Preliminary Study on Estimation of Speed of Sound in Propagation Medium Considering Target Scatterer Size

Speed of sound estimation in propagation medium of ultrasound is essential to improve an ultrasound imaging quality. In an estimation method based on received time differences among elements in a transducer array, it is generally assumed that the received ultrasound wave is scattered from the ideal point scatterer. However, there is a scatterer that has a size in a living body, such as small blood vessels. In our previous study, we confirmed that the positive estimation error occurs if the target scatterer has a size and the speed of sound is estimated without considering the target size. In the present study, we proposed the correction method of erroneously estimated speed of sound by considering the size of the target scatterer under the assumption that the target diameter is known as a preliminary study. The proposed method was confirmed in a water tank experiment using wires with several diameters. As the result, the speed of sound in water was estimated within 0.15% error regardless of target diameter.