It is very difficult to measure and evaluate the profile tolerance of complicated curve parts .Having low precision or efficiency

the available measurement and evaluation can’t meet the high precision required by the on-line parts' profile measurement. This paper provides profile measurement and evaluation method for the micro-parts based on the images. This method includes the method of profile data modeling on theory

also includes bound searching method of expansion polar angle for the related theoretical points and an evaluation method of the least -deviation method for profile errors. Moreover

the analysis and comparison between the evaluation method of least deviation profile errors and the evaluation method of classical least -squares method profile errors are performed. The experiments on actual image show that Least Deviation Method converges faster and more accurately to the minimum.