{"action":"created","issue":{"url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/478","labels_url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/478/labels{/name}","comments_url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/478/comments","events_url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/478/events","html_url":"https://github.com/Itseez/opencv_contrib/issues/478","id":123036351,"number":478,"title":"Missing rounding","user":{"login":"pieter3d","id":598246,"avatar_url":"https://avatars.githubusercontent.com/u/598246?v=3","gravatar_id":"","url":"https://api.github.com/users/pieter3d","html_url":"https://github.com/pieter3d","followers_url":"https://api.github.com/users/pieter3d/followers","following_url":"https://api.github.com/users/pieter3d/following{/other_user}","gists_url":"https://api.github.com/users/pieter3d/gists{/gist_id}","starred_url":"https://api.github.com/users/pieter3d/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pieter3d/subscriptions","organizations_url":"https://api.github.com/users/pieter3d/orgs","repos_url":"https://api.github.com/users/pieter3d/repos","events_url":"https://api.github.com/users/pieter3d/events{/privacy}","received_events_url":"https://api.github.com/users/pieter3d/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-12-18T22:23:43Z","updated_at":"2015-12-18T22:28:07Z","closed_at":null,"body":"The division performed here does not account for round correction:\r\nhttps://github.com/Itseez/opencv_contrib/blob/master/modules/xfeatures2d/src/freak.cpp#L675\r\n\r\nThis can introduce noise in the patch values, which can actually cause instability in the descriptor bits, since patch values tend to be similar for a given keypoint, and off-by-one differences will cause the pair comparisons to change."},"comment":{"url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/comments/165911422","html_url":"https://github.com/Itseez/opencv_contrib/issues/478#issuecomment-165911422","issue_url":"https://api.github.com/repos/Itseez/opencv_contrib/issues/478","id":165911422,"user":{"login":"pieter3d","id":598246,"avatar_url":"https://avatars.githubusercontent.com/u/598246?v=3","gravatar_id":"","url":"https://api.github.com/users/pieter3d","html_url":"https://github.com/pieter3d","followers_url":"https://api.github.com/users/pieter3d/followers","following_url":"https://api.github.com/users/pieter3d/following{/other_user}","gists_url":"https://api.github.com/users/pieter3d/gists{/gist_id}","starred_url":"https://api.github.com/users/pieter3d/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pieter3d/subscriptions","organizations_url":"https://api.github.com/users/pieter3d/orgs","repos_url":"https://api.github.com/users/pieter3d/repos","events_url":"https://api.github.com/users/pieter3d/events{/privacy}","received_events_url":"https://api.github.com/users/pieter3d/received_events","type":"User","site_admin":false},"created_at":"2015-12-18T22:28:07Z","updated_at":"2015-12-18T22:28:07Z","body":"Correct rounding would be to add this line:\r\n`ret_val += area/2;`"}}