An Analysis of the Effects of Speckle on Laser Scanning Systems.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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The effects of speckle on an imaging system composed of a laser scanning a rough surface and a receiver measuring the reflected field are examined. Three types of lasers and two types of receivers are considered. The lasers are designated by their bandwidths as monochromatic, quasimonochromatic, and broadband. The receivers are the heterodyne and direct detection. A second moment model is obtained for each system. The system consisting of a broadband laser and direct detection receiver is shown to be independent of speckle effects. All other systems are shown to have a noise, due to speckle, which is signal dependent. The signal to noise ratio for the direct detection system is shown to be higher than for the heterodyne systems. The system with broadband lasers are found to have a higher resolution than systems with other laser sources.
- Lasers and Masers
- Optical Detection and Detectors