#include <cv.h>  #include <highgui.h>  #include <stdlib.h>      //计算图像感知hash值。详情看：http://blog.csdn.net/lhfslhfs/article/details/9157845  int64 CalcImagePerceptualHashKey(const IplImage* pImage)  {      IplImage* pTheImage8X8 = cvCreateImage(cvSize(8, 8), pImage->depth, pImage->nChannels);      IplImage* pGrayscaleImage = cvCreateImage(cvSize(8, 8), 8, 1);          cvResize(pImage, pTheImage8X8, CV_INTER_AREA);      cvConvertImage(pTheImage8X8, pGrayscaleImage);      cvReleaseImage(&pTheImage8X8);              //计算平均值      float fElementMean = 0;      for (int y = 0; y < 8; ++y)      {          for (int x = 0; x < 8; ++x)          {              unsigned char& cElem = *(unsigned char*)(pGrayscaleImage->imageData + x + y * pGrayscaleImage->widthStep);              cElem = (unsigned char)(cElem / (float)255 * 64);              fElementMean += cElem;          }      }          fElementMean /= 64;      unsigned char cElementKey = 0;      int64 key = 0;      unsigned char* pKeyPtr = (unsigned char*)&key;          for (int y = 0; y < 8; ++y)      {          for (int x = 0; x < 8; ++x)          {              if (fElementMean > *(unsigned char*)(pGrayscaleImage->imageData + x + y * pGrayscaleImage->widthStep))              {                  //小于平均值即为0。                  cElementKey <<= 1;              }              else              {                  //否则即为1                  cElementKey <<= 1;                  cElementKey |= 1;              }          }              pKeyPtr[y] = cElementKey;      }          cvReleaseImage(&pGrayscaleImage);      return key;  }      //比较2个key的相似度，结果以1为最相似，0为不相似。  float CompareImageKeySimilarity(int64 key1, int64 key2)  {      int64 keyResult = key1 ^ key2;      int nOneCount = 0;      int i = 64;      while(i--)      {          if ((keyResult & 1) == 1)              nOneCount++;              keyResult >>= 1;      }          printf("nOneCount = %dn", nOneCount);      return nOneCount == 0 ? 1 : (64 - nOneCount) / (float)64;  }      int main(int argc, char* argv[])  {      IplImage* pSrc1 = cvLoadImage("D:\cvImg\gujinlin1.jpg");      IplImage* pSrc2 = cvLoadImage("D:\cvImg\gujinlin2.jpg");      int64 key1 = CalcImagePerceptualHashKey(pSrc1);      int64 key2 = CalcImagePerceptualHashKey(pSrc2);          printf("key1 = 0x%llX, key2 = 0x%llX, Similarity = %.2fn", key1, key2, CompareImageKeySimilarity(key1, key2));      return 0;  }