METHOD AND SYSTEM FOR ENHANCING ACCURACY IN ULTRASONIC ALIGNMENT

• US 20100204575A1
• Filed: 04/20/2010
• Published: 08/12/2010
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Roche, Martin, McIntosh, Jason, Boillot, Marc
• Granted Patent: US 8,098,544 B2
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 8/565 involving data transmission via a network
• CPC Class Codes: A61B 8/58 Testing, adjusting or calibrating the diagnostic device
• CPC Class Codes: G01S 15/104 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 15/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S15/46
• CPC Class Codes: G01S 15/50 Systems of measurement, based on relative movement of the target
• CPC Class Codes: G01S 15/66 Sonar tracking systems
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01S 7/64 Luminous indications G01S7/62 takes precedence ; short-range imaging G01S7/52076
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image

Abstract

A method for short range alignment using ultrasonic sensing is provided. The method includes shaping an ultrasonic pulse on a first device to produce a pulse shaped signal and transmitting the pulse shaped signal from the first device to a second device, receiving the pulse shaped signal and determining an arrival time of the pulse shaped, identifying a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal, identifying a pointing location of the first device from the arrival time and the relative phase, determining positional information of the pointing location of the first device, and reporting an alignment of three or more points in three-dimensional space. Other embodiments are disclosed.

Claims

1. A method for short range alignment using ultrasonic sensing, comprising:

shaping an ultrasonic pulse signal on a first device to produce a pulse shaped signal and transmitting the pulse shaped signal from the first device to a second device;

receiving the pulse shaped signal and determining an arrival time of the pulse shaped signal received at the second device;

identifying a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal at the second device;

identifying a pointing location of a tip of the first device with respect to the second device from the arrival time of the received pulse shaped signal and the relative phase;

saving most recent pulse shaped signals to a history;

selectively discarding pulse shaped signals less recently saved in the history based on a similarity measure between pulse shaped signals in the history for further resolving the pointing location;

determining positional information of the pointing location of the first device at three or more points in three-dimensional space; and

reporting the positional information and an alignment of the three or more points,

wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.

2. The method of claim 1, comprising estimating the pointing location from a frequency modulated region for the received pulse shaped signal, and an orientation from the relative phase from a continuous frequency region for the received pulse shaped signal.

3. The method of claim 1, comprising

calculating a first Time of Flight of a first pulse shaped signal emitted at a first time from a first transmitter on the first device and received on a first microphone on the second device;

calculating a second Time of Flight of a first pulse shaped signal emitted at a second time from a second transmitter on the first device and received on a second microphone on the second device; and

calculating a third Time of Flight of a first pulse shaped signal emitted at a third time from a third transmitter on the first device and received on a third microphone on the second device.

4. The method of claim 2, comprising

calculating a first phase differential between the first pulse shaped signal and a previously received pulse shaped signal both captured at the first microphone;

calculating a second phase differential between the first pulse shaped signal and a previously received pulse shaped signal both captured at the second microphone; and

calculating a third phase differential between the first pulse shaped signal and a previously received pulse shaped signal both captured at the third microphone; and

determining the pointing location of the first device from first, second, and third Time of Flight and the first, second and third phase differential.

5. The method of claim 1, further comprising

converting the time of flight and differential time of flight measurements calculated from each of the received pulse shaped signals at the three microphones to three spatial points;

transforming the three spatial points to X, Y and Z rotations around the first device at the positional location to determine an orientation of the first device.

6. The method of claim 1, where reporting the alignment identifies an angle between a first line and a second line, where the first line is defined by a first point at a first time and a second point at a second time, and the second line is defined by the pointing location of the first device at the second point and a third point at a third time.

7. The method of claim 1, wherein short range detection between the first device and the second device is 5 cm to 2 m with an angle of the first device and the second device at 60 degrees or less.

8. The method of claim 1, wherein the step of selectively discarding pulse shaped signals comprises:

selectively pruning the history based on one among an L2 norm based, spectral distortion based, log-likelihood based, or mean-squared error based metric;

creating a sparse history of pulse shaped signals based on a difference rate between pulse shaped signals; and

updating an index table to the pulse shaped signals in the history according to the sparse history,

wherein the sparse history weights echoes more heavily in the near-time than in the far-time.

9. A system for short range alignment using ultrasonic sensing, including:

a first device comprising;

three ultrasonic transmitters for each transmitting a first, second and third pulse shaped signal through the air;

an electronic circuit for generating driver signals to the three ultrasonic transmitters for generating the first, second and third pulse shaped signal;

an user interface that receives user input for assessing short range alignment determination;

a communications port for relaying the user input and receiving timing information to control the electronic circuit; and

a battery for powering the electronic circuit and associated electronics on the first device

a second device comprising;

a processor for generating timing information, registering a pointing location of a tip of the first device responsive to the user input, and determining short range alignment from three or more pointing locations of the first device with respect to the second device;

a communications interface for transmitting the timing information to the first device that in response transmits the first, second and third pulse shaped signals;

three microphones for each receiving the first, second and third pulse shaped signals transmitted through the air;

a memory for storing the first, second and third pulse shaped signals to produce a history of pulse shaped signals,

a wireless communication interface for wirelessly conveying the positional information and the short range alignment of the three or more pointing locations to a remote system;

a battery for powering the processor and associated electronics on the second device,

where the pulse shaped signals are a combination of amplitude modulation, frequency modulation, and phase modulation.

10. The system of claim 9, where the processor on the second device

identifies a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal at the second device;

identifies a pointing location of the first device with respect to a coordinate system of the second device from an arrival time of the received pulse shaped signal and the relative phase;

saves most recent pulse shaped signals to the memory as a history for determining the pointing location;

selectively discards pulse shaped signals less recently saved in the memory based on a similarity measure between pulse shaped signals in the memory for resolving the pointing location;

determines positional information of the first device at three or more points in three-dimensional space; and

reports the positional information and an alignment of the three or more points,

11. The system of claim 9, where the communications port of the first device is physically wired to the communications interface of the second device for relaying the timing information, where the processor employs the timing information to determine the first, second and third Time of Flight measurements.

12. The system of claim 9, where

the first device includes an infrared transmitter and transmits an infrared timing signal with each transmitted pulse shaped signal;

and

the second device includes a photo diode for determining when the infrared timing signal is received,

where the communications port of the first device is wirelessly coupled to the communications interface of the second device by way of the infrared transmitter and the photo diode for relaying the timing information.

13. The system of claim 9, where the remote system is a computer, laptop or mobile device that displays the positional information and alignment information in real-time.

14. A hand-held portable ultrasonic device comprising:

three ultrasonic transmitters for each transmitting a first, second and third pulse shaped ultrasonic signal through the air;

an electronic circuit for generating driver signals to the three ultrasonic transmitters for generating the first, second and third pulse shaped ultrasonic signal;

an user interface that receives user input for registering a pointing location of a tip of the hand-held portable ultrasonic device responsive to the user input;

a communications port for relaying the user input and receiving timing information to control the electronic circuit; and

a battery for powering the electronic circuit and associated electronics on the first device.

15. The hand-held ultrasonic device of claim 14, where the electronic circuit receives timing information for sequencing a transmit time and applying a shaping to the first, second and third pulse shaped ultrasonic signal, wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.

16. The hand-held ultrasonic device of claim 14, where the communications port comprises an infrared transmitter and transmits an infrared timing signal with each transmitted pulse shaped ultrasonic signal to a second device configured to

determine an arrival time of the pulse shaped signal from the infrared timing signal;

determine a relative phase of the pulse shaped signal with a previously received pulse shaped ultrasonic signal;

determine positional information of the pointing location of the hand-held ultrasonic device at three or more points in three-dimensional space; and

report the pointing location and an alignment of the three or more points.

17. A mountable ultrasonic device comprising:

a processor for generating timing information that includes pulse shape parameters, and processing received pulse shaped ultrasonic signals;

a communications interface for transmitting the timing information to a hand-held portable ultrasonic device that in response shapes and transmits a first, second and third pulse shaped ultrasonic signal according to the timing information;

three microphones for each receiving the first, second and third pulse shaped ultrasonic signals transmitted through the air;

a memory for storing the first, second and third pulse shaped signals to produce a history of received first, second and third pulse shaped signals; and

a battery for powering the processor and associated electronics on the second device,

where the processor registers a pointing location of a tip of the hand-held portable electronic device from positional information and short range alignment from three or more pointing locations of the hand-held portable electronic device.

18. The mountable ultrasonic device of claim 17, wherein the processor conveys the pointing location to a remote system that displays an orientation of the hand-held portable ultrasonic device for the pointing location.

19. The mountable ultrasonic device of claim 17, wherein the processor conveys the pointing location to a remote system that displays short range alignment of the three or more pointing locations expressed as an angle.

20. The mountable ultrasonic device of claim 17, wherein the processor

saves most recent received pulse shaped signals to the history;

and

selectively discards pulse shaped signals less recently saved in the history based on a similarity measure between pulse shaped received signals in the history for further resolving the pointing location,

wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.

21. A method for short range alignment using ultrasonic sensing, the method steps comprising:

shaping three ultrasonic pulse signals on a first device to generate three pulse shaped signals and transmitting the three pulse shaped signals by way of three transmitters on the first device to a second device;

receiving the three pulse shaped signals at each of three microphones on the second device and determining three arrival times for the three pulse shaped signals received at the three microphones;

identifying three relative phases of the three pulse shaped signals with respect to previously received pulse shaped signals at the three corresponding microphones on the second device;

identifying a pointing location of a tip of the first device with respect to a coordinate system of the second device from the three arrival times of the received pulse shaped signals and the three relative phases of the received pulse shaped signals;

determining alignment of three or more registered pointing locations of the first device at three or more three-dimensional locations and at separate times by repeated operation of the method steps above; and

reporting an alignment of the three or more pointing locations, wherein at least one portion of each pulse shaped signal is at least one among a frequency modulated region, constant frequency region, phase modulated region, and a chirp region.

22. The method of claim 21, wherein the step of identifying the pointing location comprises:

estimating the pointing location from a frequency modulated region for each of the three received pulse shaped signal, and an orientation from the relative phase from a continuous frequency region for each of the three received pulse shaped signals.

23. The method of claim 24, comprising:

wirelessly transmitting timing information from the first device to the second device to indicate a pulse shape and when to transmit each pulse shaped signal.

24. The method of claim 21, comprising delaying a transmit time for each of the three pulse shaped signals by:

transmitting a first ultrasonic pulse signal at a first time;

transmitting a second ultrasonic pulse signal at a second time; and

transmitting a third ultrasonic pulse signal at a third time.

25. The method of claim 21, comprising repeating the method steps to include:

saving most recent pulse shaped signals to a history; and

selectively discarding pulse shaped signals less recently saved in the history based on a similarity measure between pulse shaped signals in the history for further resolving the pointing location.