The laser peening process using computer control is described in AMS 2546. Like many other surface enhancement technologies, direct measuring of the results of the process on the workpiece during processing is not practical. Therefore, the process parameters of pulse energy and duration, water and opaque overlays are closely monitored during processing. Other quality control systems are also available that rely on pressure measurements such as electromagnetic acoustic transducers (EMAT), Velocity Interferometer System for Any Reflector (VISAR) and PVDF gauges, and plasma radiometers. Almen strips are also used, but they function as a comparison tool and do not provide a definitive measure of laser peening intensity. The resultant residual stresses imparted by the laser peening process are routinely measured by industry using x-ray diffraction techniques for the purposes of process optimization and quality assurance.