Echo-graphic images enhanced through Walsh functions

Echographic images can be reconstructed by means of a multi-element ultrasound probe; the emitting elements are fired in sequence, while the receivers provide echo signals in parallel. Backpropagation techniques, applied to recorded echoes, give high resolution grey level maps, but often with unacceptable noise, because of the low acoustic energy emitted. A solution can be found in Walsh functions, which allow to fire all the transmitters at the same time, and to reconstruct the Single Shot echoes. Tests have been carried out in a simplified simulation environment, in two dimensions and with electric waves replacing ultrasounds. Results are encouraging.