Proposal for roughness evaluation using median filter and investigation of the optimum filter width

Abstract

The median filter (MF) is a filter that satisfies both robustness and short calculation time. MF is used in image processing fields etc. In the field of surface roughness, MF is used to identify and remove outliers. However, it has not been used so far to calculate the mean line for evaluating the surface roughness. In this study, we propose a method for applying MF to calculate the mean line for surface roughness evaluation. As a result of the verification, even when the filter width of MF is narrowed, the results of Ra and Rz are close to those of the surface roughness evaluation using the conventionally used GF. Therefore, we confirmed that the MF can be used to evaluate the measurement of small objects whose surface roughness cannot be evaluated by the GF.

Keywords

• Surface roughness
• Gaussian filter
• Median filter
• Filter width
• Surface texture