Comparison of optical coherence tomography, X-ray computed tomography, and confocal microscopy results from an impact damaged epoxy/E-glass composite

Optical coherence tomography (OCT) is an emerging technique for imaging of synthetic materials. OCT is attractive because it combines high sensitivity (> 90 dB), high resolution (5 mum to 20 mum), and low cost, approximately US $75 K. The value of any new technology is evaluated by how well it compares with existing methods. In this work, impact damage of an epoxy/E-glass composite is imaged using OCT and the results were compared with micro-focus X-ray computed tomography. This technique is a good benchmark to compare with OCT because both techniques have the ability to locate features precisely and have comparable resolutions. OCT is considered to be a confocal technique so it was also compared to laser scanning confocal microscopy (LSCM). Contrast mechanisms, sensitivity, resolution, depth of penetration, and artifacts among the techniques are compared and contrasted. Also, impact damage features revealed using OCT are briefly discussed.