1. A method for interpolating between scanning lines of a video signal, the steps comprising: detecting values of actual pixels existing on upper and lower scanning lines of a pixel to be interpolated; obtaining a differential between pairs of the actual pixels; weighting each of the actual pixels in accordance with the differential; adding together the weighted values of the actual pixels, thereby providing value of the pixel to be interpolated, wherein a value of a pixel having a smaller differential is largely weighted than an adjacent pixel having a larger differential, and both values of the pixels are added together.