JP2015096809A - Position calculation device, position calculation method and position calculation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate a three-dimensional position of a wireless transmission tag with a simple method.SOLUTION: An azimuth information acquisition unit 11 measures an azimuth angle and elevation/depression angle from an imaging position to wireless transmission tags 2A-2D of imaging objects, and a distance information acquisition unit 12 obtains a distance between the imaging position and each of the wireless transmission tags 2A-2D, and simultaneous equations represented by equations of the distance between the imaging position and the wireless transmission tags 2A-2D are solved for three-dimensional position information of the imaging position. Thus, a three-dimensional position of the wireless transmission tags can be estimated.

Description

  The present invention relates to a technique for estimating a three-dimensional position of a target.

  If it is possible to easily estimate the three-dimensional position in a general home, it is possible to grasp the position of the user in the home and provide various services.

  Since the intensity of the radio wave emitted by the wireless transmission tag is attenuated according to the distance in the space, the distance from the wireless transmission tag to the device having the wireless reception function can be measured by the reception intensity of the radio wave. In order to estimate a three-dimensional position rather than a one-dimensional distance, it is necessary to determine the three-dimensional positions of three or more wireless transmission tags.

N. Priyantha, A. Miu, H. Balakrishnan and S. Teller, “The Cricket Compass for Context-aware Mobile Applications”, Proceedings of the 7th Annual International Conference on Mobile Computing and Networking, July 2001, pp.1- 14 Tatsuya Ishihara, Yukihiro Nakamura, Nobuhiro Muto, Yasunobu Abe, “Indoor User and Object Location Estimation for Lifelog Service”, IEICE Technical Report, Life Intelligence and Office Information System, July 2009, pp. 87-92

  To determine the three-dimensional position of the wireless tag, it is necessary to use a special measuring device, measure the room with a measure, etc., or use a sophisticated indoor map to determine the three-dimensional position of the wireless tag. There was a problem that it was difficult to realize in ordinary households.

  As a technique for estimating a three-dimensional position, for example, in Non-Patent Document 1, an ultrasonic receiver whose position is known is arranged on the ceiling at intervals of about 1.2 m square, and the three-dimensional position of a device that transmits ultrasonic waves is measured. A technique has been proposed. However, realization in a general household is not realistic because it takes a great deal of cost to arrange the devices.

  As another example, in Non-Patent Document 2, a wireless transmission tag is installed in the environment, a device having a wireless reception function is moved, and a device having a wireless reception function and a wireless transmission tag are moved using SLAM (Simultaneous Localization And Mapping) technology. A method for simultaneously estimating the three-dimensional positions of the two has been proposed. However, in the method of Non-Patent Document 2, it takes time until the calculation of the three-dimensional position of the wireless transmission tag is converged, and the receiver terminal is displayed in the environment until the calculation of the three-dimensional position is converged. There was room for improvement in the technique.

  The present invention has been made in view of the above, and an object of the present invention is to estimate the three-dimensional position of a wireless transmission tag by a simpler method.

  The position calculation device according to the first aspect of the present invention includes, for each of n (n ≧ 3) targets, azimuth information measuring means for measuring azimuth and elevation angles from different n measurement positions to the target; In each of the n measurement positions, a distance measurement unit that measures a distance to the n target objects, and an equation of a distance between the measurement position and the target object using the azimuth and elevation angles and the distance. And a position information calculating means for calculating the three-dimensional position information of the target by solving the simultaneous equations expressed for the three-dimensional position information of n measurement positions.

  In the position calculation apparatus, the distance measuring unit measures a distance to the target based on a reception intensity of a radio wave output from the target.

  In the position calculation device, the position information calculation unit represents the three-dimensional position information of the measurement position with an initial value and a correction value, and linearizes an expression of a distance between the measurement position and the target with the correction value. The three-dimensional position information of the measurement position is calculated by the Newton method using the approximate expression.

  A position calculation method according to a second aspect of the present invention is a position calculation method by a position calculation device including an azimuth information measurement unit, a distance measurement unit, and a position information calculation unit, and includes n (n ≧ 3) targets. Measuring the azimuth and elevation angle from different n measurement positions to the target, measuring the distance to the n targets at each of the n measurement positions, The three-dimensional position information of the target is obtained by solving the simultaneous equations expressed by the equation of the distance between the measurement position and the target using the azimuth and elevation angles and the distance with respect to the three-dimensional position information of the n measurement positions. And a step of calculating.

  A position calculation program according to a third aspect of the present invention is characterized by operating a computer as each means of the position calculation device.

  According to the present invention, the three-dimensional position of the wireless transmission tag can be estimated by a simpler method.

It is a functional block diagram which shows the structure of the tag position estimation apparatus in this Embodiment. It is a figure which shows the example of the imaging time information stored in the imaging time information storage part. It is a figure which shows the example of the wireless tag position information stored in the wireless tag position information storage part. It is a flowchart which shows the flow of the process in which the tag position estimation apparatus in this Embodiment obtains imaging time information. It is a figure which shows the example of a mode that the user image | photographs a radio | wireless transmission tag, and the image shown on the screen of the video display function of a tag position estimation apparatus. It is a flowchart which shows the flow of the process in which the tag position estimation apparatus in this Embodiment calculates | requires the position of a radio | wireless transmission tag. It is the figure showing the geometric relationship between the radio | wireless transmission tag seen from the user house upper direction, and an imaging | photography position.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a functional block diagram showing the configuration of the tag position estimation apparatus in the present embodiment. The tag position estimation apparatus 1 shown in FIG. 1 includes an orientation information acquisition unit 11, a distance information acquisition unit 12, a wireless tag position information calculation unit 13, a shooting time information storage unit 14, and a wireless tag position information storage unit 15. Each unit included in the tag position estimation apparatus 1 has a camera function, a video display function, an orientation sensor, and a wireless reception function, and is configured by a computer such as a portable terminal including an arithmetic processing device and a storage device. May be executed by a program. This program is stored in a storage device included in the tag position estimation apparatus 1, and can be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or provided through a network.

  The tag position estimation device 1 measures the azimuth and elevation angle from the shooting position to the wireless transmission tags 2A to 2D when the wireless transmission tags 2A to 2D arranged in the user's home are photographed using the tag position estimation device 1. At the same time, the ID signals output from the wireless transmission tags 2A to 2D are received, the distance between the photographing position and the wireless transmission tags 2A to 2D is obtained based on the radio field intensity of the received ID signal, and the wireless transmission is performed from the photographing position. The three-dimensional position information of the wireless transmission tags 2A to 2D is calculated from the azimuth and elevation angles to the tags 2A to 2D and the distance between the imaging position and the wireless transmission tags 2A to 2D. Hereinafter, each part of the tag position estimation apparatus 1 will be described.

  The azimuth information acquisition unit 11 measures the azimuth angle and the elevation angle from the position of the tag position estimation device 1 to each of the wireless transmission tags 2A to 2D. In the present embodiment, by using the camera function, the video display function, and the direction sensor, the user is allowed to photograph the wireless transmission tags 2A to 2D in accordance with the optical center coordinates of the camera. Measure azimuth and elevation.

  The distance information acquisition unit 12 measures the distance from the position (shooting position) where the azimuth information acquisition unit 11 measures the azimuth angle and the elevation angle to each of the wireless transmission tags 2A to 2D. In the present embodiment, the wireless reception function is used to receive the ID signals transmitted by the wireless transmission tags 2A to 2D, and the tag position estimation device 1 and each of the wireless transmission tags 2A to 2D are determined from the radio wave intensity of the ID signal. Find the distance.

  The azimuth and elevation angles from the tag position estimation device 1 measured by the azimuth information acquisition unit 11 to the radio transmission tags 2A to 2D and the tag position estimation device 1 measured by the distance information acquisition unit 12 and the radio transmission tags 2A to 2D Is stored in the shooting time information storage unit 14 for each of the radio transmission tags 2A to 2D shot as shooting time information. FIG. 2 shows an example of the shooting time information stored in the shooting time information storage unit 14. In the shooting time information storage unit 14, for each wireless transmission tag, an ID (photographing tag ID) output by the wireless transmission tag, an azimuth and elevation angle from the position where the wireless transmission tag is captured to the wireless transmission tag, and imaging The distance from the position to each wireless transmission tag is stored. In the figure, the azimuth angle and the elevation angle are expressed in degrees, and the distance to the wireless transmission tag is expressed in centimeters. For wireless transmission tags that have not yet been photographed, Null is stored in photographing information such as azimuth angle, elevation angle, and distance.

  The wireless tag position information calculation unit 13 reads out the shooting time information from the shooting time information storage unit 14, calculates the three-dimensional position information of each of the wireless transmission tags 2 </ b> A to 2 </ b> D, and stores it in the wireless tag position information storage unit 15. FIG. 3 shows an example of the RFID tag position information stored in the RFID tag position information storage unit 15. The wireless tag position information storage unit 15 stores three-dimensional coordinates with a predetermined position as an origin for each wireless transmission tag. In the present embodiment, one of the photographing positions is set as the origin, and expressed in centimeter units.

  Next, processing for obtaining shooting time information will be described.

  FIG. 4 is a flowchart showing a flow of processing in which the tag position estimation apparatus 1 according to the present embodiment obtains shooting time information. The processing shown in the figure is started when the tag position estimation device 1 is activated and no information at the time of photographing exists in any of the wireless transmission tags 2A to 2D.

  First, the azimuth information acquisition unit 11 refers to the shooting time information storage unit 14 to check the wireless transmission tags 2A to 2D in which no shooting time information is recorded, and the wireless transmission tags 2A to 2D in which shooting time information is not recorded. The user is instructed to take a picture (step S11), and waits for the radio outgoing tags 2A to 2D to be taken (step S12).

  FIG. 5A is a diagram illustrating a state where the user captures the wireless transmission tag 2A, and FIG. 5B is a diagram illustrating an example of an image displayed on the screen 3 of the video display function of the tag position estimation device 1. It is. On the screen 3 of the tag position estimation apparatus 1, an instruction field 31 that displays an instruction for the user, two center lines 32 indicating the optical center coordinates of the tag position estimation apparatus 1, and a shooting button 33 are displayed. In the instruction field 31, the radio transmission tag 2 </ b> A to be imaged is described so that the user can understand it, the radio transmission tag 2 </ b> A to be imaged is aligned with the optical center coordinate that is the intersection of the center lines 32, and the image capture button 33 is pressed. To instruct. As a notation example of the wireless transmission tag 2A, an ID signal transmitted by the wireless transmission tags 2A to 2D is described in the wireless transmission tags 2A to 2D, and a method of expressing the ID as “tag 1” or the like, or a wireless transmission tag There is a method in which the colors of 2A to 2D are changed and expressed as “tag red” or the like.

When the shooting button 33 is pressed (YES in step S12), the azimuth information acquisition unit 11 acquires azimuth information (azimuth angle and elevation angle) from the measured value of the azimuth sensor at the time of shooting and the optical axis direction of the camera ( Step S13). When the user photographs the wireless transmission tag 2A with the optical center coordinates, the optical axis of the camera faces the wireless transmission tag 2A. When the measured value of the azimuth sensor is (0, 0) for both the azimuth angle and the elevation angle, if the direction of the optical axis of the camera takes a value of (θ _φcam , θ _ψcam ), the image is taken from the tag position estimation device 1 at the time of shooting. orientation information to the target wireless transmitter tag 2A is a measurement of the azimuth sensor at the time of photographing _(θ φsensing, θ ψsensing) from _{(θ φsensing + θ φcam, θ} ψsensing + θ ψcam) becomes.

  When the azimuth information can be acquired, the distance information acquisition unit 12 receives ID signals from all the wireless transmission tags 2A to 2D (Steps S14 and S15). Whether or not the ID information is received from all the wireless transmission tags 2A to 2D This is determined based on the shooting tag ID in the shooting time information storage unit 14.

  When the ID signals are received from all the wireless transmission tags 2A to 2D, the distance between the tag position estimating device 1 and each of the wireless transmission tags 2A to 2D is obtained from the reception intensity of the ID signal of each of the wireless transmission tags 2A to 2D (step S16). ). The conversion from the radio wave intensity to the distance is determined based on the attenuation characteristics in the space of the radio wave output by the wireless transmission tags 2A to 2D. The direction information to the radio transmission tag 2A to be imaged and the distance to each of the radio transmission tags 2A to 2D are recorded in the imaging information storage unit 14 as imaging information.

  The wireless transmission tags 2A to 2D in which the shooting time information is not recorded are checked (step S17). If there are wireless transmission tags 2A to 2D in which the shooting time information is not recorded (NO in step S17), the process proceeds to step S11. Returning, an instruction for photographing the wireless transmission tags 2A to 2D is issued.

  Next, processing for obtaining the position of the wireless transmission tag will be described.

  FIG. 6 is a flowchart showing a flow of processing in which the tag position estimation apparatus 1 according to the present embodiment obtains the positions of the wireless transmission tags 2A to 2D. The process shown in the figure is started after the shooting time information of all the wireless transmission tags 2A to 2D is recorded by the process shown in FIG.

  The wireless tag position information calculation unit 13 reads the shooting time information from the shooting time information storage unit 14, calculates the three-dimensional position information of each of the wireless transmission tags 2A to 2D (step S21), and the wireless transmission tags 2A to 2D. Is recorded in the RFID tag position information storage unit 15 (step S22). Details of the calculation of the three-dimensional position information of each of the wireless transmission tags 2A to 2D will be described later.

  By obtaining the three-dimensional position information of the wireless transmission tags 2A to 2D arranged in the user's home, the indoor three-dimensional position of the portable terminal of the user in the user's home can be estimated. When labels such as living room and kitchen are attached to the indoor 3D position, the TV is turned on when the user moves to the sofa in the living room, and the recommended cooking menu is displayed when moving to the kitchen. It is possible to perform indoor device control according to the user's indoor three-dimensional position movement, such as turning off light when the user leaves the room, turning on a light when waking up and moving from the bed. In addition, by recording a history of indoor three-dimensional positions of elderly living alone, it can be used for a monitoring system such as estimating a health state viewed from the amount of indoor movement.

  Next, details of the calculation of the three-dimensional position information of the wireless transmission tag will be described.

FIG. 7 is a diagram showing the geometric relationship between the wireless transmission tag and the shooting position as viewed from above the user's home. In the figure, an example is shown in which three wireless transmission tags are taken from three locations. In the figure, T ₁ , T ₂ , and T ₃ indicate the positions of the wireless transmission tags, and C ₁ , C ₂ , and C ₃ indicate the shooting positions at which the T ₁ , T ₂ , and T ₃ wireless transmission tags are captured, respectively. Show. (Θ _φ1 , θ _ψ1 ), (θ _φ2 , θ _ψ2 ), and (θ _φ3 , θ _ψ3 ) are transmitted wirelessly from the imaging positions C ₁ , C ₂ , and C ₃ acquired from the direction sensor at the time of imaging the wireless transmission tag. The azimuth and elevation angles to the tags T ₁ , T ₂ , T ₃ . d ₁₁ , d ₁₂ , and d ₁₃ are distances from the photographing position C ₁ to the wireless transmission tags T ₁ , T ₂ , and T ₃ . Similarly, d ₂₁ , d ₂₂ , and d ₂₃ are distances from the photographing position C ₂ to the wireless transmission tags T ₁ , T ₂ , and T ₃ , and d ₃₁ , d ₃₂ , and d ₃₃ are each from the photographing position C _3. This is the distance to the wireless transmission tags T ₁ , T ₂ , T ₃ .

Here, the symbols shown in FIG. 7 are generalized, and n imaging positions C ₁ , C ₂ for n radio transmission tags T ₁ , T ₂ ,..., T _n satisfying n ≧ 3. ,..., we describe an algorithm for determining the three-dimensional position coordinates of each wireless transmitting tag when taken from C _n.

i places th depression angle elevation and azimuth of the radio transmitting tag T _i at the imaging position C _i from the photographing position C _i obtained upon imaging to radio transmitting tag _{T i (θ φi, θ ψi} ), the photographing position C Let the distance from _i to the wireless transmission tag T _{j be dij} . If the coordinates of C _i are (x _ci , y _ci , z _ci ), the coordinates of T _i are (x _ci + d _ii cos θ _{ψ i} cos θ _{φ i} , y _ci + d _ii cos θ _{ψ i} sin θ _{φ i} , z _ci + d _ii sin θ _{ψ i} ) Become. Thereafter, d _ii cos θ _{ψ i} cos θ _{φ i} , d _ii cos θ _{ψ i} sin θ _{φ i} , and d _ii sin θ _{ψ i} are replaced with X _i , Y _i , and Z _i for _simplicity . X _i , Y _i , and Z _i are actually measured values obtained by photographing. The distance d _ij between the shooting position C _i and the wireless transmission tag T _j can be expressed by the following equation (1).

The distance d _12, d ₁₃ serving as i ≠ j at each distance d _ij imaging position C _i and wireless transmitting tag _{T j, ···, d ij,} ···, for d n _(n-1) Equation (1 ) Is solved for (x _c1 , y _c1 , z _c1 ), (x _c2 , y _c2 , z _c2 ),..., (X _cn , y _cn , z _cn ) The coordinates of the outgoing tags T ₁ , T ₂ ,..., T _n can be obtained.

For (x _c1 , y _c1 , z _c1 ), (x _c2 , y _c2 , z _c2 ),..., (X _cn , y _cn , z _cn ), values are obtained by Newton's method in order to solve simultaneous equations . First, the value of (x _c1 , y _c1 , z _c1 ) is expressed by the following equation (2) using an initial value and a corrected value.

In Expression (2), x ′ _ci , y ′ _ci , and z ′ _ci are initial values, and Δx _ci , Δy _ci , and Δz _ci are correction values.

Here, an approximate expression (3) obtained by linearizing expression (1) with a correction value is considered.

Δd _ij is expressed by the following equation (4) as a difference calculated from the distance d _ij and an initial value.

At this time, ∂d _ij / ∂x _ci , ∂d _ij / ∂x _cj , ∂d _ij / ∂y _ci , cd _ij / ∂y _cj , ∂d _ij / ∂z _ci , ∂d _ij / ∂z _cj The equation (4) is partially differentiated with _respect to each variable x _ci , x _cj , y _ci , y _cj , z _ci , z _cj , and x ′ _ci , y ′ _ci , z ′ _ci , x ′ _cj , y ′, respectively. _cj and z ′ _cj are substituted. From the equations (3) and (4), the following equation (5) can be used.

Assuming that the origin coordinate of the three-dimensional position of the wireless transmission tag is the photographing position C ₁ , (x _c1 , y _c1 , z _c1 ) = (0, 0, 0) · (x ′ _c1 , y ′ _c1 , z ′ _c1 ) = (0,0,0) · (Δx _c1 , Δy _c1 , Δz _c1 ) = (0,0,0). If equation (5) is replaced with ΔD = AΔC, equation (5) can be replaced with the following equation (6) when n = 3.

Further, when n> 3, the following equation (7) can be used as the calculation of ΔC by the least square method.

  From the above equation, the following algorithm is used for sequential calculation to obtain the three-dimensional position coordinates of the wireless transmission tag.

First, an appropriate initial value is set for each (x ′ _ci , y ′ _ci , z ′ _ci ) (step S31).

The value of Δd _{ij and} the value of the matrix A are obtained by equation (4) (step S32).

  ΔC is obtained from equations (6) and (7) (step S33).

In the obtained ΔC, it is determined whether or not each (Δx _ci , Δy _ci , Δz _ci ) is sufficiently small, and if the value is not small enough, each (x ′ _ci , y ′ _ci , z ′ _ci ) has (Δx _ci, [Delta] y _ci, returns to step S32 by adding Delta] z _ci), if the value is sufficiently small _{(x 'ci, y' ci} , z 'ci) to (x _ci, y _ci, and outputting the results as z _ci) The three-dimensional position information of the wireless transmission tags T ₁ , T ₂ ,..., T _n is obtained (step S34).

Subsequently, in order to obtain more accurate three-dimensional position information of the wireless transmission tags T ₁ , T ₂ ,..., T _{n in} the above algorithm, the weighted least square method is applied in the equation (7). Describe the technique.

For distances d ₁₂ , d ₁₃ ,..., D _ij ,..., D _{n (n−1) where} i ≠ j measured between the tag position estimation device and the wireless transmission tag, performs estimation error variance sigma ₁₂ at each distance, sigma _13, put · · ·, sigma _ij, · · ·, in sigma _{n (n-1)} matrix W such as the following equation (8).

By using the following equation (9) when obtaining ΔC in step S33 of the above algorithm using the matrix W, an answer by the weighted least square method considering the error at the time of distance measurement can be derived. It is possible to improve the accuracy of the three-dimensional position information.

  As described above, according to the present embodiment, the azimuth information acquisition unit 11 measures the azimuth and elevation angles from the shooting position to the radio transmission tags 2A to 2D to be shot, and the distance information acquisition unit 12 The distance between the photographing position and each of the wireless transmission tags 2A to 2D is obtained, and the simultaneous equations expressed by the distance between the photographing position and the wireless transmission tags 2A to 2D are solved for the three-dimensional position information of the photographing position. Thus, the three-dimensional position of the wireless transmission tag can be estimated.

  According to the present embodiment, when measuring the azimuth and elevation angle from the shooting position to the wireless transmission tags 2A to 2D, the optical axis direction of the camera function included in the tag position estimation device 1 is used to Thus, it is possible to measure the azimuth angle and the elevation angle with a simple operation of photographing the wireless transmission tags 2A to 2D.

  According to the present embodiment, by using the wireless reception function provided in the tag position estimation device 1, the shooting position and the wireless transmission tags 2A to 2D are based on the radio wave intensity of the ID signals output from the wireless transmission tags 2A to 2D. The distance between can be measured.

  According to the present embodiment, the three-dimensional positions of the wireless transmission tags 2A to 2D are estimated using a smartphone that is a general terminal that is currently widely used, such as a camera function, a video display function, an orientation sensor, and a wireless reception function. can do.

DESCRIPTION OF SYMBOLS 1 ... Tag position estimation apparatus 11 ... Direction information acquisition part 12 ... Distance information acquisition part 13 ... Wireless tag position information calculation part 14 ... Shooting time information storage part 15 ... Wireless tag position information storage part 2A-2D ... Wireless transmission tag 3 ... Screen 31 ... Instruction field 32 ... Center line 33 ... Shooting button

Claims (5)

azimuth information measuring means for measuring azimuth and elevation angles from different n measurement positions to the target for each of n (n ≧ 3) targets;
Distance measuring means for measuring the distance to the n targets at each of the n measurement positions;
The three-dimensional position of the target is solved by solving the simultaneous equations expressed by the equation of the distance between the measurement position and the target using the azimuth and elevation angles and the distance with respect to the three-dimensional position information of the n measurement positions. Position information calculation means for calculating information;
A position calculation device comprising:   2. The position calculating apparatus according to claim 1, wherein the distance measuring unit measures a distance to the target based on a reception intensity of a radio wave output from the target.   The position information calculation means represents the three-dimensional position information of the measurement position with an initial value and a correction value, and uses an approximate expression obtained by linearizing the distance between the measurement position and the target with the correction value. The position calculation apparatus according to claim 1 or 2, wherein three-dimensional position information of the measurement position is calculated by a Newton method. A position calculation method by a position calculation device comprising an azimuth information measurement means, a distance measurement means, and a position information calculation means,
For each of n (n ≧ 3) targets, measuring azimuth and elevation angles from different n measurement positions to the target;
Measuring the distance to the n targets at each of the n measurement positions;
The three-dimensional position of the target is solved by solving the simultaneous equations expressed by the equation of the distance between the measurement position and the target using the azimuth and elevation angles and the distance with respect to the three-dimensional position information of the n measurement positions. Calculating information;
A position calculation method characterized by comprising:   A position calculation program that causes a computer to operate as each unit of the position calculation apparatus according to claim 1.

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