TIME OF ARRIVAL DELINEATION IN ECHO TRACES FOR REFLECTION ULTRASOUND TOMOGRAPHY

Ultrasound Computed Tomography (USCT) is an imaging method to map acoustic properties in soft tissues, e. g., for the diagnosis of breast cancer. A group of USCT methods rely on a passive reflector behind the imaged tissue, and they function by delineating such reflector in echo traces, e.g., to infer time-of- flight measurements for reconstructing local speed-of-sound maps. In this work, we study various echo features and delineation methods to robustly identify reflector profiles in echos. We compared and evaluated the methods on a multi-static data set o f a realistic breast phantom. Based on our results, a RANSAC based outlier removal followed by an active contours based delineation using a new " edge" feature we propose that detects the first arrival times of echo performs robustly even in complex media; in particular 2.1 times superior to alternative approaches at locations where diffraction effects are prominent.