1. A method of controlling a monitored zone ( 11 ), in particular of transport devices for permitted objects ( 13 ) within the monitored zone, comprising: scanning the monitored zone ( 11 ) using at least one spatially resolving sensor ( 15 ) that includes one of a laser scanner and a camera system; determining positions of object points ( 23 ) in the monitored zone ( 11 ); and executing a contour search in at least one sub-set ( 19 , 19 ′, 19 ″) of the determined positions wherein the sub-set of positions are examined mathematically as to whether the respective object points ( 23 ) lie on at least one model line ( 21 , 21 ′, 21 ″) that is pre-determined with respect to one of shape and length within a pre-determinable tolerance, the model line corresponding to at least a part of a contour of the permitted object ( 13 ) in the monitored zone ( 11 ), wherein the contour search is carried out independently of respective locations of the determined positions relative to the sensor ( 15 ).