减少OpenCV读取高分辨率图像的时间示例

#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp> 
#include <time.h>
#include <omp.h>
using namespace cv;

IplImage *showImage = cvCreateImage(cvSize(4096, 2048), IPL_DEPTH_8U, 3);
time_t t_start, t_end;
int main()
{
 t_start = clock();
 IplImage *image = cvLoadImage("0.jpg");
 t_end = clock();
 printf("直接读取一张4K图片花费时间为：%d\n", t_end - t_start);
 t_start = t_end;
 char imgName[4][4][40];
 IplImage *splitImg[4][4];
 #pragma omp parallel for
 for (int i = 1; i <= 4; i++)
 {
  for (int j = 1; j <= 4; j++)
  {
   sprintf_s(imgName[i][j], "%d%d%s", i, j, ".jpg");
   splitImg[i-1][j-1] = cvLoadImage(imgName[i][j]);
   cvSetImageROI(showImage, cvRect((j - 1) * 4096 / 4, (i - 1) * 2048 / 4, 4096 / 4, 2048 / 4));
   cvCopy(splitImg[i - 1][j - 1], showImage);
   cvResetImageROI(showImage);
  }
 }
 t_end = clock();

 printf("分步读取一张4K图片花费时间为：%d", t_end - t_start);
 cvShowImage("test.jpg", showImage);
 cvWaitKey(1);
 getchar();
 return 1;
}