Multiscale characterizations of painted surface appearance by continuous wavelet transform

The appearance of paint is an important factor in the overall product quality of engineered surfaces, especially in the automotive industry. This paper introduces a multiscale characterization technique of surface topography from roughness to waviness. It uses continuous wavelet transform to correlate the characteristic scale of the surface texture to the paint's appearance. The results show good correlation between the multiscale roughness spectrum and standard distinctness of image (DOI) measurement. After an extensive review of the mathematical and numerical implementations, the multiscale attenuation function of the painting process (MAF) is defined to study the effect of the successive layers of paint coat and the painting orientation modes (horizontal, oblique and vertical).