Quantifying tread rib edge locations

1. A computer-implemented method of determining a quality of a tire, comprising:

capturing a footprint of the tire at a sensor array, the tire placed on the sensor array at a misalignment angle with respect to a coordinate axis of the sensor array;

applying a geometric transformation at a processor to rotate the footprint to align with the coordinate axis;

determining, at the processor, an intensity profile of the footprint, wherein the intensity profile is a profile of force measured at the sensor array along the coordinate axis of the sensor array;

locating, at the processor, an edge of the tread rib of the tire from a change in intensity along the intensity profile; and

determining, at the processor, a relative quality of the tire from the location of the tread rib edge;

wherein the location of the tread rib edge is determined within a resolution beyond the resolution of the sensor array by obtaining the footprint at the misalignment angle.

2. The method of claim 1 , wherein obtaining the footprint at the sensor array further comprises one of: (i) applying the tire to a face of the sensor array with static load; and (ii) rolling the tire across the face of the sensor array.

3. The method of claim 1 , further comprising cropping the footprint about a centroid of the footprint.

4. The method of claim 3 , further comprising locating the tread rib edge from a location of an extremum of a derivative of the intensity profile.

5. The method of claim 1 , wherein the intensity profile is an intensity along a direction transverse to the tread ribs of the tire and the intensity at a selected location is an average of intensities recorded along a tread rib direction at the selected location.

6. An apparatus for determining a quality of a tire, comprising:

sensor array configured to capture a footprint of the tire placed thereon at a misalignment angle with respect to a coordinate axis of the sensor array; and

a processor configured to:

apply a geometric transformation to rotate the footprint to align with the coordinate axis,

determine an intensity profile of the footprint, wherein the intensity profile is a profile of force measured at the sensor array along the coordinate axis of the sensor array,

locate an edge of the tread rib of the tire from a change in intensity along the intensity profile, and

determine from the location of the tread rib edge a relative quality of the tire;

wherein the location of the tread rib edge is determined within a resolution beyond the resolution of the sensor array using the misalignment angle of the tire with the coordinate axis of the sensor array.

7. The apparatus of claim 6 , wherein the sensor array is configured to obtain the footprint by one of: (i) receiving the tire at a face of the sensor array with an applied static load; and (ii) having the tire rolled across the face of the sensor array.

8. The apparatus of claim 6 , wherein the processor is further configured to crop the footprint about a centroid of the footprint.

9. The apparatus of claim 6 , wherein the processor is further configured to create the intensity profile along a direction transverse to the tread ribs of the tire wherein the intensity at a selected location is an average of intensities record along a tread rib direction at the selected location.

10. The apparatus of claim 9 , wherein the processor is further configured locate the edge from a location of an extremum of a derivative of the intensity profile.

11. A computer-program product for determining a quality of a tire, the computer program product comprising a non-transitory computer readable storage medium, the non-transitory computer readable storage medium comprising computer executable instructions, wherein the non-transitory computer readable storage medium comprises instructions to:

capture a footprint of the tire placed on a sensor array at a misalignment angle with respect to a coordinate axis of the sensor array;

apply a geometric transformation to rotate the footprint to align with the coordinate axis,

determine an intensity profile of the footprint, wherein the intensity profile is a profile of force measured at the sensor array along a direction of the coordinate axis;

locate an edge of the tread rib of the tire from a change in intensity along the intensity profile; and

determine from the location of the tread rib edge a relative quality of the tire;

wherein the location of the tread rib edge is determined within a resolution beyond the resolution of the sensor array using the misalignment angle of the tire with the coordinate axis of the sensor array.

12. The computer-program product of claim 11 , wherein the non-transitory computer readable storage medium further comprises instructions to crop the footprint about a centroid of the footprint.

13. The computer-program product of claim 11 , wherein the non-transitory computer readable storage medium further comprises instructions to create the intensity profile along a direction transverse to the tread ribs of the tire and-the intensity at a selected location is an average of intensities record along a tread rib direction at the selected location.

14. The computer-program product of claim 13 , wherein the non-transitory computer readable storage medium further comprises instructions to locate the tread rib edge from a location of an extremum of a derivative of the intensity profile.