Active signal detection using adaptive identification of a noise floor

A device can accurately discriminate an active pulse from noise by setting a dynamic noise floor that adjusts according to environmental conditions. For example, the device may discriminate, as the active pulse, a light pulse emitted by a light emitter of the system and reflected off an object to a light sensor, from noise such as sunlight glare by determining a dynamic noise floor and identifying, as an active pulse, at least a portion of the received signal that exceeds the dynamic noise floor for a threshold number of samples. The dynamic noise floor may be determined, for example, using a moving average of the received signal and/or shifting or scaling the noise floor based on other properties of the return signal.