how load all imagens from directory and read using function imread opencv?

Question

I need some help. I created a function that read a single image. Well, it's work, but I want to create something like a loop for get all images from directory and use the imread method for get pixels values. How I can do this? follow my code below.

 public void cor() {
        String src = ("path_to_folder");
        Mat imgread;
        imgread = Imgcodecs.imread(src, IMREAD_COLOR);


        Mat rgbimage = null; //for conversion bgr2rgb

        int lin = imgread.rows(); //get the number of rows
        int col = imgread.cols(); //get the number of cols

        if (imgread.empty()) {
            Log.e("error", "is empty!");
        } else {
            rgbimage = new Mat(imgread.size(), imgread.type());
            Imgproc.cvtColor(imgread, rgbimage, Imgproc.COLOR_BGR2RGB);
        }

        for (int i = 0; i < lin; i++) {
            for (int j = 0; j < col; j++) {
                double[] rgb =rgbimage.get(i, j);
                pixels.add(rgb); //put data in arraylist

            }
        }
}

Possible duplicate of [How to read all files in a folder from Java?](https://stackoverflow.com/questions/1844688/how-to-read-all-files-in-a-folder-from-java) — Marcos Vasconcelos, Apr 26 '18 at 19:36

Shawn Wonsmos · Answer 1 · 2018-04-26T21:31:39.020

0

Using File you can get a list of all files in a directory. Then, you can loop through the list to get the absolute path of each file and do whatever you want with it.

public void cor() {
    File rootDir= new File("your/path/to/root_directory");
    File[] files = rootDir.listFiles();

    for(File file :files) {
        String src = file.getAbsolutePath();
        Mat imgread;
        imgread = Imgcodecs.imread(src, IMREAD_COLOR);

        /*
         * Do the other stuff in your method. 
         */ 
    }
}

Note: I was not 100% sure what you were doing with pixels, so I just wrote what you need to loop through a directory.

edited Apr 26 '18 at 21:31

answered Apr 26 '18 at 19:55

Shawn Wonsmos

171
8

"root_directory" is the path for my folder? – BDamsk Apr 26 '18 at 20:18
Yes. The "root_directory" is the folder that contains all of the image files. – Shawn Wonsmos Apr 26 '18 at 20:30
Checkout [this post](https://stackoverflow.com/questions/38417848/cannot-resolve-symbol-fileutils-in-codepath-todo-app-tutorial-android) – Shawn Wonsmos Apr 26 '18 at 20:36
don't worked. Error:Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'. > java.lang.RuntimeException: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex – BDamsk Apr 26 '18 at 21:13
I have updated my response to not use [FileUtils](https://commons.apache.org/proper/commons-io/javadocs/api-2.5/org/apache/commons/io/FileUtils.html). This should work now. – Shawn Wonsmos Apr 26 '18 at 21:32
the code above return for me "empty" in the "if" where verify if imgread variable contain a image. I guess that right way is getAbsolutFile(); but, the method imread (method that read a image) just accept the path type String. – BDamsk May 02 '18 at 17:53
I solved. Thank you. The problem was my own error in sintaxy. Sorry. Now it works. – BDamsk May 02 '18 at 21:13

how load all imagens from directory and read using function imread opencv?

1 Answers1