[代码片段]OSTU算法

用在片上系统上的

 //OSTU求图像的阈值
 u8 otsuThreshold(u8 **img, u16 height, u16 width)
 {
 //    int width = frame->width;
 //    int height = frame->height;
     u16 pixelCount[];
     float pixelPro[];
     u16 i, j, pixelSum = width * height, threshold = ;
     //遍历灰度级[0,255]
     float w0, w1, u0tmp, u1tmp, u0, u1, u, deltaTmp, deltaMax = ;
     //u8* data = (uchar*)frame->imageData;

     for(i = ; i < ; i++)
     {
         pixelCount[i] = ;
         pixelPro[i] = ;
     }

     //统计灰度级中每个像素在整幅图像中的个数
     for(i = ; i < height; i++)
     {
         for(j = ;j < width;j++)
         {
             pixelCount[ img[i][j] ]++;
         }
     }

     //计算每个像素在整幅图像中的比例
     for(i = ; i < ; i++)
     {
         pixelPro[i] = (float)pixelCount[i] / pixelSum;
     }

     for(i = ; i < ; i++)
     {
         w0 = w1 = u0tmp = u1tmp = u0 = u1 = u = deltaTmp = ;
         for(j = ; j < ; j++)
         {
             if(j <= i)   //背景部分
             {
                 w0 += pixelPro[j];
                 u0tmp += j * pixelPro[j];
             }
             else   //前景部分
             {
                 w1 += pixelPro[j];
                 u1tmp += j * pixelPro[j];
             }
         }
         u0 = u0tmp / w0;
         u1 = u1tmp / w1;
         u = u0tmp + u1tmp;
         deltaTmp = w0 * pow((u0 - u), ) + w1 * pow((u1 - u), );
         if(deltaTmp > deltaMax)
         {
             deltaMax = deltaTmp;
             threshold = i;
         }
     }

     return threshold;
 }