Abstract: A measuring method for determining the distance between the distal end of an endoscope and an object to be examined uses an optical radar and an endoscope, which comprises a distance measuring device. For carring out the measuring, a transmitting fiber optic and a receiving fiber optic in the endoscope are guided separately to respective separate optic modules at the front end of the endoscope. A semiconductor laser feeds a high frequency amplitude-modulated light in the transmitting fiber optic, which is projected by the transmitting optic module on the object in the form of a light spot. The light reflected from the object is received by the receiving optic module and guided through the receiving fiber optic in the endoscope to a light detector of a control unit. In the control unit a phase measurement is carried out and an evaluation device computes the distance information from the phase difference.

Abstract: In a method and apparatus for determining the concentration of optically-active substances in a fluid, such as glucose in the body fluids of a patient, two light sources are used to produce respective polarized light beams which pass through the substance to be analyzed and are incident on a detector. The second beam has a fixed polarization direction relative to the first beam. The light sources are alternatingly switched on and off at a known-frequency. A dispersing element is disposed in the path of each beam. A comparative signal is produced from the beams exiting the substance and incident on the detector.

Abstract: A method and apparatus for the quantitative determination of optically active substances includes two light-emitting diodes, each with a respective collimator lens and polarization filter, a cell filled with dialysate, an analyzer, a detector and measurement and evaluation electronics. The clocked light of the light-emitting diodes is linearly polarized by the polarization filters. The polarization directions differ by a few degrees. The polarization direction of the analyzer is aligned essentially perpendicularly relative to the polarization filters, such that the radiation of the two light-emitting diodes passing through an optically non-rotating dialysate generates the same photosignal in the detector.