**Comparative Analysis of Three Digital Signal Processing Techniques for 2D Combination of Echographic Traces Obtained from Ultrasonic Transducers Located at Perpendicular Planes**

Miguel A. Rodríguez-Hernández1, Antonio Ramos2 and J. L. San Emeterio2 *1ITACA. Universitat Politècnica de Valencia 2Lab. Ultrasonic Signal, Systems and Technologies, CSIC. Madrid Spain* 
