After the BLENDER analysis, the team spent another year gathering follow-up observations in the form of high-resolution spectroscopy, adaptive optics imaging, and speckle interferometry
to thoroughly characterize the systems.
Individual chapter topics include radial speckle interferometry
, depth-resolved displacement field measurement, optical vortex metrology, and speckle coding for optical and digital data security applications.
is 2-dimensional phase interferometry.
Several authors [7,8] have discussed various aspects of laser-based systems in general, considering holographic  and moire  methods, laser-interferometry  and laser speckle interferometry
[4,9] and have shown that most of them are more sensitive to the above-mentioned rigid body displacements than the laser speckle shift method, discussed in this paper.
In a previous article (2) we used dynamic speckle interferometry
(DSI) to study the drying process of waterborne and solventborne paints, where the drying times were long enough to follow the process properly.
He obtained the images using a modification of an observing method known as speckle interferometry
Photoelasticity, deflectometry methods and grids, holography, speckle interferometry
and image correlation are thus the subject of dedicated chapters.