Method of extracting features of image

Abstract

A method of extracting a feature of an image, includes: a first step of performing a logarithmic conversion process for each pixel of an image taken by an electron microscope to carry out non-linear image enhancement; a second step of performing an N(N is a predetermined value) valued process for each pixel of the image underwent the logarithmic conversion process, threshold values for the N valued process being obtained by dividing the whole range of gray levels of the pixels by N, and gray level of the pixel being one of N constant gray level values by the N valued process; a third step of performing a partial differentiatial process in X- and Y-directions for each pixel of the image obtained by the second step, to make "0" the gray levels of pixels within the same area divided by the N valued process and make only the boundary between different areas divided by the N valued process to have a certain gray level; and a fourth step of detecting the boundary and extracting a feature of said image.

Dependencies are inferred from the claim text.