Converting `BufferedImage` to `Mat` in OpenCV

Question

How can I convert a BufferedImage to a Mat in OpenCV?

I\'m using the JAVA wrapper for OpenCV(not JavaCV

Answer 1

To convert from BufferedImage to Mat I use the method below:

    public static Mat img2Mat(BufferedImage image) {
        image = convertTo3ByteBGRType(image);
        byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
        Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_8UC3);
        mat.put(0, 0, data);
        return mat;
    }

Before converting into Mat, I change the type of bufferedImage to TYPE_3BYTE_BGR, because to some types BufferedImages the method ((DataBufferByte) image.getRaster().getDataBuffer()).getData(); may return int[] and that would break the code.

Below is the method for converting to TYPE_3BYTE_BGR.

    private static BufferedImage convertTo3ByteBGRType(BufferedImage image) {
        BufferedImage convertedImage = new BufferedImage(image.getWidth(), image.getHeight(),
                BufferedImage.TYPE_3BYTE_BGR);
        convertedImage.getGraphics().drawImage(image, 0, 0, null);
        return convertedImage;
    }