/**        Read in an image and add Gaussian random noise
 *         to s apecified SNR
 *         @auther Will Hossack, 
 */
import uk.ac.ed.ph.signal.*;                   // Signal classes

public class SNRDisplay {
    public static void main(String args[]) {

	//            Check that argument was given.
	if (args.length < 2) {
            System.err.println("Usage: java SNRDisplay filename snr");
            System.exit(1);
        }
        String file = args[0];
	double snr = Double.parseDouble(args[1].trim());

	//            Read image (type depermined by suffix)
	RealImage im = RealImage.readImage(file);
	System.out.println("Read image is : " + im);

       
	//            Create a display panel
	ImageFrame display = new ImageFrame("Original Image");
	display.addImage(im);     // Add image with (with autscale defaults)
	display.centre();         // Display in centre of screen

	//            Get statistics
	RealStatistics stats = im.getStatistics();
	System.out.println("Image stats are " + stats);
	double imDev = Math.sqrt(stats.getVariance());
	System.out.println("Image deviation is " + imDev);

	RealImage nim = im.clone();       // Copy of image

	//           Add noise
	Noise.addGuassianIndependantNoise(nim,imDev/snr);

	//            Dsiplay noise image
	ImageFrame noisedisplay = new ImageFrame("Noisy Image");
	noisedisplay.addImage(nim); 
    }
}