自定义卷积核—模糊
OpenCV除了提供由库进行计算的kernel，还支持自定义kernel来进行自定义滤波。常见的包括模糊、锐化、梯度计算等方式。自定义kernel的实现依赖于filter2D() 函数。下面是该函数的声明：
filter2D(src, dst, ddepth, kernel);
各参数解释如下：
-
src
表示此操作的源(输入图像)的Mat对象。 -
dst
表示此操作的目标(输出图像)的Mat对象。 -
ddepth
输出图像深度，值为-1则表示与输入图像一致。 -
kernel
自定义的卷积核。
Java代码（JavaFX Controller层）
public class Controller{
@FXML private Text fxText;
@FXML private ImageView imageView;
@FXML public void handleButtonEvent(ActionEvent actionEvent) throws IOException {
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);
runInSubThread(file.getPath());
}
private void runInSubThread(String filePath){
new Thread(new Runnable() {
@Override
public void run() {
try {
WritableImage writableImage = filter2DOfSharpening(filePath);
Platform.runLater(new Runnable() {
@Override
public void run() {
imageView.setImage(writableImage);
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
private WritableImage filter2DOfSharpening(String filePath) throws IOException {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
Mat src = Imgcodecs.imread(filePath);
Mat dst = new Mat();
// Self define kernel of size 3x3.
Mat kernel = new Mat(3,3, CvType.CV_32FC1);
float[] data = new float[]{
0,-1,0,
-1,5,0,
0,-1,0
};
kernel.put(0,0,data);
Imgproc.filter2D(src, dst, -1, kernel);
MatOfByte matOfByte = new MatOfByte();
Imgcodecs.imencode(".jpg", dst, matOfByte);
byte[] bytes = matOfByte.toArray();
InputStream in = new ByteArrayInputStream(bytes);
BufferedImage bufImage = ImageIO.read(in);
WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null);
return writableImage;
}
}
图1 - 自定义3X3锐化卷积核
图2 - 自定义3X3强化锐化算子八零域卷积核
运行图
图 3 - 使用自定义的3X3锐化卷积核
