1. A method of smoothing a raster image comprising: (a) triangulating the image to create triangles having vertices, each vertex being centered on a pixel of the image; (b) comparing with a computer a cost of a first orientation of an edge of a pair of adjacent triangles that forms a quadrilateral to the cost of a second orientation of the edge of the pair of triangles, using a cost function C; (c) swapping with a computer the edge of the pair of triangles to the second orientation if the cost of the second orientation is lower than the first cost; and (d) repeating (b) and (c) for each pair of adjacent triangles that forms a quadrilateral until a stopping point is reached; wherein the cost function C includes a first cost factor that causes a triangle edge orientation that aligns with a LAB weighted color intensity contour line of the image to have a lower cost than a triangle edge orientation that does not align with the LAB weighted color intensity contour line of the image.