The random phase transducer: a new technique for incoherent processing-experimental results

Author

Laugier, Pascal ; Fink, Mathias ; Abouelkaram, Said

Author_Institution

Lab. de Biophys., Paris, France

Volume

37

Issue

2

fYear

1990

fDate

3/1/1990 12:00:00 AM

Firstpage

70

Lastpage

78

Abstract

Ultrasonic speckle is an inherent consequence of the stochastic nature of the reflectivity of biological tissues. Speckle is a source of noise on envelope detected echoes as well as on the power spectra. A technique where the spatial coherence of the transducer is controlled by moving a random phase screen (RPS) through the ultrasonic beam is described. An RPS that is a rough surface generating phase shifts that are randomly distributed between 0 and 2 pi is presented. Measurements with unfocused and focused transducers working in broadband pulse-echo mode were performed. Experimental results on the directivity pattern and the ability of the system to obtain uncorrelated speckle patterns are presented. The performance of the RPS in SNR improvements is discussed. Experimental results are in good agreement with theoretical predictions.<>

Keywords

acoustic imaging; biomedical ultrasonics; signal processing; SNR improvements; broadband pulse-echo mode; directivity pattern; envelope detected echoes; experimental results; focused transducers; incoherent processing techniques; power spectra; random phase screen; random phase transducer; reflectivity of biological tissues; spatial coherence; speckle reduction; ultrasonic speckle noise; uncorrelated speckle patterns; Biological tissues; Envelope detectors; Pulse measurements; Reflectivity; Rough surfaces; Spatial coherence; Speckle; Stochastic resonance; Surface roughness; Ultrasonic transducers;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/58.46971

Filename

46971