| 摘要 |
On issuing the document, certain parameters characteristic of the picture (2) affixed thereto are determined, these constituting a code (3) which is stored on the document itself or elsewhere. Whenever the authenticity of the document is to be verified it is necessary to redetermine the said code by constructing a distribution function of the values of brightness of the picture, calculating the integral of the said function and, by subdividing the said integrated function along the ordinate axis into X equal parts, obtaining on the abscissa axis (X-1) values representing the characteristic parameters of the picture. A comparison with the previously determined code is performed next. The apparatus for carrying out this process comprises a device (4) able to register the picture, a device (10, 11) for inputting the comparison code, a device (5, 6, 7) for converting the signals provided by the picture-registering device into digital values and a microcomputer (8). The process and the apparatus can be used to determine the authenticity of credit cards. <IMAGE> |
