The phase retrieval by a reference source

Exploiting the knowledge of the amplitude of a reference element, the authors develop a novel numerical technique in the phase retrieval problem. An example is shown in the case of a discrete source distribution. Specifically, consideration is given, in a bidimensional geometry, to an array of 18 elements spaced lambda /2 apart plus a reference element spaced 10.5 lambda above the last element of the array.<>