AUTO-SHAPE ANALYSIS OF IMAGE TEXTURES IN FRACTOGRAPHY

Abstract

The aim of this study is to estimate the velocity of fatigue crack growth (crack growth rate - CGR) from the texture in SEM images of crack surfaces. A simple and quick method is based on fitting training images as a linear combination of several small subimages selected from the images themselves. The size of basic subimages is derived from autocorrelation functions of the image in row and column direction. The selection of basic subimages is based on two indicators: "appeal" evaluating their shape content, and mutual coefficient of correlation. The method is easy to implement and quick in computations, while results of testing application are fully comparable with best ones obtained within textural fractography of fatigue failures.