Patent US 9,103,723

Systems and methods presented herein provide for optical surveillance using modulated lasers, or other forms of light, and optical detection. In one embodiment, an optical surveillance system includes a light source, such as a laser or light emitting diode, and a signal generator operable to modulate the light source. The system also includes a detector operable to detect the modulated light source and a processor communicatively coupled to the detector to distinguish the modulated light source from other detected light based on the modulating waveform of the modulated light source. The processor is also operable to determine a presence of an object between the laser and the detector based on an obscuration of the laser pulses on the detector.