Abstract: A method comprising: controlling an active reflected wave detector to measure wave reflections from an environment using a first frame rate to accrue measured wave reflection data for a classifier, after a first amount of time, determining whether a predefined criteria is satisfied, wherein satisfaction of the predefined criteria is indicative of the classifier being likely to successfully identify a fall status of a person in the environment by a second amount of time of accruing measured wave reflection data from the active reflected wave detector, the second amount of time being greater than the first amount of time; in the event that the predefined criteria is not met, the method comprising controlling the active reflected wave detector to accrue measured wave reflection data at a lower second frame rate for classifying the fall status based on measured wave reflection data accrued at the lower second rate.

Abstract: Embodiments relate to using an active reflected wave detector to classify the state of a person in an environment and optionally respond accordingly. In one embodiment there is provided a computer implemented method of determining a state of a person comprising: receiving an output of an active reflected wave detector; classifying a state of the person as being in a safe supported state based on the output using measurements of reflections associated with the person, wherein said classifying is based at least on: a height metric associated with at least one reflection from the person conveyed in the output of the active reflected wave detector; and a plurality of velocity magnitude measurements of the person corresponding to different times, each of said velocity magnitude measurements determined using the reflections associated with the person conveyed in the output of the active reflected wave detector.

Abstract: Embodiments relate to a device and method for determining a status of an environment and/or a status or condition of a person therein. The method may comprise: receiving an output of a sensor to monitor said environment; commencing a time window after the sensor detects activity in the environment; upon expiry of the time window, activating an active reflected wave detector to measure wave reflections from the environment, the detector consuming more power in an activated state than the sensor in an activated state; and determining a status of the environment and/or of a person therein based on an output of the active detector indicative of one or more of the measured reflections. The method comprises delaying expiry of the time window in response to the sensor detecting activity in the environment during the time window.