Use of a laser camera scanner to highlight the surface degradation of stone samples subjected to artificial weathering

A vision technique system was implemented in order to highlight the deterioration developing on the surfaces of stone samples during an artificial ageing test with marine spray. The system, which employs a matrix CCD camera and a laser beam, provides various kinds of information about the decay suffered by the stone samples, by comparing two types of visual information at different times throughout the ageing test: the partial digital images of the sample surfaces and then the surface relief and laser light reflection obtained by casting a sheet of laser light on to the material. The accuracy of the laser camera scanner is evaluated in the first part of this paper. The methodology was successfully used to identify the degradation morphologies occurring on five types of limestone exposed to salt spray, and to quantify the deterioration using statistical parameters computed from digitized visual data