b) Furthermore, data acquisition in general is
fraught with problems for other biometrics: techniques that
rely on hands and fingers can be rendered useless if the
epidermis tissue is damaged in some way (i.e., bruised or
cracked). Iris and retina identification require expensive
equipment and are much too sensitive to any body motion.
Voice recognition is susceptible to background noises in
public places and auditory fluctuations on a phone line or
tape recording. Signatures can be modified or forged.
However, facial images can be easily obtained with a
couple of inexpensive fixed cameras. Good face
recognition algorithms and appropriate preprocessing of
the images can compensate for noise and slight variations
in orientation, scale and illumination.
c) Finally, technologies that require multiple
individuals to use the same equipment to capture their
biological characteristics potentially expose the user to the
transmission of germs and impurities from other users.
However, face recognition is totally non-intrusive and
does not carry any such health risks.