Spatially selective detection using a dynamic mask in an image plane

摘要

A three-dimensional laser scanner instrument for acquiring three-dimensional geometric data of a scene (1) comprises an illumination system (3) for generating a light beam (2) and for scanning an illumination point of said light beam (2) through said scene (1), a light detection system (6-9) comprising at least one light detector (8), said light detection system being arranged to receive light from said scene (1), and an optical system (4) for imaging light scattered in or reflected from said scene (1) onto said light detection system (6-9). The light detection system (6-9) further comprises a controllable filter element (6) for dynamically discriminating light impinging from selected regions of said scene (1) and a control unit (9) operatively connected to said controllable filter element (6) and to said illumination system (3), wherein in operation of said scanner instrument, said filter element (6) is controlled by said control unit (9) so as to guide only light impinging from a selected, spatially delimited region around said illumination point in said scene (1) onto said at least one light detector (8).