The method of ellipse contour extraction based on Least-squares and elliptic roundness error

Abstract：In order to obtain gear axial parameters from the spiral bevel gear space positioning and three-dimensional reconstruction of digital image, the principle of the least squares, the round contour error evaluation is proposed.The simulation model of the bevel gear digital image is estascished for access to the gear axial parameters.Matlab software is used for digital images processing, such as image enhancement, the border extraction, the border value, combined with the least squares coordinates of pixels to fit oval, and to make the oval fitting error minimum by using of the round contour error evaluation.The method can fit ellipse accurately, get more accurate parameters of the oval and effectively remove the noise, improve the accuracy of fitting oval, provide a algorithm of the digital image to remove noise, and offer the more accurate data of the spiral bevel gear for positioning and three-dimensional reconstruction.

Keyword：spiral bevel gear;roundness error;ellipse fitting;boundary extraction;