In this study, integrated gray-level gradient method, locating the best focal plane, is applied to extract the 3D velocity fields of sprays in in-line digital holography. This method consists of a conventional edge-sharpness [Es] method and a new method, namely, overall-sharpness [Os] method which is an efficient supplement of the former. The respective scopes of application of above criterions were discussed by using numerical simulation holograms of particles. And then, The integrated gray-level gradient method is proved to be an effective tool for the determination of focal plane by using the calibration target. Finally, the synchronization system is designed and assembled to record double exposure spray holograms in a short time interval. Using the integrated gray-level gradient method and some image processing techniques, the 3D coordinates of droplets are easily obtained which can be used to evaluate the 3D velocity fields of sprays. It proves that the integrated gray-level gradient method is well applied to measure the characteristics of sprays in in-line digital holography.

Date Published: 15 November 2011
PDF: 8 pages
Proc. SPIE 8321, Seventh International Symposium on Precision Engineering Measurements and Instrumentation, 83213J (15 November 2011); doi: 10.1117/12.905331

Published in SPIE Proceedings Vol. 8321:
Seventh International Symposium on Precision Engineering Measurements and Instrumentation
Kuang-Chao Fan; Man Song; Rong-Sheng Lu, Editor(s)