Motion component dominance factors for motion locking of touch sensor data

Abstract

An image jaggedness filter is disclosed that can be used to detect the presence of ungrounded objects such as water droplets or coins, and delay periodic baseline adjustments until these objects are no longer present. To do otherwise could produce inaccurate normalized baseline sensor output values. The application of a global baseline offset is also disclosed to quickly modify the sensor offset values to account for conditions such as rapid temperature changes. Background pixels not part of any touch regions can be used to detect changes to no-touch sensor output values and globally modify the sensor offset values accordingly. The use of motion dominance ratios and axis domination confidence values is also disclosed to improve the accuracy of locking onto dominant motion components as part of gesture recognition.

What is claimed is: 
     
         1 . An apparatus for reconstructing a first image on a touch panel from a second image captured on the touch panel, the apparatus comprising:
 scan logic couplable to the touch panel and capable of performing a scan of the touch panel so as to capture the second image; and   a processor coupled to the scan logic and capable of
 aligning columns of image data in the second image with each other, and 
 aligning the column-aligned image data with a baseline value to reconstruct the first image. 
   
     
     
         2 . The apparatus of  claim 1 , wherein aligning the columns of image data comprises calculating an offset for each column, the offset indicative of an amount of misalignment of the column with other columns. 
     
     
         3 . The apparatus of  claim 2 , wherein the offset for each column comprises a previously computed offset value. 
     
     
         4 . The apparatus of  claim 1 , wherein aligning the column-aligned image data comprises calculating a global offset for the column-aligned image data, the offset indicative of an amount of alignment needed to reach the baseline value. 
     
     
         5 . The apparatus of  claim 1 , wherein aligning the column-aligned image data with the baseline value comprises computing an average value of a plurality of background pixels. 
     
     
         6 . The apparatus of  claim 5 , wherein the plurality of background pixels belong to an untouched region of the touch panel. 
     
     
         7 . The apparatus of  claim 5 , the processor further capable of decaying the global baseline value over time. 
     
     
         8 . The apparatus of  claim 7 , the processor further capable of adjusting a local baseline value to compensate for the decaying of the global baseline value over time. 
     
     
         9 . The apparatus of  claim 8 , wherein the baseline value comprises a sum of the local baseline value and the global baseline value. 
     
     
         10 . The apparatus of  claim 8 , wherein a maximum adjustment step size of the global baseline value is larger than a maximum adjustment step size of the local baseline value. 
     
     
         11 . The apparatus device of  claim 1 , the apparatus comprising at least one of a computing device, a media player, or a mobile telephone. 
     
     
         12 . A method for reconstructing a first image from a second image comprising:
 capturing the second image on a touch sensitive device;   aligning columns of image data in the second image with each other; and   aligning the column-aligned image data with a baseline value to reconstruct the first image.   
     
     
         13 . The method of  claim 12 , wherein aligning columns of image data comprises calculating an offset for each column, the offset indicative of an amount of misalignment of the column with the other columns. 
     
     
         14 . The method of  claim 13 , wherein the offset for each column comprises a previously computed offset value. 
     
     
         15 . The method  claim 12 , wherein aligning the column-aligned image data comprises calculating a global offset for the column-aligned image data, the offset indicative of an amount of alignment needed to reach the baseline value. 
     
     
         16 . The method of  claim 12 , wherein aligning the column-aligned image data with the baseline value comprises computing an average value of a plurality of background pixels. 
     
     
         17 . The method of  claim 16 , wherein the plurality of background pixels belong to an untouched region of the touch sensitive device. 
     
     
         18 . The method of  claim 16 , further comprising decaying the global baseline value over time. 
     
     
         19 . The method of  claim 18 , further comprising adjusting a local baseline value to compensate for the decaying of the global baseline value over time. 
     
     
         20 . The method of  claim 19 , wherein the baseline value comprises a sum of the local baseline value and the global baseline value. 
     
     
         21 . The method of  claim 19 , wherein a maximum adjustment step size of the global baseline value is larger than a maximum adjustment step size of the local baseline value. 
     
     
         22 . A touch sensitive device comprising:
 a touch panel capable of sensing a proximate object;   scan logic couplable to the touch panel and capable of performing a scan of the touch panel so as to capture a first touch image; and   a processor capable of reconstructing a second touch image from the first touch image, the reconstructing including
 calculating first alignments for portions of the first touch image, each portion having a different first alignment, 
 aligning the portions with each other according to the first alignments to form an aligned first image, 
 calculating a second alignment for the aligned first image, and 
 aligning the aligned first image according to the second alignment to meet a baseline value so as to form the reconstructed second touch image. 
   
     
     
         23 . The touch sensitive device of  claim 22 , the touch sensitive device comprising at least one of a computing device, a media player, or a mobile telephone.