1. A method for acquiring biometric information comprising: generating a plurality of frames representing image data for a finger, wherein each frame includes first and second directions, said first direction being generally perpendicular to a finger movement direction, said second direction being generally parallel to said finger movement direction; transferring a first of said plurality of frames to a reconstructed image buffer; for each of a remaining plurality of frames, determining new lines that have moved into each frame compared to lines in said reconstructed image buffer, wherein said determining comprises compensating for variations due to movement error by computing a correlation between a prior frame and a next frame and a correlation between said prior frame and an extracted frame, and wherein at least one correlation is derived from an averaged delay from two or more functions computed in said second direction; and updating said reconstructed image buffer by appending only said new lines from each of said remaining plurality of frames.