1. A method for ground plane estimation in a three dimensional (3D) point cloud in a computer vision system, the method comprising: receiving a 3D point cloud generated based on a plurality of 2D frames captured by a monocular camera; determining a distance threshold for the 3D point cloud based on an estimated height of a ground plane in the 3D point cloud; and estimating the ground plane of the 3D point cloud by performing the following for a predetermined number of iterations: identifying a random plane in the 3D point cloud from three randomly selected non-collinear 3D points in the 3D point cloud, wherein an incline of the random plane meets predetermined pitch and roll constraints; computing a cost function of the random plane, wherein the cost function is based on a number of inliers of the random plane and a number of 3D points below the random plane, wherein the distance threshold is used to determine whether or not a 3D point in the 3D point cloud is an inlier; and saving the cost function as a best cost function if the cost function is better than a previously computed cost function for a previously identified random plane.