PROCESS FOR DETERMINING THICKNESS AND EVALUATING DEGRADATION OF LAYERS BY CORROBORATING X-RAY IMAGE ANALYSIS AND X-RAY FLUORESCENCE SPECTROSCOPY

摘要

The invention relates to a process for determining thickness and evaluating the degradation of archaeological objects or objects of cultural patrimony, based on radiographs. According to the invention, the process is based on using two non-destructive techniques, namely: X-ray imagery and X-ray fluorescence spectroscopy, and the observation that the shades of grey obtained in radiographs are influenced by the acquisition parameters, the type of the investigated material and the thickness thereof, so that, by using fixed exposure parameters on samples of known composition, a correlation between the thickness of the sample and the value of the grey shade can be obtained. The claimed process consists of a stage of radiological exposures by using control samples of various thicknesses, to obtain calibration curves for various materials, at various thickness and acquisition parameters, followed by a stage of assigning a shade of grey to each thickness and of adding the calibration curves in a data base, after which radiographs of the object to be investigated are carried out, the object is elementarily characterized so as the material of which the object is made to be identified, followed by application of a calibration curve from the data base, selected depending on the material of which the object is made and on the acquisition parameters used, and information is obtained concerning the thickness and the degradation degree of layers by comparing the shades of grey from the radiograph with the shade from the calibration curve.