HEART RATE MONITOR WITH CROSS TALK REDUCTION

• US 20090043217A1
• Filed: 08/07/2007
• Published: 02/12/2009
• Est. Priority Date: 08/07/2007
• Status: Active Grant

• Current Assignee: Salutron, Inc.
• Original Assignee: Salutron, Inc.
• Inventors: Lo, Thomas Ying-Ching, Hui, Chor Kuen Eddy
• Granted Patent: US 7,797,038 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/681 Wristwatch-type devices

Abstract

A heart rate monitor determines a heart rate for a primary subject by reducing noise and cross-talk from unwanted signal transmission sources. A set of pulse peaks having about the same amplitude and an amplitude greater than any other set of peaks are processed to determine a subject'"'"'s heart rate, while data having an amplitude below that of the set of peaks is ignored. To retrieve enough data to determine a peak amplitude, the signal having heart rate information is sampled at a frequency higher than a normal sampling frequency. In some embodiments, if no data is received for a set time period which is in or above the range, the threshold resets to zero under an assumption that the primary subject is no longer within transmitting range.

Claims

1. A computer implemented method for determining a heart rate, comprising:

receiving a signal by a heart rate monitor, the signal containing heart rate information for two or more subjects;

identifying a first peak within a pulse of the signal;

determining the amplitude of the first peak;

deriving a threshold value from the amplitude of the first peak;

identifying a second peak within a second pulse of the signal;

determining the amplitude of the second peak;

comparing the second amplitude to the threshold;

determining a heart rate for a first subject of the two or more subjects using information associated with the second pulse based on said step of comparing; and

displaying the heart rate for the first subject by the heart rate monitor circuitry of the first exercising apparatus.

2. The computer implemented method of claim 1, further comprising:

sampling the signal by the heart rate monitor circuitry at a sampling frequency of between 10 KHz and 20 KHz.

3. The computer implemented method of claim 2, wherein the sampling frequency is between 11 KHz and 15 KHz.

4. The computer implemented method of claim 1, wherein the received signal contains a signal component generated from a chest strap worn by a user on a second exercising apparatus which is within transmission range of the first exercising apparatus.

5. The computer implemented method of claim 1, wherein the threshold includes a range derived from the amplitude of the first peak.

6. The computer implemented method of claim 1, wherein said step of determining a heart rate includes:

updating a current heart rate with timing information for the occurrence of the second peak.

7. The computer implemented method of claim 1, further comprising:

receiving a set number of peaks having a similar maximum amplitude; and

setting a threshold value based on the similar maximum amplitude.

8. The computer implemented method of claim 1, wherein said step of determining a heart rate includes:

determining the second peak is within a threshold range of allowed heart beats.

9. The computer implemented method of claim 1, wherein said step of determining a heart rate includes:

determining the second peak does not satisfy the threshold; and

not updating the current heart beat using the second peak.

10. The computer implemented method of claim 1, wherein said step of determining a heart rate includes:

determining the second peak is greater than the threshold; and

revising the threshold value based on the amplitude of the second peak.

11. The computer implemented method of claim 1, wherein one or more signal pulses having peak amplitudes less than the threshold are not processed.

12. The computer implemented method of claim 1, wherein the heart rate monitor is implemented as part of a treadmill, the first subject a user of the treadmill.

13. The computer implemented method of claim 1, wherein the heart rate monitor is configured to be attached to a bicycle, the first subject a user of the stationary bicycle.

14. One or more processor readable storage devices having processor readable code embodied on said processor readable storage devices, said processor readable code for programming one or more processors to perform a computer implemented method comprising:

receiving a signal with heart rate data for two or more subjects;

identifying a first set of peaks within a plurality of pulses of the received signal, the first set of peaks associated with a first amplitude;

setting a threshold based on the first amplitude;

deriving an initial heart rate for a primary subject based on the first set of peaks, the two or more subjects including the primary subject;

identifying a subsequent peak in a subsequent pulse of the received signal, the subsequent peak having a second amplitude;

comparing the second amplitude to the threshold;

updating a heart rate for primary subject based on said step of comparing; and

reporting the updated heart rate.

15. The one or more processor readable storage devices of claim 14, wherein said step of identifying a first set of peaks includes:

identifying three or more peaks within a plurality of pulses, the three or more peaks associated with a first amplitude, the signal not containing a higher amplitude for each peak in any other set of three or more peaks.

16. The one or more processor readable storage devices of claim 14, wherein said step of setting a threshold includes:

setting a threshold range based on the first amplitude.

17. The one or more processor readable storage devices of claim 14, wherein the second peak is lower than the threshold, said step of updating includes:

indicating there is no change in the heart rate for the primary subject.

18. The one or more processor readable storage devices of claim 14, wherein said step of updating includes:

updating the heart rate based on timing information for the subsequent peak if the subsequent peak amplitude is about the same as the threshold; and

setting the threshold based on the subsequent peak and updating the heart rate based on timing information for the subsequent peak if the subsequent peak amplitude is greater than the threshold.

19. The one or more processor readable storage devices of claim 14, wherein the received signal includes two or more modulated 5 KHz pulse signals.

20. The one or more processor readable storage devices of claim 14, the one or more processor readable storage devices incorporated into an exercise apparatus.

21. A computer implemented method for determining a heart rate, comprising:

receiving a signal by heart rate monitor circuitry implemented within a first exercising apparatus, the signal containing heart rate information for two or more subjects;

identifying a first set of peaks within a pulse of the signal;

determining the amplitude of each peak within the first set peaks;

deriving a threshold value from the amplitude of the first peak;

identifying a second peak within a second pulse of the signal;

determining the amplitude of the second peak;

comparing the second amplitude to the threshold;

determining a heart rate for a first subject of the two or more subjects using information associated with the second pulse based on said step of comparing; and

displaying the heart rate for the first subject by the heart rate monitor circuitry of the first exercising apparatus.

22. The computer implemented method of claim 21, wherein the threshold is a range based on the amplitude of the first set of peaks.

23. The computer implemented method of claim 21, wherein said step of determining a heart rate includes:

updating a current heart rate with timing information for the occurrence of the second peak.

24. The computer implemented method of claim 21, wherein said step of determining a heart rate includes:

determining the second peak is within a threshold range of allowed heart beats.

25. The computer implemented method of claim 21, wherein said step of determining a heart rate includes:

determining the second peak does not satisfy the threshold; and

not updating the current heart beat using the second peak.

26. The computer implemented method of claim 21, wherein said step of determining a heart rate includes:

determining the second peak is greater than the threshold; and

revising the threshold value based on the amplitude of the second peak.

27. The computer implemented method of claim 21, wherein one or more signal portions having peak amplitudes less than the threshold are not processed.

28. A computing apparatus for processing data, comprising:

a signal receiving mechanism that receives a signal;

signal selection logic in communication with said signal receiving mechanism that determines a first peak set with two or more peaks that each have amplitudes within a first range and that no other set of two or more peaks have amplitudes within a second range that is greater than the first range, the first peak set within the signal; and

heart rate determination logic in communication with said signal receiving mechanism that determines a heart rate based on timing information associated with each peak in the first peak set.

29. The computing apparatus of claim 28, further comprising:

an analog to digital converter that samples the signal at a sampling rate greater than twice the signal frequency.

30. The computing apparatus of claim 28, the signal selection logic storing a threshold value based on the amplitude of the first peak set.

31. The computing apparatus of claim 28 implemented within an exercising apparatus.