Cubic surface fitting to image with edges as constraints

Conventional polynomial interpolation methods produce images with blurred edges, while edge-directed interpolation methods make enlarged images with good quality edges but with detail distortion in the non-edge portion. A new method for constructing a fitting surface to image data is presented. Unlike existing methods which produce enlarged images using image data as interpolation data, the new method constructs the fitting surface using the image data as constraints to reverse the sampling process for improving the fitting precision. To remove the zigzagging artifact, for each pixel and its nearby region, the edge information is used to determine the quadratic polynomial which approximates the original scene with a quadratic polynomial precision. Comparison results of the new method with other methods are included.