Figure 1
From: Speckle reduction in ultrasound endoscopy using refraction based elevational angular compounding
REACT implementation in EUS. (a) REACT imaging acquisition configuration using radial transducer array. Linear translation of the annular-shaped acoustic cylindrical lens along the elevational direction in front of the stationary radial transducer array controls the elevational angular FOV. (b) Elevational angular steering in different positions of the acoustic cylindrical lens. Sound waves propagate through the water and lens substrate at speeds of cw and cLens, respectively, where cw < cLens. Example of an incidence angle and refracted angle through the lens shown in the inset. The total elevational angular FOV of the transducer (θE: union set of refracted elevational angular views from all positions of the acoustic lens) compared to its inherent elevational angular FOV (θi) is extended. (c) Schematic of annular-shaped acoustic cylindrical lens. The annular-shaped acoustic cylindrical lens is moved in consistent step sizes (δ), which are equal to the length of the acoustic lens (l) divided by the number of recorded images (N) for compounding.
