OpenCV实现Usm图像锐化算法：基于高斯模糊与对比度增强

void UnsharpMask(const IplImage* src, IplImage* dst, float amount=80, float radius=5, uchar threshold=0, intcontrast=100)
{
     if(!src)return ;

     int imagewidth = src->width;
     int imageheight = src->height;
     int channel = src->nChannels;

     IplImage* blurimage = cvCreateImage(cvSize(imagewidth,imageheight), src->depth, channel);
     IplImage* DiffImage = cvCreateImage(cvSize(imagewidth,imageheight), 8, channel);

    //原图的高对比度图像
     IplImage* highcontrast = cvCreateImage(cvSize(imagewidth,imageheight), 8, channel);
     AdjustContrast(src, highcontrast, contrast);

    //原图的模糊图像
    cvSmooth(src, blurimage, CV_GAUSSIAN, radius);

    //原图与模糊图作差
    for (int y=0; y<imageheight; y++)
     {
         for (int x=0; x<imagewidth; x++)
         {
             CvScalar ori = cvGet2D(src, y, x);
            CvScalar blur = cvGet2D(blurimage, y, x);
             CvScalar val;
             val.val[0] = abs(ori.val[0] - blur.val[0]);
             val.val[1] = abs(ori.val[1] - blur.val[1]);
             val.val[2] = abs(ori.val[2] - blur.val[2]);

            cvSet2D(DiffImage, y, x, val);
         }
    }

    //锐化
    for (int y=0; y<imageheight; y++)
    {
         for (int x=0; x<imagewidth; x++)
         {
             CvScalar hc = cvGet2D(highcontrast, y, x);
             CvScalar diff = cvGet2D(DiffImage, y, x);
            CvScalar ori = cvGet2D(src, y, x);
            CvScalar val;

             for (int k=0; k<channel; k++)
             {
                if (diff.val[k] > threshold)
                 {
                     //最终图像 = 原始*(1-r) + 高对比*r
                     val.val[k] = ori.val[k] *(100-amount) + hc.val[k] *amount;
                    val.val[k] /= 100;
                }
                 else
                 {
                    val.val[k] = ori.val[k];
                }
             }
             cvSet2D(dst, y, x, val);
         }
     }