The present invention relates to an improved interpolation based on motion compensation. In order to avoid interpolation artifacts in proximity to the image borders, in particular in letterbox type images, each motion compensated image data is subjected to a position validation in order to determine whether or not the motion compensated image data can be used for interpolation purposes. By comparing the position of the motion compensated image data in the referenced images with predefined borderlines, impermissible image data positions can be detected and interpolation based on such image data prevented.