Movement of a hand operated pointing device may be tracked by providing a source of non-coherent light in a movable housing for illuminating a work surface and providing circuitry for producing a plurality of two dimensional arrays of data related to light reflected by surface irregularities on the illuminated work surface and for processing a first array with a second array to track movement of the housing relative to the illuminated work surface. Circuitry may be provided for processing the first array with the second array to predict further movement of the housing relative to the illuminated work surface. Circuitry may be provided for selecting a different portion of the first array in accordance with the prediction for processing with a third array to track further movement of the housing. Circuitry may be provided for determining validity of the tracked movement and sending a signal to a computer related to the tracked movement unless the tracked movement is determined not to be valid.