Sensor arrangement and method for safeguarding a monitored zone

Abstract

The invention relates to a sensor arrangement and to a method for safeguarding a monitored zone at a machine. The sensor arrangement comprises a camera continuously generating 3D images, a control and evaluation unit for the position detection of objects in the monitored zone and, in the case of a hazardous position, initiating a safety-directed response of the machine, with a buffer memory unit being provided for storing last recorded images and with a 3D reference map being prepared from the stored images when the safety-directed response was initiated, a voxel identification unit being provided for flagging those voxels in the current 3D image whose coordinates differ by a specified distance from those of the corresponding voxels of the reference map, a movement recognition unit being provided in which the voxels thus identified are examined as to whether they display position changes that are above a fixed threshold in the course of a fixed number of further current images, and independently thereof, a restart signal for the machine being able to be output at an output.