The cvtColor() method of the Imgproc class changes/converts the color of the image from one to another. This method accepts three parameters −
src − A Matrix object representing source.
dst − A Matrix object representing the destination.
code − An integer value representing the color of the destination image.
You can convert a colored image to an HLS image by passing Imgproc.COLOR_RGB2HLS as a parameter to the above method.
Example
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
public class RGB2HSL {
public static void main(String args[]) throws Exception {
//Loading the OpenCV core library
System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
//Reading the image
Mat src = Imgcodecs.imread("D:\\images\\car.jpg");
//Creating the empty destination matrix
Mat dst = new Mat();
//Converting the image to gray scale
Imgproc.cvtColor(src, dst, Imgproc.COLOR_RGB2HLS);
//Instantiating the Imagecodecs class
Imgcodecs imageCodecs = new Imgcodecs();
//Writing the image
imageCodecs.imwrite("D:\\images\\hslImage.jpg", dst);
System.out.println("Image Saved");
}
}Input

Output
