A method for registering and fusing time-varying image sources to provide highest possible information rendering to an operator comprising the steps of aligning a plurality of image sources by matching target image to a reference image and minimizing visual registration error in a static sense and selecting target images which are best fused with a reference image using a dynamic, time-varying optimality maximum likelihood decision theory. The maximum likelihood decision theory is modified to account for time-varying using an orthogonal projection technique charactering changing density functions.