Abstract: Surface relief of a finger is read using an optical-fiber prism unit, with fiber terminations at one end to contact the surface, and at the other for light passages along fibers from the first. Light enters where NA<0.5 and fiber diameter is constant with longitudinal position. The device is in a 1.4-2 L case, with a battery or power unit, converter to form a corresponding data array for verifying, digital signal processor to do the verifying, and output to indicate or implement a decision. The optical fiber prism unit has a substantially circular cylindrical wall defining a longitudinal axis, fused optical fibers parallel to the longitudinal axis, a traverser face for output of a skin pattern image from the prism and a generally elliptical angled face for contacting such a skin pattern.

Abstract: Surface relief of a finger etc. is read using an optical-fiber prism unit, with fiber terminations at one end to contact the surface, and at the other for light passage along fibers from the first. Light enters where NA<0.5 and fiber diameter is constant with longitudinal position. The device is in a 1.4-2 L case, with a battery or power input, converter to form a corresponding data array for verifying, digital signal processor to do the verifying, and output to indicate or implement a decision. A video controller (with custom-programmed logic circuit) operates the sensors to develop the data array; an ADC digitizes the array; memory holds an authorized-user skin-pattern template, firmware for the processor, and data used in verifying; an output register holds the decision signal--all on a control, address, and data bus. High-power, radiative elements and a fast high-impedance data reader are on a common board in an isolating layout.