A method and an apparatus for dimensional measuring of objects of any form and depth. The apparatus comprises at least an illumination system (1) having an optical filter (4), a manipulator unit (5, 6), and an observation system having an optical filter (9). The optical filters (4, 9) are designed so that most of the light passing the object and not being influenced by the object is stopped. The manipulator unit is such that between measurements either the object is made to rotate about one or more fixed rotation centers or to follow one or more known rotation paths, or the whole or parts of the observation optics are made to carry out a coupled movement or alteration in accordance with the whole or parts of the illumination optics, such that the illumination means and the observation means are completely or partly locked together and are altered relative to the object.
A control unit repeatedly photographs an image with cameras while phase shifting a sinusoidal light pattern from light projectors. A phase calculation unit receives image signals and outputs a phase signal from a set of images photographed with a sinusoidal light pattern of different phases. Absolute phase determining units receive two of the phase signals to determine the absolute phase value of the pixel positions. An absolute phase conversion unit receives the phase signal switched by a three-dimensional signal coordinate calculation control signal and the absolute phase signals to convert the phase value of the pixel positions into absolute phase. A three-dimensional coordinate unit receives the absolute phase conversion signal and the three-dimensional coordinate calculation control signal and outputs a three-dimensional coordinate signal. A three-dimensional coordinate synthesis unit receives three-dimensional coordinate signals and synthesizes shape information to output a synthesized three-dimensional coordinate signal.
