A method for detecting a movable object in a location includes —providing a first 3D representation of at least part of a surface by scanning —providing a second 3D representation of at least part of the surface by scanning —determining for the first 3D representation a first excluded volume —determining for the second 3D representation a second excluded volume —if a portion of the surface in the first 3D representation is located in space in the second excluded volume, the portion of the surface in the first 3D representation is disregarded, and/or —if a portion of the surface in the second 3D representation is located in space in the first excluded volume, the portion of the surface in the second 3D representation is disregarded
