The invention relates to a sensor arrangement for the detection of specimen containers within a detection zone, with an optical sensor having an image sensor at a first end of the detection zone, and with a textured background at a second end of the detection zone, A specimen container arranged within the detection zone is detected by the image sensor against the textured background. The specimen container is differentiated from the textured background by an evaluation unit, based on the image signals generated by the image sensor, and object detection signals that identify the specimen container are generated.