[人工智能]OpenCV之灰度转换

灰度转换
cvtColor(Mat src, Mat dst, int code) 方法可以完成目标矩阵与输入矩阵之间的灰度转换，其中code系转换模式，这里为灰度模式，即Imgproc.COLOR_RGB2GRAY。

Java代码

	// Button事件
    @FXML public void handleButtonEvent(ActionEvent actionEvent) {
        Node source = (Node) actionEvent.getSource();
        Window theStage = source.getScene().getWindow();
        FileChooser fileChooser = new FileChooser();
        FileChooser.ExtensionFilter extFilter = new FileChooser.ExtensionFilter("PNG files (*.png)", "*.png");
        fileChooser.getExtensionFilters().add(extFilter);
        fileChooser.getExtensionFilters().add(new FileChooser.ExtensionFilter("JPG Files(*.jpg)", "*.jpg"));
        File file = fileChooser.showOpenDialog(theStage);

        imageView.setImage(this.toGray(file.getPath()));
    }

    private WritableImage toGray(String filePath){
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

        Imgcodecs imageCodecs = new Imgcodecs();
        String input = filePath;

        Mat src = imageCodecs.imread(input, Imgcodecs.IMREAD_COLOR);
        Mat dst = new Mat();

        Imgproc.cvtColor(src, dst, Imgproc.COLOR_RGB2GRAY);

        byte[] data = new byte[src.rows() * src.cols() * (int) (src.elemSize())];
        dst.get(0, 0, data);

        BufferedImage bufImage = new BufferedImage(dst.cols(), dst.rows(), BufferedImage.TYPE_BYTE_GRAY);
        bufImage.getRaster().setDataElements(0, 0, dst.cols(), dst.rows(), data);
        WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null);
        return writableImage;
    }

运行图：