{"id":247,"date":"2013-10-05T01:09:35","date_gmt":"2013-10-04T16:09:35","guid":{"rendered":"https:\/\/www.dogrow.net\/octave\/?p=247"},"modified":"2019-10-26T20:25:51","modified_gmt":"2019-10-26T11:25:51","slug":"blog28","status":"publish","type":"post","link":"https:\/\/www.dogrow.net\/octave\/blog28\/","title":{"rendered":"(28) fread\u3067BMP\u753b\u50cf\u3092\u8aad\u307f\u8fbc\u307f\u8868\u793a"},"content":{"rendered":"

octave\u3067 fopen<\/span>, fread<\/span>\u3092\u4f7f\u3063\u3066\u30d0\u30a4\u30ca\u30ea\u30d5\u30a1\u30a4\u30eb\u3092\u30ed\u30fc\u30c9\u3057\u3066\u307f\u308b\u3002<\/p>\n

\u300c\u6b63\u3057\u304f\u8aad\u3081\u305f\u304b\uff1f\u300d\u306e\u78ba\u8a8d\u306b\u306f\u3001\u753b\u50cf\u30c7\u30fc\u30bf\u3092\u8868\u793a\u3055\u305b\u3066\u307f\u308b\u3068\u308f\u304b\u308a\u3084\u3059\u3044\u3002
\n\u4ee5\u4e0b\u306e\u3088\u3046\u306a BMP\u30d5\u30a1\u30a4\u30eb bird.bmp <\/span>\u3092\u7528\u610f\u3057\u3001\u3053\u308c\u3092 octave\u3067\u8aad\u307f\u8fbc\u3093\u3067\u8868\u793a\u3057\u3066\u307f\u308b\u3002<\/p>\n

\"https:\/\/www.dogrow.net\/octave\/wp-content\/uploads\/2013\/10\/bird.bmp\"
\n\u3053\u306e\u5199\u771f\u2191\u306f\u3001\u79c1\u304c\u4e0a\u91ce\u52d5\u7269\u5712\u3067\u64ae\u5f71\u3057\u305f\u30cf\u30b7\u30d3\u30ed\u30b3\u30a6\u3067\u3059 ^^)<\/span><\/p>\n

\r\noctave:1> ls\r\nbird.bmp\r\n<\/pre>\n
\u307e\u305a\u306f\u30d0\u30a4\u30ca\u30ea\u30d5\u30a1\u30a4\u30eb\u3092 fopen<\/span>\u3067\u30aa\u30fc\u30d7\u30f3\u3059\u308b\u3002<\/p>\n
\r\noctave:4> fid=fopen<\/span>('bird.bmp','r','b')\r\nfid =  3\r\n<\/pre>\n
BMP\u30d5\u30a1\u30a4\u30eb\u306e\u5148\u982d\u306b\u306f\u3001BITMAPFILE HEADER <\/span>\u3068 BITMAPINFO HEADER <\/span>\u304c\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u3002
\n\u753b\u50cf\u30c7\u30fc\u30bf\u306e\u7e26\u6a2a\u30b5\u30a4\u30ba\u306a\u3069\u306e\u60c5\u5831\u304c\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u3002<\/p>\n
\u307e\u305a\u306f BITMAPFILE HEADER<\/span>\u3092\u8aad\u307f\u8fbc\u3093\u3067\u307f\u308b\u3002<\/p>\n
\r\noctave:5> BfType=fread(fid,1,'uint16');\r\noctave:6> BfSize=fread(fid,1,'uint32');\r\noctave:7> BfReserved1=fread(fid,1,'uint16');\r\noctave:8> BfReserved2=fread(fid,1,'uint16');\r\noctave:9> BfOffBits=fread(fid,1,'uint32');\r\n<\/pre>\n
\u6b21\u306b BITMAPINFO HEADER<\/span>\u3092\u8aad\u307f\u8fbc\u3093\u3067\u307f\u308b\u3002<\/p>\n
\r\noctave:10> BiSize=fread(fid,1,'uint32');\r\noctave:11> BiWidth=fread(fid,1,'uint32');\r\noctave:12> BiHeight=fread(fid,1,'uint32');\r\noctave:13> BiPlanes=fread(fid,1,'uint16');\r\noctave:14> BiBitCount=fread(fid,1,'uint16');\r\noctave:15> BiCompression=fread(fid,1,'uint32');\r\noctave:16> BiSizeImage=fread(fid,1,'uint32');\r\noctave:17> BiXPelsPerMeter=fread(fid,1,'uint32');\r\noctave:18> BiYPelsPerMeter=fread(fid,1,'uint32');\r\noctave:19> BiClrUsed=fread(fid,1,'uint32');\r\noctave:20> BiClrImportant=fread(fid,1,'uint32');\r\n<\/pre>\n
BITMAPINFO HEADER<\/span>\u304b\u3089\u8aad\u307f\u8fbc\u3093\u3060 BMP\u753b\u50cf\u306e\u7e26\u6a2a\u30b5\u30a4\u30ba\u3092\u8868\u793a\u3057\u3066\u307f\u308b\u3002
\n\u6a2a\u5e45\u306f BiWidth, \u9ad8\u3055\u306f BiHeight\u306b\u53d6\u5f97\u3057\u3066\u3042\u308b\u3002<\/p>\n
\r\noctave:21> BiWidth\r\nBiWidth =  3.5568e+09\r\noctave:22> BiHeight\r\nBiHeight =  2.6172e+09\r\n<\/pre>\n
\u4f55\u304b\u304a\u304b\u3057\u3044…
\n\u7e26\u6a2a\u30b5\u30a4\u30ba\u304c\u3081\u3061\u3083\u304f\u3061\u3083\u5927\u304d\u304f\u306a\u3063\u3066\u3044\u308b\u3002<\/p>\n
\u8aad\u307f\u8fbc\u3093\u3060\u30c7\u30fc\u30bf\u309216\u9032\u6570\u3067\u8868\u793a\u3057\u3066\u307f\u308b\u3068 Little endian<\/span> \u3067\u8868\u793a\u3055\u308c\u3066\u3044\u308b\u3002<\/p>\n
\r\noctave:29> printf('%x , %x\\n', BiWidth, BiHeight);\r\nd4000000 , 9c000000\r\n<\/pre>\n
swapbytes<\/span> \u3067 Big endian<\/span> \u306b\u5909\u63db\u3057\u305f\u5f8c\u306b10\u9032\u6570\u3067\u8868\u793a\u3057\u3066\u307f\u308b\u3068\u3001\u6b63\u3057\u304f\u7e26\u6a2a\u30b5\u30a4\u30ba\u304c\u8868\u793a\u3055\u308c\u305f\u3002<\/p>\n
\r\noctave:30> swapbytes<\/span>(uint32(BiWidth))\r\nans = 212\r\noctave:31> swapbytes<\/span>(uint32(BiHeight))\r\nans = 156\r\noctave:32>\r\n<\/pre>\n
BITMAPFILE HEADER, BITMAPINFO HEADER\u306b\u7d9a\u3044\u3066\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u306e\u304c\u3044\u3088\u3044\u3088\u753b\u50cf\u30c7\u30fc\u30bf\u3060\u3002
\n\u300c\u9752<\/span>\u30fb\u7dd1<\/span>\u30fb\u8d64<\/span>\u300d\u306e3\u30d0\u30a4\u30c8\u30671\u753b\u7d20\u306e\u5024\u304c\u4f5c\u3089\u308c\u3066\u304a\u308a\u3001\u3053\u308c\u304c\u6a2a\u00d7\u7e26\u30b5\u30a4\u30ba\u5206\u3060\u3051\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u3002
\n\u3053\u306e\u305f\u3081\u3001octave\u7684\u306b\u306f [ 3 212 156 ] \u306e3\u6b21\u5143\u914d\u5217\u3067\u53d6\u5f97\u3059\u308c\u3070\u3088\u3044\u3002<\/p>\n
\r\noctave:32> img=fread<\/span>(fid,[3 212* 156],'uint8');\r\noctave:33> size(img)\r\nans =\r\n       3   33072\r\noctave:34> img=reshape<\/span>(img,3,212,156);\r\noctave:35> size(img)\r\nans =\r\n     3   212   156\r\n<\/pre>\n
imshow<\/span> \u3067\u753b\u50cf\u3092\u8868\u793a\u3059\u308b\u5834\u5408\u3001\u5165\u529b\u3059\u308b\u753b\u50cf\u30c7\u30fc\u30bf\u914d\u5217\u3092 [y][x][color] \u306e\u9806\u306b\u4f5c\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002
\n\u305d\u3053\u3067\u4e0a\u8a18\u306e img\u914d\u5217\u306e\u6b21\u5143\u3092 permute<\/span> \u3067\u5165\u308c\u66ff\u3048\u3001imshow<\/span> \u3067\u8868\u793a\u3057\u3066\u307f\u308b\u3002<\/p>\n
\r\noctave:38> img=permute<\/span>(img,[3 2 1]);\r\noctave:39> imshow<\/span>(uint8(img));\r\n<\/pre>\n
\"https:\/\/www.dogrow.net\/octave\/wp-content\/uploads\/2013\/10\/20131005_01.png\"<\/p>\n
\u4e0a\u4e0b\u304c\u53cd\u5bfe\u3060…
\nflipdim<\/span> \u3067\u884c\u65b9\u5411\u306b\u53cd\u8ee2\u3059\u308b\u3002<\/p>\n
\r\noctave:40> img=flipdim<\/span>(img,1);\r\noctave:41> imshow<\/span>(uint8(img));\r\n<\/pre>\n
\"https:\/\/www.dogrow.net\/octave\/wp-content\/uploads\/2013\/10\/20131005_02.png\"<\/p>\n
\u8272\u5408\u3044\u304c\u304a\u304b\u3057\u3044…
\nimshow<\/span>\u3067\u6307\u5b9a\u3059\u308b\u753b\u50cf\u30c7\u30fc\u30bf\u306e3\u6b21\u5143\u76ee\u306f\u3001RGB(\u8d64<\/span>\u30fb\u7dd1<\/span>\u30fb\u9752<\/span>)\u306e\u9806\u306b\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002
\nBMP\u30d5\u30a1\u30a4\u30eb\u306b\u306fBGR(\u9752<\/span>\u30fb\u7dd1<\/span>\u30fb\u8d64<\/span>)\u306e\u9806\u306b\u30c7\u30fc\u30bf\u304c\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u305f\u3081\u3001\u8d64<\/span>\u3068\u9752<\/span>\u304c\u3072\u3063\u304f\u308a\u8fd4\u3063\u3066\u8868\u793a\u3055\u308c\u3066\u3044\u308b\u3002
\n\u3053\u3061\u3089\u3082 flipdim<\/span>\u3067\u753b\u50cf\u30c7\u30fc\u30bf\u914d\u5217\u306e3\u6b21\u5143\u76ee\u3092\u53cd\u8ee2\u3055\u305b\u3066\u8d64<\/span>\u3068\u9752<\/span>\u306e\u30c7\u30fc\u30bf\u3092\u5165\u308c\u66ff\u3048\u308b\u3002<\/p>\n
\r\noctave:42> img=flipdim<\/span>(img,3);\r\noctave:43> imshow<\/span>(uint8(img));\r\n<\/pre>\n
\"https:\/\/www.dogrow.net\/octave\/wp-content\/uploads\/2013\/10\/20131005_03.png\"<\/p>\n
\u6b63\u3057\u304f\u8868\u793a\u3067\u304d\u305f\uff01
\nfread<\/span> \u3092\u4f7f\u3063\u3066\u30d0\u30a4\u30ca\u30ea\u30d5\u30a1\u30a4\u30eb\u306e\u4e2d\u8eab\u3092\u8aad\u307f\u8fbc\u3080\u65b9\u6cd5\u304c\u308f\u304b\u3063\u305f\uff01<\/p>\n
\u6700\u5f8c\u306f fclose<\/span> \u3067\u30d5\u30a1\u30a4\u30eb\u3092\u30af\u30ed\u30fc\u30ba\u3057\u3066\u7d42\u308f\u308a\u3067\u3059\u3002<\/p>\n
\r\noctave:44> fclose<\/span>(fid)\r\nans = 0\r\noctave:45>\r\n<\/pre>\n
\n","protected":false},"excerpt":{"rendered":"
octave\u3067 fopen, fread\u3092\u4f7f\u3063\u3066\u30d0\u30a4\u30ca\u30ea\u30d5\u30a1\u30a4\u30eb\u3092\u30ed\u30fc\u30c9\u3057\u3066\u307f\u308b\u3002 \u300c\u6b63\u3057\u304f\u8aad\u3081\u305f\u304b\uff1f\u300d\u306e\u78ba\u8a8d\u306b\u306f\u3001\u753b\u50cf\u30c7\u30fc\u30bf\u3092\u8868\u793a\u3055\u305b\u3066\u307f\u308b\u3068\u308f\u304b\u308a\u3084\u3059\u3044\u3002 \u4ee5\u4e0b\u306e\u3088\u3046\u306a BMP\u30d5\u30a1\u30a4\u30eb bird.bmp \u3092\u7528\u610f\u3057\u3001\u3053\u2026 \u7d9a\u304d\u3092\u8aad\u3080 »<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,20],"tags":[],"class_list":["post-247","post","type-post","status-publish","format-standard","hentry","category-16","category-20"],"views":5550,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/posts\/247","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/comments?post=247"}],"version-history":[{"count":33,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/posts\/247\/revisions"}],"predecessor-version":[{"id":1000,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/posts\/247\/revisions\/1000"}],"wp:attachment":[{"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/media?parent=247"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/categories?post=247"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dogrow.net\/octave\/wp-json\/wp\/v2\/tags?post=247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}