Third generation wavelet for the extraction of morphological features from micro and nano scalar surfaces

This paper investigates wavelet theory and techniques for the extraction of morphological structures from micro/nano scalar surfaces. It will significantly extend the authors’ previous accomplishments in the programme (EU: SMT CT98-2209). This previous work identified problems in the extraction of morphological structures that requires further study. Under a new EPSRC found project, the present work tries to overcome these problems and facilitates more practical and feasible methodologies for the identification and extraction of morphological structures on micro/nano scalar surface textures. In the current work, a complex wavelet model is introduced to solve the problems of nanometre roughness analysis of surface texture with linear features and curve-like features, in which small shifts of the input signal can cause large variations in the distribution of energy between wavelet coefficients at different scales. As a result, linear and curve-like features on a surface topography can be identified and extracted with refined accuracy. Case studies are conducted using automotive cylinders and femoral heads to demonstrate the application of using the new wavelet model in the assessment of surface topography.