Abstract:Aimed at the disadvantage of low accuracy of traditional O ring size detection technology,a new size detection method was put forward.For this method,the digital image processing technology was used to detect the image edge of O ring whose shape is variable,the approximate polygon method was used to get the inside and outside perimeter of O ring,and the corresponding diameter was calculated by the inside and outside perimeter.The experimental result shows that this method has higher accuracy and can satisfy assembly requirements.