Microcracking of wood caused by drying was investigated by detecting the intensity variations of a speckle pattern induced by a focused laser beam scattered from the surface. Two trials were carried out to test the usefulness of this method. The trials were used to compare the severity of different drying treatments and to follow the development of cracking during drying. The data gathered from these experiments revealed clear correlation between the amount of cracking on a wood surface and severity of the drying treatment. Furthermore, an increase in the amount of cracks was observed as drying proceeds.
Raimo Veil Johannes Silvennoinen,
"Investigation of microcracks in wood with laser speckle intensity," Optical Engineering 40(5), (1 May 2001). http://dx.doi.org/10.1117/1.1358297