Danmarks Tekniske Universitet

Technical University of Denmark

Steen Hanson

Michael Linde Jakobsen

Christian Pedersen

Bjarke Rose

Peter John Rodrigo

Theis Iversen

A vector velocimeter includes a laser emitting a measurement beam with a wavelength &#x3bb;, for illumination of an object in a measurement volume to create a signal beam, a reference beam generator generating a reference beam, and a first detector arranged such that the signal beam and the reference beam, propagating at a first angle &#x3b8; relative to the signal beam, are incident thereon. The first detector includes an array of first detector elements to convert the intensity of the interfering signal beam and reference beam incident thereon into an oscillating electronic detector element signal when the fringe pattern formed thereby moves across the first detector array. A signal processor generates a velocity signal corresponding to a first velocity component of movement of the object in the measurement volume in the longitudinal direction thereof based on the electronic detector element signals from each of the first detector elements.

Vector velocimeter

The present invention relates to a compact and inexpensive optical displacement sensor that does not require accurate control of the distance to the object. A repetitive optical structure is utilized for formation of a repetitive optical signal emitted by an illuminated moving object. The repetitive optical structure is illuminated by the light source for formation of a fringe pattern (similar to Laser Doppler Anemometry), and/or, an object is illuminated by the light source and the repetitive optical structure diverts light from the illuminated object onto light sensors. A speckle pattern is formed on the object by the illumination. The speckle pattern moves with movement of the object, and speckle pattern movement is determined without a need for imaging the object onto the repetitive optical structure. Since the speckle pattern is not imaged onto the optical member, the distance and possible distance changes between the object and the optical member substantially do not affect system performance.

Optical displacement sensor

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Fakse, Denmark

Steen Hanson