Contact tracking and identification module for touch sensing

  • US 8,902,175 B2
  • Filed: 04/10/2009
  • Issued: 12/02/2014
  • Est. Priority Date: 01/26/1998
  • Status: Active Grant
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First Claim
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1. A method of determining a plurality of touches concurrently on or near a touch sensing surface, the method comprising:

  • obtaining a set of data representing a scan of the touch sensing surface, the set of data including a plurality of proximity values, the proximity values representing measurements of touch object proximity at different locations along first and second axes within a sensing area of the touch sensing surface;

    determining a first local maximum of the proximity values in the set of data and a second local maximum of the proximity values in the set of data, including determining that the first local maximum proximity value is greater than both a first neighbor proximity value, nearest in a first direction along the first axis, and a second neighbor proximity value, nearest in a second direction along the second axis;

    determining first contact information based on the first local maximum, the first contact information including first surface coordinates of a first contact position within the sensing area of the touch sensing surface; and

    determining second contact information based on the second local maximum, the second contact information including second surface coordinates of a second contact position within the sensing area of the touch sensing surface.

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