1. A method for processing stereo rectified images, each stereo rectified image being associated with a camera position, the method comprising: selecting a first pair of stereo rectified images; determining a first point cloud of features from the pair of stereo rectified images; determining the locations of the features of the first point cloud with respect to a reference feature in the first point cloud; selecting a second pair of stereo rectified images so that one stereo rectified image of the second pair is common to the first pair, and scaling a second point cloud of features associated with the second pair of stereo rectified images to the first point cloud of features, wherein the scaling further comprises treating each point cloud as a single vector, determining a norm for each single vector, and scaling each point in the cloud by dividing said each point by said norm for a respective single vector, and wherein the method is executed by one or more processors.