图像的熵、灰度平均值、灰度中值、方差

//图像的熵=========================================================================================
        private void Menu_Entropy_Click(object sender, EventArgs e)
        {
            if (curBitmap != null)
            {
                //计算熵
                double entropy = GetEntropy(curBitmap, curBitmap.Width, curBitmap.Height);

                MessageBox.Show("图像："+curFileName +"nn"+"图像熵为  H = " + entropy);
               
            }
        }

        //计算熵的函数-----------------------------------------------
        public double GetEntropy(Bitmap bmp, int w, int h)
        {
            int g;
            double H = 0.0;

            int[] pix = new int[256];
            Array.Clear(pix, 0, 256);

            //获取各灰度值的像素个数
            for (int i = 0; i < h; i++)
            {
                for (int j = 0; j < w; j++)
                {
                    Color c = bmp.GetPixel(j, i);
                    g = (int)(0.299*c.R + 0.587*c.B + 0.114*c.G);
                    pix[g]++;
                }
            }

           

            //计算熵
            for (int i = 0; i < 256; i++)
                if (pix[i] > 0)
                    H = H + pix[i] * Math.Log10(pix[i]);
            H = Math.Log10(w * h) / Math.Log10(2) - H / (w * h * Math.Log10(2));

            return H;

        }

 

//灰度平均值=======================================================================================
        private void Menu_GrayAverage_Click(object sender, EventArgs e)
        {
            if (curBitmap != null)
            {
                double aver = GetGrayAverage(curBitmap, curBitmap.Width, curBitmap.Height);

                MessageBox.Show("图像：" + curFileName +"nn"+ "灰度平均值为  A = " + aver);
            }
        }

        //计算灰度平均值的函数---------------------------------------
        public double GetGrayAverage(Bitmap bmp, int w, int h)
        {
            double sum = 0;

            //计算平均值
            for (int i = 0; i < w; i++)
                for (int j = 0; j < h; j++)
                {
                    Color c = bmp.GetPixel(i, j);
                    sum = sum + (int)(0.299 * c.R + 0.587 * c.B + 0.114 * c.G);
                }
            double aver = sum / (w * h);

            return aver;
        }

 

//灰度中值=========================================================================================
        private void Menu_GrayMid_Click(object sender, EventArgs e)
        {
            if (curBitmap != null)
            {
                Bitmap bmp = curBitmap;

                //由5 X 5的矩形获取值
                int[] pix = new int[25];
                for (int j = 0; j < 5; j++)
                {
                    for (int i = 0; i < 5; i++)
                    {
                        pix[i + j * 5] = bmp.GetPixel(100 + i, 100 + j).B;
                    }
                }
                pix = MedianSorter(pix,25);

                MessageBox.Show("图像：" + curFileName + "n" +
                    "左上角坐标为(100,100)的5X5矩形块n灰度中值为" +
                    "  M = " + pix[12]);
            }
        }

        //排序-------------------------------------------------------
        public int[] MedianSorter(int[] data, int m)
        {
            int tem;

            for (int i = m - 1; i >= 1; i--)
                for (int j = 1; j <= i; j++)
                    if (data[j - 1] > data[j])
                    {
                        tem = data[j];
                        data[j] = data[j - 1];
                        data[j - 1] = tem;
                    }

            return data;
        }

 

//方差=============================================================================================
        private void Menu_Variance_Click(object sender, EventArgs e)
        {
            if (curBitmap != null)
            {
                double vari = GetVariance(curBitmap, curBitmap.Width, curBitmap.Height);

                MessageBox.Show("图像：" + curFileName + "nn" + "方差值  S = " + vari);
            }
        }

        //计算方差值的函数-------------------------------------------
        public double GetVariance(Bitmap bmp, int w, int h)
        {
            double aver, vari =0;
            int data;

            //求平均值
            aver = GetGrayAverage(bmp ,w , h);

            //求方差
            for (int i = 0; i < w; i++)
            {
                for (int j = 0; j < h; j++)
                {
                    Color c = bmp.GetPixel(i, j);
                    data = (int)(0.299 * c.R + 0.587 * c.B + 0.114 * c.G);
                    vari = vari + (data - aver) * (data - aver);
                }
            }
            vari = vari / (w * h);

            return vari;
        }