Abstract: A generally time-varying boundary surface between a plurality of flowing fluids having different refractive indices, e.g. the boundary surface between water and air with an open water surface, produces an optical disturbance. Optical flow measurement procedures that occur through the boundary surface are affected by this disturbance, which can lead to significant measurement deviations or can even completely prevent a measurement from being made. The invention contributes to solving this metrological problem by proposing arrangements and methods for instantaneous, hardware-based correction of optical disturbances caused by a fluctuating boundary surface. For this purpose, a wavefront modulator is introduced into the beam path of the optical measuring method, the modulator actively compensating for the optical disturbance by means of a control system. The invention makes it possible to perform optical flow measurements through a fluctuating boundary surface.

Abstract: A generally time-varying boundary surface between a plurality of flowing fluids having different refractive indices, e.g. the boundary surface between water and air with an open water surface, produces an optical disturbance. Optical flow measurement procedures that occur through the boundary surface are affected by this disturbance, which can lead to significant measurement deviations or can even completely prevent a measurement from being made. The invention contributes to solving this metrological problem by proposing arrangements and methods for instantaneous, hardware-based correction of optical disturbances caused by a fluctuating boundary surface. For this purpose, a wavefront modulator is introduced into the beam path of the optical measuring method, the modulator actively compensating for the optical disturbance by means of a control system. The invention makes it possible to perform optical flow measurements through a fluctuating boundary surface.

Abstract: A method and a fibre-optical system for illuminating and detecting an object by light includes in situ calibration of a fibre bundle and disturbance-corrected illumination or disturbance-corrected detection of an object, in particular for endoscopic and microscopic applications, and makes it possible to directly determine the single phase distortion of the light, caused by the transmission by the fibre bundle, in order to calibrate the fibre bundle, and thus provides a possibility for determining the system function of a fibre bundle that is improved compared with the prior art of measuring the double phase distortion. The system function is used for disturbance correction when illuminating or detecting the object.

Abstract: A method and a fibre-optical system for illuminating and detecting an object by light includes in situ calibration of a fibre bundle and disturbance-corrected illumination or disturbance-corrected detection of an object, in particular for endoscopic and microscopic applications, and makes it possible to directly determine the single phase distortion of the light, caused by the transmission by the fibre bundle, in order to calibrate the fibre bundle, and thus provides a possibility for determining the system function of a fibre bundle that is improved compared with the prior art of measuring the double phase distortion. The system function is used for disturbance correction when illuminating or detecting the object.

Abstract: The invention relates to an apparatus (1) for non-incremental position and form measurement of moving solid bodies (7), containing a laser Doppler distance sensor (10) in wavelength multiplexing technique with at least two different wavelengths (?1, ?2) and with a modular fibre optic measurement head in its sensor design, which contains two additional modules, which are connected to the measuring head by means of fibre optics a light source unit (2) and a detection unit (4). Two laser light bundles (37) of different wavelengths (?1, ?2) in the light source unit (2) are coupled into a glass fibre (24). The bichromatic scattered light in the detection unit (4) is split into the different wavelengths (?1, ?2) corresponding to the two measurement channels (41, 42) and subsequently are detected separately by means of two photo detectors (43, 44).