Abstract: Techniques for detecting object motion within a monitored scene are disclosed. In an embodiment, an infrared motion sensing device can include an infrared detector configured to receive infrared radiation from the monitored scene within a detection field of view and to generate an output waveform signal indicative of time-dependent variations in the received infrared radiation in response to object motion within the detection field of view. The infrared motion sensing device can also include a processor configured to receive the output waveform signal generated by the infrared detector and perform a signal analysis based on the output waveform signal to determine whether a motion event has occurred, which can involve finding a match between the output waveform signal and the one or more reference waveform signals. Upon determination that a motion event has occurred, the processor can be controlled, for example, to trigger an image sensor to capture an image.