Bottom-up watershed dataflow method and region-specific segmentation based on historic data to identify patches on a touch sensor panel

Patent metadata

Field	Value
Publication number	US-10175805-B2
Application number	US-201113072623-A
Country	US
Kind code	B2
Filing date	Mar 25, 2011
Priority date	Jun 13, 2007
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

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.

First claim

What is claimed is:

1. A method for merging touch patches in an image of touch generated on a touch sensor panel, comprising:
identifying a plurality of touch patches, each touch patch comprising a plurality of touch pixels;
identifying a saddle point between two non-overlapping touch patches, the saddle point having an associated touch value; and
merging the two 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 touch patches, 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 touch patches includes determining a ratio of the touch value of the saddle point to at least one peak touch value of the two touch patches, and
a number of touch pixels in at least one of the two touch patches is greater than a predetermined threshold.

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 touch patches.

3. The method of claim 1 , further comprising lowering the predetermined threshold if one of the two touch patches is smaller than the other and the smaller patch is substantially aligned with the larger patch.

4. The method of claim 3 , 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.

5. A non-transitory 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 plurality of touch patches, each touch patch comprising a plurality of touch pixels;
identifying a saddle point between two non-overlapping touch patches, the saddle point having an associated touch value; and
merging the two 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 touch patches, 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 touch patches includes determining a ratio of the touch value of the saddle point to at least one peak touch value of the two touch patches, and
a number of touch pixels in at least one of the two touch patches is greater than a predetermined threshold.

6. The non-transitory computer-readable storage medium of claim 5 , 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 touch patches.

7. The non-transitory computer-readable storage medium of claim 5 , the method further comprising lowering the predetermined threshold if one of the two patches is smaller than the other, and the smaller patch is substantially aligned with the larger patch.

8. The non-transitory computer-readable storage medium of claim 7 , 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.

9. A touch-sensitive device comprising the non-transitory computer-readable storage medium of claim 5 .

10. 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 plurality of touch patches, each touch patch comprising a plurality of touch pixels,
identifying a saddle point between two non-overlapping touch patches, the saddle point having an associated touch value, and
merging the two 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 touch patches, 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 touch patches includes determining a ratio of the touch value of the saddle point to at least one peak touch value of the two touch patches, and
a number of touch pixels in at least one of the two touch patches is greater than a predetermined threshold.

11. The touch-sensitive device of claim 10 , 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 touch patches.

12. The touch-sensitive device of claim 10 , the panel processor further programmed for lowering the predetermined threshold if one of the two touch patches is smaller than the other, and the smaller patch is substantially aligned with the larger patch.

13. The touch-sensitive device of claim 12 , 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.

Assignees

• Westerman Wayne Carl
• Strickon Joshua A
• Apple Inc

Inventors

• Westerman Wayne Carl
• Strickon Joshua A

Classifications

• G06F3/038 Primary

  Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry · CPC title

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06T7/11

  Region-based segmentation · CPC title

• G06F3/0488

  using a touch-screen or digitiser, e.g. input of commands through traced gestures · CPC title

• G06T7/155

  involving morphological operators · CPC title