{"id":462,"date":"2020-12-12T23:37:28","date_gmt":"2020-12-12T23:37:28","guid":{"rendered":"http:\/\/med-space.org\/youssef-zaz-master\/?page_id=462"},"modified":"2020-12-13T18:07:16","modified_gmt":"2020-12-13T18:07:16","slug":"bruit","status":"publish","type":"page","link":"https:\/\/yzaz.net\/master\/bruit\/","title":{"rendered":"Bruit dans une image"},"content":{"rendered":"<p>Le bruit est une alt\u00e9ration de l\u2019image. Il peut \u00eatre caus\u00e9 par les processus d\u2019acquisition, de transmission ou de stockage.<br \/>\nPour tester l&#8217;efficacit\u00e9 de certains algorithmes, il est parfois utile d&#8217;ajouter un bruit \u00e0 l&#8217;image.<br \/>\nIl existe plusieurs types de bruit.<br \/>\nCi-dessous, des exemples de bruits impulsionnel, Gaussien et sinuso\u00efdal:<\/p>\n<pre class=\"brush: matlabkey; title: ; notranslate\" title=\"\">\r\n% Read the test Image\r\nmygrayimg = imread('cameraman.tif');\r\nsubplot(2,3,1); \r\nimshow(mygrayimg); \r\ntitle('Original Image');\r\n\r\n% Add Salt and pepper noise with noise density 0.001\r\nsalt = imnoise(mygrayimg,'salt &amp; pepper',0.001);\r\nsubplot(2,3,2);\r\nimshow(salt);\r\ntitle('Salt &amp; Pepper Image (bruit impulsionnel faible)');\r\n\r\n% Add Salt and pepper noise with noise density 0.03\r\nsalt = imnoise(mygrayimg,'salt &amp; pepper',0.03);\r\nsubplot(2,3,3);\r\nimshow(salt);\r\ntitle('Salt &amp; Pepper Image (bruit impulsionnel fort)');\r\n\r\n\r\n% Add Gaussian noise with mean 0 and variance 0.003 \r\ngau = imnoise(mygrayimg, 'gaussian', 0, 0.003);\r\nsubplot(2,3,4);\r\nimshow(gau);\r\ntitle('Gaussian Image- mean 0 and variance 0.003');\r\n\r\n% Add Gaussian noise with mean 0 and variance 0.02 \r\ngau = imnoise(mygrayimg, 'gaussian', 0, 0.02);\r\nsubplot(2,3,5);\r\nimshow(gau);\r\ntitle('Gaussian Image- mean 0 and variance 0.02');\r\n\r\n% Original Image plus sinusoidal noise    \r\nsubplot(2,3,6);\r\n[x y] = meshgrid(1:256,1:256);\r\nmysinusoidalnoise = 15 * sin(2*pi\/14*x+2*pi\/14*y);\r\nmynoiseimg1 = double(mygrayimg) + mysinusoidalnoise;\r\nimshow(mynoiseimg1,[]);\r\ntitle('Generated Sinusoidal noise');\r\n<\/pre>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-458 size-full\" src=\"http:\/\/med-space.org\/youssef-zaz-master\/wp-content\/uploads\/2020\/12\/bruit.jpg\" alt=\"\" width=\"1110\" height=\"615\" srcset=\"https:\/\/yzaz.net\/master\/wp-content\/uploads\/2020\/12\/bruit.jpg 1110w, https:\/\/yzaz.net\/master\/wp-content\/uploads\/2020\/12\/bruit-300x166.jpg 300w, https:\/\/yzaz.net\/master\/wp-content\/uploads\/2020\/12\/bruit-1024x567.jpg 1024w, https:\/\/yzaz.net\/master\/wp-content\/uploads\/2020\/12\/bruit-768x426.jpg 768w\" sizes=\"(max-width: 1110px) 100vw, 1110px\" \/><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<div class=\"mh-excerpt\"><p>Le bruit est une alt\u00e9ration de l\u2019image. Il peut \u00eatre caus\u00e9 par les processus d\u2019acquisition, de transmission ou de stockage. Pour tester l&#8217;efficacit\u00e9 de certains <a class=\"mh-excerpt-more\" href=\"https:\/\/yzaz.net\/master\/bruit\/\" title=\"Bruit dans une image\">[&#8230;]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":30,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/462"}],"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=462"}],"version-history":[{"count":8,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/462\/revisions"}],"predecessor-version":[{"id":514,"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/pages\/462\/revisions\/514"}],"wp:attachment":[{"href":"https:\/\/yzaz.net\/master\/wp-json\/wp\/v2\/media?parent=462"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}