Speckle in ultrasound B-mode scans

TLDR

Ultrasound images from simple linear or sector scans exhibit a granular appearance known as speckle. The authors compute speckle reduction achievable with compound scans using maximum amplitude writing, showing it depends on the number of independent amplitude values and deriving a limit based on the independence condition. Speckle is analyzed, and the reduction achieved is nearly as large as that obtained by averaging.

Abstract

Ultrasound images obtained with a simple linear or sector scan show a granular appearance, called "speckle." This speckle is analyzed. The reduction in speckle that can be obtained with a compound scan with maximum amplitude writing is computed. The reduction in speckle is almost as large as can be obtained with averaging. It depends on the number of independent amplitude values that are measured. The condition for the independence of two amplitude values is derived, and thus a limit is given for the possible reduction in speckle.