Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/18—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using ultrasonic, sonic, or infrasonic waves
  • G01S5/22—Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
  • G01S15/50—Systems of measurement, based on relative movement of the target
  • G01S15/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
  • G01S15/60—Velocity or trajectory determination systems; Sense-of-movement determination systems wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track

Definitions

• Measurement of 3D coordinates of a subject which transmits waves is useful in various applications.
• an apparatus which is configured to measure 3D coordinates of a transmitter which transmits a discontinuous wave, is generally described.
• the apparatus may include one or more sets of a receiver and a reflector, the receiver being attached asymmetrically to the reflector and being configured to receive a direct wave from the transmitter and diffracted waves thereof, the diffracted waves being diffracted at edges of the reflector, and a processing device configured to process signals received by the one or more receivers.
• an apparatus configured to measure 3D coordinates of a transmitter which transmits a discontinuous wave.
• the apparatus may include one or more sets of a receiver and a reflector, the receiver being attached asymmetrically to the reflector and being configured to receive a direct wave from the transmitter and diffracted waves thereof, the diffracted waves being diffracted at edges of the reflector, and a processing device configured to process signals received by the one or more receivers.
• a method for measuring 3D coordinates of a transmitter may include receiving with one or more sets of a receiver and a reflector a discontinuous wave transmitted by a transmitter, the receiver being attached asymmetrically to the reflector and being configured to receive a direct wave from the transmitter and diffracted waves thereof, the diffracted waves being diffracted at edges of the reflector.
• the method may include processing signals received by the one or more receivers to measure 3D coordinates of the transmitter.
• Fig. 1 is a diagram illustrating a definition of an angle of view
• Fig. 2 is a diagram illustrating an angle of view used to obtain the velocity potential of sound that is radiated by a circular piston vibration surface in an infinite baffle plane;
• Fig. 4 is a diagram illustrating an example apparatus
• Fig. 5A is a diagram illustrating an example of ultrasonic pulses emitted by a transmitter
• Fig. 5B is a diagram illustrating an example of received pulses affected by the diffracted pulses from the reflector
• Fig. 6 is a diagram illustrating the velocity potential response for the apparatus shown in Fig. 4 when a sound source (i.e., a transmitter) is on the microphone aperture axis;
• a sound source i.e., a transmitter
• Fig. 7 is a diagram illustrating the velocity potential response for the apparatus shown in Fig. 4 when a sound source is not on the microphone aperture axis;
• Fig. 8 is a diagram illustrating an example of components of a processing device
• Fig. 9 is a diagram illustrating an example of the respective wave arrival times
• Fig. 10 is a diagram illustrating a
• Fig. 11A is a diagram illustrating a case in which the sound source exists on the shorter end- aperture side
• Fig. 11B is a diagram illustrating a case in which the sound source exists on the longer end- aperture side
• Fig. 12 is a diagram illustrating a relationship used to calculate the 3D-coordinates of the sound source
• Fig. 13 is a diagram illustrating an embodiment of a system
• Fig. 14 is a diagram illustrating an example of an implementation of the system
• Fig. 15 is a flowchart illustrating an example of an operation of the ultrasonic marker
• Fig. 16 is a diagram illustrating an example of a basic configuration of the ultrasonic marker
• Fig. 17 is a diagram illustrating an example of short ultrasonic pulses.
• Fig. 18 is a diagram illustrating an example of an application for which the system may be used.
• x(t) is the sound pressure of a direct wave (pulse) received with a microphone in an anechoic chamber in which the sound pulses are radiated by a sound marker.
• y(t) is the sound pressure received with microphones with strip- shaped (ribbon-shaped) reflectors (see Fig. 4, for example) .
• DFT discrete Fourier transform
• an angle of view ⁇ represents the central angle of a sector that is defined by point P' and the extent of the set of sound sources or
• the velocity potential response is known to be proportional to the angle of view. For a direct wave, its sign remains unchanged; however, for a diffracted wave, its sign is inverted because the wave has been reflected off at the fixed end. As shown in Fig. 2 , it is possible to obtain from the geometry the velocity potential response that is radiated by a circular piston vibration surface in an infinite baffle plane. In the case of Fig. 2, the angle of view ⁇ is given by the following formula:
• Analysis of the direct wave velocity potential reveals that the time width of velocity potential response includes directional information corresponding to the circular aperture.
• Fig. 4 is a diagram illustrating an example apparatus 10 arranged in accordance with at least some embodiments described herein.
• the apparatus 10 may be used to measure 3D coordinates of a transmitter as described hereinafter.
• the transmitter may be configured to transmit a discontinuous wave.
• the discontinuous wave may be a short pulse wave.
• the discontinuous wave may be a short pulse wave.
• the transmitter may transmit one or more ultrasonic pulses
• the transmitter may transmit the discontinuous wave at regular intervals.
• the transmitter may be provided on any mobile object.
• the mobile object may include a robot, a human (a user) , a device possessed by the user, etc.
• the device may be a portable device.
• the device may be a display device which the user wears like eyeglasses.
• the apparatus 10 may include a receiver 100 and a reflector 200.
• the receiver 100 may include a microphone.
• the microphone may be MEMS (Micro Electro Mechanical Systems) microphone or condenser microphone, as shown in Fig. 4.
• the microphone may detect not only a sound wave in the audio-frequency band (30 Hz to 20 kHz) but also a sound wave in the ultrasonic band (20 kHz or higher) .
• the microphone may be asymmetrically attached to the reflector 200.
• the microphone may have an aperture with any shape. For example, the microphone may have a circular aperture as shown in Fig. 4.
• the microphone may be a unidirectional microphone .
• the reflector 200 may be substantially flat.
• the reflector 200 may have an elongate shape.
• the reflector 200 may have a substantially rectangular shape.
• the reflector 200 may be strip-shaped (ribbon-shaped) similar to the ears of many herbivorous animals.
• the reflector 200 may be an independent reflection plate which is configured to be attached to any product.
• the reflector 200 may be a part of a casing or housing of any product.
• the reflector 200 may a part of a casing or housing of a mobile phone or a laptop computer.
• the receiver 100 may be provided at an asymmetrical location with respect to opposite edges of the reflector 200.
• the receiver 100 may be provided at an asymmetrical location with respect to opposite short edges 202, 204 of the rectangular reflector 200, as shown in Fig. 4.
• the receiver 100 may be provided at a symmetrical location with respect to opposite long edges 206, 208 of the rectangular reflector 200, as shown in Fig. 4.
• the reflector 200 may have a hole for receiving sound pressure at the asymmetrical position on the surface thereof.
• the receiver 100 may be provided in the hole formed in the reflector 200.
• Fig. 5A is a diagram illustrating an example of ultrasonic pulses emitted by the transmitter.
• Fig. 5B is a diagram illustrating an example of received pulses affected by the diffracted pulses from the reflector.
• the received pulses may be affected by the diffracted pulses from the reflector 200.
• the pulses emitted by the transmitter may be reflected off at the fixed end (i.e., the edge 202, 204, 206 or 208) of the reflector 200 and diffracted to become inverted sound pressure pulses.
• the receiver 100 may receive a mixture of direct and diffracted pulses, as shown in Fig. 5B.
• Fig. 6 is a diagram illustrating the velocity potential response for the apparatus 10 shown in Fig. 4 when a sound source (i.e., a transmitter) is on the microphone aperture axis.
• a sound source i.e., a transmitter
• a sound marker which may be an example of a transmitter, is a
• the receiver 100 receives two components: a direct wave and a diffracted wave that has a sign inverted by the fixed end reflection at the reflector.
• the point P 2 of the receiver 100 (i.e., the center coordinates of the circular microphone) captures the wave radiated by the point sound source Pi-
• Fig. 6 a case is assumed where the point sound source Pi is on the center axis of the receiver 100 (i.e., on the microphone aperture axis).
• the sound wave that reaches the reflector 200 in propagation time ⁇ consistently forms one or more arc-shaped sets of crossover points between the ellipsoidal surface and the reflector 200.
• inflection points on the inversed velocity potential curve correspond one-to-one to the geometry of the reflector 200, as show by arrows Y2-Y4
• an infection point related to arrow Y3 is generated due to the diffracted wave at the left short edge 202 of the reflector 200 (fixed end) .
• an infection point related to arrow Y4 is generated due to the diffracted wave at the right short edge 204 of the reflector 200 (fixed end).
• Fig. 7 is a diagram illustrating the velocity potential response for the apparatus 10 shown in Fig. 4 when a sound source is not on the microphone aperture axis.
• Fig. 7 shows a case where a straight line drawn from a sound source and vertical to the surface of the reflector 200 has its foot on the surface of the reflector 200.
• the case shown in Fig. 7 has different inflection points from those in Fig. 6, because the propagation path difference is smaller compared with Fig. 6.
• inflection points include information on the relative position of the sound source with respect to the reflector 200.
• the geometric location of the sound source can be uniquely identified. . .
• the apparatus 10 may include a processing device 300.
• the processing device 300 may be
• a signal (see Fig. 5B, for example) received by the receiver 100.
• Fig. 8 is a diagram illustrating an example of components of a processing device 300 arranged in accordance with at least some embodiment described herein .
• the processing device 300 may include an amplifier 302, an A/D converter 304, a deconvolution calculator 306, a propagation time calculator 308 and a 3D-coordinates calculator 310.
• the processing device 300 may also include a command transmitter 312.
• the amplifier 302 may be coupled to the receiver 100.
• the amplifier may be configured to amplify the signal received by the receiver 100. It is noted that if ultrasonic sound marker is used as the transmitter, a high-pass filter (HPF) or a bandpass filter (BPF) may be used to remove environmental noise and extract only the ultrasonic components.
• HPF high-pass filter
• BPF bandpass filter
• the A/D converter 304 may be coupled to the amplifier 302.
• the A/D converter 304 may be
• the deconvolution calculator 306 may be coupled to the A/D converter 304.
• the deconvolution calculator 306 may be configured to deconvolute the digitized signal from the A/D converter 304 to
• the calculation for the velocity potential response may be done with FFT or a deconvolution calculation in the manner mentioned above based on the known information on the direct wave and the received signal.
• FFT may be used to calculate the velocity potential response from the pre-registered direct pulse patterns and the received signal (i.e., the received diffraction pulse signal) .
• the direct pulse patterns of the direct wave from a distant location may be derived based on a transfer function of the transmitter used or observed data.
• the propagation time calculator 308 may be coupled to the deconvolution calculator 306.
• the propagation time calculator 308 may be configured to detect (extract) times of the inflection points (i.e., diffracted wave arrival times) in the velocity
• the propagation time calculator 308 may also calculate time of the direct wave arrival. For example, the propagation time calculator 308 may calculate the direct wave arrival time t 0 and
• the 3D-coordinates calculator 310 may be coupled to the propagation time calculator 308.
• the 3D-coordinates calculator 310 may be configured to calculate 3D-coordinates of the transmitter (i.e., the sound source) based on the times of the inflection points.
• the way of calculating 3D-coordinates of the transmitter may be based on the principle described in connection with Fig. 6 and Fig. 7.
• the command transmitter 312 may be coupled to the propagation time calculator 308.
• the command transmitter 312 may be configured to issue a command to the transmitter (not shown in Fig. 8) to transmit the discontinuous wave.
• the command transmitter 312 may issue the command to the transmitter irregularly or regularly (i.e., at predetermined time intervals).
• the command transmitter 312 may notify the propagation time calculator 308 of the issuance of the command.
• di and d 2 of the reflector 200 are defined as shown in Fig. 10.
• di is a distance between the center of the circular aperture of the receiver 100 and one edge 202 (closer edge with respect to the receiver 100) of the
• d 2 is a distance between the center of the circular aperture of the receiver 100 and another edge 204 (farther edge with respect to the receiver 100) of the reflector 200.
• the distance d 2 may be substantially longer than the distance di .
• the side on which the edge 204 is located with respect to the receiver 100 may be referred to as “longer end-aperture distance side", and the side on which the edge 202 is located with respect to the receiver 100 may be referred to as “shorter end- aperture distance side”.
• Fig. 11A is a diagram illustrating a case in which the sound source exists on the shorter end- aperture side. In this case, the following
• t 0 is the direct wave arrival time
• ti is the first diffracted wave arrival time
• t 2 is the second diffracted wave arrival time. It is noted that the first diffracted wave arrival time ti is related to the diffracted wave at the edge 202, and the second diffracted wave arrival time t 2 is related to the diffracted wave at the edge 204.
• Fig. 11B is a diagram illustrating a case in which the sound source exists on the longer end- aperture side. In this case, the following
• the first diffracted wave arrival time ti is related to the diffracted wave at the edge 204
• the second diffracted wave arrival time t 2 is related to the diffracted wave at the edge 202.
• the 3D-coordinates of the transmitter may be
• the apparatus 10 including two sets 10L, 10R of the receiver 100 and the reflector 200 may be used, as shown in Fig. 12.
• the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may have any orientation.
• the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may be arranged in parallel with respect to each other.
• the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may be arranged in the same plane, as shown in Fig. 12.
• the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may be positioned a specified distance apart.
• the specified distance may be any distance.
• the specified distance may depend on a size of a member (such as a casing of a master unit 500 shown in Fig. 14) on which the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may be provided.
• the reflector 200 of the first set 10L and the reflector 200 of the second set 10R may be
• the coordinate system is assumed where the reflector 200 of the first set 10L and the reflector 200 of the second set 10R are in the x-y plane; the y axis is parallel with longitudinal (vertical) directions of the reflectors 200 of the first and second set 10L,
• the x axis is on the centers of the receivers 100 of the first and second set 10L, 10R; the origin is defined at the midpoint between the reflector 200 of the first set 10L and the reflector 200 of the second set 10R in a (horizontal) direction of the x axis; and the longer end-aperture distance sides are positive in the y axis.
• the respective distances Li R , L 0R , L 2r , L iL , L 0L and Li2L from the unknown coordinates of the sound source (x,y,z) to the known respective coordinates (-h,-di,0), (-h,0,0), (-h,d 2 ,0), (h,-di,0), (h,0,0) and (h,d 2 ,0) can be expressed by the following six equations:
• the distances Li R , L 2R , Li L and L 2L may be derived based on the assumption that the sound source exists on the longer end-aperture side or on the shorter end-aperture side .
• variables x, y and z can be derived from these six equations.
• the second and third variables x, y and z can be derived from these six equations.
• equations in equation No. 7 give the unknown variable y as follows: (equation No. 8)
• equation No. 7 also give the unknown variable x as follows:
• the unknown variable z can be derived by substituting the obtained variables y and x into one of the six equations (see equation No. 7) .
• the 3D-cordinates of the sound source can be derived from these six equations.
• the number of variables merely increases to four which is still less than the number of the equations (i.e., six).
• two sets 10L, 10R of the receiver 100 and the reflector 200 are used; however, the number of the sets is arbitrary. For example, it is possible to use more than three sets so as to increase accuracy. Further, one set of the receiver 100 and the reflector 200 may be used, though additional information is required to identify the 3D-coordinates of the transmitter. The additional information may be obtained in any way.
• the receiver 100 may be provided at an asymmetrical location with respect to opposite short edges 202, 204 and with respect to opposite long edges 206, 208 of the rectangular reflector 200. In this case, the distances from the center of the receiver 100 to the respective edges 202, 204, 206, 208 may differ from each other.
• Fig. 13 is a diagram illustrating an embodiment of a system 20.
• the system 20 may include the apparatus 10 and one or more transmitters 400.
• each transmitter 400 may be configured to transmit a discontinuous wave such as a pulse wave.
• each transmitter 400 may transmit ultrasonic pulses.
• Each transmitter 400 may transmit the discontinuous wave at regular intervals.
• Each transmitter 400 may be provided on any mobile object.
• the mobile object may include a robot, a human (a user) , a device possessed by the user, etc.
• the device may be a display device which the user wears like eyeglasses.
• Each transmitter 400 may be configured to transmit a discontinuous wave such as a pulse wave in response to a demand from the apparatus 10.
• a demand may be transmitted by the command transmitter 312 of the apparatus 10 (see Fig. 8) .
• the demand may be transmitted by any devices other than the apparatus 10.
• the demand may be transmitted at regular
• the demand may be ' transmitted in a time division manner to the
• the apparatus 10 may be configured to measure the 3D coordinates of one or more transmitters 400 as described earlier.
• the system 20 may be used for various applications in which the 3D coordinates of one or more transmitters 400 measured by the apparatus 10 may used to implement any functions or effects.
• Fig. 14 is a diagram illustrating an example of an implementation of the system 20.
• the system 20 may include a master unit 500 and display devices 600.
• the master unit 500 may implement the apparatus 10. Specifically, the first set 10L of the receiver 100 and the reflector 200 may be attached to the left side of the casing of the master unit 500.
• the reflector 200 may be attached to the right side of the casing of the master unit 500.
• the processing device 300 may be embedded in the master unit 500.
• the master unit 500 may use a digital HPF or a digital BPF.
• the master unit 500 may be implemented by an "Ubicomp" terminal configured to broadcast video/image contents.
• terminals with a sound input function such as stereo sound input devices, usually accept stereo sounds.
• microphones or MEMS microphones also detect ultrasonic sound of up to 20 kHz to 60 kHz, because they are usually small and have high resonant frequencies. Thus, this 20 kHz or higher band may be utilized to carry out determining the 3D-coodinates of the sound sources (i.e., transmitters 400). In this case, a small physical modification such as adding reflectors 200 may be necessary.
• the master unit 500 may be configured to provide each user individually with an image effect and/or a sound effect via the respective display devices 600 according to the 3D coordinates of the respective transmitters 400. These processes may be executed by the processing device 300 or other processing device in the master unit 500.
• the display devices 600 may be coupled to the master unit 500 via wireless communication paths.
• the display device 600 may be in a form of goggles which the user can wear.
• the display device 600 may provide the user (who wears it) with an image effect and/or a sound effect.
• the display device 600 may include an ultrasonic marker as the transmitter 400.
• the display device 600 may be numbered according to the respective users.
• the transmitter 400 embodied as the ultrasonic marker may be configured to operate according to Fig. 15. Specifically, at the time of reception of the command, the transmitter 400 may obtain the received command (S1400) .
• the command may be transmitted by the master unit 500.
• the master unit 500 may instruct (i.e., issue commands) the numbered display device 600 of each user to transmit ultrasonic pulses regularly and
• the master unit 500 may use a wired interface, an infrared interface or a wireless interface (ZigBee or Bluetooth, for example) to issue commands. Then, the transmitter 400 may determine whether the obtained command is a pulse transmission command (S1402). If the obtained command is a pulse transmission command, the transmitter 400 may transmit short ultrasonic pulses (S1404). Then, the pulse transmission command (S1402). If the obtained command is a pulse transmission command, the transmitter 400 may transmit short ultrasonic pulses (S1404). Then, the
• transmitter 400 may return to a standby status for the reception of the next command.
• the transmitter 400 embodied as the ultrasonic marker may include buffers and a piezoelectric element, as shown in Fig. 16.
• the short ultrasonic pulses may be emitted by digitally driving the piezoelectric element, as shown in Fig. 16.
• the short ultrasonic pulses may be as shown in Fig. 17.
• two and half driving pulses are used for one emission of the ultrasonic pulses; however, the width of the emitted pulses may be greater due to a transfer function property of the ultrasonic marker.
• the piezoelectric element can be driven with a voltage of about 3.3 V, for example. Since a load of the piezoelectric element is
• Fig. 18 is a diagram illustrating an example of an application for which the system 20 may be used.
• the system 20 may be configured to provide a user individually with an image effect and/or a sound effect according to the 3D coordinates of the user' s transmitter 400, as shown in Fig. 18.
• a shared augmented reality may be transformed individually according the 3D coordinates of the user' s positions measured by the apparatus 10, and such transformed reality is provided to each user to create a
• a plurality of users can share augmented reality with services tailored to the location of each user. It is noted that the implementations can be applied to a number of augmented reality systems other than ubicomp systems .
• the velocity potential response is used to measure the 3D-coordinates of the transmitter; however, a sound pressure impulse
• the peak points may be used instead of the inflection point, because they are equivalent to the inflection points in the velocity potential response.
• implementations using sound waves are described mainly; however, other waves such as radio waves may be used.
• the implementations may provide passive coordinate detection using the
• determining locations are difficult without satellites being directly overhead.
• the implementations do not require four satellites if they are applied to the GPS measurement.
• the determining of locations is possible with one or two satellites.
• a 2-channel active sonar and 3-channnel passive sonar may be able to determine 3D-coodinates .
• ASICs Application Specific Integrated Circuits
• FPGAs Field Programmable Gate Arrays
• DSPs digital signal processors
• a signal bearing medium examples include, but are not limited to, the following: a recordable type medium such as a flexible disk, a hard disk drive (HDD) , a Compact Disc (CD) , a Digital Versatile Disk (DVD) , a digital tape, a computer memory, etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.).
• a recordable type medium such as a flexible disk, a hard disk drive (HDD) , a Compact Disc (CD) , a Digital Versatile Disk (DVD) , a digital tape, a computer memory, etc.
• a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.).

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

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• 2011
  • 2011-04-27 US US13/256,670 patent/US8830791B2/en not_active Expired - Fee Related
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