Wavefront amplitude distortion and image sidelobe levels. I. Theory and computer simulations

1 November 1993

journal article
Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Vol. 40 (6) , 747-753
https://doi.org/10.1109/58.248219

Abstract

The quality of an imaging system is degraded by propagation anomalies that distort wavefronts propagating through the medium. Adaptive phase-deaberration algorithms compensate for phase errors in the wavefront. The algorithms suffer, however, when the wavefront is also significantly distorted. A theory which shows that the rise of image background level, which is the average sidelobe floor (ASF), in a single point-like source image is proportional to the amplitude distortion of the wavefront and inversely proportional to the effective number of array elements is derived. From the theory, the tolerance to the amplitude distortion, after the phasefront has been corrected by a deaberration algorithm, can be calculated based on the design requirement of the sidelobe floor for a given array. Computer simulations show good agreement with the theory.<>

Keywords

This publication has 23 references indexed in Scilit:

Time reversal of ultrasonic fields. Il. Experimental results
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 1992
Large-transducer measurements of wavefront distortion in the female breast
Ultrasonic Imaging, 1992
Experimental results with a real-time adaptive ultrasonic imaging system for viewing through distorting media
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 1990
Phase aberration correction in medical ultrasound using speckle brightness as a quality factor
The Journal of the Acoustical Society of America, 1989
Self-cohering large antenna arrays using the spatial correlation properties of radar clutter
IEEE Transactions on Antennas and Propagation, 1989
Phase-aberration correction using signals from point reflectors and diffuse scatterers: basic principles
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 1988
A theory of the effect of hard limiting and other distortions upon the quality of microwave images
IEEE Transactions on Acoustics, Speech, and Signal Processing, 1987
Measurement of Spatial Time-Of-Flight Fluctuations of Ultrasound Pulses Passing Through Inhomogeneous Layers
Published by Institute of Electrical and Electronics Engineers (IEEE) ,1987
Radar imaging from a distorted array: The radio camera algorithm and experiments
IEEE Transactions on Antennas and Propagation, 1981
The importance of phase in signals
Proceedings of the IEEE, 1981