{"id":168,"date":"2020-12-04T00:12:24","date_gmt":"2020-12-04T00:12:24","guid":{"rendered":"http:\/\/med-space.org\/youssef-zaz-master\/?page_id=168"},"modified":"2020-12-14T23:21:50","modified_gmt":"2020-12-14T23:21:50","slug":"filtre-moyen","status":"publish","type":"page","link":"https:\/\/yzaz.net\/master\/filtre-moyen\/","title":{"rendered":"Filtre Moyen"},"content":{"rendered":"

C\u2019est un filtre passe\u2010bas qui lisse l\u2019image est provoque un effet de flou. Il r\u00e9duit le bruit et aussi les d\u00e9tails. Dans le filtre moyen, chaque pixel est remplac\u00e9 par la moyenne de ses voisins.<\/p>\n\n\n\n
\n\n\n\n\n\n
1\/9<\/td>\n1\/9<\/td>\n1\/9<\/td>\n<\/tr>\n
1\/9<\/td>\n1\/9<\/td>\n1\/9<\/td>\n<\/tr>\n
1\/9<\/td>\n1\/9<\/td>\n1\/9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n <\/p>\n

ou<\/td>\n

 <\/p>\n

1\/9 x<\/td>\n

\n\n\n\n\n\n
1<\/td>\n1<\/td>\n1<\/td>\n<\/tr>\n
1<\/td>\n1<\/td>\n1<\/td>\n<\/tr>\n
1<\/td>\n1<\/td>\n1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Plus le filtre grossit, plus le lissage devient important.<\/p>\n

\"\"<\/p>\n

Code Matlab:<\/p>\n

\r\norg=imread('peppers.png');\r\nm = imnoise(org, 'gaussian', 0, 0.03); % Ajout d'un bruit blanc Gaussien, de moyenne nulle\r\nfilterWindow3 = ones(3) \/ 9;\r\nfilteredImage3 = imfilter(m, filterWindow3);\r\nfilterWindow5 = ones(5) \/ 25;\r\nfilteredImage5 = imfilter(m, filterWindow5);\r\nfilterWindow9 = ones(9) \/ 81;\r\nfilteredImage9 = imfilter(m, filterWindow9);\r\nfilterWindow15 = ones(15) \/ 225;\r\nfilteredImage15 = imfilter(m, filterWindow15);\r\nsubplot ( 2 , 3 , 1 ) ; imshow(org) ; title ( 'Image originale' ) ;\r\nsubplot ( 2 , 3 , 2 ) ; imshow(m) ; title ( 'Image bruit\u00e9e (bruit Gaussien)' ) ;\r\nsubplot ( 2 , 3 , 3 ) ; imshow(filteredImage3) ; title ( 'Image filtr\u00e9e (Moyen 3x3)');\r\nsubplot ( 2 , 3 , 4 ) ; imshow(filteredImage5) ; title ( 'Image filtr\u00e9e (Moyen 5x5)');\r\nsubplot ( 2 , 3 , 5 ) ; imshow(filteredImage9) ; title ( 'Image filtr\u00e9e (Moyen 9x9)');\r\nsubplot ( 2 , 3 , 6 ) ; imshow(filteredImage15) ; title ( 'Image filtr\u00e9e (Moyen 15x15)');\r\n<\/pre>\n
Une am\u00e9lioration du filtre moyen consiste \u00e0 jouer sur les valeurs des coefficients du masque. C’est le cas des filtres binomiaux pour lesquels les valeurs des coefficients sont g\u00e9n\u00e9r\u00e9s par le triangle de Pascal.<\/p>\n","protected":false},"excerpt":{"rendered":"
C\u2019est un filtre passe\u2010bas qui lisse l\u2019image est provoque un effet de flou. Il r\u00e9duit le bruit et aussi les d\u00e9tails. Dans le filtre moyen, […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":50,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/168"}],"collection":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/comments?post=168"}],"version-history":[{"count":17,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/168\/revisions"}],"predecessor-version":[{"id":614,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/168\/revisions\/614"}],"wp:attachment":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/media?parent=168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}