{"id":430,"date":"2011-12-23T07:00:31","date_gmt":"2011-12-23T12:00:31","guid":{"rendered":"https:\/\/blogs.mathworks.com\/steve\/?p=430"},"modified":"2019-10-29T17:04:36","modified_gmt":"2019-10-29T21:04:36","slug":"batch-processing-files-in-another-folder","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/steve\/2011\/12\/23\/batch-processing-files-in-another-folder\/","title":{"rendered":"Batch processing files in another folder"},"content":{"rendered":"
\r\n

Blog reader Asadullah posted the following question last week on my old post about batch processing<\/a>:\r\n <\/p>\r\n

I am trying to process some images by following the MATLAB demo. After getting the names of files when I try to see any of\r\n the files then it gives the error. The detail is as follows:<\/i><\/p>

 >> fileFolder = fullfile(matlabroot,'work','original');\r\n >> dirOutput = dir(fullfile(fileFolder,'AT3_1m4_*.jpg'));\r\n >> fileNames = {dirOutput.name}'<\/pre>
 fileNames =<\/pre>
     'AT3_1m4_001.jpg'\r\n     'AT3_1m4_002.jpg'\r\n     'AT3_1m4_003.jpg'\r\n     'AT3_1m4_004.jpg'\r\n     'AT3_1m4_005.jpg'\r\n     'AT3_1m4_006.jpg'\r\n     'AT3_1m4_007.jpg'<\/pre>
     [...]<\/pre>
     'AT3_1m4_116.jpg'\r\n     'AT3_1m4_117.jpg'\r\n     'AT3_1m4_118.jpg'\r\n     'AT3_1m4_119.jpg'\r\n     'AT3_1m4_120.jpg'<\/pre>
 >> I=imread(fileNames{1});\r\n ??? Error using ==> imread\r\n File \"AT3_1m4_001.jpg\" does not exist.<\/pre>
I could not understand where is the problem? Please help me to solve this.<\/i><\/p>\r\n   
Several people have asked me this same question, so I thought I should post the answer so everyone can see it instead of replying\r\n      in a comment.\r\n   <\/p>\r\n   
First, though, I want to strongly recommend against placing your own work files (data, code, etc.) underneath the MATLAB program\r\n      folder, as the Asadullah's code shows in this line:\r\n   <\/p>
   fileFolder = fullfile(matlabroot,'work','original');<\/pre>
The function matlabroot<\/tt> returns the location of the MATLAB program folder. On a typical Windows computer, for example, this location might be something\r\n      like:\r\n   <\/p>
   C:\\Program Files\\MATLAB\\R2011b<\/pre>
Windows doesn't consider this to be an area where a user will store their own files, and most backup programs will not normally\r\n      back up files that are stored here. Instead, store your own work elsewhere. On Windows, a good choice is somewhere under \"My\r\n      Documents\".\r\n   <\/p>\r\n   
OK, now back to the question at hand. The problem is that the string being passed to imread<\/tt> contains only the filename, such as 'AT3_1m4_116.jpg', and not the full folder location. That's not enough information for\r\n      imread<\/tt> to be able to find the file.\r\n   <\/p>\r\n   
You have to add the full folder location to the image filename before passing it to imread<\/tt>. In Asadullah's example, the corrected code would look something like this:\r\n   <\/p>
   I = imread(fullfile(fileFolder,fileNames{1}));<\/pre>
Hope that helps! May your days be filled with happily processing large numbers of images.<\/p>