From ultrafast ultrasound imaging to “matrix imaging”

Abstract

Both ultrasound medical imaging and NDT requires reflection-mode detection. As tissues, as well as many metallic samples, are complex disordered media, containing random distribution of scatterers, these techniques suffer various limitations as distortion induced by aberrating layers. A multi-illumination strategy is the solution to solve these problems. It was first used in the context of ultrafast imaging with multiple plane wave illumination. I will show that, recording a “reflection matrix” provides enough information to greatly improve beam-forming techniques. I will describe how to extract from the coherence properties of this reflection matrix enough information both to compensate the effects of aberrating layers and to provide quantitative information. Various strategies to measure this matrix and to exploit it will be discussed. This is the domain of “matrix imaging” recently developed for ultrasound imaging.