SENSOR AND METHOD FOR CHECKING VALUE DOCUMENTS, IN PARTICULAR BANK NOTES, AND VALUE DOCUMENT PROCESSING APPARATUS

A sensor and a method for checking value documents are provided, each having a luminescent sheet-like substrate and a luminescent feature applied to a partial surface of the substrate, and to a value document processing apparatus. From the spectral vectors obtained for a plurality of measurement points and characterizing the intensity of the luminescent radiation of the value document detected in at least two spectral ranges, substrate intensity values and feature intensity values are determined, based on which a pure substrate mask is determined, which contains only those measurement points which reliably lie outside the feature. From the spectral vectors of the measurement points contained in the pure substrate mask, a mean substrate vector is determined, based on which corrected substrate intensity values and corrected feature intensity values and/or a spectral signature of the substrate and/or of the feature are or is, respectively, determined from the spectral vectors.