1. An image-processing device for carrying out an object segmentation, comprising means for executing the object segmentation through comparison of a camera image to a received reference image of a surveillance scene; a learning device for generating the scene reference image; said learning device being configured to generate the scene reference image through evaluation of a medium-term and/or long-term observation of the surveillance scene that occurs in the situation selected from the group consisting of occurring over a time period of longer than one day, occurring over a time period which includes several states of the reference scenes, and both.