A lidar system identifies anomalous optical pulses received by the lidar system. The lidar system includes a light source configured to output a plurality of transmitted pulses of light, each transmitted pulse of light having one or more representative characteristics, a scanner configured to direct the plurality of transmitted pulses of light to a plurality of locations within a field of regard, and a receiver configured to detect a plurality of received pulses of light from the field of regard. The lidar system is configured to identify an anomalous pulse amongst the plurality of received pulses of light based on its having at least one characteristic that does not correspond to the one or more representative characteristics of the plurality of transmitted pulses of light.