BOTTOM-UP WATERSHED DATAFLOW METHOD AND REGION-SPECIFIC SEGMENTATION BASED ON HISTORIC DATA TO IDENTIFY PATCHES ON A TOUCH SENSOR PANEL

• US 20110169763A1
• Filed: 03/25/2011
• Published: 07/14/2011
• Est. Priority Date: 06/13/2007
• Status: Active Grant

• Current Assignee: Joshua A. Strickon, Wayne Carl Westerman
• Original Assignee: Joshua A. Strickon, Wayne Carl Westerman
• Inventors: STRICKON, Joshua A., WESTERMAN, Wayne Carl
• Granted Patent: US 10,175,805 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/155 involving morphological operators

Abstract

The application of a watershed algorithm to pixels and their touch values obtained from a scan of a touch sensor panel to determine patches corresponding to images of touch is disclosed. Prior to applying the watershed algorithm, background pixels having little or no touch values can be eliminated. A primary merge algorithm can then merge adjacent patches together when the saddle point between them is shallow as compared to the peak represented by the patches. However, if two candidate patches for merging have a total number of pixels below a certain threshold, these two patches may not be merged under the assumption that the patches might have been caused by different fingertips. Conversely, if two candidate patches for merging have a total number of pixels above a certain threshold, these two patches can be merged under the assumption that the patches were caused by a single thumb or palm.

Claims

1. A method for merging touch patches in an image of touch generated on a touch sensor panel, comprising:

identifying a saddle point between two adjacent touch patches, the saddle point having an associated touch value; and

merging the two adjacent touch patches when the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches.

2. The method of claim 1, wherein the touch value of the saddle point is a maximum touch value of a touch pixel among a group of touch pixels along a shared border between the two adjacent touch patches.

3. The method of claim 1, wherein determining whether the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches comprises:

determining ratios of the touch value of the saddle point to each peak touch value of the two adjacent patches, and merging the two adjacent patches if at least one of the ratios is above a predetermined threshold.

4. The method of claim 3, further comprising lowering the predetermined threshold if one of the two adjacent touch patches is smaller than the other and the smaller patch is substantially aligned with the larger patch.

5. The method of claim 4, further comprising determining whether the smaller patch is substantially aligned with the larger patch by determining whether x-coordinates of the patches are within a predetermined range.

6. A computer-readable storage medium storing program code for merging touch patches in an image of touch generated on a touch sensor panel, the program code for causing performance of a method comprising:

identifying a saddle point between two adjacent touch patches, the saddle point having an associated touch value; and

merging the two adjacent touch patches when the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches.

7. The method of claim 6, wherein the touch value of the saddle point is a maximum touch value of a touch pixel among a group of touch pixels along a shared border between the two adjacent touch patches.

8. The computer-readable storage medium of claim 6, wherein determining whether the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches comprises:

determining ratios of the touch value of the saddle point to each peak touch value of the two adjacent patches, and merging the two adjacent touch patches if at least one of the ratios is above a predetermined threshold.

9. The computer-readable storage medium of claim 8, the method further comprising lowering the predetermined threshold if one of the two adjacent patches is smaller than the other, and the smaller patch is substantially aligned with the larger patch.

10. The computer-readable storage medium of claim 9, the method further comprising determining whether the smaller patch is substantially aligned with the larger patch by determining whether x-coordinates of the patches are within a predetermined range.

11. A touch-sensitive device comprising the computer-readable storage medium of claim 6.

12. A touch-sensitive device, comprising:

a touch sensor panel; and

a panel processor for merging touch patches in an image of touch generated on the touch sensor panel, the panel processor programmed for

identifying a saddle point between two adjacent touch patches, the saddle point having an associated touch value, and

merging the two adjacent touch patches when the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches.

13. The touch-sensitive device of claim 12, wherein the touch value of the saddle point is a maximum touch value of a touch pixel among a group of touch pixels along a shared border between the two adjacent touch patches.

14. The touch-sensitive device of claim 12, wherein determining whether the touch value of the saddle point is within a predetermined magnitude of a peak touch value of at least one of the two adjacent touch patches comprises:

determining ratios of the touch value of the saddle point to each peak touch value of the two adjacent patches, and merging the two adjacent patches if at least one of the ratios is above a predetermined threshold.

15. The touch-sensitive device of claim 14, the panel processor further programmed for lowering the predetermined threshold if one of the two adjacent touch patches is smaller than the other, and the smaller patch is substantially aligned with the larger patch.

16. The touch-sensitive device of claim 15, the panel processor further programmed for determining whether the smaller patch is substantially aligned with the larger patch by determining whether x-coordinates of the patches are within a predetermined range.