Surveillance of a zone with determination of the amount of contamination of a transparent surface based on the image contrast

摘要

The device (10) has an image sensor (12) e.g. matrix shaped charge coupled device, with a transparent boundary surface (18) e.g. windscreen. An analysis unit (22) determines an image contrast of the image detected by the image sensor and a degree of pollution of the boundary surface from the image contrast. A contrast lighting device (26) is provided to illuminate a spatial area (20) with a contrast sample. The analysis unit detects object interference in the spatial area. A controller (24) provides security of a danger source within the spatial area by the object interference. An independent claim is also included for a method for monitoring a spatial area.