Image interpolation with prescribed tangent of cubic B-spline curve

We propose a novel image interpolation scheme based on prescribed tangent of cubic B-spline curve. Firstly a cubic B-spline interpolation curve is constructed by discrete pixels. Then a straight line is constructed by joining two points on the B-spline curve with respect to two neighboring pixels. The value of the interpolation point between the two points is determined based on the tangent of the B-spline curve, whose slope is equal to that of the above straight line. Finally, we use the Sobel operator to estimate the edge direction of the interpolation point. Experiments results indicate that the proposed method can greatly maintain the basic information of the original image, reduce the effects of image smoothing and edge blurring caused by the traditional cubic B-spline interpolation, and improve the sharpness of the edges.