Using dynamically scaled linear correction to improve finger tracking linearity on touch sensors

摘要

A system and method for correcting non-linear tracking of objects that may change size when moving on a large touch sensor having a relatively large space between electrodes by dynamic compensating on-the-fly by constantly calculating the size of a finger as measured by the touch sensor, and then scaling that measured size so that look-up tables may be used to compensate for any size finger in the X and Y axes.

主权项

1. A method for compensating for a non-linear response from a touch sensor when a pitch between electrodes is approximately equal to the width of the pointing object making contact, said method comprised of:
1) providing a touch sensor having a orthogonal array of X and Y electrodes disposed in two parallel planes, one plane directly over the other plane, wherein the pitch between electrodes on the same plane is approximately equal to or wider than the width of the pointing object as measured by the touch sensor; 2) providing a linear correction table that is calibrated for a predetermined size of an object that will experience non-linearity on the touch sensor; 3) measuring the size of the pointing object that is detected by the touch sensor, and measuring a position of the pointing object in a first axis; 4) determining a scale factor relative to the measured size of the pointing object so that the linear correction table may be used for correcting a measured position of the pointing object; 5) applying the scale factor to the linear correction table to find an amount of correction to be applied to the measured position of the pointing object to determine an actual position relative to the first axis and the measured size of the pointing object; and 6) repeating steps 3 through 5 for a second axis in order to determine an actual position relative to the second axis and the measured size of the pointing object.