Edge Detection In Java

package imageviewer;
 
  
import java.awt.*;
import java.awt.image.*;
import java.util.BitSet;
import javax.swing.ImageIcon;
 
public class EdgeDetector extends Component {
     
    public EdgeDetector(int hi,int wd,Image image) {
        threshold1 = 50;
        threshold2 = 230;
        width=wd;
        height=hi;
        setThreshold(128);
        setWidGaussianKernel(15);
        sourceImage = image;
        try {
            process();
        } catch (EdgeDetectorException ex) {
            ex.printStackTrace();
        }
    }
     
    public void process() throws EdgeDetectorException {
        if (threshold < 0 || threshold > 255)
            throw new EdgeDetectorException("The value of the threshold is out of its valid range.");
        if (widGaussianKernel < 3 || widGaussianKernel > 40)
            throw new EdgeDetectorException("The value of the widGaussianKernel is out of its valid range.");
        width = sourceImage.getWidth(this);
        height = sourceImage.getHeight(this);
        picsize = width * height;
        data = new int[picsize];
        magnitude = new int[picsize];
        orientation = new int[picsize];
        float f = 1.0F;
        canny_core(f, widGaussianKernel);
        thresholding_tracker(threshold1, threshold2);
        for (int i = 0; i < picsize; i++)
            if (data[i] > threshold)
                data[i] = 0xff000000;
            else
                data[i] = -1;
         
        edgeImage =  pixels2image(data);
        /*int w = edgeImage.getWidth(null);
        int h = edgeImage.getHeight(null);                
        bi = new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
         
        Graphics2D g2=(Graphics2D)edgeImage.getGraphics();*/
        data = null;
        magnitude = null;
        orientation = null;
    }
     
    private void canny_core(float f, int i) {
        boolean flag = false;
        boolean flag1 = false;
        derivative_mag = new int[picsize];
        float af4[] = new float[i];
        float af5[] = new float[i];
        float af6[] = new float[i];
        data = image2pixels(sourceImage);
        int k4 = 0;
        do {
            if (k4 >= i)
                break;
            float f1 = gaussian(k4, f);
            if (f1 <= 0.005F && k4 >= 2)
                break;
            float f2 = gaussian((float) k4 - 0.5F, f);
            float f3 = gaussian((float) k4 + 0.5F, f);
            float f4 = gaussian(k4, f * 0.5F);
            af4[k4] = (f1 + f2 + f3) / 3F / (6.283185F * f * f);
            af5[k4] = f3 - f2;
            af6[k4] = 1.6F * f4 - f1;
            k4++;
        } while (true);
        int j = k4;
        float af[] = new float[picsize];
        float af1[] = new float[picsize];
        int j1 = width - (j - 1);
        int l = width * (j - 1);
        int i1 = width * (height - (j - 1));
        for (int l4 = j - 1; l4 < j1; l4++) {
            for (int l5 = l; l5 < i1; l5 += width) {
                int k1 = l4 + l5;
                float f8 = (float) data[k1] * af4[0];
                float f10 = f8;
                int l6 = 1;
                int k7 = k1 - width;
                for (int i8 = k1 + width; l6 < j; i8 += width) {
                    f8 += af4[l6] * (float) (data[k7] + data[i8]);
                    f10 += af4[l6] * (float) (data[k1 - l6] + data[k1 + l6]);
                    l6++;
                    k7 -= width;
                }
                 
                af[k1] = f8;
                af1[k1] = f10;
            }
             
        }
         
        float af2[] = new float[picsize];
        for (int i5 = j - 1; i5 < j1; i5++) {
            for (int i6 = l; i6 < i1; i6 += width) {
                float f9 = 0.0F;
                int l1 = i5 + i6;
                for (int i7 = 1; i7 < j; i7++)
                    f9 += af5[i7] * (af[l1 - i7] - af[l1 + i7]);
                 
                af2[l1] = f9;
            }
             
        }
         
        af = null;
        float af3[] = new float[picsize];
        for (int j5 = k4; j5 < width - k4; j5++) {
            for (int j6 = l; j6 < i1; j6 += width) {
                float f11 = 0.0F;
                int i2 = j5 + j6;
                int j7 = 1;
                for (int l7 = width; j7 < j; l7 += width) {
                    f11 += af5[j7] * (af1[i2 - l7] - af1[i2 + l7]);
                    j7++;
                }
                 
                af3[i2] = f11;
            }
             
        }
         
        af1 = null;
        j1 = width - j;
        l = width * j;
        i1 = width * (height - j);
        for (int k5 = j; k5 < j1; k5++) {
            for (int k6 = l; k6 < i1; k6 += width) {
                int j2 = k5 + k6;
                int k2 = j2 - width;
                int l2 = j2 + width;
                int i3 = j2 - 1;
                int j3 = j2 + 1;
                int k3 = k2 - 1;
                int l3 = k2 + 1;
                int i4 = l2 - 1;
                int j4 = l2 + 1;
                float f6 = af2[j2];
                float f7 = af3[j2];
                float f12 = hypotenuse(f6, f7);
                int k = (int) ((double) f12 * 20D);
                derivative_mag[j2] = k >= 256 ? 255 : k;
                float f13 = hypotenuse(af2[k2], af3[k2]);
                float f14 = hypotenuse(af2[l2], af3[l2]);
                float f15 = hypotenuse(af2[i3], af3[i3]);
                float f16 = hypotenuse(af2[j3], af3[j3]);
                float f18 = hypotenuse(af2[l3], af3[l3]);
                float f20 = hypotenuse(af2[j4], af3[j4]);
                float f19 = hypotenuse(af2[i4], af3[i4]);
                float f17 = hypotenuse(af2[k3], af3[k3]);
                float f5;
                if (f6 * f7 <= (float) 0
                        ? Math.abs(f6) >= Math.abs(f7)
                        ? (f5 = Math.abs(f6 * f12))
                        >= Math.abs(f7 * f18 - (f6 + f7) * f16)
                        && f5
                        > Math.abs(f7 * f19 - (f6 + f7) * f15) : (
                        f5 = Math.abs(f7 * f12))
                        >= Math.abs(f6 * f18 - (f7 + f6) * f13)
                        && f5
                        > Math.abs(f6 * f19 - (f7 + f6) * f14) : Math.abs(f6)
                        >= Math.abs(f7)
                        ? (f5 = Math.abs(f6 * f12))
                        >= Math.abs(f7 * f20 + (f6 - f7) * f16)
                        && f5
                        > Math.abs(f7 * f17 + (f6 - f7) * f15) : (
                        f5 = Math.abs(f7 * f12))
                        >= Math.abs(f6 * f20 + (f7 - f6) * f14)
                        && f5 > Math.abs(f6 * f17 + (f7 - f6) * f13)) {
                    magnitude[j2] = derivative_mag[j2];
                    orientation[j2] = (int) (Math.atan2(f7, f6) * (double) 40F);
                }
            }
             
        }
         
        derivative_mag = null;
        af2 = null;
        af3 = null;
    }
     
    private float hypotenuse(float f, float f1) {
        if (f == 0.0F && f1 == 0.0F)
            return 0.0F;
        else
            return (float) Math.sqrt(f * f + f1 * f1);
    }
     
    private float gaussian(float f, float f1) {
        return (float) Math.exp((-f * f) / ((float) 2 * f1 * f1));
    }
     
    private void thresholding_tracker(int i, int j) {
        for (int k = 0; k < picsize; k++)
            data[k] = 0;
         
        for (int l = 0; l < width; l++) {
            for (int i1 = 0; i1 < height; i1++)
                if (magnitude[l + width * i1] >= i)
                    follow(l, i1, j);
             
        }
         
    }
     
    private boolean follow(int i, int j, int k) {
        int j1 = i + 1;
        int k1 = i - 1;
        int l1 = j + 1;
        int i2 = j - 1;
        int j2 = i + j * width;
        if (l1 >= height)
            l1 = height - 1;
        if (i2 < 0)
            i2 = 0;
        if (j1 >= width)
            j1 = width - 1;
        if (k1 < 0)
            k1 = 0;
        if (data[j2] == 0) {
            data[j2] = magnitude[j2];
            boolean flag = false;
            int l = k1;
            do {
                if (l > j1)
                    break;
                int i1 = i2;
                do {
                    if (i1 > l1)
                        break;
                    int k2 = l + i1 * width;
                    if ((i1 != j || l != i)
                    && magnitude[k2] >= k
                            && follow(l, i1, k)) {
                        flag = true;
                        break;
                    }
                    i1++;
                } while (true);
                if (!flag)
                    break;
                l++;
            }
            while (true);
            return true;
        } else {
            return false;
        }
    }
     
    private Image pixels2image(int ai[]) {
        MemoryImageSource memoryimagesource =
                new MemoryImageSource(
                width,
                height,
                ColorModel.getRGBdefault(),
                ai,
                0,
                width);
        return Toolkit.getDefaultToolkit().createImage(memoryimagesource);
    }
     
    private int[] image2pixels(Image image) {
        int ai[] = new int[picsize];
        PixelGrabber pixelgrabber =
                new PixelGrabber(image, 0, 0, width, height, ai, 0, width);
        try {
            pixelgrabber.grabPixels();
        } catch (InterruptedException interruptedexception) {
            interruptedexception.printStackTrace();
        }
        boolean flag = false;
        int k1 = 0;
        do {
            if (k1 >= 16)
                break;
            int i = (ai[k1] & 0xff0000) >> 16;
            int k = (ai[k1] & 0xff00) >> 8;
            int i1 = ai[k1] & 0xff;
            if (i != k || k != i1) {
                flag = true;
                break;
            }
            k1++;
        } while (true);
        if (flag) {
            for (int l1 = 0; l1 < picsize; l1++) {
                int j = (ai[l1] & 0xff0000) >> 16;
                int l = (ai[l1] & 0xff00) >> 8;
                int j1 = ai[l1] & 0xff;
                ai[l1] =
                        (int) (0.29799999999999999D * (double) j
                        + 0.58599999999999997D * (double) l
                        + 0.113D * (double) j1);
            }
             
        } else {
            for (int i2 = 0; i2 < picsize; i2++)
                ai[i2] = ai[i2] & 0xff;
             
        }
        return ai;
    }
     
    public void setSourceImage(Image image) {
        sourceImage = image;
    }
     
    public Image getEdgeImage() {
         
        return edgeImage;        
         
    }
     
    public void setThreshold(int i) {
        threshold = i;
    }
     
    public void setWidGaussianKernel(int i) {
        widGaussianKernel = i;
    }
     
    final float ORIENT_SCALE = 40F;
    private int height;
    private int width;
    private int picsize;
    private int data[];
    private int derivative_mag[];
    private int magnitude[];
    private int orientation[];
    private Image sourceImage;
    private Image edgeImage;
    private int threshold1;
    private int threshold2;
    private int threshold;
    private int widGaussianKernel;   
    private static ShowFrame myFrame;
}
class EdgeDetectorException extends Exception {
    public EdgeDetectorException() {
        //do something?
    }
    public EdgeDetectorException(String s) {
        super(s);
    }
}