According to the imaging characteristics

for achieving high precision measurement in linear profile of micro-parts

an evaluation algorithm of linear profile which based on discrete points is proposed. Firstly

edge detector is used to obtain the edge of the micro-parts. After that

a series of points which has tiny interval can be calculated by the expressions of designed profile. In addition

a system of coordinates is build for corresponding the point of actual profile and the point of designed profile. Finally

for every point of actual profile，we can calculate the minimum distance between it and the points of designed profile as the linear profile error of the point. The experimental results showed that the error is less than 1.5 pixels，so the proposed algorithm can significantly improve the precision and efficiency in measurement of linear profile.