{"action":"opened","issue":{"url":"https://api.github.com/repos/shadow1runner/qgroundcontrol/issues/32","repository_url":"https://api.github.com/repos/shadow1runner/qgroundcontrol","labels_url":"https://api.github.com/repos/shadow1runner/qgroundcontrol/issues/32/labels{/name}","comments_url":"https://api.github.com/repos/shadow1runner/qgroundcontrol/issues/32/comments","events_url":"https://api.github.com/repos/shadow1runner/qgroundcontrol/issues/32/events","html_url":"https://github.com/shadow1runner/qgroundcontrol/issues/32","id":153931705,"number":32,"title":"Filter Optical Flow for outliers","user":{"login":"shadow1runner","id":3902045,"avatar_url":"https://avatars.githubusercontent.com/u/3902045?v=3","gravatar_id":"","url":"https://api.github.com/users/shadow1runner","html_url":"https://github.com/shadow1runner","followers_url":"https://api.github.com/users/shadow1runner/followers","following_url":"https://api.github.com/users/shadow1runner/following{/other_user}","gists_url":"https://api.github.com/users/shadow1runner/gists{/gist_id}","starred_url":"https://api.github.com/users/shadow1runner/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/shadow1runner/subscriptions","organizations_url":"https://api.github.com/users/shadow1runner/orgs","repos_url":"https://api.github.com/users/shadow1runner/repos","events_url":"https://api.github.com/users/shadow1runner/events{/privacy}","received_events_url":"https://api.github.com/users/shadow1runner/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-05-10T06:19:43Z","updated_at":"2016-05-10T06:19:43Z","closed_at":null,"body":"@inproceedings{zingg2010mav,\r\n  title={MAV navigation through indoor corridors using optical flow},\r\n  author={Zingg, Simon and Scaramuzza, Davide and Weiss, Stephan and Siegwart, Roland},\r\n  booktitle={Robotics and Automation (ICRA), 2010 IEEE International Conference on},\r\n  pages={3361--3368},\r\n  year={2010},\r\n  organization={IEEE}\r\n}\r\n\r\nused a two-step filtering:\r\n> A simple threshold filter removes too large optical flow\r\n> amplitudes. In a further step, an angular criterion is checked.\r\n> Optical flow has to be tangential to a circle with its center at\r\n> the center of the image with a deviation of up to 50°. This\r\n> threshold seems to be large, it has been chosen experimentally\r\n> and proved to work though. It is necessary, since the\r\n> optical flow has not an exact circular shape. If the threshold\r\n> is chosen smaller, optical flow close to the direction of travel\r\n> might be filtered out, even if it was not wrongly matched.\r\n> A remarkable amount of wrong matches could be extracted\r\n> using these two criteria.\r\n\r\nTodo: Analyze OF with and without filtering"}}