The Random Phase Transducer: a New Technique for Incoherent Processing-basic Principles and Theory

It is pointed out that speckle noise can be reduced through the use of incoherent processing techniques. The theoretical limit for the SNR improvement when incoherent processing techniques are used is studied. The study leads to the concept of information grains. A simple technique for incoherent processing that is easy to implement and that allows a good physical understanding of the limitations of incoherent processing of pulse-echo signals is also studied. This technique does not require the division of the receiving aperture into many small coherent subelements, the scanning of the field as in spatial compounding, or the use of low-sensitivity CdS transducers. It involves a single coherent transducer and a moving random phase screen placed in front of it.