Characterization of optical, electronic and topographic images in fatigue research

摘要

The characterization of images containing fatigue manifestations often implies the detection and quantification of thin and elongated objects such as fatigue striations, slip bands and micro cracks. In this paper, we propose a classification of these images in three categories: (1) fractured surface imaging, (2) damaged surface imaging, and (3) deformed surface imaging. Each category has a preferential mode of acquisition (electronic, optical microscope or laser scanner), and a particular processing (conventional matrix processing, directional filter via Fourier transform, Haralick's segmentation process, shape classification). The accuracy and reliability of the algorithms presenting a novelty will be further discussed. The objectives are to measure the orientation and spacing between striations on fractured surfaces, to evaluate the relative surface of slip bands on damaged surfaces, and to assess the shape and size of a crack tip plastic zone qualitatively via deformed surface imaging.