Influences of Echo-responses SNR on Time Spectral Shifts related to Estimation of Thermal Parameters based on Overtones Processing for Medical Diagnosis

摘要

Some new researches for non-invasive diagnostic applications, by detecting local thermal gradients on internal tissues, seeking a very-early detection of some types of cancer are a promising investigation way with high medical interest. The signals processing methods and algorithms, in which those are based, must be robust enough, even when the echo-responses contain moderated levels of coherent noise. In this paper, the influences of some levels of induced noises, including those of the coherent type, are analyzed in time & frequency domains. The power spectrum shifts on overtones are also investigated. So, an analysis of time & frequency curves alterations and of finally estimated thermal distribution is made, for distinct synthetic noisy multi-pulse waveforms, similar to those appearing in real echo-acquisitions. Finally, some behaviors in waveforms and power spectra are analyzed from complex noisy echo-waveforms containing many ultrasonic pulses overlapping among them.