Method and system for side detection of 3D undetailed ear impressions

1. A method for side detection of a 3D undetailed ear impression, comprising:

receiving a 3D undetailed ear impression;

defining a local coordinate system of the 3D undetailed ear impression based on side independent features of the 3D undetailed ear impression;

detecting a skeleton of the 3D undetailed ear impression, wherein said skeleton is a center spline of the 3D undetailed ear impression; and

determining whether the 3D undetailed ear impression is a left or right ear impression based on said skeleton and said local coordinate system of the 3D undetailed ear impression.

2. The method of claim 1 , wherein said step of receiving a 3D undetailed ear impression comprises:

receiving the 3D undetailed ear impression as a 3D point cloud; and

triangulating said 3D point cloud to generate a surface for the 3D undetailed ear impression.

3. The method of claim 1 , wherein said step of defining a local coordinate system of the 3D undetailed ear impression comprises:

detecting a bottom plane of the 3D undetailed ear impression;

defining a y direction of the local coordinate system based on said bottom plane;

detecting an aperture plane of the 3D undetailed ear impression;

defining an x direction of the local coordinate system based on said aperture plane and said y direction; and

defining a z direction of the local coordinate system based on said x direction and said y direction.

4. The method of claim 3 , wherein said step of detecting a skeleton of the 3D undetailed ear impression comprises:

detecting a plurality of center points along a vertical scanning of the 3D ear impression;

fitting a first spline to the plurality of center points; and

re-scanning the 3D undetailed ear impression at each point of the spline to generate new center points; and

fitting a second spline to the new center points to generate a smooth skeleton.

5. The method of claim 4 , wherein said step of determining whether the 3D undetailed ear impression is a left or right ear impression comprises:

determining a reference direction for said skeleton;

calculating a dot product of said reference direction and said x direction of the local coordinate system;

if said dot product is positive, determining that the 3D undetailed ear impression is a right ear impression; and

if said dot product is not positive, determining that the 3D undetailed ear impression is a left ear impression.

6. The method of claim 5 , wherein said step of determining a reference direction for said skeleton comprises:

defining said reference direction as a direction from a center point of said skeleton to a point in said 3D undetailed ear impression that is the average of endpoints of said skeleton.

7. The method of claim 1 , further comprising:

detecting ear features in said 3D undetailed ear impression based on the determination of whether the 3D undetailed ear impression is a left or right ear impression.

8. The method of claim 7 , further comprising:

generating a hearing aid shell from said 3D undetailed ear impression based on the ear features detected based on the determination of whether the 3D undetailed ear impression is a left or right ear impression.

9. An apparatus for side detection of a 3D undetailed ear impression, comprising:

means for receiving a 3D undetailed ear impression;

means for defining a local coordinate system of the 3D undetailed ear impression based on side independent features of the 3D undetailed ear impression;

means for detecting a skeleton of the 3D undetailed ear impression, wherein said skeleton is a center spline of the 3D undetailed ear impression; and

means for determining whether the 3D undetailed ear impression is a left or right ear impression based on said skeleton and said local coordinate system of the 3D undetailed ear impression.

10. The apparatus of claim 9 , wherein said means for receiving a 3D undetailed ear impression comprises:

means for receiving the 3D undetailed ear impression as a 3D point cloud; and

means for triangulating said 3D point cloud to generate a surface for the 3D undetailed ear impression.

11. The apparatus of claim 9 , wherein said means for defining a local coordinate system of the 3D undetailed ear impression comprises:

means for detecting a bottom plane of the 3D undetailed ear impression;

means for defining a y direction of the local coordinate system based on said bottom plane;

means for detecting an aperture plane of the 3D undetailed ear impression;

means for defining an x direction of the local coordinate system based on said aperture plane and said y direction; and

means for defining a z direction of the local coordinate system based on said x direction and said y direction.

12. The apparatus of claim 11 , wherein said means for detecting a skeleton of the 3D undetailed ear impression comprises:

means for detecting a plurality of center points along a vertical scanning of the 3D ear impression;

means for fitting a spline to the plurality of center points; and

means for re-scanning the 3D undetailed ear impression at each point of the spline to generate new center points; and

means for fitting a second spline to the new center points to generate a smooth skeleton.

13. The apparatus of claim 12 , wherein said means for determining whether the 3D undetailed ear impression is a left or right ear impression comprises:

means for determining a reference direction for said skeleton;

means for calculating a dot product of said reference direction and said x direction of the local coordinate system; and

means for determining that the 3D undetailed ear impression is a right ear impression if said dot product is positive and a left ear impression if said dot product is not positive.

14. The apparatus of claim 13 , wherein said means for determining a reference direction for said skeleton comprises:

means for defining said reference direction as a direction from a center point of said skeleton to a point in said 3D undetailed ear impression that is the average of endpoints of said skeleton.

15. The apparatus of claim 9 , further comprising:

means for detecting ear features in said 3D undetailed ear impression based on the determination of whether the 3D undetailed ear impression is a left or right ear impression; and

means for generating a hearing aid shell from said 3D undetailed ear impression based on the ear features detected based on the determination of whether the 3D undetailed ear impression is a left or right ear impression.

16. A non-transitory computer readable medium encoded with computer executable instructions for side detection of a 3D undetailed ear impression, the computer executable instructions defining steps comprising:

receiving a 3D undetailed ear impression;

defining a local coordinate system of the 3D undetailed ear impression based on side independent features of the 3D undetailed ear impression;

detecting a skeleton of the 3D undetailed ear impression, wherein said skeleton is a center spline of the 3D undetailed ear impression; and

determining whether the 3D undetailed ear impression is a left or right ear impression based on said skeleton and said local coordinate system of the 3D undetailed ear impression.

17. The non-transitory computer readable medium of claim 16 , wherein the computer executable instructions defining the step of receiving a 3D undetailed ear impression comprise computer executable instructions defining the steps of:

receiving the 3D undetailed ear impression as a 3D point cloud; and

triangulating said 3D point cloud to generate a surface for the 3D undetailed ear impression.

18. The non-transitory computer readable medium of claim 16 , wherein the computer executable instructions defining the step of defining a local coordinate system of the 3D undetailed ear impression comprise computer executable instructions defining the steps of:

detecting a bottom plane of the 3D undetailed ear impression;

defining a y direction of the local coordinate system based on said bottom plane;

detecting an aperture plane of the 3D undetailed ear impression;

defining an x direction of the local coordinate system based on said aperture plane and said y direction; and

defining a z direction of the local coordinate system based on said x direction and said y direction.

19. The non-transitory computer readable medium of claim 18 , wherein the computer executable instructions defining the step of detecting a skeleton of the 3D undetailed ear impression comprise computer executable instructions defining the steps of:

detecting a plurality of center points along a vertical scanning of the 3D ear impression;

fitting a spline to the plurality of center points; and

re-scanning the 3D undetailed ear impression at each point of the spline to generate new center points; and

fitting a second spline to the new center points to generate a smooth skeleton.

20. The non-transitory computer readable medium of claim 19 , wherein the computer executable instructions defining the step of determining whether the 3D undetailed ear impression is a left or right ear impression comprise computer executable instructions defining the steps of:

determining a reference direction for said skeleton;

calculating a dot product of said reference direction and said x direction of the local coordinate system;

if said dot product is positive, determining that the 3D undetailed ear impression is a right ear impression; and

if said dot product is not positive, determining that the 3D undetailed ear impression is a left ear impression.

21. The non-transitory computer readable medium of claim 20 , wherein the computer executable instructions defining the step of determining a reference direction for said skeleton comprise computer executable instructions defining the step of:

defining said reference direction as a direction from a center point of said skeleton to a point in said 3D undetailed ear impression that is the average of endpoints of said skeleton.

22. The non-transitory computer readable medium of claim 16 , further comprising computer executable instructions defining the steps of:

detecting ear features in said 3D undetailed ear impression based on the determination of whether the 3D undetailed ear impression is a left or right ear impression; and

generating a hearing aid shell from said 3D undetailed ear impression based on the ear features detected based on the determination of whether the 3D undetailed ear impression is a left or right ear impression.