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

摘要

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.

主权项

1. A method for identifying touch patches on a touch sensor panel, comprising:
measuring touch values of touch pixels on the touch sensor panel; identifying a touch pixel having a largest touch value as representing a peak; associating a plurality of touch pixels in an area surrounding the peak with a patch of touch pixels including the peak; and selectively merging two or more non-overlapping patches of touch pixels into a single patch of touch pixels utilizing predetermined merging criteria upon determining that a number of touch pixels in at least one of the two or more touch patches is greater than a predetermined threshold.