Time delay estimation for strain imaging using the phase of the complex envelope of RF signal

Abstract

Time Delay Estimation is a basic technique used for locating and tracking radiating acoustic source. TDE process is common for studying signal-to-noise ratio, input signals and systems that are common in process industry. The delay estimate is acquired using the generalized cross-correlation function applied between the original and the time-lagged filtered version of the received signal. In recent years ultrasound elastography proved as a successful alternative of the invasive biopsy. The fundamental necessity lies in estimating the strain for which time delay estimation is a pre-requisite step. Taking the phase of the complex envelope of the pre and post compression RF echo signals it is possible to successfully compute the time delay between them. The ultimate target of an Elastographic process is the noiseless Elastogram which is used to identify the suspected nodules embedded into the deep of tissue column. In this paper the strain information acquired from the phase of complex envelope and the same is used to analyze the quality of Elastograms studying mainly two parameters strain and sampling frequency.