1. A method for converting an interlaced video signal to a progressive scan video signal comprising the steps of: for each pixel in each missing line of a video field in a video signal to be converted, providing correlation data for each of a set of possible interpolations between adjacent pixels to be used in reconstructing the missing pixel; deriving a confidence measure from the correlation data; determining from the confidence measure the interpolation scheme most likely to produce an accurate missing pixel; and interpolating the missing pixel using the selected interpolation scheme wherein the step of deriving a confidence measure comprises determining the number of maxima and minima in the correlation data and deriving the confidence measure in dependence on the number of maxima and minima so determined.