Displaying image and converting to grayscale - OpenCV for Android, Java API

Question

I\'m writing an Android app in Eclipse that uses the OpenCV4Android API. How can I display a Mat image easily, for debugging only? In C++, according to the OpenCV

Answer 1

While this doesn't deal with the display of the image, here is a quick pure-java static method to read an image by filepath and then convert it (and write it) into grayscale.

/**
 * Get an OpenCV matrix from an image path and write the image as grayscale.
 * @param filePath The image path.
 * @return The matrix.
 */
public static Mat loadOpenCvImage(final String filePath) {
    Mat imgMat = Highgui.imread(filePath, Highgui.CV_LOAD_IMAGE_GRAYSCALE);
    if (imgMat == null) {
        Log.e(TAG, "error loading file: " + filePath);
    } else {
        Log.d(TAG, "Ht: " + imgMat.height() + " Width: " + imgMat.width());
        final String outPath = filePath + "_gray.jpg";
        Log.d(TAG, outPath);
        Highgui.imwrite(outPath, imgMat);
    }
    return imgMat;
}