Provided is a method for analyzing image slices. The method includes extracting first and second sub-slices from first and second image slices, respectively, and computing a shift between the first and second image slices based on the first and second sub-slices. The first and second sub-slices overlap.Also provided is a method for controlling a cursor on a screen. The method includes determining a shift between a first image slice and a second image slice and determining a displacement of the cursor on the screen based on the determined shift.