The paper refers an industrial solution to 3D measurements to be used in security application. The basic assumption of the proposed solution is the visibility of a 3D reference system in the imaged scene. The corresponding vanishing points are used as stereo point pairs at infinity, to compute the rotation between the two stereo views. To achieve a metric reconstruction, the proposed approach relies on the presence in the scene of an artificial landmark having an orthogonal triangular shape with sides of one meter length.. Reflecting cylinders are positioned at the corners and along the sides at equally spaced distances. They represent the initial stereo correspondence for system calibration. This approach has been implemented in a prototype product for the planar reconstruction in case of car accidents using a digital camera. The software application provides a simple and user-friendly interface to the process. The measure errors are always within 2 % (with a 4Mp camera).