Laser light section sensor with improved accuracy by reducing speckles

A method for measuring a test specimen to a light section sensor (1) of a surface (20), comprising the steps of: a) producing a light section plane by a first laser light beam (11) for projection onto the surface (20) of the specimen; b) metrological detection of the light-section on the surface (20) having a camera sensor (53) of the light section sensor (1) and thereby generating first image data; marked by c) generating a controlled nano-shift of a laser light source (52) and / or an optical system (55) and / or of the camera sensor (53) by an actuator 51 in the light section sensor, wherein the nano-shift either longitudinally or transversely, or is generated in the longitudinal and in the transverse direction to the respective emitted light beams; and the nano-shift within a range of 0.5-1 or 1-5 or 1-20 wavelengths of the laser light is located; d) after the nano-shift generating the same light-sectional plane different by (from the first laser light beam 11), a second laser light beam (12) for projection onto the surface (20); e) detecting (by the second laser light beam 12) generated light section on the surface (20) by the camera sensor (53) and thereby generating second image data; and f) by an algorithm determining the resulting image data from the first and second image data by an arithmetic unit, wherein the algorithm is adapted to the measured light section, which is shown superimposed in the first and second image data with speckles, in the resulting image data with less reflect distinct speckles.