Fig. 2.

Speed of sound calibration for an ex vivo organ (murine kidney). The graphs show the normalized focus measures versus the speed of sound for 7 different focus measures using (a) back-projection and (b) model-based reconstruction methods. For all focus measures the global minima determine the most focused image. Panels (c) and (d) show the images at six different speeds of sound reconstructed with back-projection and model-based algorithms, respectively (values are stated in [m/s]). A zoom-in of a representative region inside the object is showcased for a better visual evaluation of the image quality enhancement achieved with the proper value of the speed of sound.