RGB Color Sensors for Occupant Detection: An Alternative to PIR Sensors

RGB color sensors are examined as an economical replacement for non-lighting based occupancy sensors such as PIR sensors and ultrasonic sensors. RGB color sensors are inexpensive and able to accurately detect and track occupants in an illuminated space by monitoring color shifts from background color distribution caused by occupants. By examining the temporal dependence of color shifts caused by small occupant movements, it is possible to avoid false occupancy/vacancy detections associated with other sensor types. Additionally, RGB color sensors provide information about the spectral reflectance of the illuminated space and this information can be used to compensate for spectral absorption properties of surfaces that alter the perceived emitted spectral power distribution (SPD) from the lighting. These changes may impact occupant perception and circadian performance.