Phase Coherence Imaging, or PCI, is a technique proposed in 2009 to improve resolution and contrast in ultrasonic testing images. It is based on evaluating the coherence between the signals detected by all the elements of phased array ultrasonic testing probe. The intensity of a PCI image depends on the nature of the indications. Omnidirectional sources such as porosities, tip diffractions, and slags tend to display high intensity as a lot of emitter-receiver pairs of the Full Matrix Capture (FMC) see them
Source: NDT