Passive Visible Light Detection Of Humans.

Area of Science:

• Optical Sensing
• Human-Computer Interaction
• Ambient Intelligence

Background:

• Passive visible light sensing (VLS) systems offer a low-cost, low-power method for environmental monitoring.
• Previous VLS research often relies on direct line-of-sight communication, limiting practical applications.
• Understanding how human presence affects ambient light reflections is crucial for developing non-intrusive sensing technologies.

Purpose of the Study:

• To experimentally investigate the feasibility of passive VLS for human detection using reflected ambient light.
• To quantify the impact of human presence, clothing color, movement, and environmental layout on received signal strength (RSS).
• To develop and validate a human pass-by detection system based on passive VLS principles.

Main Methods:

• A passive VLS system comprising a ceiling-mounted light emitting diode (LED) and photodiode receiver was implemented.
• Experiments were conducted without direct line-of-sight, focusing solely on light reflected from the environment and human presence.
• Received signal strength (RSS) variations were analyzed concerning human proximity, clothing color, walking direction, and room layout.

Main Results:

• Human presence significantly influenced RSS, with variations up to ±50% depending on the scenario.
• The system demonstrated robustness across different clothing colors, walking directions, and environmental layouts.
• A proposed human pass-by detection system achieved a 100% detection rate in 21 controlled experiments.

Conclusions:

• Passive VLS utilizing reflected ambient light is a viable technology for reliable human detection.
• The system's high detection rate in both controlled and realistic corridor settings validates its practical potential.
• This approach offers a promising, non-intrusive method for occupancy sensing and human activity monitoring.