1. A surveillance system ( 1 ), the surveillance system ( 1 ) being designed to classify objects ( 9 ) that have object characteristics in a surveillance scene ( 12 ) on the basis of object characteristic ranges as objects to be monitored, and being linked via signals to a plurality of surveillance sensors being formed as video cameras, the surveillance system comprising: a configuration module ( 7 ) being designed to define the object characteristic ranges, wherein the configuration module comprises a selection device ( 10 , 13 ) for interactive selection and/or confirmation of selection of an object ( 9 ) as a reference object ( 14 ), the object characteristic ranges being defined on the basis of and/or using the object characteristics of the reference object ( 14 ), wherein the selection device includes a display device ( 13 ) on which the surveillance scene ( 12 ) containing the objects ( 9 ) is depicted in real time, and a human-machine interface to mark an object on the display device as the reference object, wherein said object is selected by clicking on said object; an object detector which is programmed and/or electronically configured to detect moving objects in the surveillance scenes and to classify them as objects to be monitored on the basis of their object characteristics, wherein the classification is performed by comparing the object characteristics of the object to the object characteristic ranges that form classification conditions, wherein the object detector is programmed and/or electronically configured to track the moving object as soon as it is classified as the object to be monitored, and wherein the object characteristics ranges and one or all of the tolerances and the tolerance values are visualized in the display device ( 13 ).