| 摘要 |
<p>Detecting counterfeit bank notes is achieved by directing ultraviolet light at a sample from a source (2) and measuring the level of ultraviolet light reflected from the sample using a first photocell (104) and the amount of fluorescent light generated by the sample using a second photocell (106). The detected levels are compared with reference levels and only if both reflective and fluorescent criteria are satisfied is the note declared genuine. The sample, during test, is supported on a glass plate (102). The apparatus uses the value of the intensity of light reflected from the glass plate (in the absence of a sample) as a basis for producing at least one reference level against which a subsequent comparison can be made.</p> |
