OPTRA has developed a new approach to the determination of particulate size distribution from a measured, composite, laser angular scatter pattern. Drawing from the field of infrared spectroscopy, OPTRA has employed a multicomponent analysis technique which uniquely recognizes patterns associated with each particle size "bin" over a broad range of sizes. The technique is particularly appropriate for overlapping patterns where large signals are potentially obscuring weak ones. OPTRA has also investigated a method for accurately training the algorithms without the use of representative particles for any given application. This streamlined calibration applies a one-time measured "instrument function" to theoretical Mie patterns to create the training data for the algorithms. OPTRA has demonstrated this algorithmic technique on a compact, rugged, laser scatter sensor head we developed for gas turbine engine emissions measurements. The sensor contains a miniature violet solid state laser and an array of silicon photodiodes, both of which are commercial off the shelf. The algorithmic technique can also be used with any commercially available laser scatter system.

Date Published: 8 November 2005
PDF: 10 pages
Proc. SPIE 5993, Advanced Environmental, Chemical, and Biological Sensing Technologies III, 59930Q (8 November 2005); doi: 10.1117/12.630714

Published in SPIE Proceedings Vol. 5993:
Advanced Environmental, Chemical, and Biological Sensing Technologies III
Tuan Vo-Dinh; Robert A. Lieberman; Gunter Gauglitz, Editor(s)