The contour tracking is one of the important steps in reverse engineering based on industrial computed tomography. In this paper

the singular pixels of CT slice contour after edge detection

such as discontinuity

redundant

double pixels

are analyzed and the contour tracking algorithm combined eight neighborhood calculation with five neighborhood is presented

which removes the singular pixels effectively and gives a close contour with single-pixel connection. It is shown by the experiments of a vehicle engine that the contour can be obtained exactly and the method is practical.