JP5004646B2 - Position / orientation detection system, detection method thereof, and position / orientation detection apparatus - Google Patents

Description

  The present invention relates to a position / orientation detection system, a detection method therefor, and a position / orientation detection apparatus. The present invention relates to a simple position and orientation detection system, a detection method thereof, and a position and orientation detection apparatus.

  In recent years, there is an increasing need for a position and orientation detection system that detects the position and orientation of an information terminal. For example, a position / orientation detection system for detecting the position / orientation of a movable body such as a head-mounted display in motion capture, or in the field of medical equipment, such as an insertion-type endoscope or a capsule endoscope cannot be viewed. A position / orientation detection system that measures the position / orientation of an information terminal at a location can be used.

  As a method for detecting the position and orientation of these information terminals, there is a method using an alternating magnetic field. At that time, the direction in which the alternating magnetic field is generated and the direction of the magnetic sensor used for measurement become a problem. For example, an AC signal that is measured when the direction in which the output signal increases when a magnetic field enters the magnetic sensor (hereinafter referred to as the positive direction of the magnetic sensor) is the same as the positive direction of the AC magnetic field, and the magnetic sensor The AC signal measured when the positive direction is opposite to the positive direction of the AC magnetic field is apparently indistinguishable.

  12A and 12B show the case where the positive direction of the magnetic sensor is the same direction as the incident direction of the sinusoidal alternating magnetic field (FIG. 12A)) and the opposite direction (FIG. 12B). It is a figure which shows the mode of the measured output signal. 12 (a) and 12 (b), the output signal is a sine wave and is only in a state shifted by a half wavelength, and when the signal is continuously acquired from an appropriate moment, which of the alternating magnetic fields is It is impossible to distinguish whether it is incident from the direction. Therefore, even if only the signal intensity (amplitude) is detected, the direction of the magnetic sensor cannot be determined, and the amplitude cannot have a positive or negative sign (the sign is the positive direction of the magnetic sensor as shown in FIG. 12A). Is defined as a positive sign (+) if the same direction as the incident direction of the alternating magnetic field, and as a negative sign (-) if the positive direction of the magnetic sensor is opposite to the incident direction of the alternating magnetic field as shown in FIG. To do). That is, the direction of the magnetic sensor cannot be determined based on the sign of the amplitude.

  In order to solve such a problem, for example, in Patent Document 1, a magnetic field in which a sine wave A and a sine wave B are superimposed is generated from a generating coil, the magnetic field is measured by a receiving coil, and the sine wave A and sine wave B are measured. Are separated for each frequency band, and the amplitude of each is compared to determine the direction in which the generating coil outputs the magnetic field and the direction of the receiving coil.

  In the development of a capsule endoscope, for example, as in Non-Patent Document 1, an AC magnetic field in a generating coil is synchronized with the generation, a magnetic field is detected by a receiving coil, and an FFT (Fast Fourier Transform; Fast Fourier Transform) ) The signal intensity (amplitude) of each frequency is detected by performing an operation, and the phase is calculated from the data from the time of signal detection until the FFT operation is performed. If the same time is used as a reference, the orientation of the magnetic sensor and the magnetic field Since the phase is shifted by π when the direction is the same direction and the opposite direction, the sign of the amplitude of the detected AC magnetic field has been determined.

  In Japanese Patent Application No. 2007-30803, a plurality of magnetic fields having a known phase relationship are superimposed on each other so as not to require a synchronization signal, and a signal measured by the magnetic sensor is subjected to an FFT operation. The phase of the plurality of alternating magnetic fields measured is obtained, and the sign of the amplitude of the detected alternating magnetic field is determined according to the phase relationship.

JP 2006-214979 A Biomedical engineering 41-4, 239/249 (2003)

  However, the method described in Patent Document 1 described above requires a complicated configuration of intermittent drive that generates the sine wave B in synchronization with the sine wave A performing positive output. Further, a filter having a predetermined band for separating each frequency is required for each reception coil, and the frequency used for the sine wave A and the sine wave B must be different by 10 times or more. There was a problem that the degree of freedom was low. In addition, the system configuration is such that the generating coil moves, and a power source for generating a magnetic field must be installed in the information terminal, making it difficult to achieve the downsizing and power saving required for recent information terminals. was there.

  Further, in the method described in Non-Patent Document 1 described above, in order to detect a phase from the same time, a signal must be measured in synchronization with the generation of an alternating magnetic field (or current), and a trigger for that purpose. (Synchronization signal) or reference signal is always required for each generated magnetic field, and the configuration is not easy, and it is difficult to perform continuous measurement.

  In addition, only the system described in Japanese Patent Application No. 2007-30803 can detect the direction of the information terminal, but cannot detect the position.

  The present invention has been made in view of such a situation, and an object of the present invention is to enable continuous measurement using an alternating magnetic field, a large degree of freedom in setting a frequency, and a simple configuration. A position and orientation detection system, a detection method therefor, and a position and orientation detection apparatus are provided.

The present invention has been made to achieve such an object, and the invention according to claim 1 is a position and orientation detection system, wherein a first AC magnetic field having at least one directivity is generated. A second magnetic field generating unit and a second magnetic field generating at least one alternating magnetic field having a directivity different from that of the first magnetic field generating unit and having a frequency different from the frequency of the magnetic field generated by the first magnetic field generating unit. From the magnetic field generation unit, the magnetic field detection unit having a multi-axis magnetic sensor for detecting the magnetic field generated from the first and second magnetic field generation units, and the magnetic field detected by the magnetic field detection unit, the first and first A magnetic field generation unit and a calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the magnetic field generation unit and the magnetic field detection unit , wherein the first magnetic field generation unit includes: Arranged to have directivity in the direction, At least one magnetic field generating coil that generates alternating magnetic fields having different frequencies, and the second magnetic field generating unit is arranged to have directivity in the second direction and generates alternating magnetic fields having different frequencies. The calculation unit includes at least one magnetic field generation coil, and the calculation unit specifies and corresponds to which of the plurality of magnetic field generation coils has the maximum intensity in the first and second magnetic field generation units. By specifying the directional relationship between the magnetic field generating coil and the magnetic field detector, position information and posture information of the magnetic field detector are calculated .

According to a second aspect of the present invention, in the first aspect of the present invention, the arithmetic unit is configured to determine the phase of the plurality of frequency components in each axis based on an output signal of each axis of the magnetic field detection unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and the first and second magnetic fields based on an output signal from the magnetic field vector calculation unit Odor in generation part By specifying which of the plurality of magnetic field generating coils has the maximum intensity of the magnetic field and specifying the directional relationship between the corresponding magnetic field generating coil and the magnetic field detecting unit, the position information of the magnetic field detecting unit and A position / orientation calculation unit for calculating attitude information is provided.

The invention according to claim 3 is a position and orientation detection system, wherein the first magnetic field generator generates at least one alternating magnetic field having directivity, and the directivity different from the first magnetic field generator. A second magnetic field generator that generates at least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the first magnetic field generator, and the first and second magnetic field generators. A magnetic field detection unit having a multi-axis magnetic sensor for detecting a generated magnetic field, and a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit is specified from the magnetic field detected by the magnetic field detection unit. Thus, the first magnetic field generator is arranged so as to have directivity in the first direction, and alternating currents having different frequencies are provided. At least one of generating a magnetic field Made from the magnetic field generating coil, the second magnetic field generating unit is disposed so as to have directivity in a second direction, comprising at least one magnetic field generating coil for generating an alternating magnetic field with different frequencies from each other, the arithmetic unit Specifies whether the angle between the magnetic fields generated from the plurality of magnetic field generation coils in the first and second magnetic field generation units is a predetermined value, and the directional relationship between the corresponding magnetic field generation coil and the magnetic field detection unit The position information and orientation information of the magnetic field detection unit are calculated by specifying

According to a fourth aspect of the present invention, in the third aspect of the present invention, the calculation unit is configured to output the phase of the plurality of frequency components on the axes based on the output signals of the axes of the magnetic field detection unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and the first and second magnetic fields based on an output signal from the magnetic field vector calculation unit Odor in generation part By specifying whether the angle between the magnetic fields generated from any of the plurality of magnetic field generating coils is a predetermined value, and specifying the directional relationship between the corresponding magnetic field generating coil and the magnetic field detecting unit, the position information of the magnetic field detecting unit and A position / orientation calculation unit for calculating attitude information is provided.

The invention according to claim 5 is a position / orientation detection system, wherein the first magnetic field generator generates at least one alternating magnetic field having directivity, and the directivity different from the first magnetic field generator. A second magnetic field generator that generates at least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the first magnetic field generator, and the first and second magnetic field generators. A magnetic field detection unit having a multi-axis magnetic sensor for detecting a generated magnetic field, and a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit is specified from the magnetic field detected by the magnetic field detection unit. Thus, the first and second magnetic field generation units each include a magnetic field generation coil that can independently change the direction of generation of the magnetic field. , The computing unit is By changing the direction of the magnetic field generation coil so that the intensity of the magnetic field generated from the field generation coil is maximized, and specifying the directional relationship between the magnetic field detection unit and the magnetic field generation coil, the position of the magnetic field detection unit Information and posture information are calculated.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the calculation unit is configured to determine phases of the plurality of frequency components in the respective axes based on output signals of the respective axes of the magnetic field detection unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and generated from each magnetic field generation coil based on an output signal from the magnetic field vector calculation unit Magnetism By changing the direction of the magnetic field generating coil so as to maximize the intensity of the magnetic field and specifying the directional relationship between the magnetic field detecting unit and the magnetic field generating coil, the position information and the posture information of the magnetic field detecting unit are calculated. And a position / orientation calculation unit.
The invention according to claim 7 is the invention according to any one of claims 1 to 6 , wherein the alternating magnetic field is a magnetic field in which the phase relationship of a plurality of different frequency components is known. .

The invention according to claim 8 is a position and orientation detection method, wherein the first magnetic field generation step by the first magnetic field generation unit that generates at least one alternating-current magnetic field having directivity, Second magnetic field generation by a second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. From the step, a magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units, and the magnetic field detected by the magnetic field detection step, the first and by a second magnetic field generating unit to identify the direction relationship of the magnetic field detecting portion, possess a calculating step of calculating position information and attitude information of the magnetic field detecting unit, wherein the calculating step includes a first direction In The first magnetic field generation unit including at least one magnetic field generation coil that is arranged so as to have directivity, and generates alternating magnetic fields having different frequencies, and is arranged so as to have directivity in a second direction. Identify and respond to which of the plurality of magnetic field generating coils has the maximum intensity in the second magnetic field generating unit including at least one magnetic field generating coil that generates alternating magnetic fields of different frequencies By specifying the directional relationship between the magnetic field generating coil and the magnetic field detector, position information and posture information of the magnetic field detector are calculated .

The invention according to claim 9 is the invention according to claim 8 , wherein the calculating step is based on an output signal of each axis by the magnetic field detecting step, and the phases of the plurality of frequency components in each axis. And the Fourier transform step for calculating the amplitude, and the magnetic field from the first and second magnetic field generation steps based on the phase relationship of the plurality of frequency components of each axis based on the output signal from the Fourier transform step. And calculating the sign for the amplitude of each axis based on the first and second magnetic field generation steps from the amplitude and the sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and the magnetic field vector calculating step. Based on the output signal of the first and second magnetic field generating steps, it is specified which of the plurality of magnetic field generating coils has the maximum magnetic field intensity, and the corresponding coil and the magnetic field detecting unit A position / orientation calculation step of calculating position information and attitude information of the magnetic field detection unit by specifying a directional relationship is characterized.

The invention according to claim 10 is a position and orientation detection method, wherein a first magnetic field generation step by a first magnetic field generation unit that generates at least one alternating magnetic field having directivity, Second magnetic field generation by a second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. From the step, a magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units, and the magnetic field detected by the magnetic field detection step, the first and by a second magnetic field generating unit to identify the direction relationship of the magnetic field detecting unit, and a calculation step of calculating the position information and attitude information of the magnetic field detecting unit, wherein the calculating step includes a first direction Are arranged so as to have directivity, are arranged to have different said comprising an alternating magnetic field frequency from the at least one magnetic field generating coil for generating a first magnetic field generator and the directivity in the second direction to each other, each other In the second magnetic field generation unit consisting of at least one magnetic field generation coil that generates alternating magnetic fields of different frequencies, specify which of the plurality of magnetic field generation coils the angle between the magnetic fields generated is a predetermined value, The positional information and orientation information of the magnetic field detection unit are calculated by specifying the directional relationship between the corresponding magnetic field generating coil and the magnetic field detection unit.

The invention according to claim 11 is the invention according to claim 10 , wherein the calculating step is based on an output signal of each axis by the magnetic field detecting step, and the phases in the plurality of frequency components in each axis. And the Fourier transform step for calculating the amplitude, and the magnetic field from the first and second magnetic field generation steps based on the phase relationship of the plurality of frequency components of each axis based on the output signal from the Fourier transform step. And calculating the sign for the amplitude of each axis based on the first and second magnetic field generation steps from the amplitude and the sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field; and the magnetic field vector calculating step. Based on the output signal from the first and second magnetic field generation steps, it is specified which angle of the magnetic fields generated from the plurality of magnetic field generation coils is a predetermined value in the first and second magnetic field generation steps, and the corresponding coil and the magnetic field A position / orientation calculation step of calculating position information and attitude information of the magnetic field detection unit by specifying a direction relation of the detection unit is provided.

The invention according to claim 12 is a position and orientation detection method, wherein the first magnetic field generation step by the first magnetic field generation unit that generates at least one alternating magnetic field having directivity, Second magnetic field generation by a second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. From the step, a magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units, and the magnetic field detected by the magnetic field detection step, the first and by a second magnetic field generating unit to identify the direction relationship of the magnetic field detecting unit, and a calculation step of calculating the position information and attitude information of the magnetic field detecting unit, wherein the computing step are respectively magnetized The direction of the magnetic field generation coil is changed so as to maximize the intensity of the magnetic field generated from the magnetic field generation coil that can independently change the generation direction of the magnetic field, and the directional relationship between the magnetic field detection unit and the magnetic field generation coil is specified Thus, position information and posture information of the magnetic field detection unit are calculated.

Further, in the invention described in claim 13 , in the invention described in claim 12 , the calculating step is based on an output signal of each axis by the magnetic field detecting step, and the phases in the plurality of frequency components in each axis. And the Fourier transform step for calculating the amplitude, and the magnetic field from the first and second magnetic field generation steps based on the phase relationship of the plurality of frequency components of each axis based on the output signal from the Fourier transform step. And calculating the sign for the amplitude of each axis based on the first and second magnetic field generation steps from the amplitude and the sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field; and the magnetic field vector calculating step. The direction of the magnetic field generating coil is changed so that the intensity of the magnetic field generated from each magnetic field generating coil is maximized based on the output signal from the magnetic field generating coil, and the directional relationship between the magnetic field detector and the magnetic field generating coil is specified By doing so, it has a position and orientation calculation step of calculating the position information and orientation information of the magnetic field detection unit.
The invention according to claim 14 is the invention according to any one of claims 8 to 13 , wherein the alternating magnetic field is a magnetic field in which the phase relationship of different frequency components is known. .

The invention according to claim 15 is a position / orientation detection apparatus, wherein a first magnetic field generating unit that generates at least one alternating magnetic field having directivity, and a directivity different from the first magnetic field generating unit. And a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generating unit that generates at least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the first magnetic field generating unit And the positional information of the magnetic field detection unit by specifying the directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. A calculation unit that calculates posture information, and the calculation unit is arranged to have directivity in a first direction, and includes at least one magnetic field generation coil that generates alternating magnetic fields having different frequencies. Magnetic field generation And any one of the plurality of magnetic field generating coils in the second magnetic field generating unit that is arranged so as to have directivity in the second direction and includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies. The position information and the posture information of the magnetic field detection unit are calculated by specifying whether the intensity of the magnetic field generated from the maximum is specified and specifying the directional relationship between the corresponding magnetic field generation coil and the magnetic field detection unit. Features.

According to a sixteenth aspect of the present invention, in the invention according to the fifteenth aspect , the calculation unit is configured to detect phases of the plurality of frequency components in the respective axes based on output signals of the respective axes of the magnetic field detection unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and the first and second magnetic fields based on an output signal from the magnetic field vector calculation unit In the generation part The position information and orientation of the magnetic field detection unit are determined by specifying which of the plurality of magnetic field generation coils has the maximum intensity of the magnetic field and specifying the directional relationship between the corresponding coil and the magnetic field detection unit. And a position / orientation calculation unit that calculates information.

The invention according to claim 17 is a position / orientation detection device, wherein the first magnetic field generator generates at least one alternating magnetic field having directivity, and the directivity different from the first magnetic field generator. And a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generating unit that generates at least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the first magnetic field generating unit And the positional information of the magnetic field detection unit by specifying the directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. A calculation unit that calculates posture information, and the calculation unit is arranged to have directivity in a first direction, and includes at least one magnetic field generation coil that generates alternating magnetic fields having different frequencies. Magnetic field generation And are arranged so as to have directivity in a second direction, in the second magnetic field generating portion comprising at least one magnetic field generating coil for generating an alternating magnetic field of different frequencies, one of said plurality of magnetic field generating coils The position information and the posture information of the magnetic field detection unit are calculated by specifying whether the angle between the magnetic fields generated from is a predetermined value and specifying the directional relationship between the corresponding magnetic field generation coil and the magnetic field detection unit It is characterized by that.

According to an eighteenth aspect of the present invention, in the invention according to the seventeenth aspect , the arithmetic unit is configured to detect phases of the plurality of frequency components in the respective axes based on output signals of the respective axes of the magnetic field detecting unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and the first and second magnetic fields based on an output signal from the magnetic field vector calculation unit In the generation part The position information of the magnetic field detection unit is determined by specifying which of the plurality of magnetic field generation coils the angle between the magnetic fields generated is a predetermined value and specifying the directional relationship between the corresponding coil and the magnetic field detection unit. And a position / orientation calculation unit for calculating attitude information.

The invention according to claim 19 is a position and orientation detection device, wherein the first magnetic field generator generates at least one alternating magnetic field having directivity, and the directivity different from that of the first magnetic field generator. And a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generating unit that generates at least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the first magnetic field generating unit And the positional information of the magnetic field detection unit by specifying the directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. A calculation unit that calculates posture information, and the calculation unit changes the direction of the magnetic field generation coil so that the intensity of the magnetic field generated from the magnetic field generation coil that can change the generation direction of the magnetic field independently is maximized. Let By identifying the magnetic field detecting unit directional relationship of the magnetic field generating coil, and calculates the position information and attitude information of the magnetic field detecting unit.

According to a twentieth aspect of the present invention, in the invention according to the nineteenth aspect , the calculation unit is configured to determine phases of the plurality of frequency components in the respective axes based on output signals of the respective axes of the magnetic field detection unit. And the Fourier transform unit for calculating the amplitude, and based on the output signal from the Fourier transform unit, the phase relationship of the plurality of frequency components of each axis is changed to the magnetic field from the first and second magnetic field generation units. And calculating a sign for the amplitude of each axis based on the first and second magnetic field generators based on the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit that calculates first and second magnetic field vectors representing the direction and magnitude based on the generated magnetic field, and generated from each of the magnetic field generation coils based on an output signal from the magnetic field vector calculation unit By changing the direction of the magnetic field generating coil so that the intensity of the magnetic field is maximized and specifying the directional relationship between the magnetic field detecting unit and the magnetic field generating coil, the position information and orientation information of the magnetic field detecting unit are calculated. And a position / orientation calculation unit.
The invention according to claim 21 is the invention according to any one of claims 15 to 20 , wherein the alternating magnetic field is a magnetic field in which the phase relationship of a plurality of different frequency components is known. .

  According to the present invention, a magnetic field detection unit having a plurality of magnetic sensors mounted on an information terminal by configuring a plurality of magnetic field generation units having a plurality of different frequencies and having directivity for generating a strong magnetic field in a specific direction. It is possible to calculate the directional relationship between the magnetic field detection unit and the plurality of magnetic field generation units in the calculation unit from the signal detected by the above, and to detect the position and orientation of the information terminal.

  In addition, it is possible to provide a position and orientation detection system that can continuously measure using an alternating magnetic field, has a high degree of freedom in setting a frequency, and has a simple configuration. Similarly, the position and orientation detection method and the position and orientation detection apparatus can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
[Example 1]
FIG. 1 is an overall configuration diagram showing a first embodiment of a position / orientation detection system of the present invention. In FIG. Denotes a Yg-axis direction magnetic field generation unit, 2a denotes a Yg-axis coil power supply group, 2b denotes a Yg-axis coil group, 3 denotes an information terminal having a magnetic field detection unit 11, 4 denotes a calculation unit, and 5 denotes a data display unit. Reference numeral 10 denotes an azimuth angle sensor.

  There is a space in which a right-handed XgYgZg coordinate system is defined. The Xg-axis direction magnetic field generation unit 1 generates a magnetic field in the Xg-axis direction, and the Yg-axis direction magnetic field generation unit 2 generates a magnetic field in the Yg-axis direction. The Xg-axis direction magnetic field generator 1 includes an Xg-axis coil power supply group 1a and an Xg-axis coil group 1b. Similarly, the Yg-axis direction magnetic field generator 2 includes a Yg-axis coil power supply group 2a and a Yg-axis coil group 2b.

  The Xg-axis coil group 1b is a group of a plurality of coils arranged at equal intervals so as to generate a magnetic field in the Xg-axis direction on a plane parallel to the YgZg plane, and one row arranged in the Yg-axis direction. , N rows are arranged in the Zg axis direction. The Yg-axis coil group 2b is a group of a plurality of coils arranged at equal intervals so as to generate a magnetic field in the Yg axis direction on a plane parallel to the XgZg plane, and m rows arranged in the Xg axis direction. , N rows are arranged in the Zg axis direction. Note that l, m, and n are integers of 1 or more.

  Each row of n rows arranged in the Zg-axis direction of the Xg-axis coil group 1b and each row of n rows arranged in the Zg-axis direction of the Yg-axis coil group 2b are on the same plane parallel to the XgYg plane. It is in. Further, both the Xg-axis coil group 1b and the Yg-axis coil group 2b are arranged so that one coil group does not overlap a space for generating a magnetic field. Each coil generates the strongest magnetic field on the central axis of the magnetic field generation surface. For example, a spiral coil is used. Therefore, the Xg-axis coil group 1b generates a strong magnetic field in the Xg-axis direction, and the Yg-axis coil group 2b generates a strong magnetic field in the Yg-axis direction.

  The position / orientation detection system of the present invention includes an information terminal 3 having an Xg-axis direction magnetic field generation unit 1, a Yg-axis direction magnetic field generation unit 2, and a magnetic field detection unit 11, a calculation unit 4, and a data display unit 5.

  The Xg-axis direction magnetic field generator (first magnetic field generator) 1 including the Xg-axis coil power supply group 1a and the Xg-axis coil group 1b generates at least one alternating-current magnetic field having directivity. The Yg-axis direction magnetic field generation unit (second magnetic field generation unit) 2 including the Yg-axis coil power supply group 2a and the Yg-axis coil group 2b has directivity different from that of the Xg-axis direction magnetic field generation unit 1 and Xg At least one alternating magnetic field having a frequency different from the frequency of the magnetic field generated by the axial magnetic field generator 1 is generated.

  The magnetic field detection unit 11 in the information terminal 3 includes multi-axis magnetic sensors 10a, 10b, and 10c that detect magnetic fields generated from the Xg-axis direction magnetic field generation unit 1 and the Yg-axis direction magnetic field generation unit 2. . Further, the calculation unit 4 specifies the positional relationship and orientation of the magnetic field detection unit 11 by identifying the directional relationship among the Xg axis direction magnetic field generation unit 1, the Yg axis direction magnetic field generation unit 2, and the magnetic field detection unit 11 from the detected magnetic field. Information is calculated.

FIG. 2 is an explanatory diagram of the arrangement of the Xg-axis coil group 1b and the Yg-axis coil group 2b and the arrangement of the information terminal 3 at a certain Zg coordinate (plane _where Zg = Zk).

Xg-axis coil group 1b are arranged so that the l-number of coils from the coil X ₁ to coil X _l generates a magnetic field in the direction of the Xg-axis at equal intervals parallel to the Yg axis. Similarly, it is arranged as the m from the coil Y ₁ also Yg axis coil group 2b to coil Y _m generates a magnetic field in the direction of the Yg axis at equal intervals parallel to the Xg-axis.

Such an arrangement forms a XgYg coordinates in Zg = Z _k in the point of intersection of the center axes of the coils of each axis coil groups. Then, planes having the same arrangement as those of these coils are formed by n planes in the Zg axis direction, thereby forming an XgYgZg coordinate space having l × m × n coordinates.

2, the information terminal 3 is disposed at the intersection on the central axis of the coil X _i and the coil Y _j. In this case, the position coordinates are (X _i , Y _j , Z _k ). For the following description of this embodiment will be described as being the information terminal 3 to the plane of Zg = Z _k.

  The Xg-axis coil power supply group 1a is a group of a plurality of power supplies that can supply alternating currents having two different frequencies to each of the coils. The same applies to the Yg-axis coil power supply group 2a. The alternating current (or voltage) from each power source is expressed as Mω and Nω, respectively, by using positive integers M and N having different even and odd angular frequencies of the first and second frequencies ( The frequency ratio is M: N as the smallest integer ratio). For example, M = 1 and N = 2.

  These two frequencies are all different for each power source. A magnetic field can be generated by supplying alternating currents of two different frequencies from each power source to each coil as described above, and the magnetic field generated from each coil has a frequency component of the alternating current supplied from each power source. The frequency components are different from each other.

And the magnitude | size of the magnetic field which generate | occur | produces from each coil of Xg axis coil group 1b will be all equal if the distance from a coil to the position to measure is the same. The same applies to the magnetic field generated from each coil of the Yg-axis coil group 2b. The phase relationship of each frequency component of the magnetic field from each coil is known. For example, the phases Θ and Φ of the first and second frequency components are expressed as follows.
Θ = Mωt + Ω _θ (1)
Φ = Nωt + Ω _φ (2)
(It is assumed that the first frequency component and the second frequency component are respectively Ω _θ and Ω _φ at time t = 0).

  The information terminal 3 includes a magnetic field detection unit (azimuth angle sensor 10 and data transmission unit 16; see FIG. 4 described later) 11 and detects magnetic fields from the Xg-axis direction magnetic field generation unit 1 and the Yg-axis direction magnetic field generation unit 2. It is arranged in a space that can.

  Inside the information terminal 3, a magnetic field detector 11 for detecting the magnetic field generated from each of the coils is mounted. The azimuth sensor 10 has a triaxial magnetic sensor facing surfaces orthogonal to each other. The x-axis magnetic sensor 10a, the y-axis magnetic sensor 10b, and the z-axis magnetic sensor 10c are mounted.

  The magnetic sensors 10a to 10c are semiconductor type magnetic sensors such as a Hall element, an MR element, a GMR element, and an MI element. Further, the data transmission unit 16 receives magnetic data obtained by converting the magnetic field detected by the three-axis magnetic sensors 10 a to 10 c in the azimuth sensor 10 into a digital signal, and receives the data in the calculation unit 4 outside the information terminal 3. It can be transmitted to the unit 17. In FIG. 1, a state in which magnetic data is wirelessly transmitted from the data transmission unit 16 of the information terminal 3 to the calculation unit 4 is illustrated (a dotted dotted arrow represents magnetic data transmitted wirelessly). )

  Depending on the application, it is not always necessary to be wireless, and the information terminal 3 and the arithmetic unit 4 may be connected by wire to transmit and receive data. Further, although the calculation unit 4 is also drawn outside the information terminal 3, the calculation unit 4 is mounted inside the information terminal 3, and the data of the calculation unit 4 is exchanged with the data display unit 5 outside the information terminal 3. You may do it. At this time, it may be wireless or wired depending on the application. The information terminal 3 means a part or part from which a user can obtain some information. For example, a mobile phone, a PDA (Personal Digital Assistant), a capsule endoscope, an endoscope, It means various things such as game machines. The calculation unit 4 is, for example, a mobile phone, a PDA, a game machine, a capsule endoscope, a measuring instrument for an endoscope, or a CPU (Central Processing Unit) in a PC (Central Processing Unit). A processing device), a DSP (Digital Signal Processor), a microcomputer, and the like are configured using a storage device such as a memory and a hard disk, a communication function with the outside, and the like. The data display unit 5 has a function of displaying the output signal from the calculation unit 4 to the user. For example, the data display unit 5 uses a display for the above-described mobile phone, PDA, game machine, measuring instrument, and PC. Constitute.

  FIG. 3 is an explanatory diagram of the coordinate system of the information terminal 3. A right-handed coordinate system xyz coordinate system (referred to as a terminal coordinate system) is defined by a z-axis perpendicular to the x-axis and the y-axis, where the longitudinal direction of the information terminal 3 is the x-axis and the short-side direction is the y-axis. In addition, it is assumed that the directions of the three-axis magnetic sensors 10a to 10c orthogonal to each other included in the azimuth angle sensor 10 mounted on the information terminal 3 coincide with the directions of the respective axes constituting the xyz coordinate system. That is, there are the x-axis, y-axis, and z-axis magnetic sensors 10a to 10c, and the increasing direction (positive direction) of each output is the positive direction of each axis of the xyz coordinate system.

  FIG. 4 is a block diagram showing a specific configuration of the position / orientation detection apparatus according to the first embodiment of the position / orientation detection system of the present invention. The position / orientation detection apparatus includes a magnetic field detection unit 11 and a calculation unit 4, and the calculation unit 4 includes a data reception unit 17, a Fourier transform unit 18, a magnetic field vector calculation unit 19, and a position / orientation calculation unit 20. Yes. The magnetic field detection unit 11 includes the azimuth angle sensor 10 and the data transmission unit 16 as described above.

  The azimuth sensor 10 includes a three-axis magnetic sensor including an x-axis magnetic sensor 10a, a y-axis magnetic sensor 10b, and a z-axis magnetic sensor 10c, and a magnetic sensor with a selected axis selected by selecting the three-axis magnetic sensor. A multiplexer unit 12 for acquiring an output signal from the magnetic sensor, a magnetic sensor driving unit 13 for driving the magnetic sensor via the multiplexer unit 12, a signal amplifying unit 14 for amplifying the output signal from the multiplexer unit 12, and the signal amplification The A / D converter 15 is configured to A / D convert the amplified signal from the unit 14 and output it to the data transmitter 16. The data transmission unit 16 transmits the signal converted by the A / D conversion unit 15 to the calculation unit 4.

  With such a configuration, the magnetic sensor driving unit 13 drives the magnetic sensors 10 a to 10 c via the multiplexer unit 12. The multiplexer unit 12 selects the magnetic sensor of the axis to be measured. The signal of the magnetic sensor on the selected axis is amplified to an appropriate magnitude by the signal amplifier 14 and converted from an analog signal to a digital signal by the A / D converter 15. The digitized signal is transmitted from the data transmission unit 16 to the calculation unit 4 as magnetic data.

  In the calculation unit 4, the data reception unit 17 receives magnetic data from the data transmission unit 16 of the magnetic field detection unit 11 and sends it to the Fourier transform unit 18. The Fourier transform unit 18 receives a desired amount from the data reception unit 17 (for example, when measurement is performed at a sampling frequency of 128 Hz, if the frequency resolution of 1 Hz is necessary, 128 data amounts are obtained). After obtaining the magnetic data, the FFT operation is performed on them, and the signal measured by the magnetic sensor of each axis in each frequency component of the alternating magnetic field generated from each coil (the angular frequency components are Mω and Nω, respectively) The intensity (amplitude) and phase are calculated and sent to the magnetic field vector calculation unit 19.

The magnetic field vector calculation unit 19 calculates the magnetic field vector from each coil by the method described in Japanese Patent Application No. 2007-30803 from the amplitude and phase of each frequency component measured by the magnetic sensor of each axis from the Fourier transform unit 18. To do. Here, the process of calculating the magnetic field vector in the magnetic field vector calculation unit 19 will be briefly described. Here, only the calculation of the magnetic field vector m _xi from the coil X _i will be described.

As shown in (Expression 1) and (Expression 2) described above, the generated magnetic field B _xi from the coil X _i has first and second frequency components Mω and Nω whose phases can be expressed as Θ and Φ. To do. The desired amount of magnetic data measured from the x-axis magnetic sensor is subjected to an FFT operation, and the amplitude and phase of these frequency components are represented by A_x (Mω), θ_x (Mω), φ_x (Nω) (where the amplitude is the first 1), the sign of the amplitude (representing the relationship between the positive direction of the x-axis sensor and the positive direction of _Bxi ) can be determined as follows.

First, a numerical value η_x (sign determination value) for determining the sign of the amplitude is defined by the following equation.
η_x = M × φ_x (Nω) −N × θ_x (Mω) (where 0 ≦ η_x <2π) (Equation 3)
If the positive direction of the magnetic sensor and the positive direction of the generated magnetic field match,
θ_x (Mω) = Mωt + Ω _θ− 2πp (Expression 4)
φ_x (Nω) = Nωt + Ω _φ− 2πq (Expression 5)
(Where p and q are integers for setting 0 ≦ θ_x (Mω), φ_x (Nω) <2π), and from Equation (3), η_x = (MΩ _θ− NΩ _φ ) + 2π (Np−Mq) −2πν ... (Formula 6)
(Where ν is an integer for making 0 ≦ η_x <2π).

On the other hand, if the positive direction of the magnetic sensor does not match the positive direction of the generated magnetic field,
θ_x (Mω) = Mωt + Ω _θ + π-2πp ′ (Expression 7)
φ_x (Nω) = Nωt + Ω _φ + π−2πq ′ (Expression 8)
(Where p ′ and q ′ are integers for setting 0 ≦ θ_x (Mω), φ_x (Nω) <2π),
η_x = (MΩ _θ− NΩ _φ ) + π (MN) + 2π (Np′−Mq ′) − 2πν ′ (Equation 9)
Where ν ′ is an integer for making 0 ≦ η_x <2π. The amplitude sign determination values of (Expression 6) and (Expression 9) are different by π (MN). From this, the relationship between the positive direction of the magnetic sensor and the positive direction of the generated magnetic field can be determined.

Here, if MΩ _θ −NΩ _φ = π / 2, and M and N are positive integers that are even and different from each other, the amplitude A_x (Mω) of B _xi measured by the x-axis magnetic sensor is a positive or negative sign. Amplitude with
A_x ′ (Mω) = A_x (Mω) × Sign (Sin (η_x)) (Equation 10)
(Where Sign (k) represents the sign of k and is -1 or +1). It should be noted that MΩ _θ −NΩ _φ = π / 2 is not necessary if the Sign function is determined so that an appropriate code can be calculated by η_x.

In the same way, the signed amplitude detected by the magnetic sensors of the y-axis and z-axis is obtained from the magnetic field B _xi , and these are A_y ′ (Mω) and A_z ′ (Mω). It can be obtained as a magnetic field vector m _xi representing the magnitude and direction of B _xi at the position measured by the azimuth sensor 10. That is,
m _xi = (A_x ′ (Mω), A_y ′ (Mω), A_z ′ (Mω)) ^T (Expression 11)
(A ^T represents transposition of A). Similarly, magnetic field vectors can be calculated for the magnetic fields from other coils.

Coils X ₁ ~ coils X _l et of the magnetic field vector _{m x1, m x2, ... m} xl coils Y ₁ ~ coils Y _m et a magnetic field vector m _y1, m _y2, ... m to _ym. These magnetic field vectors are output to the position / orientation calculation unit 20. These magnetic field vectors are expressed as vectors in the terminal coordinate system.

  The position / orientation calculation unit 20 calculates position data (position information) and attitude data (attitude information) representing the position and orientation from the magnetic field vector from the magnetic field vector calculation unit 19 as follows.

When the information terminal 3 is at the Xg axis coordinate X _i , in the measured magnetic field vector from the Xg axis coil group 1b, m _xi-1 , m _xi and m _{xi + 1} are larger than the magnitude of the magnetic field vector from the other coils. And m _xi has the largest size. When | m _xi | (| x | represents the absolute value of x) is maximum,
R _{i-1, i} = | m _xi-1 | / | m _xi | (Formula 12)
R _{i + 1, i} = | m _{xi + 1} | / | m _xi | (Formula 13)
As
R _{i-1, i} = R _{i + 1, i} (Formula 14)
Then, it can be determined as the Xg coordinate X _i on the central axis of the coil X _i . Further, if R _{i−1, i} <R _{i + 1, i} , the coil is between coil X _i and coil X _{i + 1} . If R _{i-1, i} > R _{i + 1, i} , the coil is between coil X _i-1 and coil X _i . Alternatively, if it deviates from the relationship of (Equation 14), a certain threshold R _th is determined
1−R _th <R _{i−1, i} / R _{i + 1, i} <1 + R _th (Formula 15)
Xg coordinates may be determined as X _i when the relationship is satisfied. That is, the magnetic field vector m _xi having the maximum magnitude is detected from each coil group, and the ratio between the magnitude and the magnitude of the magnetic field from the next adjacent coil is used to determine the Xg axis coil group 1b. The position coordinates of the information terminal 3 can be detected. Further, the coil X _i generating the maximum magnetic field vector m _xi is in the direction of the shortest distance from the information terminal 3 in the Xg axis coil group 1b. In a similar manner, to detect the magnetic field vector m _yj the size relative Yg axis coil group 2b is maximized, can detect Yg coordinate Y _j. Note that the Zg axis coordinates, to determine the position coordinates in a magnetic field vector from Xg-axis coil group 1b, since it is understood that a coil of which column, Zg coordinate Z _k detection is made. In this way, the position data (X _i , Y _j , Z _k ) of the information terminal 3 can be calculated. That is, by specifying the magnetic field vector having the maximum magnitude, the coil of the shortest distance of each magnetic field generation unit from the current position of the information terminal 3 is specified, and the directional relationship between the corresponding coil and the information terminal 3 is specified. Thus, the position information is calculated.

Further, an inner product between magnetic field vectors may be used. The inner product is zero between the magnetic field vectors on the central axis of each coil. That, Xg-axis coil group 1b, respectively m _x or the magnetic field vector from the Yg axis coil group 2b, when the m _{y,
m x · m y = 0 ···} ( Equation 16)
The position data may be calculated by detecting the combination m _xi and my _yj of the magnetic field vectors. That is, the coil of each magnetic field generation unit that generates a magnetic field in which the angle between the magnetic fields is a predetermined value (90 degrees) is specified from the desired inner product (Formula 16) of the magnetic field vectors, and the corresponding coil and information terminal By specifying the directional relationship 3, the position information is calculated.

And the attitude | position data of the information terminal 3 are computable as follows.
The detected magnetic field vector m _xi terminal coordinate system, orthonormal basis vectors e _x representing the absolute coordinate system from m _yj, e _y, e _z can be expressed as follows.
e _x = m _xi / | m _xi | (Expression 17)
e _y = m _yj / | m _yj | (Expression 18)
_{e z = m xi × m y} / | m xi × m yj | ··· ( 19)

Here, x is an operator representing an outer product operation between vectors. When representing the _{X = (e x e y e} z) in 3 3 matrix, an arbitrary vector r _g of any of the absolute coordinate system is represented as a vector r of the terminal coordinate system by the following conversion Will be.
Xr _g = r (Expression 20)

That is, from the terminal coordinate system vector r,
r _g = X ⁻¹ r = X ^T r (Equation 21)
As it can be converted into vector r _g in the absolute coordinate system.

While the longitudinal direction of the information terminal 3 (x-axis direction of the terminal coordinate system) is expressed as r _x = (1, 0, 0) ^T, a vector r _xg representing this vector by X ^T the absolute coordinate system = ( Rx, Ry, Rz) If converted into ^T , the angle ψ formed by this longitudinal direction with the Xg axis and the angle α formed with the XgYg plane can be calculated by the following equations.
ψ = tan ⁻¹ (Ry / Rx) (Equation 22)
α = tan ⁻¹ (Rz / (Rx ² + Ry ² ) ^1/2 ) (Equation 23)

  These are attitude data representing the attitude of the information terminal 3 in the longitudinal direction. Similarly, the posture in the short direction or the z-axis direction of the terminal coordinate system can also be expressed.

  FIG. 5 is a flowchart for explaining the operation of the position / orientation detection system according to the first embodiment of the present invention. First, a magnetic field having two different frequencies is generated from each coil of each of the axial coil groups 1a and 2a facing the Xg axis and the Yg axis (step S1). Next, the magnetic field generated from each coil is measured by the azimuth angle sensor 10 having a three-axis magnetic sensor, and magnetic data for each axis is acquired as a digital signal (step S2).

  Next, it is determined whether a desired amount of magnetic data necessary for the FFT operation has been acquired (step S3). If the desired amount of magnetic data required for the FFT calculation has been acquired, the process proceeds to the next step S4, and if the desired amount of magnetic data required for the FFT calculation has not been acquired, the process returns to step S2.

  Next, an FFT operation is performed on the desired amount of magnetic data of each axis obtained to calculate the amplitude and phase of each axis in the frequency component of each magnetic field (step S4). Then, a magnetic field vector from each coil necessary for position and orientation detection representing the magnitude and direction of each magnetic field is calculated from the amplitude and phase of each axis in the frequency component of each magnetic field (step S5).

  Next, the magnetic field vector having the maximum magnitude for each coil group is calculated from the calculated magnetic field vector from each coil (step S6). Then, the position data of the information terminal 3 is calculated by comparing the magnitude of the detected magnetic field vector with the magnitude of the magnetic field vector from the next adjacent coil (step S7). Then, the attitude data of the information terminal 3 is calculated from the magnetic field vector having the maximum magnitude (step S8).

  FIG. 6 is a flowchart for explaining the operation of the position / orientation detection system according to the first embodiment of the present invention shown in FIG. 5, in which steps S6 to S8 are replaced with those using inner products. FIG.

  That is, after step S5 in FIG. 5, a set of two magnetic field vectors for which the inner product is not calculated is selected from each axial coil group from the calculated magnetic field vectors from the respective coils (step S6a). Then, it is determined whether or not the inner product calculated from the selected set of magnetic field vectors matches a desired inner product (0 in the embodiment because the Xg axis and Yg axis are orthogonal) (step S7a).

  If they do not match, the process returns to step S6a. If they match, the process proceeds to step S8a. Then, the current position data of the information terminal 3 is calculated from the combination of magnetic field vectors matching the desired inner product (step S8a). Then, the attitude data of the information terminal 3 is calculated from the combination of the magnetic field vectors (step S9a).

  As described above, the magnetic field vector having the maximum magnitude is detected, and the generated magnetic field coil is generated, or the magnetic field having the predetermined angle (90 degrees) between the magnetic fields is generated by the inner product. The position data and orientation data could be calculated by specifying the coil of each magnetic field generation unit to be identified and specifying the directional relationship between each coil and the magnetic field detection unit 11 (azimuth angle sensor 10). The calculated data is sent to the data display unit 5, and the position and orientation of the information terminal 3 are displayed to the user.

In addition, even if the angle formed by the two magnetic field generation units is not necessarily 90 degrees, the present invention can be used by a similar procedure.
The first embodiment can also be applied to position and orientation detection on a two-dimensional plane. In that case, an azimuth angle sensor having a biaxial magnetic sensor may be used.

[Example 2]
FIG. 7 is an overall configuration diagram showing Embodiment 2 of the position / orientation detection system of the present invention. This position and orientation detection system includes a magnetic field generator 30 a, a magnetic field generator 30 b, an information terminal 3 having a magnetic field detector 11, an arithmetic unit 4, and a data display unit 5.

  The magnetic field generation unit (first magnetic field generation unit) 30a includes a coil power supply 31a, a coil magnetic field generation direction change unit 32a, and a coil 33a. Similarly, the magnetic field generation unit (second magnetic field generation unit) 30b includes The coil power supply 31b, the coil magnetic field generation direction changing unit 32b, and the coil 33b are included. The magnetic field generator 30a generates at least one alternating magnetic field having directivity. The magnetic field generator 30b generates at least one AC magnetic field having a directivity different from that of the magnetic field generator 30a and a frequency different from the frequency of the magnetic field generated by the magnetic field generator 30a. Each magnetic field generator is composed of a magnetic field generating coil that can independently change the magnetic field generation direction.

  FIG. 8 is a block diagram showing a specific configuration of the position / orientation detection apparatus according to the second embodiment of the position / orientation detection system of the present invention. This position / orientation detection apparatus includes a magnetic field detection unit 11, a calculation unit 4, and magnetic field generation units 30a and 30b. The magnetic field generators 30a and 30b are as shown in FIG.

The magnetic field detection unit 11 includes an azimuth angle sensor 10 and a data transmission unit 16. The calculation unit 4 includes a data reception unit 17, a Fourier transform unit 18, a magnetic field vector calculation unit 19, and a position / orientation calculation unit 20. FIG. 9 is a diagram showing the directions of the magnetic fields B _A and B _B from the coils (coils 33a and 33b) and the arrangement of the information terminal 3. A right-handed coordinate system XgYgZg coordinate system (referred to as an absolute coordinate system, where the Xg axis, the Yg axis, and the Zg axis are orthogonal to each other) is defined, and the coil 33a is positioned at the position coordinate (0, 0, 0). 33b is disposed on the position coordinates _{(X b, Y b, 0} ). In FIG. 9, the magnetic fields B _A and B _B from the respective coils are directed to the direction position coordinates (X _p , Y _p , Z _p ) where the information terminal 3 exists. Further, a terminal coordinate system is defined for the information terminal 3 as in the first embodiment, and the information terminal 3 is in an arbitrary posture.

  The coil 33a can change the direction in which the magnetic field is generated from the output of the coil magnetic field generation direction changing unit 32a. For example, a mechanical movable part is provided, and the orientation of the coil is changed to change the magnetic field generation direction. A magnetic field can be generated by the current supplied from the coil power supply 31a in the changed direction. Similarly, the direction in which the magnetic field is generated can be changed from the output of the coil magnetic field generation direction changing unit 32b. A magnetic field can be generated by the current supplied from the coil power supply 31b in the changed direction. The coils 33a and 33b generate a magnetic field having the strongest directivity on the central axis of the magnetic field generation surface. For example, a spiral coil.

The coil power supplies 31a and 31b supply two alternating currents (or voltages) having different frequencies to the coils 33a and 33b in a superimposed manner. The alternating current (or voltage) from the coil power supply 31a is obtained by using M _A ω _A and N _A ω, which are positive integers M _A and N _A with different angular frequencies of the first and second frequencies. it is _a (frequency ratio M _a as a minimum integer ratio: is N _a). Similarly, an alternating current (or voltage) having angular frequencies of M _B ω _B and N _B ω _B is supplied from the coil power supply 31b to the coil 33b. These angular frequencies are different from each other.

Then, each coil can generate a magnetic field by supplying a current from the power supply, the magnetic field B _A of the coil 33a, the magnetic field B _B from the coils 33b, respectively, M _A omega _A and N _{A ω A,} M _It has an angular frequency of a combination of _B ω _B and N _B ω _B.

As for the phase relationship between the frequency components B _A and B _B , for example, the phases Θ _A and Φ _A of the first and second frequency components of B _A are expressed as follows.
Θ _A = M _A ω _A t + Ω _θA (24)
_{Φ A = N A ω A t} + Ω φA ··· (25)
(It is assumed that the first frequency component and the second frequency component are respectively Ω _θA and Ω _φA at time t = 0). It shall be expressed in the same format applies to B _B.

  The coil magnetic field generation direction changing unit 32 a changes the direction in which the coil 33 a generates a magnetic field from the output of the position and orientation calculation unit 20 of the calculation unit 4. The coil magnetic field generation direction changing unit 32 b changes the direction in which the coil 33 b generates a magnetic field from the output of the position and orientation calculation unit 20 of the calculation unit 4.

  The data display unit 5 displays the position and orientation of the information terminal 3 to the user from the output of the calculation unit 4. Since the configuration and operation of the magnetic field detector 11 are the same as those in the first embodiment, description thereof is omitted.

In the calculation unit 4, the data reception unit 17 receives magnetic data from the data transmission unit 16 of the magnetic field detection unit 11 and sends it to the Fourier transform unit 18. The Fourier transform unit 18 is a three-axis magnetic sensor of a desired amount from the data reception unit 17 (for example, when measurement is performed at a sampling frequency of 128 Hz, if the frequency resolution of 1 Hz is required, the data amount is 128). After the magnetic data is acquired, the FFT operation is performed on them, and the AC magnetic field generated from each coil, the frequency components of B _A and B _B (the angular frequency components are M _A ω _A and N _A ω, respectively). _The signal intensity (amplitude) and phase measured by the magnetic sensor of each axis in _A , M _B ω _B and N _B ω _B ) are calculated and sent to the magnetic field vector calculation unit 19.

The magnetic field vector calculation unit 19 calculates the angular frequency from the amplitude and phase of each frequency component measured by the magnetic sensor of each axis from the Fourier transform unit 18 according to the method described in Japanese Patent Application No. 2007-30803 (or Example 1). Calculates magnetic field vectors of frequency components M _A ω _A and M _B ω _B , m _a and m _b , respectively. These are at the position where the azimuth sensor 10 is measured, B _A, that the angular frequency of B _B is representing the magnitude and direction of the magnetic field component of the _{M A ω A, M B ω} B as a vector of the terminal coordinate system It has become.

Then, the position / orientation calculation unit 20 calculates the attitude data (position information) and position data (attitude information) of the information terminal 3 (in the absolute coordinate system) from the magnetic field vectors m _a and m _b calculated by the magnetic field vector calculation unit 19. Is calculated and sent to the data display unit 5.

Here, an example of a procedure in which the position / orientation calculation unit 20 calculates the attitude data and position data of the information terminal 3 will be described. First, position data of the information terminal 3 is obtained.
In the first magnetic field generation direction of each coil (coils 33a, 33b), the magnetic field vectors m _a and m _b of the terminal coordinate system calculated by the magnetic field vector calculation unit 19 are first held, and then the magnetic field generation direction of each coil is determined. After the change, the measurement is performed again to calculate the magnetic field vectors m _a ′ and m _b ′. When this operation is repeated and several magnetic field vectors for several magnetic field generation directions are obtained, there are magnetic field vectors m _max and m _bmax in which the absolute value (the magnitude of the vector) has a maximum. Then, the direction of the magnetic field vector indicating the maximum value is the direction that is the shortest distance between each coil and the information terminal 3, and the direction of the magnetic field generated from each coil coincides with the direction in which the information terminal 3 is present. That is, the directional relationship between the coils (coils 33a and 33b) and the magnetic field detector 11 (azimuth angle sensor 10) of each magnetic field generator is specified.

The angle obtained by projecting the magnetic fields B _Amax and B _Bmax showing the maximum values onto the XgYg plane is α _i and the angle between the Xg Yg axis and −β _i Subscript to distinguish it as B)
B _Amax = B _A (cos α _A cos β _A , sin α _A cos β _A , −sin β _A ) (Equation 26)
B _Bmax = B _B (cos α _B cos β _B , sin α _B cos β _B , -sin β _B ) (Equation 27)
Can be expressed.

  When the triangles connecting the coils 33a and 33b formed by these vectors and the information terminal 3 are projected onto the XgZg plane and the YgZg plane, each angle of the triangle formed by each plane can be calculated, and the position coordinates of each coil are known. The position of the information terminal 3 can be determined.

FIG. 10 is an explanatory diagram of triangles formed when the magnetic fields B _Amax and B _Bmax from each coil are projected onto the XgZg plane. On the XgZg plane, the positions of the coils 33a and 33b and the information terminal 3 are projected onto the A ′ point (0, 0), the B ′ point (X _B , 0), and the P ′ point (X _p , Z _p ) to form a triangle. I am doing. The vectors B _A ′ and B _B ′ obtained by projecting B _Amax and B _Bmax onto the XgYg plane are on the line segments A′P and B′P. Assuming that the angles viewed clockwise from the Zg axis to B _A ′ and B _B ′ are σ _A ′ and σ _B ′, respectively, the triangle interior angles ∠P′A′B ′ and ∠P′B′A ′ are Since it is obtained from the x component and the z component of (Equation 26) and (Equation 27),
σ _A '= ∠P'A'B'-3π / 2 (Formula 28)
σ _B '= π / 2−∠P′B′A ′ (Expression 29)
Thus, X _p and Z _p at the point P ′ can be calculated as follows.
X _p = (− Z _A + Z _B + X _A tan σ _A ′ −X _B tan σ _B ′) / (tan σ _A ′ −tan σ _B ′) (Equation 30)
Z _p = (− X _A + X _B + Z _A cot σ _A ′ −Z _B cot σ _B ′) / (cot σ _A ′ −cot σ _B ′) (Equation 31)

Here, X _A and Z _A are 0 as the Xg and Zg coordinate values of the A ′ point, and Z _B is 0 as the Zg coordinate of the B ′ point. Similarly, Y _p can be calculated in the same procedure from the triangle projected onto the YZ plane. Thus, the position data (X _p , Y _p , Z _p ) representing the position of the information terminal 3 can be calculated.

Next, attitude data of the information terminal 3 is obtained.
M _A = B _Amax / | B _Amax | (Expression 32)
M _B = B _Bmax / | B _Bmax | (Expression 33)
Then, these are vectors indicating the generation direction of the magnetic field, and form a first-order independent orthonormal basis. _A transformation matrix H from the M _A M _B coordinate system represented by the orthonormal basis to the ground coordinate system is obtained, and the vector r _H of the M _A M _B coordinate system is changed to a vector r _g of an arbitrary absolute coordinate system. Is converted.
Hr _H = r _g (Formula 34)

The terminal coordinate system measured magnetic field vector m _amax, m _bmax likewise can form an orthonormal basis, it is demanded transformation matrix L from M _A M _B coordinate system to the terminal coordinate system, the vector r _H Is converted to a vector r _p in the terminal coordinate system.
Lr _H = r _p (Formula 35)

The matrix L has an inverse matrix,
HL ⁻¹ r _p = r _g (Formula 36)
Can be converted from the terminal coordinate system to the ground coordinate system. Therefore, the attitude data of the information terminal 3 can be calculated in the same manner as in the first embodiment.

  As described above, position data and posture data could be calculated. The calculated data is sent to the data display unit 5 to display the position of the information terminal 3 to the user.

  FIG. 11 is a flowchart for explaining the operation of the position / orientation detection system according to the second embodiment of the present invention. That is, the initial magnetic field generation direction of each coil is determined (step S1). A magnetic field having two different frequencies is generated from each coil (step S2). Next, the magnetic field generated from each coil is measured by the azimuth sensor 10 having a triaxial magnetic sensor, and magnetic data for each axis is acquired as a digital signal (step S3).

  Next, it is determined whether a desired amount of magnetic data necessary for the FFT operation has been acquired (step S4). If the desired amount of magnetic data required for the FFT calculation has been acquired, the process proceeds to the next step S5, and if the desired amount of magnetic data required for the FFT calculation has not been acquired, the process returns to step S3.

  Next, an FFT operation is performed on the acquired desired amount of magnetic data of each axis, and the amplitude and phase of each axis in the frequency component of each magnetic field are calculated (step S5). Then, a magnetic field vector representing the magnitude and direction of each magnetic field is calculated from the amplitude and phase of each axis in the frequency component of each magnetic field (step S6). Then, it is determined whether a direction in which the magnitude of the magnetic field vector from each coil is maximized exists in all the coils between the initial magnetic field generation direction of each coil and the current setting direction (step S7). .

  If the maximum direction does not exist in all the coils, the next magnetic field generation direction is changed to the coil in which the maximum direction does not exist (step S8), and the process returns to (step S3). When the maximum direction exists in all the coils, the process proceeds to step S9. Then, the position data of the information terminal 3 is calculated from the magnetic field generation direction of each coil in which the magnitude of each magnetic field vector is maximized (step S9). Attitude data of the information terminal 3 is calculated from each magnetic field vector and the magnetic field generation direction of each coil (step S10).

  According to the procedure as described above, the direction of the magnetic field generation from the two magnetic field generation units 30a and 30b has directivity, so that the direction of the coil of each magnetic field generation unit (30a and 30b) is specified, and each coil and the magnetic field detection are detected. By specifying the directional relationship of the unit 11 (azimuth angle sensor 10), the position where the information terminal 3 exists and the attitude of the information terminal 3 could be obtained. The second embodiment can also be applied to position and orientation detection on a two-dimensional plane. In that case, an azimuth angle sensor having a biaxial magnetic sensor may be used. In the present invention, a magnetic field having directivity refers to a magnetic field having a high intensity in a specific direction.

  As described above, according to the present invention, by calculating a plurality of magnetic field generators having different frequencies and having directivity, an arithmetic unit is obtained from a signal detected by a magnetic field detector having a plurality of magnetic sensors mounted on an information terminal. , It is possible to calculate the directional relationship between the magnetic field detector and the plurality of magnetic field generators and detect the position and orientation of the information terminal.

  Further, since it is known that the magnetic field to be detected has a specific frequency, it is not affected by other frequency components, and can be identified even in a magnetic field environment having an AC magnetic field or a noise magnetic field of other frequencies. Furthermore, since the magnetic field to be generated includes only frequency components whose frequency ratio represented by the smallest integer is even to odd and the phase is known, the configuration of magnetic field generation is simple, and the measured signal is frequency-converted. Since it is not necessary to use a filter that separates each band, the degree of freedom in frequency selection is high. In addition, the frequency can be freely selected after the system is configured.

  Further, the fact that the filter for separating the frequency band for each measurement axis in the magnetic field detection unit is not necessary can be realized as a small and inexpensive magnetic sensor with a small circuit scale. Moreover, since it is not necessary to synchronize the generation and measurement of the magnetic field, the configuration is easy. Once the magnetic field is generated, measurement can be started at an arbitrary timing, and then continuous measurement is possible.

  The present invention is not limited to the above-described embodiments, and design changes within a range not departing from the gist of the present invention are included in the present invention.

It is a whole lineblock diagram showing Example 1 of a position and orientation detection system of the present invention. Xg-axis coil group in a certain Zg coordinates (Zg = Z _k and planes), is an explanatory view of an arrangement of a Yg axis coil group arrangement and the information terminal. It is explanatory drawing about the coordinate system of an information terminal. 1 is a block diagram illustrating a specific configuration of a position / orientation detection apparatus according to a first embodiment of the position / orientation detection system of the present invention. FIG. It is a figure which shows the flowchart for demonstrating operation | movement of Example 1 of the position and orientation detection system of this invention. In the flowchart for demonstrating operation | movement of Example 1 of the position and orientation detection system of this invention shown in FIG. 5, it is a figure which shows a procedure at the time of replacing step S6-step S8 with the thing using an inner product in a flowchart. is there. It is a whole block diagram which shows Example 2 of the position and orientation detection system of this invention. It is a concrete block diagram of the position and orientation detection apparatus of the second embodiment in the position and orientation detection system of the present invention. The direction of the magnetic field B _A, B _B from each coil is a diagram showing the arrangement of an information terminal. It is explanatory drawing of the triangle formed when the magnetic fields B _Amax and B _Bmax from each coil are projected onto the XgZg plane. It is a figure which shows the flowchart for demonstrating operation | movement of Example 2 of the position and orientation detection system of this invention. It is a figure which shows the mode of the output signal measured when the positive direction of a magnetic sensor is the same direction (b) with respect to the incident direction of a sinusoidal alternating magnetic field.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Xg axis direction magnetic field generation part 1a Xg axis coil power supply group 1b Xg axis coil group 2 Yg axis direction magnetic field generation part 2a Yg axis coil power supply group 2b Yg axis coil group 3 Information terminal 4 Calculation part 5 Data display part 10 Azimuth angle sensor 10a x-axis magnetic sensor 10b y-axis magnetic sensor 10c z-axis magnetic sensor 11 magnetic field detection unit 12 multiplexer unit 13 magnetic sensor drive unit 14 signal amplification unit 15 A / D conversion unit 16 data transmission unit 17 data reception unit 18 Fourier transform unit 19 Magnetic field vector calculation unit 20 Position / orientation calculation unit 30a, 30b Magnetic field generation unit 31a, 31b Coil power supply 32a, 32b Coil magnetic field generation direction change unit 33a, 33b Coil

Claims (21)

A first magnetic field generator for generating at least one alternating magnetic field having directivity;
A second magnetic field generator for generating at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and having a frequency different from the frequency of the magnetic field generated by the first magnetic field generator;
A magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. It equipped with a door,
The first magnetic field generation unit is arranged to have directivity in a first direction, and includes at least one magnetic field generation coil that generates alternating magnetic fields having different frequencies, and the second magnetic field generation unit includes: It is arranged so as to have directivity in the second direction, and includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies.
The calculation unit specifies which of the plurality of magnetic field generation coils has the maximum intensity in the first and second magnetic field generation units, and the corresponding magnetic field generation coil, the magnetic field detection unit, A position and orientation detection system that calculates position information and orientation information of the magnetic field detection unit by specifying a directional relationship between The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation unit, the first and second magnetic field generation units specify which of the plurality of magnetic field generation coils has the maximum intensity, and the corresponding magnetic field by identifying the generating coil the direction relationship of the magnetic field detecting unit, the position and orientation of claim 1, characterized in that a position and orientation calculation unit for calculating position information and attitude information of the magnetic field detecting unit Detection system. A first magnetic field generator for generating at least one alternating magnetic field having directivity;
A second magnetic field generator for generating at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and having a frequency different from the frequency of the magnetic field generated by the first magnetic field generator;
A magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. And
The first magnetic field generation unit is arranged to have directivity in a first direction, and includes at least one magnetic field generation coil that generates alternating magnetic fields having different frequencies, and the second magnetic field generation unit includes: It is arranged so as to have directivity in the second direction, and includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies.
The calculation unit identifies whether the angle between the magnetic fields generated from the plurality of magnetic field generation coils in the first and second magnetic field generation units is a predetermined value, and the corresponding magnetic field generation coil, the magnetic field detection unit, of by identifying directional relationship, position postures detection system that and calculates the position information and attitude information of the magnetic field detecting unit. The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation unit, the first and second magnetic field generation units specify whether the angle between the magnetic fields generated from the plurality of magnetic field generation coils is a predetermined value, and the corresponding magnetic field The position / orientation according to claim 3 , further comprising: a position / orientation calculation unit that calculates position information and attitude information of the magnetic field detection unit by specifying a directional relationship between the generating coil and the magnetic field detection unit. Detection system. A first magnetic field generator for generating at least one alternating magnetic field having directivity;
A second magnetic field generator for generating at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and having a frequency different from the frequency of the magnetic field generated by the first magnetic field generator;
A magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. And
Each of the first and second magnetic field generation units includes a magnetic field generation coil capable of independently changing the generation direction of the magnetic field,
The calculation unit changes the direction of the magnetic field generation coil so that the intensity of the magnetic field generated from each magnetic field generation coil is maximized, and specifies the directional relationship between the magnetic field detection unit and the magnetic field generation coil. , position postures detection system that and calculates the position information and attitude information of the magnetic field detecting unit. The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation unit, the direction of the magnetic field generation coil is changed so that the intensity of the magnetic field generated from each magnetic field generation coil becomes maximum, and the magnetic field detection unit and the magnetic field generation coil The position / orientation detection system according to claim 5 , further comprising: a position / orientation calculation unit that calculates position information and orientation information of the magnetic field detection unit by specifying a directional relationship between The alternating magnetic field, the position and orientation detection system according to any one of claims 1 to 6 phase relationship different frequency components are characterized by a magnetic field are known. A first magnetic field generation step by a first magnetic field generation unit that generates at least one alternating magnetic field having directivity;
A second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. Two magnetic field generation steps;
A magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation step for calculating position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection step. It has a door,
The calculation step includes:
The first magnetic field generation unit including at least one magnetic field generating coil that is arranged to have directivity in the first direction and generates alternating magnetic fields having different frequencies, and has directivity in the second direction. In the second magnetic field generating unit, which is arranged in the second magnetic field generating unit and includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies, it is determined which of the plurality of magnetic field generating coils has the maximum intensity. A position and orientation detection method characterized in that the position information and orientation information of the magnetic field detection unit are calculated by specifying and specifying the directional relationship between the corresponding magnetic field generating coil and the magnetic field detection unit . The calculation step includes:
Based on the output signal of each axis by the magnetic field detection step, a Fourier transform step to calculate the phase and amplitude in the plurality of frequency components in each axis,
Based on the output signal from the Fourier transform step, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation steps from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generation steps based on the amplitude and sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculating step, it is specified which of the plurality of magnetic field generating coils has the maximum intensity in the first and second magnetic field generating steps, and the corresponding coil The position / orientation detection method according to claim 8 , further comprising: a position / orientation calculation step of calculating position information and attitude information of the magnetic field detection unit by specifying a directional relationship between the magnetic field detection unit and the magnetic field detection unit. A first magnetic field generation step by a first magnetic field generation unit that generates at least one alternating magnetic field having directivity;
A second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. Two magnetic field generation steps;
A magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation step for calculating position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection step. And
The calculation step includes:
The first magnetic field generation unit including at least one magnetic field generating coil that is arranged to have directivity in the first direction and generates alternating magnetic fields having different frequencies, and has directivity in the second direction. The angle between the magnetic fields generated from any one of the plurality of magnetic field generating coils in the second magnetic field generating unit that includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies from each other is a predetermined value. and determine whether the corresponding by identifying a direction relationship between the magnetic field generating coil and the magnetic field detecting unit, position postures detected how to and calculates the position information and attitude information of the magnetic field detecting unit. The calculation step includes:
Based on the output signal of each axis by the magnetic field detection step, a Fourier transform step to calculate the phase and amplitude in the plurality of frequency components in each axis,
Based on the output signal from the Fourier transform step, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation steps from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generation steps based on the amplitude and sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation step, it is specified whether the angle between the magnetic fields generated from the plurality of magnetic field generation coils in the first and second magnetic field generation steps is a predetermined value. The position / orientation detection according to claim 10 , further comprising: a position / orientation calculation step of calculating position information and attitude information of the magnetic field detection unit by specifying a directional relationship between the coil to perform and the magnetic field detection unit. Method. A first magnetic field generation step by a first magnetic field generation unit that generates at least one alternating magnetic field having directivity;
A second magnetic field generator that generates at least one alternating magnetic field having a directivity different from that of the first magnetic field generator and a frequency different from the frequency of the magnetic field generated by the first magnetic field generator. Two magnetic field generation steps;
A magnetic field detection step by a magnetic field detection unit having a multi-axis magnetic sensor for detecting a magnetic field generated from the first and second magnetic field generation units;
A calculation step for calculating position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection step. And
The calculation step includes:
The direction of the magnetic field generating coil is changed so that the intensity of the magnetic field generated from the magnetic field generating coil that can independently change the direction of generation of the magnetic field is maximized, and the directional relationship between the magnetic field detector and the magnetic field generating coil is changed. by identifying, you and calculates the position information and attitude information of the magnetic field detecting unit position postures detection method. The calculation step includes:
Based on the output signal of each axis by the magnetic field detection step, a Fourier transform step to calculate the phase and amplitude in the plurality of frequency components in each axis,
Based on the output signal from the Fourier transform step, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation steps from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generation steps based on the amplitude and sign of each axis based on the magnetic field from the first and second magnetic field generation steps. A magnetic field vector calculating step for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation step, the magnetic field generating coil and the magnetic field generating coil are changed by changing the direction of the magnetic field generating coil so that the intensity of the magnetic field generated from each magnetic field generating coil is maximized. The position / orientation detection method according to claim 12 , further comprising: a position / orientation calculation step of calculating position information and attitude information of the magnetic field detection unit by specifying the directional relationship. 14. The position / orientation detection method according to claim 8 , wherein the alternating magnetic field is a magnetic field in which a phase relationship among different frequency components is known. A first magnetic field generation unit that generates at least one alternating magnetic field having directivity, and a frequency of the magnetic field generated by the first magnetic field generation unit that is different from the first magnetic field generation unit. A magnetic field detector having a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generator that generates at least one alternating magnetic field having a different frequency;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. It equipped with a door,
The computing unit is
The first magnetic field generation unit including at least one magnetic field generating coil that is arranged to have directivity in the first direction and generates alternating magnetic fields having different frequencies, and has directivity in the second direction. In the second magnetic field generating unit, which is arranged in the second magnetic field generating unit and includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies, it is determined which of the plurality of magnetic field generating coils has the maximum intensity. A position / orientation detection apparatus characterized in that the position information and the attitude information of the magnetic field detection unit are calculated by specifying and specifying a directional relationship between the corresponding magnetic field generating coil and the magnetic field detection unit . The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on an output signal from the magnetic field vector calculation unit, the first and second magnetic field generation units specify which of the plurality of magnetic field generation coils has the maximum intensity, and the corresponding coil The position and orientation detection apparatus according to claim 15 , further comprising: a position and orientation calculation unit that calculates position information and orientation information of the magnetic field detection unit by specifying a directional relationship between the magnetic field detection unit and the magnetic field detection unit. . A first magnetic field generation unit that generates at least one alternating magnetic field having directivity, and a frequency of the magnetic field generated by the first magnetic field generation unit that is different from the first magnetic field generation unit. A magnetic field detector having a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generator that generates at least one alternating magnetic field having a different frequency;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. And
The computing unit is
The first magnetic field generation unit including at least one magnetic field generating coil that is arranged to have directivity in the first direction and generates alternating magnetic fields having different frequencies, and has directivity in the second direction. The angle between the magnetic fields generated from any one of the plurality of magnetic field generating coils in the second magnetic field generating unit that includes at least one magnetic field generating coil that generates alternating magnetic fields having different frequencies from each other is a predetermined value. and determine whether the corresponding by identifying a direction relationship between the magnetic field generating coil and the magnetic field detecting unit, wherein the magnetic field detecting portion of the position information and the position postures detector you and calculates the attitude information. The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation unit, the first and second magnetic field generation units specify which angle of the magnetic fields generated from the plurality of magnetic field generation coils is a predetermined value, and The position / orientation according to claim 17 , further comprising: a position / orientation calculation unit that calculates position information and attitude information of the magnetic field detection unit by specifying a directional relationship between the coil to be operated and the magnetic field detection unit. Detection device. A first magnetic field generation unit that generates at least one alternating magnetic field having directivity, and a frequency of the magnetic field generated by the first magnetic field generation unit that is different from the first magnetic field generation unit. A magnetic field detector having a multi-axis magnetic sensor for detecting a magnetic field generated from a second magnetic field generator that generates at least one alternating magnetic field having a different frequency;
A calculation unit that calculates position information and posture information of the magnetic field detection unit by specifying a directional relationship between the first and second magnetic field generation units and the magnetic field detection unit from the magnetic field detected by the magnetic field detection unit. And
The computing unit is
The direction of the magnetic field generating coil is changed so that the intensity of the magnetic field generated from the magnetic field generating coil that can independently change the direction of generation of the magnetic field is maximized, and the directional relationship between the magnetic field detecting unit and the magnetic field generating coil is changed. by identifying, you and calculates the position information and attitude information of the magnetic field detecting unit position postures detector. The computing unit is
Based on the output signal of each axis of the magnetic field detection unit, a Fourier transform unit that calculates phases and amplitudes in the plurality of frequency components in each axis;
Based on an output signal from the Fourier transform unit, a sign is calculated for the amplitude of each axis based on the magnetic field from the first and second magnetic field generation units from the phase relationship of the plurality of frequency components of each axis. And the direction and magnitude based on the magnetic field generated from the first and second magnetic field generators from the amplitude and the sign of each axis based on the magnetic fields from the first and second magnetic field generators. A magnetic field vector calculation unit for calculating first and second magnetic field vectors representing
Based on the output signal from the magnetic field vector calculation unit, the direction of the magnetic field generation coil is changed so that the intensity of the magnetic field generated from each magnetic field generation coil becomes maximum, and the magnetic field detection unit and the magnetic field generation coil The position / orientation detection apparatus according to claim 19 , further comprising: a position / orientation calculation unit that calculates position information and attitude information of the magnetic field detection unit by specifying a directional relationship between 21. The position / orientation detection apparatus according to claim 15 , wherein the alternating magnetic field is a magnetic field in which a phase relationship between a plurality of different frequency components is known.

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