  == Expansion ==  This article needs some major expansion on numerous fronts.  Techniques that should be added or expanded: stereoscopic piv dual-plane stereoscopic piv micropiv scanning piv holographic piv  Equipment should be expanded on to include some mention of the optics and lasers utilized.  Software and analysis techniques should also be mentioned to complete the entry.  I do have experience in the field but haven't done large edits before.  So if you see a formatting error please point it out.