Method and apparatus for automatically testing whether a subject matter of a film is covered

摘要

The present invention relates to a method and a device for automatically testing whether a subject matter (ps, ps - 2) comprises a section, which is covered by a film, or not. A focused light beam (ls) is generated. The light beam (ls) is made to the surface of the object to be examined (ps, ps - 2) directed. The light beam (ls) in such a way is the object (ps - ps - 2) that passes through the following: between the light beam (ls) and a vertical (se) on the surface of the object at the point at which the light beam (ls) the surface of the object (ps, ps - 2), if an angle greater than zero to. By the object (ps, ps - 2), the reflection (r - 1, r - 2) of the light beam (ls) is made to a light sensor (5) guided. The light sensor (5) as a function of output signals generated light impinging. The output signals are evaluated. The evaluation, the check whether or not the reflection (r - 1, r - 2) in only one field or in at least two spatial regions separated from one another on the light sensor (5) is incident. When the reflection (r - 1, r - 2) in two separate regions on the light sensor (5), it is decided that the object (ps, ps - 2) a partial region which is covered by a film.