Auto-focus technology and its application based on image processing

Auto-focusing technique is an important method to improve the precision,intelligentization,automatization for the indentation diameter measurement.The paper introduces an auto-focus method of indentation diameter measurement based on image processing.Hard core of the auto-focusing technique is the evaluation function's selection.Based on the auto-focusing algorithms investigation,image sharpness evaluation functions are built based on vector model and DCT.Using experiments,it is found that the algorithms put forward in this paper have evidently improved the unimodality,accuracy,stability,reliability and rapidity.And software design is realized by the mixed programming between VB and MATLAB based on the COM technology.