Method and apparatus for retrieval of similar heart sounds from a database

• US 8,137,283 B2
• Filed: 08/22/2008
• Issued: 03/20/2012
• Est. Priority Date: 08/22/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Syeda-Mahmood, Tanveer Fathima, Wang, Fei
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): EL-KAISSI, HIBA CARINE
• Application Number:
  US12/196,821
• Publication Number:
  US 20100049072A1
• Time in Patent Office: 1,306 Days
• Field of Search: 600/528, 607/9, 607/17, 607/18, 607/23, 607/24, 381/67
• US Class Current: 600/528
• CPC Class Codes: A61B 7/00 Instruments for auscultation

Abstract

The present invention exploits a visual rendering of heart sounds and models the morphological variations of audio envelopes through a constrained non-rigid translation transform. Similar heart sounds are then retrieved by recovering the corresponding alignment transform using a variant of shape-based dynamic time warping.

Claims

1. A computer-implemented method for detecting audio similarity of heart sounds, said computer-implemented method implemented by executing computer readable program code in a processor, said method comprising:

recording a first heart sound;

pre-processing the first heart sound to create a second heart sound;

constructing a line segment approximation of the second heart sound;

defining an audio envelope around the second heart sound using the line segment approximation, said audio envelope having a plurality of fiduciary points;

isolating said plurality of fiducial points on the audio envelope;

matching the second heart sound to a plurality of similar stored heart sound in a database based on said isolated fiducial points and fiducial points associated with said stored heart sounds in said database, said matching based on a function of matched fiducial points and a total number of fiducial points; and

outputting the matched similar heart sounds.

2. The method of claim 1, wherein the step of pre-processing comprises identifying a single periodic segment.

3. The method of claim 1, wherein the matching comprises:

identifying a non-rigid alignment transform based on a shape-based dynamic time warping to determine a correspondence between the fiducial points of said audio envelope and fiducial points from said database of heart sounds;

defining a measure of shape similarity as said function of a number matched fiducial points and a total number of fiducial points; and

outputting the measure of shape similarity.

4. The method of claim 3, wherein the function comprises a ratio of the number of matched fiducial points to the total number of fiducial points.

5. The method of claim 4, wherein the matching further comprises ranking the matching based on the ratio.

6. The method of claim 3, wherein the database of heart sounds comprises a database of heart sounds associated with diseases.

7. The method of claim 6, wherein the step of outputting the measure of shape similarity further comprises:

assembling disease statistics from the database of heart sounds; and

presenting the disease statistics as a decision support system showing disease labels that are associated with a plurality of heart sounds from the database of heart sounds.

8. The method of claim 3, wherein the matching further comprises time scaling and amplitude scaling.

9. The method of claim 1, wherein the fiducial points comprise local extremes of the audio envelope only on one side of a baseline of the second heart sound.

10. A computer program product comprising:

a non-transitory computer storage medium having computer usable program code for detecting audio similarity of heart sounds, said computer program product including;

computer usable program code for recording a first heart sound;

computer usable program code for pre-processing the first heart sound, wherein the computer usable program code for pre-processing comprises;

program code for selecting a time duration of a portion of the first heart sound to use as a second heart sound;

computer usable program code for constructing a line segment approximation of the second heart sound;

computer usable program code for defining an audio envelope around the second heart sound using the line segment approximation, said audio envelope having a plurality of fiduciary points;

computer usable program code for isolating said plurality of fiducial points on the audio envelope; and

computer usable program code for matching the second heart sound to a plurality of similar heart sounds, wherein the computer usable program code matching comprises;

program code for identifying a non-rigid alignment transform based on a shape-based dynamic time warping to determine a correspondence between the fiducial points of the audio envelope and fiducial points from a database of heart sounds;

program code for defining a measure of shape similarity by determining a ratio of matched fiducial points to a total number of fiducial points;

program code for ranking the matching based on the ratio; and

computer usable program code for outputting ranked matches.

11. A system for detecting audio similarity of heart sounds comprising:

an audio transducer for recording a first heart sound;

a processor;

wherein the processor is configured to pre-processes the first heart sound to create a second heart sound, constructs a line segment approximation of the second heart sound, defines an audio envelope around the second heart sound using the line segment approximation, and isolates a plurality of fiducial points on the audio envelope;

an input/output interface is configured to communicate with a database of heart sounds;

wherein the processor matches the second heart sound to a plurality of similar heart sounds retrieved from the database through the input-output interface, said matching comprising;

identifying a non-rigid alignment transform based on a shape-based dynamic time warping to determine a correspondence between the fiducial points of the audio envelope and fiducial points from a database of heart sounds;

defining a measure of shape similarity as a function of a number matched fiducial points and a total number of fiducial points; and

outputting the measure of shape similarity.

12. The system of claim 11, wherein the function comprises a ratio of the number of matched fiducial points to the total number of fiducial points.

13. The system of claim 12, wherein the processor ranks the matching based on the ratio.

14. The system of claim 11, wherein the database of heart sounds comprises a database of heart sounds associated with diseases.

15. The system of claim 14, wherein outputting the measure of shape similarity further comprises:

assembling disease statistics from the database of heart sounds; and

presenting the disease statistics as a decision support system showing disease labels that are associated with a plurality of heart sounds from the database of heart sounds.

16. The system of claim 11, wherein the processor is configured to adjust the second heart sound by time scaling and amplitude scaling.

17. The system of claim 11, wherein the fiducial points comprise local extremes of the audio envelope only on one side of a baseline of the second heart sound.