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Hi,

We develop an Android App that reads camera images and calculates the difference of two subsequent images using the method Core.add():

gryImage.convertTo(gryImage, CvType.CV_16SC1);
refImage.convertTo(refImage, CvType.CV_16SC1, -1);
Core.add(gryImage, refImage, result);

This works fine with opencv version 3.0.0. Now, updating to 3.1.0 or 3.2.0 (both behave the same) the add-method does not write anything to the result matrix.

Note: The add function is already a workaround for the subtract function, which does not work in version 3.0.0, 3.1.0 nor 3.2.0.

This behavior can be reproduced like this:

    public static void testOperations() {
    Mat mat1 = Mat.ones(new Size(10, 10), CvType.CV_16SC1);
    Mat mat2 = Mat.ones(new Size(10, 10), CvType.CV_16SC1);
    Mat mat3;
    double pix;
    /* addition */
    mat3 = Mat.ones(new Size(10, 10), CvType.CV_16SC1);
    Core.add(mat1, mat2, mat3);
    pix = mat3.get(0, 0)[0];
    System.out.println(pix); /* 3.0.0: pix=2 (correct), 3.1.0/3.2.0: pix=1 (wrong) */
    /* subtraction */
    mat3 = Mat.ones(new Size(10, 10), CvType.CV_16SC1);
    Core.subtract(mat1, mat2, mat3);
    pix = mat3.get(0, 0)[0];
    System.out.println(pix); /* 3.0.0: pix=1 (wrong), 3.1.0/3.2.0: pix=1 (wrong) */
}

I would like to have a correct result in either of the two operations in version 3.1.0 or 3.2.0. Can anyone help?