{"action":"created","comment":{"url":"https://api.github.com/repos/scikit-image/scikit-image/pulls/comments/38746529","id":38746529,"diff_hunk":"@@ -3,17 +3,61 @@\n Entropy\n =======\n \n-Image entropy is a quantity which is used to describe the amount of information\n-coded in an image.\n+In information theory, information entropy is the log-base-2 of the number of\n+possible outcomes for a message.\n+\n+For an image, local entropy is related to the complexity contained in a given\n+neighborhood, typically defined by a structuring element. A large number of\n+various gray levels has a higher entropy than an homogeneous neighborhood.\n+\n+Entropy filter can detect subtle variations of local gray level distribution,\n+in the example, the image is composed of two surfaces with two slightly\n+different distributions.\n+\n+Image center has a random distribution in the range [-14,+14] centered on 128,\n+while the borders has a random distribution in the range [-15,+15] centered\n+on 128.\n+\n+We apply the local entropy measure using a circular structuring element of\n+radius 10. As a result, one can detect the central square. Radius should be big","path":"doc/examples/plot_entropy.py","position":22,"original_position":22,"commit_id":"f0d201599377c62a140089ac1085e5114e47c3b5","original_commit_id":"f0d201599377c62a140089ac1085e5114e47c3b5","user":{"login":"ahojnnes","id":134307,"avatar_url":"https://avatars.githubusercontent.com/u/134307?v=3","gravatar_id":"","url":"https://api.github.com/users/ahojnnes","html_url":"https://github.com/ahojnnes","followers_url":"https://api.github.com/users/ahojnnes/followers","following_url":"https://api.github.com/users/ahojnnes/following{/other_user}","gists_url":"https://api.github.com/users/ahojnnes/gists{/gist_id}","starred_url":"https://api.github.com/users/ahojnnes/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ahojnnes/subscriptions","organizations_url":"https://api.github.com/users/ahojnnes/orgs","repos_url":"https://api.github.com/users/ahojnnes/repos","events_url":"https://api.github.com/users/ahojnnes/events{/privacy}","received_events_url":"https://api.github.com/users/ahojnnes/received_events","type":"User","site_admin":false},"body":"should be big enough -> is big enough","created_at":"2015-09-04T12:33:35Z","updated_at":"2015-09-04T12:33:35Z","html_url":"https://github.com/scikit-image/scikit-image/pull/1676#discussion_r38746529","pull_request_url":"https://api.github.com/repos/scikit-image/scikit-image/pulls/1676","_links":{"self":{"href":"https://api.github.com/repos/scikit-image/scikit-image/pulls/comments/38746529"},"html":{"href":"https://github.com/scikit-image/scikit-image/pull/1676#discussion_r38746529"},"pull_request":{"href":"https://api.github.com/repos/scikit-image/scikit-image/pulls/1676"}}},"pull_request":{"url":"https://api.github.com/repos/scikit-image/scikit-image/pulls/1676","id":43691286,"html_url":"https://github.com/scikit-image/scikit-image/pull/1676","diff_url":"https://github.com/scikit-image/scikit-image/pull/1676.diff","patch_url":"https://github.com/scikit-image/scikit-image/pull/1676.patch","issue_url":"https://api.github.com/repos/scikit-image/scikit-image/issues/1676","number":1676,"state":"open","locked":false,"title":"add entropy example","user":{"login":"odebeir","id":270313,"avatar_url":"https://avatars.githubusercontent.com/u/270313?v=3","gravatar_id":"","url":"https://api.github.com/users/odebeir","html_url":"https://github.com/odebeir","followers_url":"https://api.github.com/users/odebeir/followers","following_url":"https://api.github.com/users/odebeir/following{/other_user}","gists_url":"https://api.github.com/users/odebeir/gists{/gist_id}","starred_url":"https://api.github.com/users/odebeir/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/odebeir/subscriptions","organizations_url":"https://api.github.com/users/odebeir/orgs","repos_url":"https://api.github.com/users/odebeir/repos","events_url":"https://api.github.com/users/odebeir/events{/privacy}","received_events_url":"https://api.github.com/users/odebeir/received_events","type":"User","site_admin":false},"body":"to contribute to #1231, here is a simple example to illustrate how local entropy is able to detect small noise level variation in an 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