1. A method for calibrating a lidar subsystem with a video subsystem, the method comprising: receiving a plurality of three-dimensional measurements generated by the lidar subsystem, each of the plurality of three-dimensional measurements corresponding to a point on a target, each of the plurality of three-dimensional measurements comprising a location of the point on the target and an amplitude of a return signal from the point on the target; receiving at least one image of the target generated by the video subsystem; determining a calibration offset between the lidar subsystem and the video subsystem from a misalignment between an iris of the target identified from the plurality of three-dimensional measurements generated by the lidar subsystem and the iris of the target found in the at least one image generated by the video subsystem, wherein the plurality of three-dimensional measurements generated by the lidar subsystem are independent from the at least one image generated by the video subsystem, wherein the calibration offset is determined by: determining a lidar location of the iris of the target in the plurality of three-dimensional measurements from the amplitude of the return signal of at least some of the plurality of three-dimensional measurements, determining a video location of the iris of the target in the at least one image of the target, determining the calibration offset between the lidar subsystem and the video subsystem as the difference between the lidar location of the iris and the video location of the iris; and calibrating the lidar subsystem with the video subsystem using the calibration offset.