1. A method of recursive filtering a video image comprising the steps of: a. determining, using a computer system, a local variance σ 2 in luminosity in the vicinity of a picture element on the image; b. selecting, using the computer system, an estimated value of noise variance σ r 2 indicative of characteristics of that noise; c. obtaining, using the computer system, a surface for value of a proportional parameter K from the equation K = α ⁡ [ ρ · λ · σ 2 ρ · λ · σ 2 + τ · σ r 2 ] + β where 1≦σ≦128, 1≦σ r ≦64 and ρ, τ, α and β are empirical constants; d. electing, using the computer system, a value of λ to scale a relative contribution to the value of the proportional parameter K by the luminosity variance and the noise variance; and e. recursively filtering, using the computer system, the image using the proportional parameter K to sum proportions of the current image and an immediately preceding image.