A method for detecting objects on systems, includes providing a three-dimensional representation of the system, wherein the position and orientation of the representation and the system are known, and capturing a first image and a second image of the system, the two images being captured from different positions above the system. For a plurality of sections of the system, a respective comparison of the first and the second image is carried out using a parallax effect. If the images in a region surrounding the system match, an object is detected on the system.