【OpenCV学习】OpenMP并行化实例

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/

#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>
#include <omp.h>void EdgeOpenMP(IplImage *src,IplImage *dst,int thresh)
{int height    = src->height;int width     = src->width;int step      = src->widthStep;uchar *data1      = (uchar *)src->imageData;uchar *data2      = (uchar *)dst->imageData;int i=step;#pragma omp parallel forfor(i=step+1;i<height*width;i++){if(abs(data1[i]-data1[i-1])>thresh || abs(data1[i]-data1[i-step])>thresh)data2[i]=255;/* 对于单通道，前后两帧差分大于门限或者对于多通道前后两帧的一个指标差分大于门限，则视为边缘*/elsedata2[i]=0;}
}void Edge(IplImage *src,IplImage *dst,int thresh)
{int height    = src->height;int width     = src->width;int step      = src->widthStep;uchar *data1      = (uchar *)src->imageData;uchar *data2      = (uchar *)dst->imageData;int i=step;for(i=step+1;i<height*width;i++){if(abs(data1[i]-data1[i-1])>thresh || abs(data1[i]-data1[i-step])>thresh)data2[i]=255;elsedata2[i]=0;}
}int main()
{char filename[512];IplImage *src,*edge1,*edge2;puts("File name:");gets(filename);src = cvLoadImage(filename,CV_LOAD_IMAGE_GRAYSCALE );edge1=cvCloneImage(src);edge2=cvCloneImage(src);cvNamedWindow("src", CV_WINDOW_AUTOSIZE);cvMoveWindow("src", 100, 100);cvShowImage( "src", src);cvNamedWindow("Edge", CV_WINDOW_AUTOSIZE);cvMoveWindow("Edge", 200, 100);cvNamedWindow("EdgeOpenMP", CV_WINDOW_AUTOSIZE);cvMoveWindow("EdgeOpenMP", 300, 100);/* 以上都是准备一些窗口和图形基本数据 */int tekrar=100;//运行次数int thresh=30;double start, end,t1, t2;/* 计算没有使用OpenMP优化的时间 */start= (double)cvGetTickCount();//记下开始的时钟计数，以便计算函数或用户代码执行时间for(int i=0;i<tekrar;i++)Edge(src,edge1,thresh);end= (double)cvGetTickCount();//记下结束的时钟计数t1= (end-start)/((double)cvGetTickFrequency()*1000.);//计算运行时间，以毫秒为单位printf( "Run time without OpenMP = %g ms/n", t1 );/* 计算使用了OpenMP优化的时间 */start= (double)cvGetTickCount();for(int i=0;i<tekrar;i++)EdgeOpenMP(src,edge2,thresh);end= (double)cvGetTickCount();t2= (end-start)/((double)cvGetTickFrequency()*1000.);printf( "Run time with OpenMP = %g ms/n", t2 );printf( "Performance ratio (%%) = %% %.1f /n", 100*(t1/t2-1) );cvShowImage( "Edge", edge1);cvShowImage( "EdgeOpenMP", edge2);cvWaitKey();cvDestroyWindow("Edge");cvDestroyWindow("EdgeOpenMP");cvReleaseImage(&src);cvReleaseImage(&edge1);cvReleaseImage(&edge2);
}这是我的结果：
File name:
dog.jpg
Run time without OpenMP = 647.627 ms
Run time with OpenMP = 453.001 ms
Performance ratio (%) = % 43.0

 

作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/