A theoretical and experimental study of speckle, as applied to ultrasonic imaging, is presented. The concept of laser speckle is briefly reviewed and is used as a starting point to explain the origin of acoustic speckle. The primary differences between these two phenomena are discussed and are confirmed by experiment. An experimental study of speckle reduction by summation of multiple images is also presented. Several techniques for generating independent speckle patterns for use in image summation schemes are proposed. A phased array, dynamically focused sector imaging system was used in all of the experimental studies reported.
Weak-scattering static diffuser by fast pumping dispersed-nanoparticles in a long distance using microfluidic flows for efficient laser speckle reduction