Method and an apparatus for checking objects to be checked for authenticity

摘要

A number of high-permeability magnetic elements are dispersed in a scanning region of a checking object. A core of a processing apparatus is provided with an exciting coil and a sensor coil. When a bias magnetic field is applied to the core, and the scanning region is passed in the vicinity of a gap, the permeability of the gap varies depending on the density of the magnetic elements, so that a magnetic flux passing through the core changes. A detection signal corresponding to the change of the magnetic flux is detected by means of the sensor coil. This detection signal is converted into a cipher code and then recorded in a code indicator section of the checking object. In checking the authenticity of the object, a detection signal obtained by scanning the scanning region by means of the processing apparatus and a code for collation obtained by decoding the cipher code recorded in the code indicator section are compared, and it is concluded that the checking object is real when the detection signal and the collation code correspond to each other.