Canny Edge Detector

[nasreen_laghari]

Hello Every body,

I'm new here n in the .Net atmosphere as well. I don’t know nothing about VB.
Currently I’m working on object detection project and need help in Canny Edge Detector. I have a piece of code written in Java. Can somebody help me to translate that code into VB.NET formate.


Thanks Indeed

package tools;

import java.awt.*;
import java.awt.image.*;

public class EdgeDetector extends Component {

public EdgeDetector() {
threshold1 = 50;
threshold2 = 230;
setThreshold(128);
setWidGaussianKernel(15);
}

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);
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;
}

//second file

package tools;

public class EdgeDetectorException extends Exception
{
public EdgeDetectorException()
{
//do something?
}
public EdgeDetectorException(String s)
{
super(s);
}
}

[jmcilhinney]

What use is VB.NET code to you if you know nothing about VB.NET? Perhaps you should learn something about VB.NET first, then think about what that code is doing and how that would be implemented in VB.NET. You could then have a go yourself and post back the parts that give you trouble. Help is one thing but it sounds to me like you just want someone to do the work for you. Just my thoughts.