Abstract: The invention relates to a method and a device for monitoring an area of coverage around a working tool with the aid of at least one camera. In a first method step, an object-free security zone within the area of coverage is recorded with the camera as reference background. Subsequently, the reference background is checked with respect to its non-homogeneity. In the process, the reference background is rejected as non-valid only if within a predetermined variance distance, the detected non-homogeneity falls below a predetermined level. Otherwise, the reference background is classified as valid. If the reference background is classified as valid, the detection of safety-critical objects entering the security zone is released. The detection occurs through a comparison of the actual images of the security zone recorded with the camera and the valid reference background. A safety-critical object is considered recognized if the respective actual image deviates significantly from the reference background.