1. A method for determining a three-dimensional structure in an environment, the method performed by a system mountable in a host vehicle, wherein the system includes a camera operatively connectable to a processor, the method comprising: capturing a plurality of image frames in a field of view of the camera, wherein the plurality of image frames includes a first image frame and a second image frame; identifying a road of the environment in the first image frame; in the first image frame, selecting a line, wherein the line separates a first portion of the first image frame determined to include the road of the environment and a second portion of the first image frame determined to exclude the road of the environment; detecting a feature in the first portion of the first image frame; matching the feature in the first portion of the first image frame with image data in the second image frame to produce a first matching; warping the first portion of the first image frame according to a road homography and ego-motion of the host vehicle to produce a warped portion of the image frame, wherein the ego-motion is based on at least one of speed, inertia, and steering angle of the host vehicle; detecting the feature in the warped portion of the first image frame; matching the feature in the warped portion of the first image frame with the image data in the second image frame to produce a second matching; and selecting from among the first matching and the second matching to produce a selected matching.