Patent ID: 8325160

Claim:
A touch sensitive device comprising: a substrate capable of supporting bending waves having a first surface, a portion of the first surface defining a touch sensitive area; a plurality of sensors coupled to the touch sensitive surface and configured to (a) sense bending waves propagating through the substrate and generated by dragging one or more objects across the first surface, and (b) provide electronic signals representative of the bending waves; and, electronics communicatively coupled to the plurality of sensors and configured to: receive the electronic signals from the sensors; and determine based on the electronic signals whether the bending waves are generated by temporally overlapping first and second traces, the first trace defined by a first object dragged across a first portion of the first surface and the second trace defined by a second object dragged across a second portion of the first surface; the electronics being further configured to: determine first and second candidate coordinates defining possible positions of the first and second objects at a point in time; assign first and second predictive filters to the first and second traces; predict locations of the first and second traces from the predictive filters; and assign the candidate coordinates to the first and second traces based on the predicted locations of the first and second traces; and calculate constituent coordinates of the first and second traces based on the assigned candidate coordinates.