1. A method for enlarging a digital image, the method comprising: (1) selecting an enlargement factor λ for an input image; (2) selecting a pixel in the input image; (3) placing a (λ+γ)±(λ+γ) supporting window over the input image, the supporting window being substantially centered in the selected pixel; (4) producing a λ×λ block of output pixels, wherein each pixel in the block of output pixels is produced by summing the results of multiplying the pixels located inside the supporting window by one of a set of λ 2 distinct (λ+γ)×(λ+γ) weight matrices; (5) assembling the block of output pixels into an output image; and (6) repeating (2)-(5) for each of the remaining pixels in the input image.