A spatial resolution smaller than that of a pixel. Although digital images are composed of pixels, it can be very useful to resolve image detail to smaller than pixel size, i.e., sub-pixel. For example, the data for generating a smooth curve on television needs to be created to a finer accuracy than the pixel grid itself, otherwise the curve will look jagged.

Again, when tacking an object in a scene or executing a DVE move, the size and position of the manipulated picture must be calculated, and the picture resolved, to a far finer accuracy than the pixels, otherwise the move will appear jerky.