1. A method comprising: determining a set of candidate keypoints based on a first image captured with a camera; determining, for each candidate keypoint in the set of candidate keypoints, a corresponding first similarity score, wherein the first similarity score corresponding to each candidate keypoint is determined, in part, by comparing an image patch associated with the corresponding candidate keypoint to a plurality of corresponding image sections in the first image in a region around the image patch; and selecting a first subset of the candidate keypoints, wherein the first subset comprises a predefined number of candidate keypoints with lowest similarity scores.
1. A method comprising: determining a set of candidate keypoints based on a first image captured with a camera; determining, for each candidate keypoint in the set of candidate keypoints, a corresponding first similarity score, wherein the first similarity score corresponding to each candidate keypoint is determined, in part, by comparing an image patch associated with the corresponding candidate keypoint to a plurality of corresponding image sections in the first image in a region around the image patch; and selecting a first subset of the candidate keypoints, wherein the first subset comprises a predefined number of candidate keypoints with lowest similarity scores. 2. The method of claim 1 , wherein determining the first similarity score corresponding to each candidate keypoint comprises: determining a plurality of second similarity scores corresponding to each candidate keypoint, wherein each second similarity score is determined from a comparison of the image patch associated with the corresponding candidate keypoint with one of the plurality of corresponding image sections in the region around the image patch, and wherein each second similarity score is indicative of a similarity between the image patch associated with the corresponding candidate keypoint and the corresponding image section; and selecting, as the first similarity score, a maximum of the second similarity scores for that candidate keypoint.