private void 图片二值化ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            
            if (m_Bitmap!=null)
            {
                Rectangle rect = new Rectangle(0, 0, m_Bitmap.Width, m_Bitmap.Height);
                BitmapData bmpData = m_Bitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, m_Bitmap.PixelFormat);
                IntPtr ptr = bmpData.Scan0;
                int bytes = m_Bitmap.Width * m_Bitmap.Height*3;
                byte[] grayValues = new byte[bytes];
                
                System.Runtime.InteropServices.Marshal.Copy(ptr, grayValues, 0, bytes);

                byte temp = 0;
                byte T = 0;
                byte maxGray = 0;
                byte minGray = 255;
                int[] countPixel = new int[256];
                double mu1, mu2;
                double numerator, denominator;

                //计算直方图
                for (int i = 0; i < grayValues.Length; i++)
                {
                    temp = grayValues[i];
                    countPixel[temp]++;
                    if (temp > maxGray) 
                    {
                        //最大灰度等级
                        maxGray = temp;
                    }
                    if (temp < minGray) 
                    {
                        //最小灰度等级
                        minGray = temp;
                    }
                }

                //迭代法
                byte oldT;
               
                //初始阈值
                T = oldT = Convert.ToByte((maxGray + minGray) / 2);

                //迭代过程
                do
                {
                    oldT = T;
                    numerator = denominator = 0;

                    //迭代法公式1
                    for (int i = minGray; i <T; i++)
                    {
                        numerator += i * countPixel[i];
                        denominator += countPixel[i];
                    }
                    mu1 = numerator / denominator;

                    numerator = denominator = 0;
                    for (int i = T; i < maxGray; i++)
                    {
                        numerator += i * countPixel[i];
                        denominator += countPixel[i];
                    }

                    mu2 = numerator / denominator;

                    //迭代法公式2
                    T = Convert.ToByte((mu1 + mu2)/2);
                }
                while (T!=oldT);

                //图像二值化
                for (int i = 0; i < bytes ; i++)
                {
                    if (grayValues[i]<T)
                    {
                        grayValues[i] = 0;
                    }
                    else
                    {
                        grayValues[i] = 255;
                    }
                }
                System.Runtime.InteropServices.Marshal.Copy(grayValues, 0, ptr, bytes);
                m_Bitmap.UnlockBits(bmpData);
                pictureBox1.Image = m_Bitmap;
            }
           
           
        }