C# 内存法图像处理

内存法通过把图像储存在内存中进行处理，效率大大高于GetPixel方法，安全性高于指针法。

笔者当初写图像处理的时候发现网上多是用GetPixel方法实现，提到内存法的时候也没有具体实现，所以笔者在这里具体实现一下- -，望指正。

首先讲一下用到的一些方法。

1.LockBits和UnlockBits：使用 LockBits 方法，可在系统内存中锁定现有的位图，以便通过编程方式进行更改，每调用LockBits之后都应该调用一次UnlockBits。

2.Scan0：图像的第一个字节地址。

3.Stride：步幅，扫描宽度，形象的说就是一行的长度。

4.PixelFormat：数据的实际像素格式。

给出原图：

一、灰度

对每个像素点进行加权平均，（方法不唯一）。

        /// <summary>
        /// 灰化实现方法
        /// </summary>
        void Image_Ashing()
        {
            if (pbshowbox.Image != null)
            {
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;

                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                unsafe
                {
                    byte* pin = (byte*)(oldData.Scan0.ToPointer());
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {
                            byte Result = (byte)(pin[0] * 0.1 + pin[1] * 0.2 + pin[2] * 0.7);//加权平均实现灰化
                            pout[0] = (byte)(Result);
                            pout[1] = (byte)(Result);
                            pout[2] = (byte)(Result);
                            pin = pin + 3;
                            pout = pout + 3;
                        }
                        pin += oldData.Stride - oldData.Width * 3;
                        pout += newData.Stride - newData.Width * 3;
                    }

                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;

                }

            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }

        }

二、柔化

像素点与周围像素点差别较大时取平均值。

        /// <summary>
        /// 柔化实现方法
        /// </summary>
        void Image_Soften()
        {
            if (pbshowbox.Image != null)
            {
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;

                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);
                unsafe
                {
                    byte* pin = (byte*)(oldData.Scan0.ToPointer());
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    //高斯模板
                    int[] Gauss = { 1, 2, 1, 2, 4, 2, 1, 2, 1 };
                    for (int i = 1; i < Width - 1; i++)
                    {
                        for (int j = 1; j < Height - 1; j++)
                        {
                            int r = 0, g = 0, b = 0;
                            int Index = 0;

                            for (int col = -1; col <= 1; col++)
                            {
                                for (int row = -1; row <= 1; row++)
                                {
                                    int off = ((j + row) * (Width) + (i + col)) * 4;
                                    r += pin[off + 0] * Gauss[Index];
                                    g += pin[off + 1] * Gauss[Index];
                                    b += pin[off + 2] * Gauss[Index];
                                    Index++;
                                }
                            }
                            r /= 16;
                            g /= 16;
                            b /= 16;
                            //处理颜色值溢出
                            if (r < 0) r = 0;
                            if (r > 255) r = 255;
                            if (g < 0) g = 0;
                            if (g > 255) g = 255;
                            if (b < 0) b = 0;
                            if (b > 255) b = 255;
                            int off2 = (j * Width + i) * 4;
                            pout[off2 + 0] = (byte)r;
                            pout[off2 + 1] = (byte)g;
                            pout[off2 + 2] = (byte)b;
                        }
                    }
                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;
                }




            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }

        }

三、锐化

突出显示颜色值大的像素点。

        /// <summary>
        /// 锐化实现方法，显示数值最大像素点
        /// </summary>
        void Image_Sharpen()
        {
            if (this.pbshowbox.Image != null)
            {
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;

                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);
                unsafe
                {
                    byte* pin = (byte*)(oldData.Scan0.ToPointer());
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    //拉普拉斯模板
                    int[] Laplacian = { -1, -1, -1, -1, 9, -1, -1, -1, -1 };
                    for (int i = 1; i < Width - 1; i++)
                    {
                        for (int j = 1; j < Height - 1; j++)
                        {
                            int r = 0, g = 0, b = 0;
                            int Index = 0;

                            for (int col = -1; col <= 1; col++)
                            {
                                for (int row = -1; row <= 1; row++)
                                {
                                    int off = ((j + row) * (Width) + (i + col)) * 4;
                                    r += pin[off + 0] * Laplacian[Index];
                                    g += pin[off + 1] * Laplacian[Index];
                                    b += pin[off + 2] * Laplacian[Index];
                                    Index++;
                                }
                            }

                            if (r < 0) r = 0;
                            if (r > 255) r = 255;
                            if (g < 0) g = 0;
                            if (g > 255) g = 255;
                            if (b < 0) b = 0;
                            if (b > 255) b = 255;
                            int off2 = (j * Width + i) * 4;
                            pout[off2 + 0] = (byte)r;
                            pout[off2 + 1] = (byte)g;
                            pout[off2 + 2] = (byte)b;
                        }
                    }
                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;
                }

            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }
        }

四、浮雕

对图像像素点的像素值分别与相邻像素点的像素值相减后加上128, 然后将其作为新的像素点的值。

        /// <summary>
        /// 浮雕实现方法
        /// </summary>
        void Image_Relief()
        {
            if (this.pbshowbox.Image != null)
            {
               
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;
                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                unsafe
                {
                    byte* pin_1 = (byte*)(oldData.Scan0.ToPointer());
                    byte* pin_2 = pin_1 + (oldData.Stride);                
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height - 1; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {                           
                            int b = (int)pin_1[0] - (int)pin_2[0] + 128;
                            int g = (int)pin_1[1] - (int)pin_2[1] + 128;
                            int r = (int)pin_1[2] - (int)pin_2[2] + 128;

                            if (r < 0) r = 0;
                            if (r > 255) r = 255;
                            if (g < 0) g = 0;
                            if (g > 255) g = 255;
                            if (b < 0) b = 0;
                            if (b > 255) b = 255;
                            pout[0] = (byte)(b);
                            pout[1] = (byte)(g);
                            pout[2] = (byte)(r);
                            pin_1 = pin_1 + 3;
                            pin_2 = pin_2 + 3;
                            pout = pout + 3;                          
                        }
                        pin_1 += oldData.Stride - oldData.Width * 3;
                        pin_2 += oldData.Stride - oldData.Width * 3;
                        pout += newData.Stride - newData.Width * 3;
                    }
                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;
                }

            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }
        }

五、底片

颜色值取反。

        /// <summary>
        /// 底片实现方法
        /// </summary>
        void Image_Negative()
        {
            if (pbshowbox.Image != null)
            {
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;
                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                unsafe
                {
                    byte* pin = (byte*)(oldData.Scan0.ToPointer());
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {
                            pout[0] = (byte)(255 - pin[0]);
                            pout[1] = (byte)(255 - pin[1]);
                            pout[2] = (byte)(255 - pin[2]);
                            pin = pin + 3;
                            pout = pout + 3;
                        }
                        pin += oldData.Stride - oldData.Width * 3;
                        pout += newData.Stride - newData.Width * 3;
                    }
                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;
                }
            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }
        }

六、积木

低像素置0，高像素置255。

        /// <summary>
        /// 积木实现方法
        /// </summary>
        private void Image_Block()
        {
            if (this.pbshowbox.Image != null)
            {
                int Height = this.pbshowbox.Image.Height;
                int Width = this.pbshowbox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height);
                Bitmap Mybitmap = (Bitmap)this.pbshowbox.Image;
                BitmapData oldData = Mybitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                unsafe
                {
                    byte* pin = (byte*)(oldData.Scan0.ToPointer());
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {
                            int avg = (pin[0] + pin[1] + pin[2]) / 3;
                            if (avg > 128)
                            {
                                pout[0] = 255;
                                pout[1] = 255;
                                pout[2] = 255;
                            }
                            else
                            {
                                pout[0] = 0;
                                pout[1] = 0;
                                pout[2] = 0;
                            }
                            pin = pin + 3;
                            pout = pout + 3;
                        }
                        pin = pin + oldData.Stride - oldData.Width * 3;
                        pout = pout + newData.Stride - newData.Width * 3;
                    }
                    bitmap.UnlockBits(newData);
                    Mybitmap.UnlockBits(oldData);
                    this.pbshowbox.Image = bitmap;

                }
            }
            else
            {
                MessageBox.Show("请先打开一张图片！");
            }

        }

有些图片效果看起来不明显是因为笔者把图缩小了，其实效果挺明显的- -。