Suppose two instruments Io and I1 measure the same quantity with the same resolution, where it is know Io is more reliable. The second, I1 , is assumed a distortion of Io in some sense. A method is outlined whereby: 1. The information from both Io , I1 is combined to increase the reliability of Io . 2.. The distortion is qualified. An example is given in terms of ship borne precipitation radar and a space borne radiometer both measuring rain rate.