DIGITAL FOCUSING

THE PROPOSED EFFORT DEVELOPS A SYSTEM USING A VIDEO IMAGE PROCESSING TO MEASURE THE FOCUS, OR DEFOCUS, OF AN OPTICAL INSTRUMENT OVER A SELECTABLE AREA OF THE IMAGE, AND THEN TO ADJUST THE FOCUS. THE TECHNIQUE CAN BE APPLIED TO OBJECTS THAT ARE SILHOUETTES OR TO OBJECTS OR REGIONS THAT HAVE ONLY RANDOM TEXTURE, I.E., HAVE NO EDGES. THE KEY PROBLEM SOLVED BY THIS TECHNIQUE IS TO SENSE THE DEFOCUS EVEN WHEN THE IMAGE IS NOT NOTICEABLE DEFOCUSED. THIS IS NECESSARY BECAUSE THE VIDEO IMAGE IS ALSO BEING USED FOR SUCH AUTOMATIC TASKS AS MOUNT-CONTROL TRACKING AND/OR FOR DATA COLLECTION. ADDITIONAL DESIGN CRITERIA FOR THE PROPOSED DIGITAL FOCUSING SYSTEM ARE SPEED OF OPERATION AND COST. THE GOAL IS TO MEASURE THE FOCUS TEN TIMES PER SECOND AND TO CORRECT IT FIVE TIMES PER SECOND. THE PROPOSED SYSTEM WILL KEEP THE COST OF THE IMAGE PROCESSING HARDWARE LOW BY SELECTING ONLY OFF-THE-SHELF, COMMERCIALLY AVAILABLE HARDWARE. NO ESOTERIC, SPECIALLY BUILT HARDWARE SYSTEMS ARE NEEDED FOR THE IMAGE PROCESSING.