Question

我想在应用canny方法后显示图像。图像是一个字节数组，方法也返回一个字节数组，这里是代码：

public byte[] doCanny(byte[] image) {
        byte[] buff;

        try {


            Mat mat = Imgcodecs.imdecode(new MatOfByte(image), Imgcodecs.CV_LOAD_IMAGE_UNCHANGED);
            Mat gray = new Mat();
            Mat draw = new Mat(); 
            Mat wide = new Mat();

            Imgproc.cvtColor(mat, gray, Imgproc.COLOR_BGR2GRAY);
            Imgproc.Canny(gray, wide, 50, 150, 3, false);
            wide.convertTo(draw, CvType.CV_8U);

            int size = (int) draw.total() * draw.channels();
            buff = new byte[size];

            draw.put(50, 150, buff);
            System.out.println("Should return image");

            return buff;

//            if (Imgcodecs.imwrite(filename, draw)) { 
//                System.out.println("edge is detected ......."); 
//            } 
        } catch (Exception e) { 
            e.printStackTrace();
        } 
        return image;
    }
when I run this method it dose not return any image.

Answer 1

OpenCV Quick Guide中有一个例子解释了如何将MatOfByte对象转换为字节数组。尝试这样做：

public byte[] doCanny(byte[] image) {

    try {

        Mat color = Imgcodecs.imdecode(new MatOfByte(image), Imgcodecs.CV_LOAD_IMAGE_UNCHANGED);

        Mat gray = new Mat();
        Mat draw = new Mat();
        Mat wide = new Mat();

        Imgproc.cvtColor(color, gray, Imgproc.COLOR_BGR2GRAY);
        Imgproc.Canny(gray, wide, 50, 150, 3, false);
        wide.convertTo(draw, CvType.CV_8U);

        // Encoding the image
        MatOfByte matOfByte = new MatOfByte();
        Imgcodecs.imencode(".jpg", draw, matOfByte);

        return matOfByte.toArray();

    } catch (Exception e) {
        e.printStackTrace();
    }
    return image;
}

Opencv canny方法返回字节数组

1 个答案: