Stochastic explanation of speckle contrast detection in ultrasound-modulated optical tomography.
Ultrasound-modulated optical tomography is an imaging technique that detects ultrasonically tagged light in optically turbid media to obtain images with optical contrast and ultrasonic spatial resolution. A CCD-camera-based speckle contrast detection scheme has been introduced previously to detect modulated light emerging from the ultrasonic sample volume. Differences in speckle contrast were experimentally observed when ultrasound was applied compared to when it was not. In this paper we provide an analytic explanation for this phenomenon and connect speckle statistics with ultrasonic field parameters. The theory predicts that speckle contrast changes linearly with applied acoustic intensity. This prediction is experimentally validated for both 1 and ultrasound. Signal dependence on ultrasound frequency is discussed.
Zemp
Roger
R
Optical Imaging Laboratory, Department of Biomedical Engineering, Texas A and M University, College Station, Texas 77843-3120, USA.
Sakadzić
Sava
S
Wang
Lihong V
LV
D005780:Gelatin / Q000737:chemistry; D007089:Image Enhancement; D019047:Phantoms, Imaging; D013213:Starch / Q000737:chemistry; D013269:Stochastic Processes; D041622:Tomography, Optical / Q000295:instrumentation / Q000379:methods*; D014465:Ultrasonics
D005780:Gelatin; D013213:Starch