Speckle noise reduction is best tested on a precise speckle contrast measurement bench, which should be able to measure 100% contrast in fully developed speckle as well as the smallest contrast (for example, less than 10%) after its reduction. On such a test bench, we have measured very efficient speckle contrast reduction by temporal averaging using a moving diffuser on a tuning fork, which vibrates at over in amplitude, a distance that is three times the surface roughness correlation length of the diffuser.
© 2010 Optical Society of America
Equations on this page are rendered with MathJax. Learn more.