Sharpening an image is the opposite of blur. To alter the sharpness of an image using the OpenCV library, you need to smooth/blur it using the Gaussian filter and subtract the smoothed version from the original image.
Example
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.Size;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
public class AlteringSharpness {
public static void main (String[] args) {
//Loading the OpenCV core library
System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
//Reading the Image from the file
String file ="D:\\Image\\lamma1.jpg";
Mat src = Imgcodecs.imread(file, Imgcodecs.IMREAD_COLOR);
//Creating an empty matrix
Mat dest = new Mat(src.rows(), src.cols(), src.type());
Imgproc.GaussianBlur(src, dest, new Size(0,0), 10);
Core.addWeighted(src, 1.5, dest, -0.5, 0, dest);
// Writing the image
Imgcodecs.imwrite("D:\\Image\\altering_sharpness_100.jpg", dest);
}
}Input
Output
