计算每一个 像素值出现的次数

for(int y = 0; y < m_image->GetHeight(); y++) {     for(int x = 0; x < m_image->GetWidth();x++)     {         COLORREF rgb = m_image->GetPixel(x,y);          int rValue  = GetRValue(rgb);  //  记录每一个像素出现次数。          hist[rValue]++;     } }

计算归一化直方图和累计直方图 

int hist[256] = {0};  double phist[256];  for (int i = 0; i <= 255 ;i++) {     phist [i] = (double) hist[i] / (m_image->GetHeight() * m_image->GetWidth());  //归一化直方图 即每个像素出现概率 } double dSum[256] = {0.0};  for(int i = 0; i<=255;i++) {     if(i != 0)     {         dSum[i] = dSum[i-1] + phist[i];     }     else//累积直方图     {         dSum[i]  = phist[i];     } }


均衡化映射关系，得到新图像 

for(int y = 0; y < m_image->GetHeight(); y++) {     for(int x = 0; x < m_image->GetWidth();x++)     {         COLORREF rgb = m_image->GetPixel(x,y);          int rValue = GetRValue(rgb);          rValue = Mapping[rValue];        //根据映射关系实现均衡化         rgb = RGB(rValue,rValue,rValue);         m_image->SetPixel(x,y,rgb);     } }