Patent ID: 7526969

Claim:
Method for the contactless detection of flat objects, such as papers in sheet form with respect to a single sheet, a missing sheet and multiple sheets of said flat objects, said flat objects being placed in a beam path of at least one transmitter and an associated receiver of a sensor device, wherein a radiation transmitted between said at least one transmitter and said receiver is received by said receiver in the form of a measuring signal (U M ), said measuring signal (U M ) is supplied to a following evaluation for generating a corresponding detection signal, wherein a characteristic of an input voltage (U E , U M ) of said measuring signal (U M ) is formed, and wherein at least one correction characteristic (KK) is provided for evaluation, said correction characteristic (KK) transforms said characteristic of the input voltage (U E , U M ) of said measuring signal (U M ) from said receiver (R) as a function of a weight per unit area of said flat objects to a target characteristic (ZK), that for said papers in sheet form an approximately linear characteristic approaching an ideal single sheet characteristic with a gradient of approximately “0” is obtained as said target characteristic between an output voltage (U A , U Z ) at an output of the evaluation and said weight per unit area, in order to generate said corresponding detection signal.