Permute of Image in OpenCV Java Preset Or Conversion of Mat to Java array.

[ashish bhutani]

Hi

Is there any equivalent of permute (http://in.mathworks.com/help/matlab/ref/permute.html?requestedDomain=www.mathworks.com) for image in OpenCV Java Preset ? I am not able to find one.

My image is represented as org.bytedeco.javacpp.Mat I can use permute provided by Nd4j. But to use Nd4j, I will need to convert Mat to int[]/float[] and that too is not clear to me.

Any chance someone can help ?

I have tried below approaches for conversion of Mat to int[] but they doesn't work.

private static int[] MatToFloatArray1(Mat mat) {
        org.bytedeco.javacpp.BytePointer matData = mat.data();
        byte[] d = new byte[matData.capacity()];
        return toIntArray(d);
    }


private static int[] MatToFloatArray2(Mat mat) {
    org.bytedeco.javacpp.BytePointer matData = mat.data();
    IntBuffer intBuffer = matData.asBuffer().asIntBuffer();
    return intBuffer.array();

}
    private static int[] toIntArray(byte[] d) {
        IntBuffer intBuf =
                ByteBuffer.wrap(d)
                        .order(ByteOrder.BIG_ENDIAN)
                        .asIntBuffer();
        int[] array = new int[intBuf.remaining()];
        return array;


    }

[Samuel Audet]

There's nothing that I know of for that in OpenCV, I'm afraid. We can use Mat.createBuffer() to access the raw data and use that with ND4J though.

Samuel

2016/03/03 6:45 "ashish bhutani" <bhutani....@gmail.com>:

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[ashish bhutani]

Thanks Samuel.

I was trying createBuffer() to access the raw data but could not make it work. Below is the code.

ByteBuffer buffer =  resizedImage.<ByteBuffer>createBuffer();
byte[] byteArray = new byte[buffer.remaining()];
int[] intArray = toIntArray(d);

private static int[] toIntArray(byte[] d) {
    IntBuffer intBuf = ByteBuffer.wrap(d)
                        .order(ByteOrder.BIG_ENDIAN)
                        .asIntBuffer();
    int[] array = new int[intBuf.remaining()];
    return array;

}

Arrays byteArray and intArray has all entries as 0. 

Any possibility you can provide a help here ? Thanks. 

Also, I asked the question in SO as well (http://stackoverflow.com/questions/35758568/javacpp-equivalent-of-matlabs-permute?noredirect=1#comment59191988_35758568)

One of the comment there is to use mixChannel function to achieve permute functionality. But I can't find any mixChannel equivalent in Java OPenCV preset.

[Samuel Audet]

You'll probably need to convert the bytes to ints here...

2016/03/03 16:45 "ashish bhutani" <bhutani....@gmail.com>: