Patent ID: 7190812
Filing Date: 2007-03-13
Classification: G06F

Abstract:
1. A method of calculating sub-pixel movement through a position tracking sensor, comprising: setting a reference frame and receiving a current surface image illuminated by light as a sample frame; calculating a correlation between the reference frame and the sample frame to obtain a first movement value; updating the reference frame to the sample frame when the first movement value is above a first value, and outputting the first movement value and simultaneously updating an auxiliary reference frame to the sample frame when the first movement value is above a second value; and calculating a second movement value of the sample frame with respect to the auxiliary reference frame, and outputting the second movement value when the second movement value is above a third value; wherein the auxiliary reference frame has the same number of pixels as the reference frame, but a different frame update speed and a different condition for outputting a movement value from that of the reference frame.