PURPOSE: To prevent the copying of the copyright object by adding the identification information which cannot be discriminated by the vision of humans to the image information which is the copyright object.

CONSTITUTION: Each paper 1 has areas α and β having a different reflection factor and by deciding the shape of the α(β) areas, the meaning and characteristic held by respective symbols can be extracted. On these sheets of paper 1, the image of the copyright object is actually impressed and the copying machine scans the whole screen by a line sensor 2. In this case, the symbol on each paper 1 for example is changed to the reflection factor of the area of the infrared ray, and for the sensor 2, the type of the sensor to induce even to the signal of the wavelength of an infrared ray area is used, and thus, even when the symbols cannot be decided by the eyes, by scanning on the paper 1 by the CCD sensor, an electric signal including the information of the reflection factor at two types of the area having those different reflection factors can be obtained.