Papers by Keyword: Laser Spot

Abstract: Measurement of the energy distribution of laser spots is an effective way in characterizing and diagnosing laser beam quality. After comparing conventional direct-detection and indirect-detection methods, a novel direct-detection scheme, which is based on detector-array controlled by single-chip microprocessors, is proposed. On the basis of analyzing key technologies such as data transmission and optical-electrical conversion, a block diagram of the system is proposed. In this system, a distributed structure was adopted which was composed of a host PC, a main microprocessor and lower microprocessors. This system is capable of measuring the parameters of laser beam in outfield such as size and shape of the spot, the energy of pulse and its distribution etc. It is suitable for most of lasers with repetition rate ranging from single pulse to several hundred per second and different energy up to moderate-high level. The system is more accurate than any former systems.

Abstract: A new system for measuring bridge deflections based on laser imaging process is introduced. Firstly, principle of this system is analyzed with geometrical optics theory. Secondly, hardwares of measuring system are illuminated in detail, and the key software problems are discussed, including laser spot center location and accurate control of motorized TV zoom lens. The laser spot center location is realized by using image fuzzy edge extraction algorithm and Hough transform algorithm. The accurate control of motorized TV zoom lens' motors is realized by using a control-driving card based on ISA bus. At last, the contrastive experiments are operated on a certain continuous steel bridge with this system and dial test indicator. The experimental results show that this system is equal precision with dial test indicator, and can get over defects of traditional measuring methods. The security and reliability is much higher relatively and the precision can match to the engineering requirement.