1. A method for controlling a cursor on a screen, comprising: determining at least one dimension for a first sub-slice and for a second sub-slice; extracting, using a computer processor, the first and second sub-slices from first and second image slices, respectively, wherein each of the first and second image slices capture an image of a portion of a finger and wherein the first and second image slices overlap in a first overlapping region and the first and second sub-slices overlap in a second overlapping region; computing a shift between the first image slice and the second image slice based information included in the second overlapping region while ignoring at least a portion of information included in the first overlapping region that is outside of the second overlapping region; and determining a displacement of the cursor on the screen based on the computed shift.