4,731,726 A 3/1988 Allen, I11 et al. 5,243,983 A 9/1993 Tarr et al. 5,291,560 A 3/1994 Daugman . 5,308,356 A 5/1994 Blackshear, 5,336,970 A 8/1994 Einbinder 5,377,681 A 1/1995 Drane ..... 5,433,197 A 7/1995 Stark .......................... 128/633 5,471,203 A 11/1995 Sasaki et al. 5,521,392 A 5/1996 Kennedy et a 5,535,743 A 7/1996 Backhaus et al. ........... 128/633 5,553,617 A * 9/1996 Barkenh...