POSITION DETECTING SYSTEM AND POSITION DETECTING METHOD

• US 20110184690A1
• Filed: 09/10/2010
• Published: 07/28/2011
• Est. Priority Date: 03/10/2009
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Medical Systems Corporation (Olympus Corporation)
• Inventors: IIDA, Takahiro, KIMURA, Atsushi, CHIBA, Atsushi
• Granted Patent: US 8,868,372 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: A61B 1/00016 using wireless means
• CPC Class Codes: A61B 1/00032 internally powered
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 1/0684 using light emitting diodes [LED]
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00

Abstract

A position detecting system that detects the position of a body-insertable apparatus inserted into a subject includes: a driving-magnetic-field generating unit that generates a driving magnetic field in a detection space in which the subject into which the body-insertable apparatus, which generates a resonant magnetic field induced by the driving magnetic, is inserted is surrounded; a magnetic sensor that detects a magnetic field generated in the detection space; a position detecting unit that detects, based on the magnetic field detected by the sensor, a position and a direction of the body-insertable apparatus; a guiding unit that guides at least one of the position and the direction of the body-insertable apparatus to at least one of a position and a direction set as targets; a predicting unit that predicts, using the position and the direction detected by the position detecting unit, a position and a direction at certain time of the body-insertable apparatus; and a control unit that controls the driving-magnetic-field generating unit and the position detecting unit based on the position and the direction at the certain time predicted by the predicting unit.

Claims

1. A position detecting system comprising:

a detected object that includes a magnetic-field generating unit that generates a magnetic field;

at least one magnetic sensor that detects the magnetic field generated by the magnetic-field generating unit;

a position detecting unit that calculates, based on a detection value of the magnetic sensor, at least one of a position and a direction of the detected object;

a memory unit that stores a calculation result of the position detecting unit;

a moving-amount calculating unit that calculates, based on the calculation results at a plurality of times different from one another stored in the memory unit, a moving amount by which the detected object is predicted to move between first time when the position detecting unit calculates the at least one of the position and the direction of the detected object and second time after a predetermined time from the first time;

a predicting unit that predicts, based on a calculation result of the position detecting unit at the first time stored in the memory unit and a calculation result of the moving-amount calculating unit, at least one of a position and a direction of the detected object at the second time; and

a control unit that controls the position detecting system based on the at least one of the position and the direction of the detected object at the second time predicted by the predicting unit.

2. The position detecting system according to claim 1, wherein the control unit includes a position-calculation control unit that controls the position detecting unit.

3. The position detecting system according to claim 2, wherein

the position detecting unit includes a convergence calculating unit that changes, when a detection value of the magnetic sensor is set as a true value and a detection value of the magnetic sensor predicted when it is assumed that the detected object is present in an estimation position is set as an estimation value, the estimation position such that a difference between the true value and the estimation value is equal to or smaller than a predetermined value, and

the position-calculation control unit includes a convergence-calculation-initial-value changing unit that changes an initial value of the estimation position.

4. The position detecting system according to claim 2, wherein

the position detecting system includes a plurality of the magnetic sensors,

the position detecting unit includes a magnetic-sensor selecting unit that selects at least one of the magnetic sensors that is a target from which the detection value is read out, and

the position-calculation control unit includes a magnetic-sensor-selection changing unit that changes the magnetic sensor selected by the magnetic-sensor selecting unit.

5. The position detecting system according to claim 2, wherein

the position detecting unit includes an interference correcting unit that corrects the detection value by removing, from the detection value, a component of an interference magnetic field, which is caused when a coil arranged near the magnetic-field generating unit is induced by the magnetic field, in the detection value, and

the position-calculation control unit includes an interference-correction-value changing unit that changes the component of the interference magnetic field that should be removed by the interference correcting unit.

6. The position detecting system according to claim 1, wherein

the magnetic-field generating unit includes a resonance circuit that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency,

the position detecting system further comprises a driving-magnetic-field generating unit that generates the driving magnetic field, and

the control unit includes a driving-magnetic-field-generation control unit that controls the driving-magnetic-field generating unit.

7. The position detecting system according to claim 6, wherein

the driving-magnetic-field generating unit includes

a driving coil that generates the driving magnetic field;

and

a driving-signal generating unit that generates a driving signal having a frequency same as the specific frequency and inputs the driving signal to the driving coil, and

the driving-magnetic-field-generation control unit includes a driving-signal-generation control unit that controls generation of the driving signal by the driving-signal generating unit.

8. The position detecting system according to claim 6, wherein the driving-magnetic-field generating unit includes

a plurality of driving coils that generate the driving magnetic field;

a driving-signal generating unit that generates a driving signal having the specific frequency; and

a switching unit that switches, among the driving coils, a driving coil to which the driving signal generated by the driving-signal generating unit should be input, and

the driving-magnetic-field-generation control unit controls switching of the driving coil by the switching unit.

9. A position detecting system comprising:

a detected object having a magnetic-field generating unit that generates a magnetic field and a magnet;

at least one magnetic sensor that detects the magnetic field generated by the magnetic-field generating unit;

a position detecting unit that calculates, based on a detection value of the magnetic sensor, at least one of a position and a direction of the detected object;

a guidance-magnetic-field generating unit that generates a guidance magnetic field acting on the magnet;

a guidance-magnetic-field control unit that controls, based on guide information as information concerning any one of a position and a direction set as targets or both concerning the detected object, information concerning any one of target speed and target angular velocity or both, or information concerning any one of target acceleration and target angular acceleration or both, the guidance magnetic field generated by the guidance-magnetic-field generating unit;

a memory unit that stores a calculation result of the position detecting unit;

a moving-amount calculating unit that calculates, based on the guide information, a moving amount by which the detected object moves between first time when the position detecting unit calculates the at least one of the position and the direction of the detected object and second time after a predetermined time from the first time;

a predicting unit that predicts, based on a calculation result of the position detecting unit at the first time stored in the memory unit and a calculation result of the moving-amount calculating unit, at least one of a position and a direction of the detected object at the second time; and

a control unit that controls the position detecting unit based on the at least one of the position and the direction of the detected object at the second time predicted by the predicting unit.

10. The position detecting system according to claim 9, wherein the control unit includes a position-calculation control unit that controls the position detecting unit.

11. The position detecting system according to claim 10, wherein

the position detecting unit includes a convergence calculating unit that changes, when a detection value of the magnetic sensor is set as a true value and a detection value of the magnetic sensor predicted when it is assumed that the detected object is present in an estimation position is set as an estimation value, the estimation position such that a difference between the true value and the estimation value is equal to or smaller than a predetermined value, and

the position-calculation control unit includes a convergence-calculation-initial-value changing unit that changes an initial value of the estimation position.

12. The position detecting system according to claim 10, wherein

the position detecting system includes a plurality of the magnetic sensors,

the position detecting unit includes a magnetic-sensor selecting unit that selects at least one of the magnetic sensors that is a target from which the detection value is read out, and

the position-calculation control unit includes a magnetic-sensor-selection changing unit that changes the magnetic sensor selected by the magnetic-sensor selecting unit.

13. The position detecting system according to claim 10, wherein

the position detecting unit includes an interference correcting unit that corrects the detection value by removing, from the detection value, a component of an interference magnetic field, which is caused when a coil arranged near the magnetic-field generating unit is induced by the magnetic field, in the detection value, and

the position-calculation control unit includes an interference-correction-value changing unit that changes the component of the interference magnetic field that should be removed by the interference correcting unit.

14. The position detecting system according to claim 9, wherein

the magnetic-field generating unit includes a resonance circuit that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency,

the position detecting system further comprises a driving-magnetic-field generating unit that generates the driving magnetic field, and

the control unit includes a driving-magnetic-field-generation control unit that controls the driving-magnetic-field generating unit.

15. The position detecting system according to claim 14, wherein

the driving-magnetic-field generating unit includes

a driving coil that generates the driving magnetic field;

and

a driving-signal generating unit that generates a driving signal having a frequency same as the specific frequency and inputs the driving signal to the driving coil, and

the driving-magnetic-field-generation control unit includes a driving-signal-generation control unit that controls generation of the driving signal by the driving-signal generating unit.

16. The position detecting system according to claim 14, wherein the driving-magnetic-field generating unit includes

a plurality of driving coils that generate the driving magnetic field;

a driving-signal generating unit that generates a driving signal having the specific frequency; and

a switching unit that switches, among the driving coils, a driving coil to which the driving signal generated by the driving-signal generating unit should be input, and

the driving-magnetic-field-generation control unit controls switching of the driving coil by the switching unit.

17. A position detecting method comprising:

detecting, with at least one magnetic sensor, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field;

performing, when a detection value of the magnetic sensor that detects the magnetic field is set as a true value and a detection value of the magnetic sensor predicted when it is assumed that the detected object is present in an estimation position is set as an estimation value, convergence calculation for changing the estimation position such that a difference between the true value and the estimation value is equal to or smaller than a predetermined value and calculates at least one of a position and a direction of the detected object;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing an initial value of the estimation position based on the predicted at least one of the position and the direction of the detected object at the second time.

18. A position detecting method comprising:

detecting, with at least one magnetic sensor among a plurality of magnetic sensors, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field;

calculating, based on a detection value of the magnetic sensor, at least one of a position and a direction of the detected object;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

selecting, based on the predicted at least one of the position and the direction of the detected object at the second time, a magnetic sensor as a target of readout of the detection value out of the magnetic sensors.

19. A position detecting method comprising:

detecting, with at least one magnetic sensor, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field;

correcting the detection value by removing, from a detection value of the magnetic sensor that detects the magnetic field, a component of an interference magnetic field, which is caused when a coil arranged near the magnetic-field generating unit is induced by the magnetic field, in the detection value and calculating, based on the detection value after the correction, at least one of a position and a direction of the detected object;

calculating, based on a detection value of the magnetic sensor, at least one of a position and a direction of the detected object;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing, based on the predicted at least one of the position and the direction of the detected object at the second time, the component of the interference magnetic field that should be removed from the detection value of the magnetic sensor.

20. A position detecting method comprising:

supplying a driving signal to a driving coil to generate a driving magnetic field having a specific frequency;

detecting, with at least one magnetic sensor, a magnetic field generated in the driving magnetic field by a magnetic-field generating unit of a detected object including the magnetic-field generating unit, the magnetic-field generating unit including a resonance circuit that generates a resonant magnetic field induced by the driving magnetic field;

calculating, based on a detection value the magnetic sensor that detects the magnetic field, at least one of a position and a direction of the detected object;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing the driving signal based on the predicted at least one of the position and the direction of the detected object at the second time.

21. A position detecting method comprising:

detecting, with at least one magnetic sensor, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field and a magnet;

performing, when a detection value of the magnetic sensor that detects the magnetic field is set as a true value and a detection value of the magnetic sensor predicted when it is assumed that the detected object is present in an estimation position is set as an estimation value, convergence calculation for changing the estimation position such that a difference between the true value and the estimation value is equal to or smaller than a predetermined value and calculates at least one of a position and a direction of the detected object;

generating, based on guide information as information concerning any one of a position and a direction set as targets or both concerning the detected object, information concerning any one of target speed and target angular velocity or both, or information concerning any one of target acceleration and target angular acceleration or both, a guidance magnetic field acting on the magnet;

guiding, with the guidance magnetic field, at least one of a position and a direction of the detected object to at least one of a position and a direction set as targets;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing an initial value of the estimation position based on the predicted at least one of the position and the direction of the detected object at the second time.

22. A position detecting method comprising:

detecting, with at least one magnetic sensor among a plurality of magnetic sensors, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field and a magnet;

calculating, based on a detection value of the magnetic sensor that detects the magnetic field, at least one of a position and a direction of the detected object;

generating, based on guide information as information concerning any one of a position and a direction set as targets or both concerning the detected object, information concerning any one of target speed and target angular velocity or both, or information concerning any one of target acceleration and target angular acceleration or both, a guidance magnetic field acting on the magnet;

guiding, with the guidance magnetic field, at least one of a position and a direction of the detected object to at least one of a position and a direction set as targets;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

selecting, based on the predicted at least one of the position and the direction of the detected object at the second time, a magnetic sensor as a target of readout of the detection value out of the magnetic sensors.

23. A position detecting method comprising:

detecting, with at least one magnetic sensor, a magnetic field generated by a magnetic-field generating unit of a detected object having the magnetic-field generating unit that generates a magnetic field and a magnet;

correcting the detection value by removing, from a detection value of the magnetic sensor that detects the magnetic field, a component of an interference magnetic field, which is caused when a coil arranged near the magnetic-field generating unit is induced by the magnetic field, in the detection value and calculating, based on the detection value after the correction, at least one of a position and a direction of the detected object;

generating, based on guide information as information concerning any one of a position and a direction set as targets or both concerning the detected object, information concerning any one of target speed and target angular velocity or both, or information concerning any one of target acceleration and target angular acceleration or both, a guidance magnetic field acting on the magnet;

guiding, with the guidance magnetic field, at least one of a position and a direction of the detected object to at least one of a position and a direction set as targets;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing, based on the predicted at least one of the position and the direction of the detected object at the second time, the component of the interference magnetic field that should be removed from the detection value of the magnetic sensor.

24. A position detecting method comprising:

supplying a driving signal to a driving coil to generate a driving magnetic field having a specific frequency;

detecting, with at least one magnetic sensor, a magnetic field generated in the driving magnetic field by a magnetic-field generating unit of a detected object including the magnetic-field generating unit and a magnet, the magnetic-field generating unit including a resonance circuit that generates a resonant magnetic field induced by the driving magnetic field;

generating, based on guide information as information concerning any one of a position and a direction set as targets or both concerning the detected object, information concerning any one of target speed and target angular velocity or both, or information concerning any one of target acceleration and target angular acceleration or both, a guidance magnetic field acting on the magnet;

guiding, with the guidance magnetic field, at least one of a position and a direction of the detected object to at least one of a position and a direction set as targets;

calculating a moving amount by which the detected object is predicted to move between first time when the at least one of the position and the direction of the detected object is calculated and second time after a predetermined time from the first time;

predicting, based on a result of the calculation performed at the first time and a result of the calculation of the moving amount, at least one of a position and a direction of the detected object at the second time; and

changing the driving signal based on the predicted at least one of the position and the direction of the detected object at the second time.

25. A position detecting system comprising:

a body-insertable apparatus that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency;

a driving-magnetic-field generating unit that generates the driving magnetic field having the specific frequency in a detection space in which a subject into which the body-insertable apparatus is inserted is surrounded;

a magnetic sensor that detects a magnetic field generated in the detection space;

a position detecting unit that detects, based on the magnetic field detected by the magnetic sensor, at least one of a position and a direction of the body-insertable apparatus;

a guiding unit that guides the at least one of the position and the direction of the body-insertable apparatus to at least one of a position and a direction set as targets;

a predicting unit that predicts, using the at least one of the position and the direction detected by the position detecting unit and guide information used by the guiding unit in guiding the body-insertable apparatus to the at least one of the position and the direction set as the targets, at least one of a position and a direction at certain time of the body-insertable apparatus; and

a control unit that controls the driving-magnetic-field generating unit and the position detecting unit based on the at least one of the position and the direction at the certain time predicted by the predicting unit.

26. A position detecting system comprising:

a body-insertable apparatus that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency;

a driving-magnetic-field generating unit that generates the driving magnetic field having the specific frequency in a detection space in which a subject into which the body-insertable apparatus is inserted is surrounded;

a magnetic sensor that detects a magnetic field generated in the detection space;

a position detecting unit that detects, based on the magnetic field detected by the magnetic sensor, at least one of a position and a direction of the body-insertable apparatus;

a predicting unit that predicts, based on the at least one of the position and the direction at different time detected by the position detecting unit, at least one of a position and a direction at certain time of the body-insertable apparatus; and

a control unit that controls the driving-magnetic-field generating unit and the position detecting unit based on the at least one of the position and the direction at the certain time predicted by the predicting unit.

27. A position detecting method for detecting, with a position detecting system including a guiding unit that guides at least one of a position and a direction of a body-insertable apparatus that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency to at least one of a position and a direction set as targets, at least one of a position and a direction of the body-insertable apparatus, the position detecting method comprising:

generating the driving magnetic field having the specific frequency in a detection space in which a subject into which the body-insertable apparatus is inserted is surrounded;

generating the resonant magnetic field from the body-insertable apparatus with the driving magnetic field having the specific frequency;

detecting a magnetic field generated in the detection space;

calculating, based on the detected magnetic field, at least one of a position and a direction of the body-insertable apparatus;

predicting, using the calculated at least one of the position and the direction and guide information used by the guiding unit in guiding the body-insertable apparatus to the at least one of the position and the direction set as the targets, at least one of a position and a direction at certain time of the body-insertable apparatus; and

controlling the driving magnetic field based on the predicted at least one of the position and the direction at the certain time.

28. A position detecting method for detecting, with a position detecting system, at least one of a position and a direction of a body-insertable apparatus that generates a resonant magnetic field induced by a driving magnetic field having a specific frequency, the position detecting method comprising:

generating the driving magnetic field having the specific frequency in a detection space in which a subject into which the body-insertable apparatus is inserted is surrounded;

generating the resonant magnetic field from the body-insertable apparatus with the driving magnetic field having the specific frequency;

detecting a magnetic field generated in the detection space;

detecting, based on the detected magnetic field, at least one of a position and a direction of the body-insertable apparatus;

predicting, based on the detected at least one of the position and the direction at different time, at least one of a position and a direction at certain time of the body-insertable apparatus; and

controlling the driving magnetic field based on the predicted at least one of the position and the direction at the certain time.