Determination of the velocity of sound with high resolution by ultrasonic imaging of wedge shaped objects in transmissionwith vector contrast

摘要

The determination of the velocity of sound for small objects suffers from limited resolution concerning as well the determination of the extension along the path of the sound waves as the determination of the time-of-flight. Imaging of planar objects with a wedge shaped boarder allows imaging in transmission with no object and the full object in the path of the acoustic waves in a continuous manner. Such phase tracking available by PSAM can be used to determine the variation of the time-of-flight with ultimate resolution. Furthermore, for a coupling fluid with a speed equal to the speed of the object under study, the extension of the object does not contribute to the result. Similarly for coupling fluids with sound velocities close to the one of the object under study the error concerning the extension which can be substantial for microscopic objects is reduced and can be minimized by selection of suitable fluids. The method is demonstrated and application involving different objects and fluids are demonstrated.