Abstract: Artificial circular targets are popularly used image features in computer vision and close-range photogrammetry applications.It is vital important to determine their elliptic projections in an accurate manner.A novel technique for accurately determining an ellipse center was presented.The technique,called the moment and curvature preserving(MCP),utilizes the first three intensity moments and the intensity gradient of the image for sub-pixel edge detection,then performs direct least squares fitting(LSF) for ellipse center location.