a method and a device to reduce the avstaandsberoende foer foerstaerkningsfaktorn at maetning of stroemningsroerelser with a bildgivande laser doppler technologyin particular, at maetning of blodperfusion through a vaevnad

摘要

PCT No. PCT/SE92/00570 Sec. 371 Date Apr. 21, 1993 Sec. 102(e) Date Apr. 21, 1993 PCT Filed Aug. 21, 1992 PCT Pub. No. WO93/03667 PCT Pub. Date Mar. 4, 1993.The invention relates to a method and to a system for reducing the distance-dependent amplification factor when measuring fluid flow movements with the aid of an image-producing laser-Doppler technique, in particular when measuring blood perfusion through tissue. A laser beam source (1) directs a laser beam (2) onto a measurement object (5), which scatters and reflects the beam (2). The reflected light is received by a detector (9) which senses the broadening in frequency caused by the Doppler effect. One or more lenses (12: 15, 16) are placed in the path of the beam (2) and are intended to maintain constant the number of coherence areas on the detecting surface of the detector and independent of the distance between detector and measurement object.