JP2000081304A - Shape estimation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate the shape even when metal exists on the perimeter of a source coil and a sense coil unit. SOLUTION: A first sense coil more invulnerable to effect of metal as compared with a second sense coil is set to be turned in the direction of the Y axis so that an output thereof can be detected larger and the second sense coil is set to be turned in the direction of the Z axis. The sense coil in the direction of the X axis is installed at a position farthest from a post 29 in a sense coil unit 50. Since the position and the orientation of the sense coils are so set in the sense coil unit to hinder effect of metal on a three-dimensional space, a less error is possible in the estimation of the position of a source coil to reduce the deformation of the shape of an endoscope in the insertion thereof. Coils in the directions of the X, Y and Z axes are arranged at four corners in the sense coil unit thereby permitting evenly maintaining of error in the estimation of the position of the source coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape estimating device, and more particularly, to a shape estimating device having a characteristic in a sense coil arrangement portion.

[0002]

2. Description of the Related Art In recent years, endoscopes have been widely used in the medical and industrial fields. This endoscope, especially if the insertion part is flexible, can be inserted into a bent body cavity to diagnose organs deep inside the body cavity without making an incision, and if necessary, insert a treatment tool into the channel. Therapeutic treatment such as resection of polyps and the like.

[0003] In this case, for example, as in the case of examining the lower digestive tract from the anal side, some skill may be required to smoothly insert the insertion portion into a bent body cavity.

[0004] In other words, when the insertion operation is performed, it is necessary to perform an operation such as bending a bending portion provided in the insertion portion in accordance with the bending of the conduit to perform smooth insertion. It is convenient to be able to know the position of the distal end and the like in the body cavity, the current bending state of the insertion portion, and the like.

Accordingly, various position estimating apparatuses (shape estimating apparatuses) using a magnetic field have been proposed, for example, as disclosed in Japanese Patent Application No. 10-69075 previously filed by the present applicant.

In Japanese Patent Application No. 10-69075, the arrangement of sense coils in a sense coil unit is as follows.
Uniform measurement errors in the measurement space of the source coil,
Three single-core coils in the X, Y, and Z-axis directions are arranged at four corners in the sense coil unit so as to improve the estimation accuracy of the source coil by increasing the distance between the sense coils facing in the same direction as much as possible. Was.

[0007]

However, in the above conventional apparatus, when a metal object exists in the measurement space, the magnetic field passing through the metal is affected, the output of the sense coil changes, and the position of the source coil is correctly determined. The problem that estimation cannot be performed occurs.

That is, when metal exists around the source coil and the sense coil unit, there is a problem that the estimated shape is distorted.

The present invention has been made in view of the above circumstances, and provides a shape estimating apparatus capable of accurately estimating a shape even when metal exists around a source coil and a sense coil unit. It is intended to be.

[0010]

According to the present invention, there is provided a shape estimating apparatus comprising: a source coil for generating a magnetic field by a single-core coil;
A shape estimating apparatus comprising: a plurality of three single-core coils orthogonal to each other in a three-dimensional space as sense coils; and estimating means for estimating a position and an orientation of the source coil from an output of the sense coil. In the case where a metal body is arranged near the coil, the mutually orthogonal three coils constituting the sense coil which vertically pass the magnetic field generated by the source coil on a plane parallel to the plane where the cross section of the metal body exists In two of the single-core coils, a single-core coil parallel to the cross section of the metal body is arranged farther from the metal body than the other single-core coil.

In the shape estimating apparatus according to the present invention, when a metal body is arranged near the sense coil, the magnetic field generated by the source coil is vertically set on a plane parallel to a plane where the cross section of the metal body exists. In two single-core coils of the three orthogonal single-core coils constituting the sense coil passing therethrough, a single-core coil parallel to a cross section of the metal body is connected to the metal body from the other single-core coil. By arranging them far away, even if metal exists around the source coil and the sense coil unit, it is possible to accurately estimate the shape.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 to FIG. 19 relate to a first embodiment of the present invention, FIG. 1 is a configuration diagram showing a configuration of an endoscope system, and FIG. 2 is an endoscope of FIG. FIG. 3 is a block diagram showing a functional configuration of the mirror device shape detection device, FIG. 3 is a configuration diagram showing a configuration of the endoscope device shape detection device of FIG. 2, and FIG. 4 is a main part of the endoscope device shape detection device of FIG. FIG. 5 is a timing chart showing the operation of the two-port memory shown in FIG. 4, FIG. 6 is a flowchart showing the operation of the endoscope system shown in FIG. 1, and FIG. FIG. 8 is a flowchart showing the flow of the FFT processing, FIG. 8 is a timing chart showing the parallel processing timing in the operation of the endoscope system in FIG. 6, and FIG. 9 is a first diagram for explaining the principle of the source coil estimated position coordinate calculation processing in FIG. FIG. 10 is a diagram showing the estimated position coordinates of the source coil in FIG. FIG. 11 is a second explanatory diagram illustrating the principle of the source coil estimated position coordinate calculation process of FIG. 6, and FIG. 12 is a third explanatory diagram illustrating the principle of the source coil estimated position coordinate calculation process of FIG. FIG. 13 is a fifth explanatory view for explaining the principle of the source coil estimated position coordinate calculating process in FIG. 6, and FIG. 14 is a first explanatory view for explaining the arrangement of the sense coils in FIG. FIG. 15 is an explanatory view of FIG.
FIG. 16 is a second explanatory view for explaining the arrangement of the sense coils of FIG.
Is a third explanatory view for explaining the arrangement of the sense coils in FIG. 1,
17 is a fourth explanatory view illustrating the arrangement of the sense coils in FIG. 1, FIG. 18 is a fifth explanatory view illustrating the arrangement of the sense coils in FIG. 1, and FIG. 19 is an explanatory view illustrating the arrangement of the sense coils in FIG. It is the 6th explanatory view which does.

(Configuration) As shown in FIG. 1, an endoscope system 1 according to the present embodiment is an endoscope apparatus 2 for performing an endoscopic inspection.
And an endoscope device shape detection device 3 used for assisting an endoscopy. The endoscope shape detection device 3 inserts an electronic endoscope 6 into a body cavity of a patient 5 lying on a bed 4. Part 7
Is used as an insertion assisting means when performing endoscopy.

The electronic endoscope 6 has an operating section 8 provided with a bending operation knob at the rear end of a flexible elongated insertion section 7, and a universal cord 9 extends from the operating section 8. It is connected to a video imaging system (or video processor) 10.

The electronic endoscope 6 transmits the illumination light from the light source unit in the video processor 10 through the light guide, and emits the transmitted illumination light from the illumination window provided at the tip of the insertion unit 7. Illuminate the affected area. The illuminated subject such as a diseased part forms an image on an imaging device arranged at an image forming position by an objective lens attached to an observation window provided adjacent to the illumination window, and the imaging device performs photoelectric conversion.

The photoelectrically converted signal is supplied to a video processor 1
The video signal is processed by a video signal processing unit in 0 to generate a standard video signal, which is displayed on an image observation monitor 11 connected to a video processor 10.

The electronic endoscope 6 has a forceps channel 12
Is provided, and an insertion port 12a of the forceps channel 12 is provided.
, A source coil 14i is installed in the insertion portion 7 by inserting a probe 15 having, for example, 16 magnetism generating elements (or source coils) 14a, 14b,. Is done.

The source cable 16 extending from the rear end of the probe 15 has a connector at the rear end detachably connected to the device main body 21 of the endoscope shape detecting device 3. Then, by applying a high-frequency signal (drive signal) to the source coil 14i, which is a magnetic generation unit, via the source cable 16 as a high-frequency signal transmission unit from the apparatus main body 21 side, the source coil 14i transmits an electromagnetic wave accompanied by a magnetic field to the surroundings. Radiate.

A plurality of sense coils each composed of a single-core coil are arranged in a three-dimensional space.
Sense coil 22 oriented to, for example, the X axis which is the Z coordinate of
a, 22b, 22c, 22d, sense coils 22e, 22f, 22g, 22h oriented to the Y axis which is a second Z coordinate whose center Z coordinate is different from the first Z coordinate; Sense coils 22i, 22j, 22k, and 2 directed to a Z-axis that is a third Z-coordinate different from the first and second Z-coordinates;
Twenty-two 12 sense coils are arranged (hereinafter, the sense coil is represented by 22j).

The sense coil 22j is
j is connected to the apparatus main body 21 via a sense cable 23 as a detection signal transmitting means from a connector of the sense coil unit 50 in which the j is stored. This device body 2
1 is provided with an operation panel 24 or a keyboard for a user to operate the apparatus. Further, a monitor 25 is connected to the apparatus main body 21 as display means for displaying the detected endoscope shape.

Further, a detailed configuration of the endoscope shape detecting device 3 will be described. As shown in FIG. 2, the endoscope shape detection device 3 includes a drive block 26 for activating the source coil 14i, a detection block 27 for detecting a signal received by the sense coil 22j, and a signal detected by the detection block 27. And a host processor 28 for signal processing.

As shown in FIG. 3, the probe 15 installed in the insertion section 7 of the electronic endoscope 6 has, as described above, 16 source coils 14i for generating a magnetic field at predetermined intervals. These source coils 14i
Is a source coil drive circuit 31 that generates 16 different high-frequency drive signals constituting the drive block 26
It is connected to the.

The source coil drive circuit 31 drives each of the source coils 14i with a sine wave drive signal current having a different frequency, and each drive frequency is stored in a drive frequency setting data (not shown) inside the source coil drive circuit 31. The driving frequency setting data (also referred to as driving frequency data) stored in the driving frequency setting data storage means. The drive frequency data is transferred to a drive frequency data in a source coil drive circuit unit 31 via a PIO (parallel input / output circuit) 33 by a CPU (central processing unit) 32 which performs an endoscope shape calculation process and the like in a host processor 28. It is stored in storage means (not shown).

On the other hand, the twelve sense coils 22j are connected to a sense coil signal amplifying circuit 34 constituting the detection block 27.

As shown in FIG. 4, in the sense coil signal amplifying circuit section 34, a single-core coil 22j is connected to an amplifying circuit 35j provided for one system for each single-core coil 22j. After the minute signal is amplified by the amplifier circuit 35j and the filter circuit 36j has a band through which a plurality of frequencies generated by the source coil group pass and removes unnecessary components and is output to the output buffer 37j, the ADC (analog-to-digital converter) ) Is converted into a digital signal which can be read by the host processor.

The detection block 27 comprises a sense coil signal amplifier circuit 34 and an ADC 38j. The sense coil signal amplifier circuit 34 comprises an amplifier circuit 35j, a filter circuit 36j and an output buffer 37j.

Returning to FIG. 3, the outputs of the 12 systems of the sense coil signal amplifying circuit section 34 are output from the 12 ADCs 38.
j, and is converted into digital data of a predetermined sampling cycle by a clock supplied from the control signal generation circuit unit 40. This digital data is transmitted to the local data bus 4 by a control signal from the control signal generation circuit 27.
The data is written to the two-port memory 42 via 1.

As shown in FIG. 4, the two-port memory 42 functionally includes a local controller 42a, a first RAM 42b, a second RAM 42c, and a bus switch 42d. Accordingly, the ADC 38j starts A / D conversion in response to an A / D conversion start signal from the local controller 42a, and the bus switch 42d alternately reads the first RAMs 42b and 42c while switching between the RAMs 42b and 42c in response to a switching signal from the local controller 42a. It is used as a memory and a write memory, and always receives data after power is turned on by a write signal.

Returning to FIG. 3 again, the CPU 32 transfers the digital data written to the two-port memory 42 by the control signal from the control signal generation circuit 27 to the local data bus 43, the PCI controller 44, and the PCI bus 45.
(See FIG. 4) via an internal bus 46,
Using the main memory 47, frequency extraction processing (Fourier transform: FFT) is performed on digital data as described later.
Is performed to separate and extract magnetic field detection information of a frequency component corresponding to the driving frequency of each source coil 14i. Each source provided in the insertion unit 7 of the electronic endoscope 6 is extracted from each digital data of the separated magnetic field detection information. The spatial position coordinates of the coil 14i are calculated.

Further, the insertion state of the insertion section 7 of the electronic endoscope 6 is estimated from the calculated position coordinate data, display data for forming an endoscope shape image is generated, and output to the video RAM 48. The data written in the video RAM 48 is read out by the video signal generation circuit 49, converted into an analog video signal, and output to the monitor 25. When the analog video signal is input, the monitor 25 displays the insertion shape of the insertion section 7 of the electronic endoscope 6 on the display screen.

In the CPU 32, each source coil 14
The magnetic field detection information corresponding to i, that is, the electromotive force (the amplitude value of the sine wave signal) generated in each sense coil 22j and the phase information are calculated. Note that the phase information is the polarity of the electromotive force ±
Is shown.

In the endoscope system 1 of this embodiment, when the power is turned on, as shown in FIG. 6, each system parameter is initialized based on the parameter file in step S1, and the hardware initialization is performed in step S2. Perform the conversion.

After the power is turned on, the 2-port memory 42 stores F
The data for the number of FFT points for performing the FT processing is constantly updated (see FIG. 5), and in step S3, the CP
U32 takes in the data for the number of FFT points. Then, in step S4, the data is corrected by a process using the window function method, and in step S5, an FFT process described later is performed. After the FFT processing, the frequency components for the driving frequency are extracted in step S6, the amplitude value and the phase difference are calculated in step S7, and the amplitude value and the phase difference calculated in step S8 are corrected.

Then, in step S9, the eight ADCs
38j (hereinafter also referred to as channel: CH)
It is determined whether or not all the detections have been completed. If the detection has not been completed, the process returns to step S3. If the detection has been completed, the amplitude values for all the channels are corrected in step S10 according to the sense coil characteristics. The estimated position coordinate of the source coil 14i is calculated from the amplitude value and the phase difference by the method described later.

Thereafter, in step S12, it is determined whether or not the system end switch of the endoscope system 1 is turned on. If not, an endoscope shape detection image image display process described later is performed in step S13, and the process returns to step S3. Repeat the process. When the system end SW of the endoscope system 1 is turned on in step S12, the system ends after saving each system parameter in a parameter file in step S14.

In the FFT processing in step S5, as shown in FIG. 7, the CPU 32 determines in step S21 whether all the channels are in a signal state (a state in which data for the number of FFT points are completed). Step S2
If it is not in the signal state, the process waits until it becomes the signal state in step S23, and proceeds to step S22.

In step S22, C for performing FFT processing
The state of the H bit (if the bit is 0, the data for the current process, if the bit is 1, the processed data) is determined, and if the bit is 0, FFT is performed in step S24.
After the FFT, the state of the bit is set to 1 in step S25. If the bit is 1 in step S22, the process returns to step S21, and the process is repeated for all the second and subsequent channels to perform the FFT process on all the channels.

In step S26 after step S25,
It is determined whether the bit status of all CHs is 1 and all C bits are determined.
If the bit state of H is not 1, the step S21 is performed to perform the FFT processing on the CH whose bit state is not 1.
Return to In step S26, the bit status of all CHs is 1
When all the CHs are set to the non-signal state in step S27, the process waits. When the data for the number of FFT points are completed, the signal state is set in step S28.
Return to 21.

In the processing of FIG. 6, in order to perform high-speed processing, as shown in FIG. 8, each processing unit is processed in parallel. In particular, the FFT, which has a long processing time and is an iterative operation, is configured to process the same processing unit almost simultaneously. This parallel processing supports CP
The speed is increased by effectively using the idle time of U32.

Next, the source coil estimated position coordinate calculation processing in step S11 of FIG. 6 will be described. First, a method of calculating source coil estimated position coordinates will be described, and then specific processing contents will be described.

As shown in FIG. 9, in a thin circular coil having a very small radius, as described in Japanese Patent Application Laid-Open No. 9-84745, when a current is passed through the circular coil, a three-dimensional coil is formed in the same manner as a magnetic dipole. The magnetic potential of a point P in space can be expressed by the following equation.

[0043]

(Equation 1) μ: magnetic permeability N ₁ : number of turns of a circular coil a: radius of a circular coil I: current flowing in a circular coil Accordingly, magnetic fields (H _Px , H _Py , H _Pz ) at the point P in the same direction as the X, Y, and Z axes. Is

(Equation 2) Is required. In three-dimensional space as shown in FIG. 10 (hereinafter the world coordinate system X _W -Y _W -Z _W), the position of the single core coil (hereinafter source coil) for generating a magnetic field _{(x gW, y gW, z} gW) And an arbitrary position on the three-dimensional space is defined as a point P (x _PW , y _PW , z _PW ).

[0044] When coordinate system relative to the source coil and the local coordinate system X _L -Y _L -Z _L, of the point P in the local coordinate system coordinates _{(x Pl, y Pl, z} Pl) is

(Equation 3) P _l : vector from the origin O to the point P in the local coordinate system P _W : vector from the origin O to the point P in the world coordinate system G _W : vector from the position of the source coil in the world coordinate system R: rotation matrix be able to.

Here, R is a rotation matrix, and the rotation matrix R of the polar coordinate system shown in FIG.

(Equation 4) Becomes α is the amount of rotation around the Z _W-axis, beta represents the rotation amount around the X _W axis.

In the local coordinate system based on the source coil, the magnetic field H ₁ (H _Pxl , H _Pyl ,
H _Pzl ) is from equation (10)

(Equation 5) Becomes

Therefore, X at point P in the world coordinate system
The magnetic field H _W (H _PxW , H _P) in the same direction as the _W , Y _W , and Z _W axes
_PyW , H _PzW )

(Equation 6) Becomes

As shown in FIG. 13, one source coil for generating a magnetic field in a three-dimensional space XYZ is located at a position (x _g ,
y _g , z _g ) and orientation (g _x , g _y , g _z )
Suitable position _{P (x d, y d,} Z d) a magnetic field generated in the H _x, H
_y and _Hz are expressed as follows from Expression (6).

[0049]

(Equation 7) Here, k _S is a constant, r is the distance between the source coil and the point P, and the directions of the magnetic fields H _x , H _y , and H _z are the same as the X, Y, and Z axes.

The point coordinate X to the position of P, Y, Z and single-fiber coil C _x facing the same, if the C _y, is C _z are arranged, each of the single-core coil C _x, C _y, the C _z Generated voltage V _x , V
_y and V _z are

(Equation 8) Becomes Here, single core single core coil C _x is facing the X-axis, a coil axis and in the X-axis in the same direction when winding a conductive wire constituting the coil, the Y-axis, oriented the same as Z axis The coils C _y and C _z are similar coils.

As shown in FIG. 1, since the voltages, positions, and directions of the twelve sense coils are all known, the position (x _g , y _g , z _g ) and direction of the source coil can be _calculated by the equation (8). Twelve nonlinear equations with (g _x , g _y , g _z ) as unknowns are obtained.

The solution of these 12 nonlinear equations, that is, the position and orientation of the source coil are obtained by iterative improvement (Gauss-Newton method).

_Let x be the position of the source coil (x _g , y _g ,
z _g ) and orientation (g _x , g _y , g _z ) parameters, and the initial values of the parameters are x ⁽⁰⁾ .

Now, the k-th estimated value x ^{(k) is obtained} by iterative improvement.
Is obtained, and the model function V of the power generated in the sense coil is obtained.
When (X) is Taylor-expanded around x ^(k) , its first-order approximation is

(Equation 9) Becomes

At this time, if Vm is the voltage measured by the sense coil, the observation equation is

(Equation 10) Here, the reason why the expression is not equal but rather equal is that Vm includes a measurement error.

## EQU5 ## Moving the first term on the right side of equation (10) to the left side

[Equation 11] Becomes However,

ΔVm ^(k) = Vm−V (x ^(k) ) = Vm−Vm ^(k) (12)

[Expression 13] Δx ^(k) = x−x ^(k) (13)

[Equation 14] (I = 1 to n, j = 1 to m) (row direction: number n of unknowns, column direction: number m of sense coils). The solution Δx ^(k) is given by equation (11)

Δx ^(k) = (B ^(k) WA ^(k) ) ⁻¹ B ^(k) WΔVm ^(k) (15) Here, B is the transposition of A, and W is the weight matrix.

Therefore, the parameter estimation value improved from the equation (13) is

X ^{(k + 1)} = x ^(k) + Δx ^(k) (16)

As shown in FIG. 1, when 12 single-core coils (sense coils) are arranged, the matrix A is

[Equation 17] The weight matrix W is

(Equation 18) It is expressed as Here, σ _i (i = 0, 1,
..., 12) are the fluctuations of the measured voltage of each sense coil.
For example, there is environmental noise.

The k-th ΔVm is

[Equation 19] Therefore, the position and orientation of the source coil can be obtained by the following procedures (1) to (4).

Procedure (1): k = 0, and the initial values of the source coil are set to the position (x _g , y _g , z _g ) ⁽⁰⁾ and the directions (g _x , g _y ,
g _z ) ⁽⁰⁾ (for example, the center position of the space for measuring the source coil and the vector (0, 0, 1) in the Z-axis direction). Procedure (2): Calculate the k-th matrix according to equations (17), (18), and (19). Procedure (3): k-th update amount Δx according to equation (16)
Calculate ^(k) . Procedure (4): The above procedures (2) to (4) are repeated until the update amount Δx ^(k) becomes small.

In this embodiment, the position of the source coil is estimated by arranging the sense coils oriented in the X, Y, and Z axis directions at the same height, but the present invention is not limited to this. Even if it is arranged at an arbitrary position or orientation, the position of the source coil can be estimated if the position and orientation of the sense coil are known.

As shown in FIG. 1, the sense coil unit 50 includes a plurality of sense coils 22j for detecting a magnetic field generated by the source coil 14i. The sense coil unit 50 is fixed to the side of the bed by a pillar 29.

As shown in FIG. 1, when the pillar 29 for fixing the sense coil unit 50 on the side of the bed 4 is made of metal,
The arrangement of the sense coil 22j in the sense coil unit 50 is set according to the size of the sense coil unit 50, the position of the metal, and the space (measurement area) where the source coil 14i exists.

Now, the position of the sense coil 22j at which the magnitude of the stove pressure induced in the coil with respect to the magnetic field generated by one source coil 14i is determined.

As shown in FIG. 14, the source coil is arranged at the coordinates (-a, 0) in parallel with the Z axis on the XZ plane.
When the sense coil and the second sense coil are arranged in a direction perpendicular to the magnetic field generated by the source coil, the magnetic field generated in each sense coil is expressed by Expression (7).

(Equation 20)

(Equation 21) Becomes

Here, _assuming that H _1x = H _2z and b = ka,

(Equation 22) Is obtained.

By calculating k in equation (22), a space (ellipsoid) where the sense coil is present in which the magnitude of the voltage induced in the sense coil with respect to the magnetic field generated by the source coil is constant is obtained. (However, when the sense coil is arranged perpendicular to the magnetic field of the source coil).

FIG. 15 is a diagram two-dimensionally showing a magnetic field when one source coil is arranged in a three-dimensional space. Each ellipse has a different voltage induced in the sense coil.

As shown in FIG. 16, the column 29 to which the sense coil unit 50 is fixed is made of a hollow metal, and the position of the first sense coil in the sense coil unit 50 is (a, b, c). The position of the second sense coil is (a ′,
b ', c').

FIGS. 17 and 18 show the center positions of the first and second sense coils and the state of the magnetic field passing through the column 29 when the position of the source coil is fixed and rotated. 17 and 18 show a state where a magnetic field passes on a plane that passes through the center positions of the first and second sense coils and is parallel to the YZ plane.

The output of the sense coil connects the source coil and the center of the sense coil. The closer the metal is to the magnetic field, the more susceptible the groove is. The source coil generating the magnetic field is separated from the sense coil unit 50. In this case, since the angle of rotation of the source coil of the first sense coil is smaller than that of the second sense coil (θA <θB), the first sense coil is more sensitive to a change in the rotation of the source coil. It can be seen that it is hardly affected by the metal pillar 29.

When the magnetic field passes perpendicular to the sense coil, the output of the sense coil is detected to be the largest, and a large value of the output of the sense coil greatly affects the position estimation of the source coil.

Accordingly, as shown in FIG. 19, the first sense coil, which is less affected by the metal than the second sense coil, is set in the Y-axis direction so that the output can be largely detected. Are set in the Z-axis direction. The sense coil in the X-axis direction is installed at a position farthest from the column 29 in the sense coil unit 50.

As described above, in the present embodiment, the position and orientation of the sense coil in the sense coil unit are set so as to be hardly affected by metal in the three-dimensional space. The deformation of the endoscope insertion shape can be reduced. Further, as shown in FIG. 19, since the XYZ axis direction coils are arranged at the four corners in the sense coil unit, it is possible to keep the error of the position estimation of the source coil uniform.

FIGS. 20 to 23 relate to the second embodiment of the present invention. FIG. 20 is a view showing the structure of a bed provided with a sense coil unit, and FIG. 21 shows the effect of the frame of the bed of FIG. FIG. 22 is a second explanatory diagram illustrating the arrangement of the sense coils excluding the influence of the bed frame of FIG. 20, and FIG. 23 is a second explanatory diagram illustrating the arrangement of the sense coils excluding the effect of the bed of FIG. FIG. 11 is a third explanatory diagram illustrating the arrangement of the sense coils excluding the influence of the frame.

Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, the system configuration is the first
The arrangement of the sense coils in the sense coil unit 50 is different from that of the first embodiment.

That is, in this embodiment, the bed 4 is formed of a hollow metal frame 55 as shown in FIG. 20, and the sense coils in the sense coil unit 50 are arranged.

When the source coil generating the magnetic field is separated from the sense coil unit 50, as shown in FIGS. 21 and 22, the position of the first sense coil and the second sense coil is equal to that of the second sense coil. Since the angle of rotation of the source coil is narrower at the position (θA <θB), the rotation of the source coil at a fixed position is easily affected by the metal frame of the bed 4.

Therefore, the position of the first sense coil is X
An axial sense coil is arranged, and a Z-axis sense coil is arranged at the position of the second sense coil. Note that Y
The sense coil in the axial direction is arranged at a position as far away from the bed 4 as possible. In order to make the position estimation error of the source coil uniform in the measurement space, FIG.
So that each sense coil is arranged.

As described above, in the present embodiment, in addition to the effects of the first embodiment, the influence of the metal on the bed constituted by the metal frame is reduced so as to reduce the influence of the metal. The position and orientation of the sense coil can be arranged.

FIGS. 24 and 25 relate to the third embodiment of the present invention. FIG. 24 is a configuration diagram showing a configuration of a bed provided with a sense coil unit. FIG. FIG. 9 is an explanatory diagram illustrating an arrangement of sense coils that has been eliminated.

Since the third embodiment is almost the same as the first embodiment, only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, the system configuration is the first
The arrangement of the sense coils in the sense coil unit 50 is different from that of the first embodiment.

In the present embodiment, as shown in FIG.
The bed 4 has a frame 57 for fixing a bed mat 56 made of a hollow metal. Further, in order to bring the measurement space of the source coil and the sense coil unit 50 close to each other, the sense coil unit 50 is fixed to the bed 4 in an area having relatively little metal.

The arrangement of the sense coils in the fixed sense coil unit 50 is, as described in the first and second embodiments, the source coil and the sense coil unit 5.
When 0 is apart, the sense coils in the X, Y, and Z-axis directions are arranged so that they are hardly affected by the metal frame (FIG. 25).

That is, as shown in FIG. 25, in order to dispose the sense coil so that the metal frame surrounding the periphery of the sense coil unit 50 is hardly affected by the output of the sense coil, the metal frame 57 must be close to the metal frame 57. The magnetic field generated by the source coil hardly intersects with the frame 57 at the set position, and is constituted by sense coils in the X and Z axes, and the sense coil in the Y axis is arranged at a position distant from the metal frame 57. Although there is a possibility that the output of the magnetic field passing through the frame may be obtained from the sense coil in the X-axis direction, the detected value is small because the angle of entry of the magnetic field passing through the center of the sense coil in the X-axis direction is small. The influence on the position estimation of the source coil is small. Therefore, the sense coil in the X-axis direction is larger than the sense coil in the Y-axis direction in the metal frame 5.
It is arranged at a position close to 7.

As described above, in this embodiment, in addition to the effect of the first embodiment, the sense coil unit and the sense coil unit can be arranged close to each other, and the sense coil unit can be arranged at a position with relatively few metals. , The position of the source coil can be estimated with less influence of the metal.

[Supplementary Note] (Supplementary Note 1) A plurality of source coils, each of which generates a magnetic field by a single-core coil, and three single-core coils, which are orthogonal to each other in a three-dimensional space, are arranged as sense coils. In a shape estimating apparatus including an estimating unit for estimating a position and an orientation of the source coil, when a metal body is arranged near the sense coil, on a plane parallel to a plane in which a cross section of the metal body exists. In the two single-core coils of the three orthogonal single-core coils constituting the sense coil that vertically passes the magnetic field generated by the source coil, a single-core coil parallel to the cross section of the metal body is used. A shape estimating device, which is disposed farther from the metal body than the other single-core coil.

(Additional Item 2) The shape estimating apparatus according to additional item 1, wherein the source coil is disposed in an insertion portion of an endoscope.

(Additional Item 3) A source coil for generating a magnetic field by a single-core coil and a plurality of single-core coils as sense coils at different positions in a three-dimensional space are provided. In a shape estimating apparatus provided with estimating means for estimating a position and an orientation, an arrangement position and an orientation of the sense coil are set by a metal object arranged in a three-dimensional space and a space where the source coil exists. Shape estimating device.

[0092]

As described above, according to the shape estimating apparatus of the present invention, when the metal body is arranged near the sense coil, the source coil is placed on a plane parallel to the plane where the cross section of the metal body exists. In two single-core coils of three mutually orthogonal single-core coils constituting a sense coil passing vertically through a generated magnetic field, a single-core coil parallel to a cross section of a metal body is made of metal than the other single-core coil. Since it is located far from the body, there is an effect that even if metal exists around the source coil and the sense coil unit, the shape can be accurately estimated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an endoscope system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of the endoscope device shape detection device of FIG. 1;

FIG. 3 is a configuration diagram showing a configuration of the endoscope device shape detection device in FIG. 2;

4 is a diagram showing a main part 2 of the endoscope device shape detection device in FIG.
Configuration diagram showing the configuration of port memory, etc.

FIG. 5 is a timing chart showing the operation of the two-port memory of FIG. 4;

FIG. 6 is a flowchart showing the operation of the endoscope system of FIG. 1;

FIG. 7 is a flowchart showing the flow of the FFT processing of FIG. 6;

FIG. 8 is a timing chart showing parallel processing timing in the operation of the endoscope system of FIG. 6;

FIG. 9 is a first explanatory diagram illustrating the principle of the source coil estimated position coordinate calculation process of FIG. 6;

FIG. 10 is a second explanatory diagram illustrating the principle of the source coil estimated position coordinate calculation process in FIG. 6;

FIG. 11 is a third explanatory view illustrating the principle of the source coil estimated position coordinate calculating process in FIG. 6;

FIG. 12 is a fourth explanatory diagram illustrating the principle of the source coil estimated position coordinate calculation process in FIG. 6;

FIG. 13 is a fifth explanatory view illustrating the principle of the source coil estimated position coordinate calculating process in FIG. 6;

FIG. 14 is a first explanatory diagram illustrating the arrangement of the sense coils in FIG. 1;

FIG. 15 is a second explanatory diagram illustrating the arrangement of the sense coils in FIG. 1;

FIG. 16 is a third explanatory view illustrating the arrangement of the sense coils in FIG. 1;

FIG. 17 is a fourth explanatory view illustrating the arrangement of the sense coils in FIG. 1;

18 is a fifth explanatory view for explaining the arrangement of the sense coils in FIG. 1;

FIG. 19 is a sixth explanatory view illustrating the arrangement of the sense coils in FIG. 1;

FIG. 20 is a configuration diagram showing a configuration of a bed provided with a sense coil unit according to the second embodiment of the present invention;

FIG. 21 is a first explanatory view illustrating the arrangement of sense coils excluding the influence of the frame of the bed of FIG. 20;

FIG. 22 is a second explanatory diagram illustrating the arrangement of the sense coils excluding the influence of the bed frame of FIG. 20;

FIG. 23 is a third explanatory view illustrating the arrangement of the sense coils excluding the influence of the bed frame of FIG. 20;

FIG. 24 is a configuration diagram showing a configuration of a bed provided with a sense coil unit according to a third embodiment of the present invention.

FIG. 25 is an explanatory diagram illustrating the arrangement of sense coils excluding the influence of the bed frame of FIG. 24;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Endoscope system 2 ... Endoscope apparatus 3 ... Endoscope shape detection apparatus 4 ... Bed 6 ... Electronic endoscope 7 ... Insertion part 8 ... Operation part 9 ... Universal code 10 ... Video processor 11 ... Image observation Monitor 12 ... Forceps channel 12a ... Insertion port 14i ... Source coil 15 ... Probe 16 ... Source cable 21 ... Device body 22j ... Sense coil 23 ... Sense cable 24 ... Operation panel 25 ... Monitor 26 ... Drive block 27 ... Detection block 28 ... Host Processor 31 ... Source coil drive circuit 32 ... CPU 33 ... PIO 34 ... Sense coil signal amplifier circuit 35k ... Amplifier circuit 36k ... Filter circuit 37k ... Output buffer 38k ... ADC 40 ... Control signal generator circuit 41 ... Local data bus 42 ... 2-port memory 46 ... internal bus 47 ... main memo 48 ... video RAM 49 ... video signal generating circuit 50 ... sense coil unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Yoshizawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Inventor Akira Taniguchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Within Olympus Optical Co., Ltd. (72) Ken Kawabata 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Fumiyuki Onoda 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Chieko Aizawa 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Masanori Hara 1-34-14, Hatsudai, Shibuya-ku, Tokyo Hatsudai TN Building Olympus Systems Corporation (72) Inventor Kazutaka Tsuji 1-34-14 Hatsudai, Shibuya-ku, Tokyo First TN Building Olympus Systems Corporation F term (reference) 2F063 AA04 AA41 BA30 BC02 BC10 BD01 BD11 BD15 CA08 DA01 DD04 DD10 GA29 LA06 LA11 LA19 LA29 LA30 MA05 PA10 ZA01 2H040 BA23 DA03 DA11 DA54 GA02 GA11 4C061 AA04 AA29 BB00 CC06 JJ17 NN05 NN07 SS11 SS21 VV04 WW11 YY18 5C054 CC07 HA01 HA12

Claims (1)

[Claims] 1. A source coil for generating a magnetic field by a single-core coil, and a plurality of three single-core coils orthogonal to each other in a three-dimensional space as sense coils, and a position of the source coil based on an output of the sense coil. A shape estimating device comprising: estimating means for estimating a direction; when a metal body is arranged near the sense coil, the source coil is generated on a plane parallel to a plane on which a cross section of the metal body exists. In two single-core coils among the three orthogonal single-core coils constituting the sense coil that vertically passes through a magnetic field, a single-core coil parallel to a cross section of the metal body is replaced with another single-core coil. A shape estimating device, wherein the shape estimating device is disposed far from the metal body.