Patent ID: 8203457

Claim:
Apparatus for detecting the value of a currency bill with a security stripe that fluoresces upon illumination by radiation of a stimulating frequency in a color uniquely associated with the value of the currency, said apparatus comprising: a) a radiation source emitting radiation at said stimulating frequency; b) at least one sensor, disposed opposite said radiation source and spaced to allow swiping of said bill between them, that provides a signal output varying directly with the sensed intensity of said associated color; c) at least one sensor, disposed opposite said radiation source, spaced to allow swiping of said bill between them, and if different from said first said sensor, positioned such that said security stripe passes said sensors simultaneously upon swiping of said bill, that provides a signal output varying directly with the sensed intensity of light of multiple frequencies including those of said associated color and at least one other; and d) circuitry adapted to calculate a composite value indicating a discontinuity of refraction of said light of multiple frequencies associated with the presence of said security stripe and to indicate said currency value if the maximum of said calculated composite value across the swiping of said currency occurs at a time coincident with a local maximum of the sensed intensity of said associated color.