Abstract: It proposes a new method to detect automatically badminton appearance. First, images of badmintons were collected and processed in a series of steps. Then, by using the method of regiondependent segmentation, based on polarcoordinate, the feature points of binary images were located. Thirdly, the leastsquare method was adopted for fitting. Finally, the related indices were propounded to assess roundness errors. The experimental results prove that this method is feasible to differentiate badmintons of the C and D grades, making the nontouched online measurement possible.

Key words: machine vision; nontouched measurement; regiondependent segmentation; leastsquare method; roundness error