Abstract: The CCD camera is installed on the crossbeam of coordinate measuring machine, and three consecutive pictures of the object are taken by camera at first in its initial position, then translating horizontally over a distance d1 along x-axis, and lowering down over a distance d2 along y-axis respectively. Feature points of the surface boundary are extracted from one image, then 3D-coordinates of points are acquired by matching with other two images. B-spline is used to generate surface boundary according to these points.