Aiming at the gear involute-error of the small module gear with small dimension

the measurement method based on the CCD and image processing technique is presented.In order to acquired precise edge location data

the median filter

binarization

edge extraction arithmetic and sub-pixel fitting arithmetic are used in the image processing.The calculation of circle center

the conversion relations of pixel and real dimension

the image splicing is solved.After the measurement method and measurement process of gear involute error is analyzed

the measurement model is established.Experiments result show the method adopted is feasible

the absolute error of measurement is less than 9.2 mm and the method adopted is usegul for the gear involute error of small module gear with small dimension.