A shearlet-based separation method of 3D engineering surface using high definition metrology

• A shearlet-based filter method is proposed for separation of 3D engineering surface.
• This method has similar performance as current ISO standardized Gaussian filter has.
• This method is expected to be superior to Gaussian filter due to its nice properties.

The 3D engineering surfaces are considered as having a range of spatial frequency components including roughness, waviness and form. Before the characterization of a 3D engineering surface, filtering is done first to separate these different components. To overcome the shortcomings of the traditional filtering methods, this paper presents a shearlet-based separation method using high definition metrology (HDM) that has the ability to measure a huge number of data points to represent a 3D surface. The 3D engineering surface is decomposed into different sub-bands of coefficients with non-subsampled shearlet transform (NSST). Then the surface components at different levels are reconstructed by applying an inverse NSST on the shearlet coefficients and combined into the above three surface components. The performance of the proposed method is validated by both simulated surface data and real-world 3D surface data, and the results demonstrate that the proposed shearlet-based method is effective for the separation and extraction of different surface components.