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Today’s occupancy sensors rely on motion or sound to detect whether or not a person or object is in the room. This method, however, is prone to providing false positives and negatives and is not a reliable way of sensing a number of people in an enclosed space. 

Recently, researchers at the U.S. Department of Energy's National Renewable Energy Laboratory have introduced a way of using computer imaging software to analyze actual visual evidence taken of the surrounding area in order to determine occupancy. Unlike previous attempts at improving this sensor technology, the visual analyzation software doesn’t add excess strain on the sensor’s battery, nor does it have a have an unreasonably limited range.