High density print circuit board line widths measurement based on partial differential equations

In order to measure high density print circuit board line widths, an algorithm of image preprocessing is proposed. Methods of image de-noising are especially researched. This technique can remove noise with adaptive anisotropic diffusion equation filter model based on morphology. Prominent edges can be preserved or even enhanced when noise is removed. Experimental results show that the proposed image preprocessing method has strong de-noising and preserving edge capability. The accuracy of line widths measurement is improved to satisfy real-time detection. It can be applied to practical engineering measurement system.