opencv4.0.0图像处理：边缘检测（一） | chenying99'blog - 君子博学而日参省乎己，则知明而行无过矣

opencv是一个C++语言库，对于java程序员来说，貌似不是很友好；不过java程序员可以利用jni调用的方式来处理

for example:

public static void main1(String[] args) throws Exception {
        NativeLoader.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        Mat hello = Mat.eye(150, 150, CvType.CV_8SC3);
        System.out.println(hello.dump());
        hello.setTo(new Scalar(180,80,250));
        Mat sub=hello.submat(0,50,0,50);
        sub.setTo(new Scalar(0,0,100));
        //imwrite("E:\\idea-workspace\\hellocv\\dev\\hello.png",hello);
        //System.out.println(hello.dump());
    }

/**
    * 边缘检测算子
    * @param args
    * @throws Exception
    */
   public static void main(String[] args) throws Exception {
       NativeLoader.loadLibrary(Core.NATIVE_LIBRARY_NAME);
       Mat tools=Imgcodecs.imread("images/tools.jpg");
       Imgproc.cvtColor(tools, tools, Imgproc.COLOR_RGB2GRAY);
       Imgproc.Canny(tools, tools,100.0, 300.0,3,true);

       Mat invetedTools=tools.clone();
       bitwise_not(invetedTools, invetedTools);
       Imgcodecs.imwrite("output/tools-04.png", invetedTools);
   }

图像掩模

static Scalar WHITE = new Scalar(255,255,255);
 /**
     * 图像掩模
     * @param args
     * @throws Exception
     */
	public static void main(String[] args) throws Exception {
		
		NativeLoader.loadLibrary(Core.NATIVE_LIBRARY_NAME);
		
		Mat kittens = imread("images/tools.jpg");

		Imgproc.cvtColor(kittens, kittens, Imgproc.COLOR_RGB2GRAY);
		Imgproc.Canny(kittens, kittens, 100.0, 300.0, 3, true);
		bitwise_not(kittens, kittens);
		// System.out.println(kittens.dump());

		Mat target = new Mat(kittens.height(), kittens.width(), CvType.CV_8UC3, WHITE);
		Mat bg = imread("images/light-blue-gradient.jpg");
		Imgproc.resize(bg, bg, target.size());
		bg.copyTo(target, kittens);		

		imwrite("output/kittens-03.png", target);
	}