1. A system for detecting a face contour, the system comprising: a lidar subsystem configured to direct at least two beams toward the target, generate a set of 3D measurements for a plurality of points on a target for each of the at least two beams, and determine a plurality of 3D face contour points associated with the target, wherein the set of 3D measurements of points on a target comprises a set of range measurements of points on the target, wherein each of the plurality of 3D face contour points associated with the target corresponds to a discontinuity in range measurement between two adjacent ones of the plurality of points; a video subsystem configured to provide at least one video frame of the target; and a processor configured to: receive, from the lidar subsystem, the set of 3D measurements and the plurality of 3D face contour points, receive, from the video subsystem, the at least one video frame of the face, transform each of the plurality of 3D face contour points to a video frame time associated with the at least one video frame based on a plurality of first transformation parameters, and determine a face contour of the face in the video frame based on the transformed plurality of 3D face contour points.