SIGNAL COMPRESSION BASED ON CURVATURE PARAMETERS

• US 20090192395A1
• Filed: 02/24/2009
• Published: 07/30/2009
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: Robert J. Sweeney
• Original Assignee: Robert J. Sweeney
• Inventors: Sweeney, Robert J.
• Granted Patent: US 8,280,508 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation
• CPC Class Codes: G06F 2218/08 Feature extraction
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/20 for the management or administration of healthcare resources or facilities, e.g. managing hospital staff or surgery rooms
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction

Abstract

For a sampled signal, storing characteristic points generated based on parameters corresponding to curvature of the signal. The characteristic points include a time of occurrence of a lobe in a curvature series based on the signal and a corresponding amplitude of the signal. The characteristic points provide a compressed version of the sampled signal. The signal is reconstructed by establishing a function between a chronological sequence of characteristic points. For a repetitive signal, the stored data includes a code to indicate a time of reoccurrence of a previous cycle or data corresponding to differences between a previous cycle and a current cycle.

Claims

1. A system comprising:

an input circuit adapted to receive a sampled signal;

a curvature series generator coupled to the input circuit and adapted to generate a curvature series as a function of the sampled signal; and

a memory coupled to the curvature series generator and adapted to store a plurality of characteristic points, each characteristic point having time data and amplitude data derived from the curvature series.

2. The system of claim 1 wherein the input circuit is coupled to a cardiac electrode.

3. The system of claim 1 wherein the curvature series generator includes a circuit adapted to identify a centroid of a lobe in the curvature series.

4. The system of claim 1 wherein the curvature series generator includes a circuit adapted to identify a start time of a lobe in the curvature series.

5. The system of claim 1 wherein the curvature series generator includes a circuit adapted to identify an end time of a lobe in the curvature series.

6. The system of claim 1 wherein the curvature series generator includes a processor.

7. The system of claim 1 wherein the curvature series generator includes a processor adapted to generate an area of a lobe in the curvature series.

8. The system of claim 1 further including a telemetry circuit to wirelessly communicate the plurality of characteristic points stored in the memory.

9. An implantable medical device, comprising:

an input circuit to provide a sampled cardiac signal;

a controller coupled to the input circuit wherein the controller receives the sampled cardiac signal and generates a plurality of characteristic points as a function of a curvature series based on the sampled cardiac signal, wherein each characteristic point includes a time component corresponding to a time of occurrence of a lobe of the curvature series and wherein each characteristic point includes an amplitude component of the sampled cardiac signal at the time of occurrence; and

a memory coupled to the controller and adapted to store each characteristic point of the plurality of characteristic points.

10. The device of claim 9 wherein the controller is adapted to generate, for each characteristic point, a size component as a function of an area of the lobe of the curvature series.

11. The device of claim 10 wherein the controller is adapted to discard without storing in the memory, a characteristic point associated with a size less than a predetermined value.

12. The device of claim 9 wherein the controller is adapted to generate a first data set corresponding to a first group of characteristic points and the memory is adapted to store the first data set.

13. The device of claim 12 wherein the controller is adapted to store a repetition marker corresponding to a second data set wherein the second data set includes a second group of characteristic points that substantially match the first group of characteristic points and wherein the repetition marker identifies the first data set.

14. The device of claim 13 wherein the controller is adapted to store a time value associated with the repetition marker, the time value determined as a function of a time of occurrence of the second data set.

15. The device of claim 12 wherein the controller is adapted to store a difference marker corresponding to a second data set wherein the second data set includes a second group of characteristic points that differs from the first group of characteristic points and wherein the difference marker identifies the first data set.

16. The device of claim 15 wherein the controller is adapted to store difference data associated with the difference marker, the difference data corresponding to a difference between the first data set and the second data set.

17. The device of claim 9 wherein the controller includes a processor and wherein the memory includes executable instructions accessible to the processor.

18. The device of claim 9 wherein the controller includes hardwired circuitry.

19. The device of claim 9 wherein the controller includes a filter adapted to generate a running average of the sampled cardiac signal.

20. The device of claim 9 wherein the controller includes a comparator.

21. The device of claim 9 wherein the time of occurrence of the lobe includes a time of occurrence of a centroid of the lobe.