CN117442336A - Rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system - Google Patents

Rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system Download PDF

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Publication number
CN117442336A
CN117442336A CN202311402562.4A CN202311402562A CN117442336A CN 117442336 A CN117442336 A CN 117442336A CN 202311402562 A CN202311402562 A CN 202311402562A CN 117442336 A CN117442336 A CN 117442336A
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coordinate system
endoscope
flexible
rigid
sensor
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龙忠杰
池永汀
张鲜波
李典耕
杨德金
蒋周翔
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Beijing Information Science and Technology University
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Beijing Information Science and Technology University
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/20—Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00002—Operational features of endoscopes
    • A61B1/00004—Operational features of endoscopes characterised by electronic signal processing
    • A61B1/00009—Operational features of endoscopes characterised by electronic signal processing of image signals during a use of endoscope
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/20—Analysis of motion
    • G06T7/246—Analysis of motion using feature-based methods, e.g. the tracking of corners or segments
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/70—Determining position or orientation of objects or cameras
    • G06T7/73—Determining position or orientation of objects or cameras using feature-based methods
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • A61B2034/101—Computer-aided simulation of surgical operations
    • A61B2034/102—Modelling of surgical devices, implants or prosthesis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/20—Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
    • A61B2034/2046—Tracking techniques
    • A61B2034/2051—Electromagnetic tracking systems
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10028—Range image; Depth image; 3D point clouds
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10068—Endoscopic image

Abstract

The invention relates to a rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system, which comprises: the sensor data acquisition module records a sensor coordinate system { O during one-cycle movement by rotating the rigid-flexible endoscope one-cycle s Each position is relative to the transmitter coordinate system { O } t Location of } t Q sk To obtain the mass center of the circular motion track of the sensor t P b Normal vector t V and circumference radius r; pose model building module, through mass center t P b Solving endoscope sleeve length by circumference radius rl elevation angle of the sleeve posture s θ v And azimuth angleSo as to obtain a pose model of the flexible tip of the rigid-flexible integrated endoscope; the flexible tip actual position acquisition module acquires the actual position of the flexible tip of the endoscope through the plane plate attached with the ECG; and the position error acquisition module is used for comparing the actual position of the flexible tip with the position of the flexible tip obtained by the pose model to acquire the three-dimensional position error of the flexible tip of the endoscope so as to track the tip of the tail end of the rigid-flexible integrated endoscope.

Description

Rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system
Technical Field
The invention relates to the technical field of medical equipment, in particular to a rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system.
Background
The flexible endoscope is an instrument which is used for checking the internal structure of an organ and can be operated in a cavity channel by being inserted into a surgical incision, and has the advantages of high flexibility, small working space, safety to the organ or tissue and the like as a minimally invasive surgical instrument. In minimally invasive procedures, an endoscope is typically inserted into a patient to guide the surgical procedure, and since the tip of a rigid endoscope cannot be bent to manipulate, it is difficult to completely view the interior region of some lumens, and therefore, multiple incisions are required to be mated in order to view the complete focal region; compared with a rigid endoscope, the flexible endoscope can detect more areas, and is commonly used in various fields such as digestive tracts, respiratory tracts, urinary tracts and the like because of the flexible characteristic. However, an additional calibration is necessary to obtain the pose of the flexible endoscope tip.
At present, visual servo under the control of a mechanical arm is mainly adopted for tracking the tip of the flexible endoscope, but certain difficulty still exists in tracking the position of the tip of the handheld flexible endoscope.
Disclosure of Invention
Aiming at the problems, the invention aims to provide a rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system which can accurately acquire the three-dimensional pose and position of a flexible endoscope tip; the movement tracking of the endoscope is realized.
In order to achieve the above purpose, the present invention adopts the following technical scheme: a rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system, comprising: the sensor data acquisition module records a sensor coordinate system { O during one-cycle movement by rotating the rigid-flexible endoscope one-cycle s Each position is relative to the transmitter coordinate system { O } t Location of } t Q sk ＝[ t X sk ， t Y sk ， t Z sk ] T To obtain the mass center of the circular motion track of the sensor t P b Normal vector t V and circumference radius r; pose model building module, through mass center t P b And the circumference radius r is used for solving the length l of the endoscope sleeve and the elevation angle of the sleeve posture s θ v And azimuth angleSo as to obtain a pose model of the flexible tip of the rigid-flexible integrated endoscope; the flexible tip actual position acquisition module acquires the actual position of the flexible tip of the endoscope through the plane plate attached with the ECG; and the position error acquisition module is used for comparing the actual position of the flexible tip with the position of the flexible tip obtained by the pose model to acquire the three-dimensional position error of the flexible tip of the endoscope so as to track the tip of the tail end of the rigid-flexible integrated endoscope.
Further, from the sensor coordinate system { O s Each position corresponds to a position in the transmitter coordinate system { O } t Position under } t Q sk Calculating the mass center of the circular motion trail of the sensor t P b ：
Where N is the total number of samples.
Further, in the pose model construction module, the construction of the pose model of the flexible tip of the rigid-flexible endoscope comprises the following steps:
the coordinate transformation module is used for transforming the mass center of the circular motion track of the sensor t P b And normal vector t V consists of transmitter coordinate system { O t Conversion to the sensor coordinate System { O } s Lower };
the angle calculation module calculates { O in a sensor coordinate system s Elevation angle of normal vector under } s θ v And azimuth angle
The pose model acquisition module determines the length of the flexible part according to the length l of the sleeve of the endoscope, and establishes a joint P of the rigidity and the flexible part of the endoscope f Coordinate systemCalculating the point of contact P from elevation and azimuth f Coordinate system->Relative to the sensor coordinate system { O s Location of origin s p f Further get->Lower point Pf p i In { O t Pose model under }.
Further, solving for the endoscope sleeve length/includes:
the flexible tip of the endoscope and known points on the ECG paper t P a ＝[ t X a ， t Y a ， t Z a ] T Contact to obtain a sensor coordinate system { O s Origin of } t O s And a known point t P a The distance s between them to calculate the mass center t P b Distance to flexible tip/as endoscope sleeve length/:
in the method, in the process of the invention, t O s ＝[ t X s ， t Y s ， t Z s ] T 。
further, in the angle calculation module, the { O { sensor coordinate system }, is calculated s Elevation angle of normal vector under } s θ v And azimuth angleComprising the following steps:
according to the sensor coordinate system { O s Relative to the transmitter coordinate system { O } t Matrix under }Transmitter coordinate system { O t Relative to the sensor coordinate system { O } s Matrix ∈>Calculating the emitter coordinate system { O } t Centroid under } s p b ＝[ s x b ， s y b ， s z b ] T Normal vector s v b ＝[ s v x ， s v y ， s v z ] T In the sensor coordinate system { O s Position under };
calculating the coordinate system { O of the sensor based on the obtained position s Elevation angle of normal vector under } s θ v And azimuth angle
Further, elevation angle s θ v And azimuth angleThe method comprises the following steps of:
further, in the pose model acquisition module,lower point Pf p i In { O t Pose model acquisition under }, comprising:
determination of flexible portion length l from endoscope sleeve length l f Calculate the phase point P f Coordinate systemOrigin { O relative to sensor coordinate System s Location of origin s p f ；
According to the position s p f Obtain the phase point P f Coordinate system { O Pf Relative to the sensor coordinate system { O } s Matrix of }
The flexible part adopts a snake bone structure, and a bending model is obtained according to coordinate system definition and geometric relation;
according to the sensor coordinate system { O s Relative to the transmitter coordinate system { O } t Matrix of }Phase point P f Coordinate systemRelative to the sensor coordinate system { O s Matrix ∈>And bending the model to obtain a pose model, and calculating from the pose modelLower point Pf p i In { O t Position under } t P ei ＝[ t x ei ， t y ei ， t z ei ] T 。
Further, the pose model is:
further, the obtaining the actual position of the flexible tip of the endoscope in the actual position obtaining module of the flexible tip comprises:
multiple rotations of the endoscope operating handle, recording the tip of the flexible portion at the point of abutment P on ECG paper f Coordinate systemLower different positions->
Measuring recorded points on ECG paper at { O } t Position under } t P ri To t P ri As the actual location.
Further, the centroid is obtained t P b When the centroid t P b With the center of a circle t P c Deviation determination between locations, comprising:
selecting three points, so that the distances between every two of the three points are equal, and connecting the three points must form a regular triangle;
the circle center is obtained through mathematical calculation of the regular triangle t P c ＝[ t X cr ， t Y cr ， t Z cr ] r ；
By transmitter coordinate system { O t Relative to the sensor coordinate system { O } s Matrix under }Calculation of s p b And (3) with s p c In { O s Error e of azimuth angle under } cθ Error of elevation angle->
Due to the adoption of the technical scheme, the invention has the following advantages:
1. according to the invention, through the pose model, the three-dimensional pose of the endoscope tip can be accurately expressed according to the bending angle of the endoscope.
2. The calibration method is simple in calibration operation, the electromagnetic sensor can be arranged on the endoscope handle in any posture and any position, and the inconvenience in operation caused by the arrangement of the specific position of the sensor to doctors can be effectively avoided.
3. The unknown number in the calibration can be obtained by quickly solving the unknown number through the program code pre-programmed by a computer, so that the movement tracking navigation of the endoscope is realized.
In conclusion, the pose mathematical model adopted by the invention can accurately acquire the three-dimensional pose and position of the tip of the flexible endoscope by combining an electromagnetic tracking algorithm, and realize the movement tracking of the endoscope.
Drawings
FIG. 1 is a block diagram of a three-dimensional pose calibration and motion tracking system for a rigid-flexible endoscope in an embodiment of the present invention;
FIG. 2 is a schematic diagram of a three-dimensional pose calibration and motion tracking system for a rigid-flexible endoscope in accordance with an embodiment of the present invention;
FIG. 3 is a schematic diagram of a configuration of a rotational endoscope solving for normal vectors in the transmitter coordinate system in an embodiment of the present invention;
FIG. 4 is a schematic diagram of a configuration for solving for center-to-tip distance (i.e., total length of an endoscope sleeve) in an embodiment of the present invention;
FIG. 5 shows the sensor coordinate system and P in an embodiment of the invention f A structural schematic diagram of transformation between coordinate systems;
FIG. 6 is a schematic view of a snake bone (flexible portion of an endoscope) according to an embodiment of the invention;
FIG. 7 is a schematic diagram of a method for verifying pose calibration in an embodiment of the present invention;
FIG. 8 is an error plot of the three-dimensional position of the endoscope tip in the xyz direction under the transmitter coordinate system in an embodiment of the present invention;
reference numerals:
1-endoscope, 2-sensor, 3-fixed support, 4-emitter, 5-measuring plate, 6-flexible part tip bending track.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which are obtained by a person skilled in the art based on the described embodiments of the invention, fall within the scope of protection of the invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
In one embodiment of the invention, a rigid-flexible one-body endoscope three-dimensional pose calibration and motion tracking system is provided. In this embodiment, as shown in fig. 1 and 2, the system includes:
the sensor data acquisition module records a sensor coordinate system { O during one-cycle movement by rotating the rigid-flexible endoscope one-cycle s Each position is relative to the transmitter coordinate system { O } t Location of } t Q sk ＝[ t X sk ， t Y sk ， t Z sk ] T ToAcquiring centroid of circular motion trail of sensor t P b Normal vector (i.e. sleeve pose) t V and circumference radius r; where k=1, 2,3, …, N represents the number of samples.
Pose model building module, through mass center t P b And the circumference radius r is used for solving the length l of the endoscope sleeve and the elevation angle of the sleeve posture s θ v And azimuth angleSo as to obtain a pose model of the flexible tip of the rigid-flexible integrated endoscope;
the flexible tip actual position acquisition module acquires the actual position of the flexible tip of the endoscope through the plane plate attached with the ECG;
and the position error acquisition module is used for comparing the actual position of the flexible tip with the position of the flexible tip obtained by the pose model to acquire the three-dimensional position error of the flexible tip of the endoscope so as to track the tip of the tail end of the rigid-flexible integrated endoscope.
In an alternative embodiment, in the sensor data acquisition module, the sensor 2 is mounted in an arbitrary posture at the steering handle of the rigid-flexible integrated endoscope 1.
In this embodiment, the sensor 2 is an electromagnetic sensor, and the transmitter 4 is an electromagnetic transmitter. The electromagnetic transmitter is fixed on a measuring plate 5 attached with ECG (Electrocardiogram) paper, and a sleeve of an endoscope, which includes a rigid sleeve and a flexible sleeve, is inserted into the fixed bracket 3 to smoothly rotate the handle of the endoscope by one turn.
Wherein, the fixed bracket 3 is made of nonmetallic materials so as to avoid the interference on the precision of the electromagnetic sensor. The measuring plate adopts an acrylic measuring plate.
In the above embodiment, as shown in FIG. 3, the sensor coordinate system { O } s Each position corresponds to a position in the transmitter coordinate system { O } t Position under } t Q sk Calculating the mass center of the circular motion trail of the sensor t P b ；
Where N is the total number of samples.
In the above embodiment, the normal vector t And (3) calculating y, namely: the circle is calculated to be { O by Singular Value Decomposition (SVD) t Normal vector under }
By two mutually perpendicular vector pointsIs zeroI.e.Wherein the method comprises the steps ofLet->Then A · t V=0, singular value decomposition of a can be performed to obtain the normal vector +.>
In the above embodiment, the calculation of the radius r of the circumference is specifically:
any point on the circumferential track t P cr ＝[ t X cr ， t Y cr ， t Z cr ] T Calculating the mass center of the circular motion trail of the sensor by using the formula (2) t P b Distance from the point taken, the circumference radius r can be obtained:
in an alternative embodiment, in the pose model construction module, constructing the pose model of the flexible tip of the rigid-flexible endoscope includes:
the coordinate transformation module is used for transforming the mass center of the circular motion track of the sensor t P b And normal vector t V consists of transmitter coordinate system { O t Conversion to the sensor coordinate System { O } s Lower };
the angle calculation module calculates { O in a sensor coordinate system s Elevation angle of lower normal vector (i.e. cannula pose) s θ v And azimuth angle
The pose model acquisition module determines the length of the flexible part according to the length l of the sleeve of the endoscope, and establishes a joint P of the rigidity and the flexible part of the endoscope f Coordinate systemCalculating the point of contact P from elevation and azimuth f Coordinate system->Relative to the sensor coordinate system { O s Location of origin s p f Further get->Lower point Pf p i In { O t Pose model under }.
In the above embodiment, the solving method for the endoscope sleeve length l is:
as shown in fig. 4, the flexible tip of the endoscope is attached to a known point on the ECG paper t P a ＝[ t X a ， t Y a ， t Z a ] T Contact (where T represents the transpose of the matrix), sensor coordinate system { O }, is known s Origin of } t O s And a known point t P a The distance s between them, and thus calculate the centroid t P b Distance to flexible tip i.e. endoscope sleeve length i:
in the method, in the process of the invention, t O s ＝[ t X s ， t Y s ， t Z s ] T 。
in the above embodiment, in the angle calculation module, the { O { sensor coordinate system s Elevation angle of lower normal vector (i.e. cannula pose) s θ v And azimuth angleThe method comprises the following steps:
under the electromagnetic tracking system (LIBERTY, polhemus, colchester, USA), the sensor coordinate System { O s Relative to the transmitter coordinate system { O } t The three-dimensional transformation matrix under } isAnd transmitter coordinate system { O t Relative to the sensor coordinate system { O } s The three-dimensional inverse transformation matrix under +.>Using a three-dimensional transformation matrix->Three-dimensional inverse transformation matrix->The emitter coordinate system { O } can be calculated t Centroid under } s p b ＝[ s x b ， s y b ， s z b ] T Normal vector s v b ＝[ s v x ， s v y ， s v z ] T In the sensor coordinate system { O s Position under };
wherein the three-dimensional transformation matrixThe method comprises the following steps:
where c and s are simplified forms of cos and sin functions, respectively, α, β and γ are Euler angles when the endoscope is rotated counterclockwise, dx, dy and dz are sensor coordinate systems { O }, respectively s Relative to the transmitter coordinate system { O } t Position of };
centroid of mass s p b Normal vector s v b In the sensor coordinate system { O s The position under } is:
using equations (7) and (8), the { O } in the sensor coordinate system can be calculated s Elevation angle of normal vector under } s θ v And azimuth angle
In the above embodiment, in the pose model acquisition module,lower point Pf p i In { O t The pose model under the } is obtained specifically as follows:
the endoscope is placed on the measuring plate (the flexible part is required to be completely positioned on the measuring plate) and is fixed by a nonmetal fixing bracket, so that the flexible partEnergy distribution inCurved in a plane. Determination of flexible portion length l from endoscope sleeve length l f As shown in FIG. 5, the phase point P can be calculated by using the formula (9) f Coordinate system->Origin { O relative to sensor coordinate System s Location of origin s p f The method comprises the following steps:
wherein the parameter theta,Elevation angle for cannula pose s θ v And azimuth->Is a shorthand for (2).
As shown in FIG. 5, the position obtained according to equation (9) s p f Can obtain the phase contact point P f Coordinate system { O Pf Relative to the sensor coordinate system { O } s Matrix of }
Wherein R is z (θ) represents a rotation matrix of the coordinate system about its z-axis;representing a rotation matrix of the coordinate system about its y-axis.
As shown in fig. 6, the flexible portion is designed in a snake bone structure, and the snake bone is designed to be bent with equal curvature, so that a bending model can be obtained according to the coordinate system definition and the geometric relationship:
wherein d is the joint length, n is the total joint number, Θ i For the ith bending angle, Φ is the bending direction. Pf x j 、 Pf y j 、 Pf z j Indicating that the j (j=1, 2,3, …, n) th joint is at the phase point P f Coordinate system { O Pf A coordinate point of }.
According to the sensor coordinate system { O s Relative to the transmitter coordinate system { O } t Matrix of }Phase point P f Coordinate systemRelative to the sensor coordinate system { O s Matrix ∈>And bending the model to obtain a pose model, and calculating from the pose modelAt the ith bending angle theta i Lower end point Pf p i In { O t Position under } t P ei ＝[ t x ei ， t y ei ， t z ei ] T ；
Wherein, the pose model is:
in an alternative embodiment, the actual position of the flexible tip of the endoscope is obtained in the actual position obtaining module of the flexible tip, specifically:
as shown in fig. 7, the endoscope operating handle was turned multiple times, and the tip of the flexible portion was recorded on ECG paper at the point of abutment P f Coordinate systemLower different positions->
Measuring recorded points on ECG paper at { O } t Position under } t P ri ＝[ t x ri ， t y ri， t z ri ] T And by t P ri As the true position, i.e. the actual position.
In an alternative embodiment, in the position error obtaining module, comparing the actual position of the flexible tip with the position of the flexible tip obtained by the pose model, to obtain the three-dimensional position error of the flexible tip of the endoscope, specifically:
comparing actual positions t P ri With measuring the transition position t P ei Can calculate the { O } of each point in the transmitter coordinate system t Error under };
e xi ＝| t x ri - t x ei | (13)
e yi ＝| t y ri - t y ei | (14)
e zi ＝| t z ri - t z ei | (15)
in the formula e xi 、e yi 、e zi To at the ith bending angle theta i Lower end point Pf p i Errors in the x, y, and z axes.
In use, { O t The axial error of xyz in the x-axis direction was 0.52.+ -. 0.29mm for mean.+ -. SD in the y-axis direction, 0.33.+ -. 0.11mm for mean.+ -. SD in the z-axis direction, and 0.29.+ -. 0.17mm for mean.+ -. SD in the z-axis direction, as shown in FIG. 8.
In an alternative embodiment of the present invention,at the moment of acquiring centroid t P b In time, the mass center is caused by the influence of unstable factors (such as rotation speed, shake in rotation and the like) in the rotation of the endoscope t P b With the center of a circle t P c The position has deviation, and the deviation is determined through an optimal search algorithm of the position of the sensor at the circumferential track point:
firstly, selecting three points, so that the distances between every two of the three points are equal, and connecting the three points must form a regular triangle;
then, the circle center can be obtained through mathematical calculation of the regular triangle t P c ＝[ t X cr ， t Y cr ， t Z cr ] T 。
Using equations (5), (16), (17) and (18), one can calculate s p b And (3) with s p c In { O s Error e of azimuth angle under } cθ Error in elevation angle
By means of the calculation in step (17), t P b and (3) with t P c In { O s Mean±sd of elevation angle at 0.09±0.06mm, mean±sd of azimuth angle at 0.03±0.19mm.
In sum, by comparing the position of the actual recording point with the position obtained by the pose model, the three-dimensional position error of the endoscope tip is obtained, the accuracy and the effectiveness of the pose model are verified, and the tracking of the tip of the rigid-flexible integrated endoscope tip can be realized by using the formula (12) and has higher precision.
The experimental results show that: (i) Describing elevation angle of endoscope sleeve pose under electromagnetic sensor coordinate system s θ v And azimuth angleMean±sd of (a) are respectively: 0.06mm and 0.19mm. (ii) The three-dimensional position of the endoscope tip in the Mean + -SD of the xyz direction of the electromagnetic transmitter coordinate system is respectively: 0.52.+ -. 0.29mm, 0.33.+ -. 0.11mm and 0.29.+ -. 0.17mm. The precision is superior to that of the existing rigid endoscope calibration method (Lahanas V, loukas C, georgiou E.A simple sensor calibration technique for estimating the 3D pose of endoscopic instruments[J)].Surgical endoscopy，2016，30：1198-1204.)。
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system is characterized by comprising:
the sensor data acquisition module records a sensor coordinate system { O during one-cycle movement by rotating the rigid-flexible endoscope one-cycle s Each position is relative to the transmitter coordinate system { O } t Location of } t Q sk ＝[ t X sk , t Y sk , t Z sk ] T To obtain the mass center of the circular motion track of the sensor t P b Normal vector t V and circumference radius r;
pose model building module, through mass center t P b Endoscope sleeve for solving circumference radius rTube length l and elevation angle of the sleeve attitude s θ v And azimuth angleSo as to obtain a pose model of the flexible tip of the rigid-flexible integrated endoscope;
the flexible tip actual position acquisition module acquires the actual position of the flexible tip of the endoscope through the plane plate attached with the ECG;
and the position error acquisition module is used for comparing the actual position of the flexible tip with the position of the flexible tip obtained by the pose model to acquire the three-dimensional position error of the flexible tip of the endoscope so as to track the tip of the tail end of the rigid-flexible integrated endoscope.
2. The three-dimensional pose calibration and motion tracking system of a rigid-flexible endoscope according to claim 1 and being characterized by a sensor coordinate system { O } s Each position corresponds to a position in the transmitter coordinate system { O } t Position under } t Q sk Calculating the mass center of the circular motion trail of the sensor t P b ：
Where N is the total number of samples.
3. The three-dimensional pose calibration and motion tracking system of a rigid-flexible endoscope according to claim 1, wherein in the pose model construction module, the construction of the pose model of the flexible tip of the rigid-flexible endoscope comprises:
the coordinate transformation module is used for transforming the mass center of the circular motion track of the sensor t P b And normal vector t V consists of transmitter coordinate system { O t Conversion to the sensor coordinate System { O } s Lower };
the angle calculation module calculates { O in a sensor coordinate system s Elevation angle of normal vector under } s θ v And azimuth angle
The pose model acquisition module determines the length of the flexible part according to the length l of the sleeve of the endoscope, and establishes a joint P of the rigidity and the flexible part of the endoscope f Coordinate systemCalculating the point of contact P from elevation and azimuth f Coordinate system->Relative to the sensor coordinate system { O s Location of origin s p f Further get->Lower point Pf p i In { O t Pose model under }.
4. A rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system according to claim 3 and wherein said solving for said endoscope sleeve length/comprises:
the flexible tip of the endoscope and known points on the ECG paper t P a ＝[ t X a , t Y a , t Z a ] T Contact to obtain a sensor coordinate system { O s Origin of } t O s And a known point t P a The distance s between them to calculate the mass center t P b Distance to flexible tip/as endoscope sleeve length/:
in the method, in the process of the invention, t O s ＝[ t X s , t Y s , t Z s ] T 。
5. a rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system according to claim 3 and characterized in that in the angle calculation module, the calculation is performed in a sensor coordinate system { O } s Elevation angle of normal vector under } s θ v And azimuth angleComprising the following steps:
according to the sensor coordinate system { O s Relative to the transmitter coordinate system { O } t Matrix under }Transmitter coordinate system { O t Relative to the sensor coordinate system { O } s Matrix ∈>Calculating the emitter coordinate system { O } t Centroid under } s p b ＝[ s x b , s y b , s z b ] T Normal vector s v b ＝[ s v x , s v y , s v z ] T In the sensor coordinate system { O s Position under };
calculating the coordinate system { O of the sensor based on the obtained position s Elevation angle of normal vector under } s θ v And azimuth angle
6. The rigid-flexible endoscope three-dimensional pose calibration and motion tracking system according to claim 5, wherein elevation angle s θ v And azimuth angleThe method comprises the following steps of:
7. the three-dimensional pose calibration and motion tracking system of a rigid-flexible integrated endoscope according to claim 3, wherein in the pose model acquisition module,lower point Pf p i In { O t Pose model acquisition under }, comprising:
determination of flexible portion length l from endoscope sleeve length l f Calculate the phase point P f Coordinate systemOrigin { O relative to sensor coordinate System s Location of origin s p f ；
According to the position s p f Obtain the phase point P f Coordinate system { O Pf Relative to the sensor coordinate system { O } s Matrix of }
The flexible part adopts a snake bone structure, and a bending model is obtained according to coordinate system definition and geometric relation;
according to the sensor coordinate system { O s Relative to the transmitter coordinate system { O } t Matrix of }Phase point P f Coordinate system->Relative to the sensor coordinate system { O s Matrix ∈>And bending the model to obtain a pose model, and calculating +.>Lower point Pf p i In { O t Position under } t P ei ＝[ t x ei , t y ei , t z ei ] T 。
8. The rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system of claim 7, wherein the pose model is:
9. the three-dimensional pose calibration and motion tracking system of a rigid-flexible endoscope according to claim 1, wherein the obtaining the actual position of the flexible tip of the endoscope in the actual position obtaining module of the flexible tip comprises:
multiple rotations of the endoscope operating handle, recording the tip of the flexible portion at the point of abutment P on ECG paper f Coordinate systemLower different positions->
Measuring recorded points on ECG paper at { O } t Position under } t P ri To t P ri As the actual location.
10. The rigid-flexible endoscope three-dimensional pose calibration and motion tracking system according to claim 1, wherein a centroid is obtained t P b When the centroid t P b With the center of a circle t P c Deviation determination between locations, comprising:
selecting three points, so that the distances between every two of the three points are equal, and connecting the three points must form a regular triangle;
the circle center is obtained through mathematical calculation of the regular triangle t P c ＝[ t X cr , t Y cr , t Z cr ] T ；
By transmitter coordinate system { O t Relative to the sensor coordinate system { O } s Matrix under }Calculation of s p b And (3) with s p c In { O s Error e of azimuth angle under } cθ Error of elevation angle->
CN202311402562.4A 2023-10-27 2023-10-27 Rigid-flexible integrated endoscope three-dimensional pose calibration and motion tracking system Pending CN117442336A (en)

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