Sensor and method for verifying value documents

A sensor for verifying a value document which comprises a multiplicity of fibers distributed over the value document, and which is brought into a capture region of the sensor for the purpose of verifying said value document,

• wherein the sensor comprises:
• an image capture device configured to capture a value document image of the value document,
• wherein the value document image shows a characteristic optical or magnetic signal of the fibers, and
• an evaluation device, which, for the purpose of evaluating the value document image, is configured,
• to localize the fibers contained in the respective value document image, and
• to ascertain for one or more different locations of the value document image in each case at least one local fiber characteristic value which applies to the respective location and optionally to surroundings of the respective location on the value document image, and
• to classify the value document as suspected counterfeit depending on the at least one local fiber characteristic value.