Patent ID: 7567272

Claim:
A device for monitoring an area of coverage around a working tool comprising: at least two cameras, which form a redundant camera system, onto which a beam divider projects images of the area of coverage; at least two computer units that are coupled to the at least two cameras and at least one switching output that is coupled to the working tool, said switching output having means, integrated into the at least two computer units, for storing and classifying a reference background, wherein the reference background is an image, recorded with at least one of the at least two cameras, of an object-free security zone within the area of coverage, wherein one respective computer unit being associated with one of the at least two cameras for evaluating the image information recorded therein and wherein both computer units are coupled so as to perform mutual checks and the two computer units have different software structures; means for checking the reference background with respect to non-homogeneity, wherein the reference background is rejected as non-valid only if the non-homogeneity detected within a predetermined variance distance falls below a predetermined level and the reference background is otherwise classified as valid; means, integrated into the at least two computer units, for releasing an object detection system in dependence on the classification of the reference background; and means, integrated into one of the computer units, for comparing actual images of the security zone, recorded with one of the cameras and a reference background classified as valid, wherein a binary control signal having switching states is generated in the one of the computer units, the switching states of which indicate whether the existing reference background is classified as valid or non-valid, the switching states of the binary control signal being output via an indicator output that is coupled to the one of the computer units, wherein a detection of a safety-critical object within the security zone occurs if the actual image differs significantly from the reference background and wherein the working tool is activated via the switching output that is triggered by the computer unit, but only if no safety-critical object is located within the security zone.