C#图像处理

（1）在Form1窗体中的PictureBox1控件中显示通过OpenFileDialog指定的图像文件内容。

将SizeMode设置成StretchImage

private void 打开ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            OpenFileDialog open = new OpenFileDialog();
            open.Filter = "所有文件|*.*";
            if (open.ShowDialog() == DialogResult.OK)
            {
                Bitmap im = new Bitmap(open.FileName);
                pictureBox1.Image = im;
                //pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
            }
        }

（2）编制一个图像格式转换的应用程序，实现BMP图像与JPEG图像的格式转换。

private void bMPToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Bitmap box = new Bitmap(pictureBox1.Image);
            SaveFileDialog sv1 = new SaveFileDialog();
            sv1.Filter = "bmp|*.bmp";
            sv1.ShowDialog();
            string str = sv1.FileName;
            box.Save(str, System.Drawing.Imaging.ImageFormat.Bmp);
        }

private void jPEGToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Bitmap box = new Bitmap(pictureBox1.Image);
            SaveFileDialog sv1 = new SaveFileDialog();
            sv1.Filter = "jpeg文件|*.jpeg";
            sv1.ShowDialog();
            string str = sv1.FileName;
            box.Save(str, System.Drawing.Imaging.ImageFormat.Jpeg);
        }

（3）在窗体中添加两个PictureBox，然后利用OpenFileDialog控件选择一彩色图像文件并在pictureBox1中加载，然后将这一彩色图像转换为灰度图像，并在pictureBox2中进行显示，将此图像保存为a.bmp。

private void 灰度ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
            Color c = new Color();
            Bitmap b1 = new Bitmap(pictureBox1.Image);
            int rr, gg, bb, cc;
            for (int i = 0; i < pictureBox1.Image.Width; i++) 
            {
                for (int j = 0; j < pictureBox1.Image.Height; j++)
                {
                    c = b1.GetPixel(i, j);
                    rr = c.R;
                    gg = c.G;
                    bb = c.B;
                    cc = (int)((rr + gg + bb) / 3);
                    if (cc < 0) cc = 0;
                    if (cc > 255) cc = 255;
                    Color nc = Color.FromArgb(cc, cc, cc);
                    b1.SetPixel(i, j, nc);
                }
            }
            pictureBox2.Refresh();
            pictureBox2.Image = b1;
        }
private void 灰度图像存储ToolStripMenuItem_Click(object sender, EventArgs e)
        {

            if (pictureBox2.Image != null)
            {
                Bitmap box = new Bitmap(pictureBox2.Image);
                SaveFileDialog sv1 = new SaveFileDialog();
                sv1.Filter = "bmp文件|*.bmp";
                sv1.ShowDialog();
                string str = sv1.FileName;
                box.Save(str, System.Drawing.Imaging.ImageFormat.Bmp);
                //pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
            }
            else MessageBox.Show("没有生成灰度图像");
        }

（4）将（3）中制作的a.bmp图像加载到PictureBox1，把a.bmp转换为二值图像，并在pictureBox2中进行显示。

 private void 转化ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            //Bitmap m = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            Bitmap map=new Bitmap(pictureBox1.Image);
            Color c;
            for (int i = 0; i < map.Height; i++)
            {
                for (int j = 0; j < map.Width; j++)
                {
                    c = map.GetPixel(j, i);
                    if (c.R > 100) c = Color.FromArgb(255, 255, 255); //红色分量值大于100则设成白色
                    else c = Color.Black;
                    map.SetPixel(j, i, c);
                }
            }
            pictureBox2.Image = map;
            pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
        }

（5）建立对比度增强算法，并对a.bmp图像进行对比度增强，显示在pictureBox2中显示出来,与PictureBox1中的a.bmp图像进行比较。

private void 对比ToolStripMenuItem_Click(object sender, EventArgs e)
        { 
            Color c = new Color();
            Bitmap box1 = new Bitmap(pictureBox1.Image);
            int lev=30, wid=170;
            int[] map = new int[256];
            for(int i=0;i<=lev;i++)
            {
                map[i]=0;
            }
            for (int i=lev;i<=wid;i++)  //对比度增强
            {
                map[i] = (int)((i * 1.0 - lev) / wid * 255);
            }
            for (int i = lev + wid; i < 256; i++)
            {
                map[i] = 255;
            }
            int gray;
            for (int i = 0; i < box1.Width; i++)
            {
                for (int j = 0; j < box1.Height; j++)
                {
                    c = box1.GetPixel(i, j);
                    gray = c.R;
                    c = Color.FromArgb(map[gray], map[gray], map[gray]);
                    box1.SetPixel(i, j, c);
                }
            }
            pictureBox2.Image = box1;
            pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
        }

灰度图像：

二值图像:

对比度增强：