L'algo de Sobel en C#

**sali lala** · 06/12/2008, 11h44

bonjour,
jai fait l'algo de Sobel ,voici le code;

Code :

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            Bitmap myBitmap = new Bitmap(pictureBox1.Image);
            int width = myBitmap.Width;
            int height = myBitmap.Height;
            unsafe
            {
                BitmapData bmpData = myBitmap.LockBits(new Rectangle(0, 0, width,
                height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
 
                byte* newPixel = (byte*)(void*)bmpData.Scan0;                
                //syntaxe equivalente
                //byte* pixel = (byte*)bmpData.Scan0.ToPointer();
 
                //creation de la matrice de NDG.
 
                byte[,] image = new byte[width, height];                
                for (int y = 0; y < height; y++)
                    for (int x = 0; x < width; x++)
                    {
                        image[x, y] = newPixel[0];                                          
                        newPixel += 4;                       
                    }
                myBitmap.UnlockBits(bmpData);
 
                // une cpoier de la matrice de ND.
 
                byte[,]image1 =new byte[width,height];
                for (int y = 0; y < height; y++)
                    for (int x = 0; x < width; x++)
                    {
                        image1[x, y] = image[x,y];                        
                    }
 
                int npix;
 
                // calcule de filtre de soble Gx
                /* _______
                 * -1|0|1
                 * -------
                 * -2|0|2
                 * -------
                 * -1|0|1                                   
                 * _______
                 */
 
                for (int j = 1; j < height-1; j++)
                    for (int i = 1; i < width-1; i++)
                    {
 
                        npix = image[i - 1, j - 1] * (-1) + image[i + 1, j - 1] + image[i - 1, j] * (-2) +
                            image[i + 1, j] * (2) + image[i - 1, j + 1] * (-1) + image[i + 1, j + 1];
                       if (npix > 255) npix = 255;
                       if (npix < 0) npix = 0;
                        image[i, j] = (byte)npix;
 
                    }
 
                // calcule de filtre de soble Gy
                /* ________
                 *  1|2|1
                 * --------
                 *  0|0|0
                 * --------
                 * -1|-2|-1                                   
                 * ________
                 */
 
                for (int j = 1; j < height - 1; j++)
                    for (int i = 1; i < width - 1; i++)
                    {
                         npix =image1[i - 1, j - 1]+ image1[i, j - 1]*(2)+image1[i + 1, j - 1] + image1[i - 1, j+1]*(-1)
                            +image1[i,j+1] * (-2) + image1[i +1, j + 1] * (-1);
                        if (npix > 255) npix = 255;
                        if (npix < 0) npix = 0;                        
                        image1[i, j] = (byte)npix;
                    }
                // Construction de l'image filtrer
 
                BitmapData bmp= myBitmap.LockBits(new Rectangle(0, 0, width,
                height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
                byte* Pixel = (byte*)(void*)bmp.Scan0;
                int x1;
                byte x2;
                for (int y = 0; y < height; y++)
                    for (int x = 0; x < width; x++)
                    {
                        x1 = (int)Math.Sqrt((image1[x, y] *image1[x, y]) + (image[x, y]*image[x, y]));
                        if (x1 > 255) x1 = 255;
                        if (x1 < 0 ) x1 = 0;
                        x2 = (byte)x1;
                        Pixel[0] = x2;
                        Pixel[1] = x2;
                        Pixel[2] = x2; 
                        Pixel += 4;
                    }              
                         myBitmap.UnlockBits(bmp);
            }
            pictureBox2.Image = myBitmap;