Experimental determination of correlation in scattered light by moving surfaces

In the application of speckle velocimetry to real physical situations in phisics of fluids (fundamentally, in the PIV mode) several problems arise. The analysis of the information stored in a specklegram only is reasonably available if a automatic method is carried out. The fundamental problem is however the quantity and quality of such information. The research has followed fundamentally two approach, one in which the principal task is the automatic adquisition of information from the fringe pattern and other in which the principal goal is the formation of reasonably good fringe pattern. In this line, two methods, the multiple exposure and the two-step or copy one has been implemented that show a good performance. There are however certain physical situations in which a ntmiber of problems arise , between them , the apparition of non regular fringe pattern. The experiment proposed here try to reach a more profund insight into de problem so as a systematic research about the relation between speckle photography (SP) and holographic interferometry (HI).