图像直方图均衡化（C#）

  private Bitmap picequalization(Bitmap basemap, int width, int height)
        {
            Bitmap retmap = new Bitmap(basemap, width, height);
            int size = width * height;
            int[] gray = new int[256];
            double[] graydense = new double[256];
            for(int i=0;i<width;++i)
                for (int j = 0; j < height; ++j)
                {
                    Color pixel = basemap.GetPixel(i,j);
                    gray[Convert.ToInt16(pixel.R)] += 1;
                }
            for (int i = 0; i < 256; i++)
            {
                graydense[i] = (gray[i]*1.0) / size;
            }

            for (int i = 1; i < 256; i++)
            {
                graydense[i] += graydense[i-1];
            }

            for (int i = 0; i < width; ++i)
                for (int j = 0; j < height; ++j)
                {
                    Color pixel = basemap.GetPixel(i, j);
                    int gg = Convert.ToInt16(pixel.R);
                    int g = 0;
                    if(gg==0)
                       g=0;
                    else
                    g =Convert.ToInt16( graydense[Convert.ToInt16(pixel.R)] * Convert.ToInt16(pixel.R));
                    
                    pixel = Color.FromArgb(g,g,g);
                    retmap.SetPixel(i, j, pixel);
                    //gray[Convert.ToInt16(pixel.R)] += 1;
                }
                return retmap;
        }

 private Bitmap rgb2gray(Bitmap basemap,int width,int height)
        {
            Bitmap retmap = new Bitmap(basemap, width, height);
            for (int i = 0; i < width; ++i)
                for (int j = 0; j < height; ++j)
                {
                    Color pixel = basemap.GetPixel(i, j);
                    pixel = getgray(Convert.ToByte(pixel.R), Convert.ToByte(pixel.G), Convert.ToByte(pixel.B));
                    retmap.SetPixel(i, j, pixel);
                }
                    return retmap;
        }

        private Color  getgray(int r, int g, int b)
        {
            int gray = 0;
            gray = (r * 30 + g * 59 + b * 11 + 50) / 100;

            Color retcolor = Color.FromArgb(gray,gray,gray);
            return retcolor;
            }
        /// <summary>
        /// 获取直方图数据
        /// </summary>
        /// <param name="rule"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <returns></returns>
        private double[] getsquare(Bitmap rule, int width, int height)
        {
            //double[] rule = new double[256];
            int sizerule = width * height;
            int[] grayrule = new int[256];
            double[] grayruledense = new double[256];
            for (int i = 0; i < width; ++i)
                for (int j = 0; j < height; ++j)
                {
                    Color pixel = rule.GetPixel(i, j);
                    grayrule[Convert.ToInt16(pixel.R)] += 1;
                }
            for (int i = 0; i < 256; i++)
            {
                grayruledense[i] = (grayrule[i] * 1.0) / sizerule;
            }
            return grayruledense;
        }

        private double[] getrule(Bitmap rule, int rulewidth, int heightrule)
        {
            //double[] rule = new double[256];
            int sizerule = rulewidth * heightrule;
            int[] grayrule = new int[256];
            double[] grayruledense = new double[256];
            for (int i = 0; i < rulewidth; ++i)
                for (int j = 0; j < heightrule; ++j)
                {
                    Color pixel = rule.GetPixel(i, j);
                    grayrule[Convert.ToInt16(pixel.R)] += 1;
                }
            for (int i = 0; i < 256; i++)
            {
                grayruledense[i] = (grayrule[i] * 1.0) / sizerule;
            }
            return grayruledense;
        }
        private double[] getdense(double[] zhifang)
        {
            for (int i = 1; i < 256; i++)
            {
                zhifang[i] += zhifang[i - 1];
            }
            return zhifang;
        }