Laser triangulation apparatus and calibration method

A method for determining a distance of an apparatus to an object, the method comprising:

• providing a beam of radiation;
• projecting the beam of radiation onto a transmissive device with at least one tunable reflective surface comprising a switchable mirror, the transmissive device being arranged in the apparatus;
• irradiating the object with at least a portion of the beam of radiation transmitted through the transmissive device;
• receiving at least a portion of a first part of the beam of radiation reflected by a first surface of the transmissive device on a first location on a detector;
• receiving at least a portion of a second part of the beam of radiation reflected by a second surface of the transmissive device on a second location on the detector;
• receiving at least a portion of the beam of radiation after interaction with the transmissive device and with the object on a third location on the detector;
• and
• deriving the distance of the apparatus to the object based on a spatial distance between the first location and the second location, and at least one of:
• a spatial distance between the first location and the third location, and
• a spatial distance between the second location and the third location.