Sensor signal alignment

• US 7,454,246 B2
• Filed: 09/08/2005
• Issued: 11/18/2008
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: Massachusetts Eye And Ear Infirmary (Foundation of The Massachusetts Eye and EAR Infirmary Incorporated)
• Original Assignee: Massachusetts Eye And Ear Infirmary (Foundation of The Massachusetts Eye and EAR Infirmary Incorporated)
• Inventors: Merfeld, Daniel Michael
• Primary Examiner(s): Layno; Carl H.
• Assistant Examiner(s): MORALES, JON ERIC C
• Application Number:
  US11/221,477
• Publication Number:
  US 20070055331A1
• Time in Patent Office: 1,167 Days
• Field of Search: 607/2
• US Class Current: 607/2
• CPC Class Codes: A61F 11/00 Methods or devices for treatment of the ears or hearing sense implantable prostheses that substitute or replace internal ear parts, e.g. ear-drums, A61F2/18; methods or devices to cause a change in the state of auditory consciousness A61M21/00; electrotherapy applying electrical stimulation of the auditory system, or circuits therefor A61N1/36; radiotherapy using optical stimulation of the auditory system A61N5/06; electro-acoustic hearing aids H04R25/00; Non-electric hearing aids; Methods or devices for enabling ear patients to achieve auditory perception through physiological senses other than hearing sense; Protective devices for the ears, carried on the body or in the hand headwear, e.g. caps or helmets, with means for protecting the ears A42B1/0188, A42B3/16

Abstract

Methods and systems, including computer readable mediums, are provided for transforming a measurement made relative to a first reference frame into a corresponding measurement relative to a second reference frame. Sensor signals that are produced by sensors in response to the sensors'"'"' motion relative to the first reference frame are transformed using a transformation matrix. The transformation generates corrected sensor signals that are relative to the axes of the second reference frame.

Claims

1. A method for transforming a measurement made relative to a first reference frame into a corresponding measurement relative to a second reference frame, the method comprising:

storing a transformation matrix;

receiving sensor signals produced by sensors in response to the sensors'"'"' motion relative to the first reference frame;

transforming the sensor signals using the transformation matrix to generate a corrected sensor signals relative to axes of the second reference frame;

sending the corrected sensor signals to a vestibular prosthesis;

encoding the corrected signals as stimulation signals; and

applying the stimulation signals to a vestibular nerve.

2. The method of claim 1, wherein transforming the sensor signals comprises orthogonalizing the sensor signals relative to the axes of the second reference frame.

3. The method of claim 1, further comprising:

moving the sensors with respect to each of the axes of the second reference frame;

measuring signal values produced by the sensors in response to the sensors'"'"' movement relative to each of the axes of the second reference frame;

incorporating the signal values into a sensitivity matrix, wherein the signal values are components of the sensitivity matrix; and

calculating an inverse of the sensitivity matrix to obtain the transformation matrix.

4. The method of claim 3, wherein moving the sensors comprises rotating the sensors about each of the axes of the second reference frame.

5. The method of claim 1 wherein transforming the sensor signals comprises calculating the corrected sensor signals in real-time.

6. The method of claim 1 wherein transforming the sensor signals comprises calculating a product of the transformation matrix and a sensor-signal vector that includes, as elements, the sensor signal from each sensor.

7. The method of claim 3 wherein calculating an inverse of the sensitivity matrix comprises:

determining that rows of the sensitivity matrix define vectors that are linearly independent; and

calculating a transpose of the sensitivity matrix.

8. A system for transforming a measurement made relative to a first reference frame into a corresponding measurement relative to a second reference frame, the system comprising:

a signal measuring system configured to measure sensor signal values produced by sensors in response to the sensors'"'"' movement relative to axes of the first reference frame;

a computer connected to the signal measuring system, wherein the computer is configured to;

incorporate the sensor signal values into a sensitivity matrix;

calculate an inverse of the sensitivity matrix to obtain a transformation matrix that transforms sensor signals produced by the sensors into corrected signals relative to axes of the second reference frame;

sending the corrected sensor signals to a vestibular prosthesis;

encoding the corrected signals as stimulation signals; and

applying the stimulation signals to a vestibular nerve.

9. The system of claim 8, further comprising:

correction circuitry interfaced to the sensors, the correction circuitry configured to;

store the transformation matrix in memory;

receive sensor signals from the sensors; and

transform the sensor signals using the transformation matrix to generate corrected sensor signals that are relative to the second reference frame.

10. The system of claim 9, wherein:

the sensors are aligned with predefined axes of rotation that are misaligned with the axes of the second reference frame;

the signals produced by the sensors correspond to angular motion of the sensors about the predefined axes of rotation; and

the corrected signals correspond to signals that the sensors would have produced had the sensors been aligned with the axes of the second reference frame.

11. The system of claim 9, wherein:

the sensors are aligned with predefined axes of linear acceleration that are misaligned with the axes of the second reference frame;

the signals produced by the sensors correspond to linear acceleration of the sensors along the predefined axes of linear acceleration; and

the corrected signals correspond to signals that the sensors would have produced had the sensors been aligned with the axes of the second reference frame.

12. The system of claim 9, wherein the correction circuitry is further configured to transform the sensor signals in real-time.

13. The system of claim 9, wherein the correction circuitry comprises analog circuitry.

14. The system of claim 9, wherein the correction circuitry is further configured to transform the sensor signals using mathematical operations that are limited to addition operations, subtraction operations, and multiplication operations.

15. The system of claim 9, further comprising a wireless communication network configured to transmit the transformation matrix between the computer and the correction circuitry.

16. The system of claim 8, wherein the computer is configured to determine whether the sensitivity matrix is invertible.

17. A computer readable medium having, stored thereon, software for transforming a measurement made relative to a first reference frame into a corresponding measurement relative to a second reference frame, the software comprising instructions for causing a computer to:

store a transformation matrix;

receive sensor signals produced by sensors in response to the sensors'"'"' motion relative to the first reference frame;

transform the sensor signals using the transformation matrix to generate corrected sensor signals that correspond to the signals that the sensors would have produced had the sensors been aligned with the axes of the second reference frame;

sending the corrected sensor signals to a vestibular prosthesis;

encoding the corrected signals as stimulation signals; and

applying the stimulation signals to a vestibular nerve.

18. The computer readable medium of claim 17, wherein the software further comprises instructions that cause the computer to:

move the sensors with respect to each of the axes of the second reference frame;

measure signal values produced by the sensors in response to the sensors'"'"' movement relative to each of the axes of the second reference frame;

incorporate the signal values into a sensitivity matrix, wherein the signal values are components of the sensitivity matrix; and

calculate an inverse of the sensitivity matrix to obtain the transformation matrix.

19. The computer readable medium of claim 17, wherein the software further comprises instructions that cause the computer to rotate the sensors about each of the axes of the second reference frame.

20. The computer readable medium of claim 17, wherein the software further comprises instructions that cause the computer to:

determine that rows of the sensitivity matrix define vectors that are linearly independent;

calculate a transpose of the sensitivity matrix;

calculate a product of the transformation matrix and a sensor-signal vector that includes, as elements, the sensor signal from each sensor; and

calculate the corrected signals in real-time.