edgedetect.cs

一个C#开发的类似PHOTOSHOP的软件,用到了很多图形算法.

      m.TopLeft = m.MidLeft = m.BottomLeft = 5;
      Bitmap b7 = m.Convolute((Bitmap)b.Clone());

      //    5  5 -3
      //    5  0 -3
      //   -3 -3 -3
      m.Init(-3);
      m.Center = 0;
      m.TopLeft = m.MidLeft = m.TopMid = 5;
      Bitmap b8 = m.Convolute((Bitmap)b.Clone());

      // 梯度运算
      Bitmap b9 = Gradient(Gradient(b1, b2), Gradient(b3, b4));
      Bitmap b10 = Gradient(Gradient(b5, b6), Gradient(b7, b8));
      b = Gradient(b9, b10);

      b1.Dispose(); b2.Dispose(); b3.Dispose(); b4.Dispose();
      b5.Dispose(); b6.Dispose(); b7.Dispose(); b8.Dispose();
      b9.Dispose(); b10.Dispose();

      return b;
    } // end of Kirsch


    /// <summary>
    /// 按 GaussLaplacian 算子进行边缘检测
    /// </summary>
    /// <param name="b"></param>
    /// <returns></returns>
    public Bitmap GaussLaplacian(Bitmap b)
    {
      int[,] kernel = { 
        {-2, -4, -4, -4, -2},
        {-4,  0,  8,  0, -4},
        {-4,  8, 24,  8, -4},
        {-4,  0,  8,  0, -4},
        {-2, -4, -4, -4, -2}
      };

      MatrixNxN m = new MatrixNxN();
      m.Kernel = kernel;

      return m.Convolute(b);
    } // end of GaussLaplacian


    /// <summary>
    /// 按水平边缘检测算子进行边缘检测
    /// </summary>
    /// <param name="b"></param>
    /// <returns></returns>
    public Bitmap EdgeDetectHorizontal(Bitmap b)
    {
      int[,] kernel = { 
        { 0,  0,  0,  0,  0,  0,  0},
        { 0,  0,  0,  0,  0,  0,  0},
        {-1, -1, -1, -1, -1, -1, -1},
        { 0,  0,  0,  0,  0,  0,  0},
        { 1,  1,  1,  1,  1,  1,  1},
        { 0,  0,  0,  0,  0,  0,  0},
        { 0,  0,  0,  0,  0,  0,  0},
      };

      MatrixNxN m = new MatrixNxN();
      m.Kernel = kernel;

      return m.Convolute(b);
    } // end of EdgeDetectHorizontal


    /// <summary>
    /// 按垂直边缘检测算子进行边缘检测
    /// </summary>
    /// <param name="b"></param>
    /// <returns></returns>
    public Bitmap EdgeDetectVertical(Bitmap b)
    {
      int[,] kernel = { 
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
        { 0,  0, -1,  0,  1,  0,  0},
      };

      MatrixNxN m = new MatrixNxN();
      m.Kernel = kernel;

      return m.Convolute(b);
    } // end of EdgeDetectVertical


    /// <summary>
    /// 边缘增强
    /// </summary>
    /// <param name="b">位图流</param>
    /// <param name="threshold">阈值</param>
    /// <returns></returns>
    public Bitmap EdgeEnhance(Bitmap b, int threshold)
    {
      int width = b.Width;
      int height = b.Height;

      Bitmap dstImage = (Bitmap)b.Clone();

      BitmapData srcData = b.LockBits(new Rectangle(0, 0, width, height),
        ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
      BitmapData dstData = dstImage.LockBits(new Rectangle(0, 0, width, height),
        ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);

      // 图像实际处理区域
      // 不考虑最左 1 列和最右 1 列
      // 不考虑最上 1 行和最下 1 行
      int rectTop = 1;
      int rectBottom = height - 1;
      int rectLeft = 1;
      int rectRight = width - 1;

      unsafe
      {
        byte* src = (byte*)srcData.Scan0;
        byte* dst = (byte*)dstData.Scan0;

        int stride = srcData.Stride;
        int offset = stride - width * BPP;

        int pixel = 0;
        int maxPixel = 0;


        // 指向第 1 行
        src += stride;
        dst += stride;
        for (int y = rectTop; y < rectBottom; y++)
        {
          // 指向每行第 1 列像素
          src += BPP;
          dst += BPP;

          for (int x = rectLeft; x < rectRight; x++)
          {
            // Alpha
            dst[3] = src[3];

            // 处理 B, G, R 三分量
            for (int i = 0; i < 3; i++)
            {
              // 右上-左下
              maxPixel = src[i - stride + BPP] - src[i + stride - BPP];
              if (maxPixel < 0) maxPixel = -maxPixel;

              // 左上-右下
              pixel = src[i - stride - BPP] - src[i + stride + BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 上-下
              pixel = src[i - stride] - src[i + stride];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 左-右
              pixel = src[i - BPP] - src[i + BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 进行阈值判断
              if (maxPixel < threshold) maxPixel = 0;
              
              dst[i] = (byte)maxPixel;
            }

            // 向后移一像素
            src += BPP;
            dst += BPP;
          } // x

          // 移向下一行
          // 这里得注意要多移 1 列，因最右边还有 1 列不必处理
          src += offset + BPP;
          dst += offset + BPP;
        } // y
      }

      b.UnlockBits(srcData);
      dstImage.UnlockBits(dstData);

      b.Dispose();

      return dstImage;
    } // end of EdgeEnhance


    /// <summary>
    /// 边缘均衡化
    /// </summary>
    /// <param name="b">位图流</param>
    /// <param name="threshold">阈值</param>
    /// <returns></returns>
    public Bitmap EdgeHomogenize(Bitmap b, int threshold)
    {
      int width = b.Width;
      int height = b.Height;

      Bitmap dstImage = (Bitmap)b.Clone();

      BitmapData srcData = b.LockBits(new Rectangle(0, 0, width, height),
        ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
      BitmapData dstData = dstImage.LockBits(new Rectangle(0, 0, width, height),
        ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);

      // 图像实际处理区域
      // 不考虑最左 1 列和最右 1 列
      // 不考虑最上 1 行和最下 1 行
      int rectTop = 1;
      int rectBottom = height - 1;
      int rectLeft = 1;
      int rectRight = width - 1;

      unsafe
      {
        byte* src = (byte*)srcData.Scan0;
        byte* dst = (byte*)dstData.Scan0;

        int stride = srcData.Stride;
        int offset = stride - width * BPP;

        int pixel = 0;
        int maxPixel = 0;

        // 指向第 1 行
        src += stride;
        dst += stride;
        for (int y = rectTop; y < rectBottom; y++)
        {
          // 指向每行第 1 列像素
          src += BPP;
          dst += BPP;

          for (int x = rectLeft; x < rectRight; x++)
          {
            // Alpha
            dst[3] = src[3];

            // 处理 B, G, R 三分量
            for (int i = 0; i < 3; i++)
            {
              // 上
              maxPixel = src[i] - src[i - stride];
              if (maxPixel < 0) maxPixel = -maxPixel;

              // 右上
              pixel = src[i] - src[i - stride + BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 右
              pixel = src[i] - src[i + BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 右下
              pixel = src[i] - src[i + stride + BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 下
              pixel = src[i] - src[i + stride];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 左下
              pixel = src[i] - src[i + stride - BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 左
              pixel = src[i] - src[i - BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 左上
              pixel = src[i] - src[i - stride - BPP];
              if (pixel < 0) pixel = -pixel;
              if (pixel > maxPixel) maxPixel = pixel;

              // 进行阈值判断
              if (maxPixel < threshold) maxPixel = 0;

              dst[i] = (byte)maxPixel;
            }

            // 向后移一像素
            src += BPP;
            dst += BPP;
          } // x

          // 移向下一行
          // 这里得注意要多移 1 列，因最右边还有 1 列不必处理
          src += offset + BPP;
          dst += offset + BPP;
        } // y
      }

      b.UnlockBits(srcData);
      dstImage.UnlockBits(dstData);

      b.Dispose();

      return dstImage;
    } // end of EdgeHomogenize


  }
}