Tim Jenison has always thought of himself as an inventor, the kind of person who keeps a running list of practical puzzles for when he can devote spare brain cells to solving them.

“When I discover that someone else has already done it, it’s a huge relief, because I can take it off that to-do list,” Mr. Jenison, a successful San Antonio entrepreneur whose innovations usually take the form of video equipment, said recently.

“But ideas pop up at the weirdest time,” he added. “Who knows why our subconscious does what it does?”

For reasons he cannot quite explain, Mr. Jenison hit upon a technological sleight of hand, using optical gadgetry that has been available for centuries, that he believed could have aided the work of the old master painters — particularly Johannes Vermeer, the 17th-century Dutchman with a startling talent for photorealistic work.