Time-of-flight lidar systems measure pulse-return time of arrival based on the transition of the pulse return’s rising edge through a detection threshold. These systems are subject to systematic range error, termed range walk, caused by variations in pulse-return amplitude: For two otherwise identical pulse returns of differing amplitude that are both strong enough to exceed a fixed detection threshold, the rising edge of the weaker pulse return will cross the threshold at a time closer to the center of the pulse than the rising edge of the stronger pulse return.