17.3.2.5 灰度（内存处理）

版权声明：本文为博主原创文章，转载请在显著位置标明本文出处以及作者网名，未经作者允许不得用于商业目的。

灰度的算法请参看第17.3.1.3节。17.3.1.3 灰度-CSDN博客

【例 17.43】灰度算法一：最大值法。

       //灰度:最大值
        private void btnGray1_Click(object sender, EventArgs e)
        {
            Bitmap destImg = new Bitmap(sourceImg.Width, sourceImg.Height);
            BitmapData sourceData = sourceImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
            BitmapData destData = destImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
            IntPtr pSource = sourceData.Scan0;
            int allBytes = sourceData.Stride * sourceData.Height;
            byte[] rgbvalues = new byte[allBytes];
            Marshal.Copy(pSource, rgbvalues, 0, allBytes);
 
            int pos = 0;
            int R, G, B;
            int avgValue;
 
            for (int j = 0; j < sourceData.Height; j++)
            {
                for (int i = 0; i < sourceData.Width; i++)
                {
                    B = rgbvalues[pos];
                    G = rgbvalues[pos + 1];
                    R = rgbvalues[pos + 2];
                    byte MaxColor;
                    MaxColor =(byte)( R > G? R: G);
                    MaxColor = MaxColor > (byte)B ? MaxColor: (byte)B;
                    rgbvalues[pos] = MaxColor;
                    rgbvalues[pos + 1] = MaxColor;
                    rgbvalues[pos + 2] = MaxColor;
                    pos = pos + 3;
                }
                pos = pos + sourceData.Stride - sourceData.Width * 3;
            }
            IntPtr pDest = destData.Scan0;
            Marshal.Copy(rgbvalues, 0, pDest, allBytes);
            sourceImg.UnlockBits(sourceData);
            destImg.UnlockBits(destData);
            picDest.Image = destImg;
        }

【例 17.44】灰度算法二：平均值法。

       //灰度:均值法
        private void btnGray2_Click(object sender, EventArgs e)
        {
            Bitmap destImg = new Bitmap(sourceImg.Width, sourceImg.Height);
            BitmapData sourceData = sourceImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
            BitmapData destData = destImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
            IntPtr pSource = sourceData.Scan0;
            int allBytes = sourceData.Stride * sourceData.Height;
            byte[] rgbvalues = new byte[allBytes];
            Marshal.Copy(pSource, rgbvalues, 0, allBytes);
 
            int pos = 0;
            int R, G, B;
            int avgValue;
 
            for (int j = 0; j < sourceData.Height; j++)
            {
                for (int i = 0; i < sourceData.Width; i++)
                {
                    B = rgbvalues[pos];
                    G = rgbvalues[pos + 1];
                    R = rgbvalues[pos + 2];
                    avgValue = (B + G + R) / 3;
                    rgbvalues[pos] = (byte)avgValue;
                    rgbvalues[pos + 1] = (byte)avgValue;
                    rgbvalues[pos + 2] = (byte)avgValue;
                    pos = pos + 3;
                }
                pos = pos + sourceData.Stride - sourceData.Width * 3;
            }
            IntPtr pDest = destData.Scan0;
            Marshal.Copy(rgbvalues, 0, pDest, allBytes);
            sourceImg.UnlockBits(sourceData);
            destImg.UnlockBits(destData);
            picDest.Image = destImg;
        }

【例 17.45】灰度算法三：指数加权法。

       //灰度:指数加权法
        private void btnGray3_Click(object sender, EventArgs e)
        {
            Bitmap destImg = new Bitmap(sourceImg.Width, sourceImg.Height);
            BitmapData sourceData = sourceImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
            BitmapData destData = destImg.LockBits(new Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
            IntPtr pSource = sourceData.Scan0;
            int allBytes = sourceData.Stride * sourceData.Height;
            byte[] rgbvalues = new byte[allBytes];
            Marshal.Copy(pSource, rgbvalues, 0, allBytes);
 
            int pos = 0;
            int R, G, B;
            byte y;
 
            for (int j = 0; j < sourceData.Height; j++)
            {
                for (int i = 0; i < sourceData.Width; i++)
                {
                    B = rgbvalues[pos];
                    G = rgbvalues[pos + 1];
                    R = rgbvalues[pos + 2];
 
                    y =(byte)( R * 0.3 + G * 0.59 + B * 0.11);
                    rgbvalues[pos] = y;
                    rgbvalues[pos + 1] = y;
                    rgbvalues[pos + 2] = y;
                    pos = pos + 3;
                }
                pos = pos + sourceData.Stride - sourceData.Width * 3;
            }
            IntPtr pDest = destData.Scan0;
            Marshal.Copy(rgbvalues, 0, pDest, allBytes);
            sourceImg.UnlockBits(sourceData);
            destImg.UnlockBits(destData);
            picDest.Image = destImg;
        }

学习更多vb.net知识，请参看vb.net 教程 目录

学习更多C#知识，请参看 C# 教程 目录