endoscope apparatus 50.

[Third Embodiment]
Next, an endoscope apparatus according to a third embodiment of the present invention will be described.
As shown in FIG. 1, the endoscope apparatus 500 according to the present embodiment includes a control unit 200 instead of the control unit 100 of the first endoscope apparatus 50, and has a different capture operation control method. Is. Hereinafter, a description will be given focusing on differences from the first embodiment.
FIG. 10 is a flowchart for explaining the operation of the endoscope apparatus according to the third embodiment of the present invention. FIG. 11A is a schematic diagram illustrating an example of an overall image of a subject. FIG. 11B is a schematic explanatory diagram for explaining contrast measurement. 11C, 11D, 11E, and 11F are examples of images acquired in the process of capturing an initial subject image on FIG. 11A.

The endoscope apparatus 500 of the present embodiment includes an image shift detection unit that detects the position shift of the subject 20 from the captured image information, and as shown in FIG. The movement of the subject image center p to be captured is performed so as to perform the motion capture operation (first subject capture operation) and the fine motion capture operation (second subject capture operation) for correcting the amount of curvature by the detection output of the image shift detection means. This is intended to improve the positional accuracy.
In the present embodiment, an example in which image contrast information is used as image information will be described. The image shift detection unit includes the control unit 200 that performs image processing on the parallax image 301 obtained by the imaging unit 4 having the binocular lens 4A.

  Steps S40 to S44 in FIG. 10 are operations for storing the initial bending state related to the coarse motion capturing operation of the present embodiment, and the same operations as steps S1 to S5 in FIG. 3 are performed, respectively. It is like that.

Step S45 subsequent to step S44 is for acquiring initial image information for performing the fine movement capturing operation. In this embodiment, the image captured by the imaging means 4 at the start of the capturing operation, that is, the subject 20 is captured. The contrast of the image centered on the subject image center p (see FIG. 4A) is detected.
For example, the subject 20 is the amorphous grayscale image shown in FIG. 11 (a), it is assumed that the imaging range in the initial state is represented by the frame F _1. Subject image center p is located at the center of the frame F _1.
In step S45, the image of the frames _{F 1} is captured as an image signal 300 to CCU104. Then, after processing the contrast detection image 305 by the CCU 104, it is sent to the control unit 200.
Contrast detection image 305, if the image to quickly detect the movement of the image, can be employed an appropriate image, in this embodiment, for example, as shown in FIG. 11 (b), frames F ₁ It is possible to adopt two-dimensional luminance distribution data in which the inside is divided into a grid shape and divided into image areas G, and the average luminance in each section is calculated and converted into a mosaic image.
In step S46, the contrast detection image 305 is stored in the memory 101. This image is referred to as a contrast detection image 305A.

Subsequent steps S47 to S48 are preparation steps for performing the coarse motion capturing operation, and perform substantially the same operations as steps S6 to S7 in FIG. 3, respectively.
However, the bending target value calculated in step S48 is referred to as a bending target value I.
In step S49, it is determined whether or not the curvature target value I calculated in step S48 is equal to or less than a lower limit threshold value for performing the coarse motion capturing operation set in the memory 101 in advance. That is, when the curvature target value I is very small and the subject image center p is calculated to be within a deviation within the imaging range, the coarse motion capturing operation step is omitted, and only the fine motion capturing operation is performed. is there. In this case, since the coarse motion capturing operation is omitted, there is an advantage that a high speed capturing operation can be performed accordingly.
When the curvature target value I is equal to or less than the lower limit threshold value for performing the coarse motion capturing operation, the process proceeds to step S53.
When the curvature target value I is larger than the lower limit threshold value for performing the coarse motion capturing operation, step S50 is executed.

In step S50, it is determined whether or not the bending target value I calculated in step S48 is equal to or greater than the upper limit threshold value of bending set in the memory 101 in advance.
When the bending target value I is equal to or greater than the upper limit threshold for bending, step S52 is executed to display a warning. For example, the image data 303 containing a message warning that the capture operation cannot be performed because it tried to bend beyond the limit is sent to the monitor 13 and the capture servo ON flag in the memory 101 is reset to end the capture servo. . Then, control goes to a step S57.

  Step S51 is the same operation as the bending operation shown in FIG. 7, and the coarse motion capturing operation is completed by the end of step S51.

As described in the first embodiment, such a coarse motion capturing operation is advantageous over the case where the curvature amount is determined by acquiring the position information of the subject image center p from the image information that increases the data amount. There are many.
However, since the position information of the subject image center p is not directly acquired from the subject image and fed back, there may be a case where the position of the subject image center p deviates from the imaging center due to, for example, an acceleration detection error. It is done.
For example, in the course of the coarse motion capturing operation, as shown in FIG. 4A, the insertion unit 1 is moved and curved in the state of a broken line, a two-dot chain line, and a solid line, and the center of the imaging range is set to the points p, q, When moving like r and p, the captured image may change as shown in FIGS. 11C, 11D, 11E, and 11F, respectively, for example.
That is, after the coarse motion capturing operation is finished, the image captured in the frame F ₄ (see FIG. 11 (f)) is not shown because of a capture error or a change in the distance between the imaging unit 4 and the subject image center p. The image is in the frame F ₄ slightly wider than the initial frame F ₁ shown in FIG. 11C, and the image center is a point p ′ slightly shifted from the subject image center p.
In the present embodiment, in the state where the subject image center p is captured within the imaging range as described above, the fine motion capturing operation using the image information of the subject 20 is performed as follows.

  In step S53, as in step S45, the CCU 104 processes the contrast detection image 305 from the image signal 300 at the current position, and sends it to the control unit 200. The control unit 200 stores the acquired contrast detection image 305 in the work area of the memory 101. This image is referred to as a contrast detection image 305B.

  In step S54, the control unit 200 compares the contrast detection image 305A stored in the memory 101 in step S46 with the contrast detection image 305B stored in the memory 101 in step S53, and moves the image within the imaging range. The amount is calculated, and the shift amount of the subject image center p is obtained. Then, the bending angle and the bending direction are calculated according to the deviation amount, and the bending target value II from the current position is calculated.

In step S55, it is determined whether or not the bending target value II calculated in step S54 is equal to or lower than a lower limit threshold value for performing the fine movement capturing operation set in the memory 101 in advance.
The lower limit value of the threshold range for performing the fine movement capturing operation is for determining the convergence of the capturing, and is set as necessary from the capturing accuracy of the subject image center p.
In the present embodiment, since it has been found that the coarse motion capturing operation is executed in the process before step S55 or the target is a curve target that does not require the coarse motion capturing operation, an upper limit threshold is provided. The determination process is omitted.
When the curvature target value II is equal to or lower than the lower limit threshold value for performing the fine movement capturing operation, the process proceeds to step S57.
When the curvature target value II is smaller than the lower limit threshold value for performing the fine movement capturing operation, step S56 is executed.
Step S56 is the same operation as the bending operation of FIG. When step S56 ends, the process proceeds to step S57.
This completes the fine movement capturing operation.

In step S57, the same operation as in step S11 of FIG. 3 is performed. That is, referring to the memory 101, the presence / absence of the capture servo ON flag is determined.
If the capture servo ON flag is set, the process returns to step S47 and the above process is repeated. Therefore, even if a disturbance is received during the execution of these steps, for example, every time steps S47 to S48 or steps S53 to S54 are executed, the curvature target value I or II for correcting the disturbance is set, The acquisition servo functions effectively.
When the acquisition servo ON flag is reset, the acquisition operation is stopped.

  According to the present embodiment, when the subject image center p is out of the imaging range due to disturbance, the coarse motion capturing operation is performed and the subject image center p is captured in the imaging range. Then, based on the image information around the subject image center p, the amount of deviation of the subject image center p from the center of the imaging range is detected, and the fine motion capturing operation is executed. For this reason, even if the insertion unit 1 moves in a wide range, the coarse motion capturing operation and the fine motion capturing operation are performed sequentially or selectively depending on the case, so that a highly accurate and efficient subject capturing operation can be performed. it can.

Next, a modification of the third embodiment will be described.
As shown in FIG. 8, an endoscope apparatus 700 according to this modification includes a control unit 205 having a function of an image shift detection unit instead of the control unit 105 of the second embodiment.
That is, this modification is an example in which the coarse motion capturing operation and the fine motion capturing operation of the third embodiment are performed when the bending drive mechanism uses fluid pressure drive.
Since the configuration of the control unit 205 and the operation of the endoscope apparatus 700 are easily understood from the second and third embodiments, description thereof will be omitted.

  In the above description, an example in which stereo measurement means is used as distance measurement means has been described. In this way, there is an advantage that the imaging unit can be used as a stereo measurement unit, but the configuration is not limited to this configuration as long as the distance between the subject and the imaging optical system can be measured. For example, a distance measuring unit that irradiates the subject with detection light and measures the distance by the reflected light, or a distance measuring unit that focuses on the subject and measures the distance may be employed.

  In the above description, the imaging unit is described as an example of the stereo measurement unit. However, when there is no need to capture a stereo image of the subject, the image obtained by the objective lens on one side is monitored as the imaging unit. The stereo image may be acquired only when the entire image is displayed and observed, and the distance to the subject is measured.

  In the above description, the acceleration detection unit is used as the bending portion position / orientation control unit. However, the present invention is not limited to this as long as the position and posture of the distal end of the bending unit can be detected. For example, by arranging a plurality of sensor coils at the curved distal end portion and the proximal end portion and exposing them to a magnetic field, inclination and displacement, that is, position and posture can be detected from the self-induced electromotive force of the coil. Good.

  In the description of the third embodiment, contrast information is used as the image information of the image shift detection unit. However, the image information is not limited to this, and image information that has been appropriately processed is used. Can be adopted. For example, an image shift amount may be detected by processing an object image into an edge image by performing edge extraction processing and extracting features of the edge image.

In the above description, the example in which the subject capturing operation is performed so that the optical axis of the imaging optical system is directed to the initial imaging center position has been described. It is more advantageous if the distance is measured and the zoom range is changed according to the distance measurement, so that the imaging range is also kept constant.
The zoom function is easy to electronic zoom, but may be provided in the imaging optical system.

BRIEF DESCRIPTION OF THE DRAWINGS It is the structure explanatory drawing typically drawn in order to demonstrate schematic structure of the endoscope apparatus which concerns on the 1st Embodiment of this invention. It is a perspective explanatory view explaining the positional relationship between the tip and the base end in the bending state of the bending portion of the endoscope apparatus according to the first embodiment of the present invention. It is a flowchart for demonstrating operation | movement of the endoscope apparatus which concerns on the 1st Embodiment of this invention. FIG. 5 is an operation explanatory diagram for explaining the principle of a subject image capturing operation of the endoscope apparatus according to the first embodiment of the present invention and a vector diagram for explaining a displacement vector thereof. FIG. 5 is an auxiliary explanatory diagram illustrating a geometric relationship for calculating a bending angle and a bending direction in the capturing operation of FIG. It is a principle explanatory view for explaining distance measurement using a parallax image. It is a flowchart for demonstrating the detail of bending operation | movement. It is the structure explanatory view typically drawn in order to demonstrate schematic structure of the endoscope apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating the detail of bending operation | movement of the endoscope apparatus of the 2nd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the endoscope apparatus which concerns on the 3rd Embodiment of this invention. FIG. 4 is a schematic diagram illustrating an example of a whole image of a subject, a schematic explanatory diagram for explaining contrast measurement, and an example of an image acquired in the process of capturing an initial subject image.

Explanation of symbols

1 Insertion part (endoscope insertion part)
2 Bending portion 3 Bending tip (tip of bending portion)
4 Imaging means 4A Binocular lens (imaging optical system)
4a, 4b Objective lens 4B Image sensor 5A, 5B Acceleration sensor (acceleration detection means)
8 curved base end (base end of curved section)
9, 9A, 9B Motor 10, 10A, 10B Wire 12, 12A, 12B Strain gauge 14 Operation unit 16a Lock button (capturing operation setting means)
16b Unlock button (capture operation setting means)
20 Subject 21, 22, 23, 24 Optical axis (optical axis of imaging optical system)
33, 33A, 33B, 34, 34A, 34B Solenoid valve 35, 35A, 35B Pressure sensor 36, 36A, 36B Supply tube 37, 37A, 37B Bending tube 50, 70, 500, 700 Endoscopic device 51, 71 Device body Units 52, 72 Bending drive mechanisms 53, 73 Control unit 54 Tension detection unit 74 Pressure detection units 100, 105, 200, 205 Control unit (imaging position stabilization means)
101 Memory (storage means)
102 Motor driver 104 Camera control unit (CCU)
p Subject image center (initial imaging center position)
q, r, p ′ Subject image center (imaging center position)
F ₁ , F ₂ , F ₃ , F ₄ frames (imaging range)

Claims (7)

An endoscope apparatus having a bending portion on the distal end side of an endoscope insertion portion to be inserted into a subject,
An imaging unit provided with the imaging optical system in the distal end side of the curved portion,
A bending drive mechanism for bending the bending portion;
A bending portion position / posture detection means for detecting the posture of the bending portion;
Capture operation setting means for starting or canceling an object capture operation for maintaining the imaging center position of the subject substantially constant by the imaging means;
When the capture operation start is instructed by the capture operation setting unit, the imaging center position of the subject is calculated from the detection output of the bending portion position / orientation detection unit, and the detection unit outputs the detection result according to the detection output of the bending unit position / orientation detection unit. Te, wherein such imaging optical system of the optical axis is directed to the imaging center position, the endoscope apparatus characterized by comprising an imaging position stabilization means for driving and controlling the bending drive mechanism.   It further comprises distance measuring means for measuring the distance between the subject and the imaging optical system, and the imaging center position is calculated from detection outputs of the bending portion position / orientation detecting means and the distance measuring means. The endoscope apparatus according to claim 1. The endoscope apparatus according to claim 2 , wherein the distance measuring unit includes a stereo measuring unit that images a subject from a plurality of viewpoints, at least a part of which also serves as the imaging unit. The endoscope apparatus according to any one of claims 1 to 3, wherein the bending portion position / posture detection means is a plurality of acceleration detection means provided respectively at a distal end and a proximal end of the bending portion. Image deviation detection means for detecting a deviation amount of the imaging center position of the subject from image data of the subject imaged by the imaging means;
When the capturing operation start is instructed by the capturing operation setting unit, the imaging position stabilizing unit controls the bending drive mechanism according to the shift amount of the imaging center position detected by the image shift detecting unit. The endoscope apparatus according to any one of claims 1 to 4 , wherein drive control can be performed. 6. The image shift detection unit according to claim 5 , wherein the image shift detection unit extracts the contrast information of the image of the subject as the image data, and detects the shift amount of the imaging center position of the subject based on the contrast information. Endoscopic device. The imaging position stabilizing means is
A first subject capturing operation is performed by driving the bending drive mechanism in accordance with a detection output of the bending portion position / posture detection means,
The second subject capturing operation is performed by driving the bending drive mechanism in accordance with a detection output of the image shift detection unit after completing the first subject capturing operation. Item 5. The endoscope device according to Item 5 or 6 .

Images