SPIE Proceedings [SPIE International Symposium on Photoelectronic Detection and Imaging 2011 - Beijing, China (Tuesday 24 May 2011)] International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging - Measurement of the light backward scattering characteristics from a target with rough surface and its image processing