Wholefield NDT of Porous Materials Using Digital Holography

NDT of porous material using conventional methods is difficult due to signal attenuation, low sensitivity, problems due to surface irregularities etc. In this paper the feasibility of using digital holographic interferometry to detect defects in porous materials is investigated and discussed. The basic methodology of digital holographic interferometry for defect detection is presented. Proper excitation should be applied on the test object to detect the defect from the anomalous holographic fringe pattern. Extensive experiments have been carried out with different types and magnitudes of excitation to obtain the most suited one. Application of the method to detect defects in porous materials like silica and ceramic material is presented with experimental results.