qt下OpenCV编程例子笔记一

以下所有例子来源于http://wiki.opencv.org.cn

一、读入图片显示

#include "cv.h"
#include "cxcore.h"
#include "highgui.h"

#if 1
using namespace cv;
int main() {
//声明IplImage指针
IplImage* pImg;
//载入图片
pImg=cvLoadImage("../Lena.jpg",CV_LOAD_IMAGE_COLOR);  //C:\2.jpg 要使用'/' 而不是windows的 '\'
if(NULL==pImg)
{
printf("image can't read!\n");
return -1;
}
// Mat image(pImg); //有这句话，为什么会出错
//创建窗口
//cvNamedWindow("Image",CV_WINDOW_AUTOSIZE);  // 为什么注释掉这句话，程序尼玛也运行
//显示图像
cvShowImage("Image",pImg);
//等待按键
cvWaitKey(0);
//销毁窗口
cvDestroyWindow("Image");
//释放图像
cvReleaseImage(&pImg);     // 为什么我把这条语句放在cvWaitKey前面时，窗口任然有图像显示，放在cvShowImage前面时才没有图片显示
return 0;
}
#else
#if 0
using namespace cv; //下面函数要cv前缀
int main()
{
Mat image;
image=imread("C:/2.jpg");
imshow("li",image);
waitKey();
return 0;
}
#else
using namespace cv;//下面的所有cv相关类型不用加上前缀了,这里的前缀为cv::
int main(int argc, char* argv[])
{
Mat img = imread("Lena.jpg"); //声明Mat变量并调入lena的照片,图片放在工程目录中直接使用"Lena.jpg"不行,要把图片放在工程目录的上一层
//然后使用../Lena.jpg,对于使用vs的这使用..\\Lena.jpg,第一个\为转义字符

if(!img.data) //判断图片调入是否成功
return -1; //调入图片失败则退出
//创建窗口,并确定其为大小不可变类型窗口
namedWindow("loveLena", CV_WINDOW_AUTOSIZE);

//显示图片。如果你不介意窗口大小可变，可以直接注释掉上一句。因为imshow可以直接创建窗口
imshow("loveLena", img);

waitKey(); //等待按键

return 0;
}

#endif
#endif

二、图像创建、保存和复制

最终在工程目录上一级目录中生成copy.jpg

#include "cv.h"
#include "highgui.h"

int main( int argc, char** argv )
{
IplImage* pImg; //声明IplImage指针

//载入图像，强制转化为Gray
pImg = cvLoadImage("../Lena.jpg", 0);
if(pImg != NULL )
{
IplImage* pImg2 = cvCreateImage(cvGetSize(pImg),
pImg->depth,
pImg->nChannels);
cvCopy(pImg, pImg2, NULL);

cvSaveImage("../copy.jpg", pImg2);//把图像写入文件

cvNamedWindow( "Image", 1 );//创建窗口
cvShowImage( "Image", pImg );//显示图像

cvWaitKey(0); //等待按键

cvDestroyWindow( "Image" );//销毁窗口
cvReleaseImage( &pImg ); //释放图像
cvReleaseImage( &pImg2 ); //释放图像
return 0;
}

return -1;
}

三、canny边缘检测

重点函数：

cvCanny(pImg, pCannyImg, 50, 150, 3);

#include "cv.h"
#include "cxcore.h"
#include "highgui.h"

int main( int argc, char** argv )
{

//声明IplImage指针
IplImage* pImg = NULL;
IplImage* pCannyImg = NULL;

//载入图像，强制转化为Gray
pImg = cvLoadImage("../Lena.jpg", 0);

if(pImg != NULL )

{
//为canny边缘图像申请空间
pCannyImg = cvCreateImage(cvGetSize(pImg),
IPL_DEPTH_8U,
1);

//canny边缘检测
cvCanny(pImg, pCannyImg, 50, 150, 3);

//创建窗口
cvNamedWindow("src", 1);
cvNamedWindow("canny",1);

//显示图像
cvShowImage( "src", pImg );
cvShowImage( "canny", pCannyImg );
cvWaitKey(0); //等待按键

//销毁窗口
cvDestroyWindow( "src" );
cvDestroyWindow( "canny" );

//释放图像
cvReleaseImage( &pImg );
cvReleaseImage( &pCannyImg );
return 0;
}

return -1;
}

四、轮廓(contour)检测

#ifdef _CH_
#pragma package <opencv>
#endif

#ifndef _EiC
#include "cv.h"
#include "cxcore.h"
#include "highgui.h"
#include <math.h>

#endif
#define w 500
int levels = 3;
CvSeq* contours = 0;

void on_trackbar(int pos)

{
IplImage* cnt_img = cvCreateImage( cvSize(w,w), 8, 3 );
CvSeq* _contours = contours;
int _levels = levels - 3;

if( _levels <= 0 ) // get to the nearest face to make it look more funny

_contours = _contours->h_next->h_next->h_next;
cvZero( cnt_img );
cvDrawContours( cnt_img, _contours, CV_RGB(255,0,0), CV_RGB(0,255,0), _levels, 3, CV_AA, cvPoint(0,0) );
cvShowImage( "contours", cnt_img );
cvReleaseImage( &cnt_img );
}

int main( int argc, char** argv )
{
int i, j;
CvMemStorage* storage = cvCreateMemStorage(0);
IplImage* img = cvCreateImage( cvSize(w,w), 8, 1 );
cvZero( img );

for( i=0; i < 6; i++ )
{
int dx = (i%2)*250 - 30;
int dy = (i/2)*150;
CvScalar white = cvRealScalar(255);
CvScalar black = cvRealScalar(0);

if( i == 0 )
{
for( j = 0; j <= 10; j++ )
{
double angle = (j+5)*CV_PI/21;
cvLine(img, cvPoint(cvRound(dx+100+j*10-80*cos(angle)),
cvRound(dy+100-90*sin(angle))),
cvPoint(cvRound(dx+100+j*10-30*cos(angle)),
cvRound(dy+100-30*sin(angle))), white, 1, 8, 0);
}
}

cvEllipse( img, cvPoint(dx+150, dy+100), cvSize(100,70), 0, 0, 360, white, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+115, dy+70), cvSize(30,20), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+185, dy+70), cvSize(30,20), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+115, dy+70), cvSize(15,15), 0, 0, 360, white, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+185, dy+70), cvSize(15,15), 0, 0, 360, white, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+115, dy+70), cvSize(5,5), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+185, dy+70), cvSize(5,5), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+150, dy+100), cvSize(10,5), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+150, dy+150), cvSize(40,10), 0, 0, 360, black, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+27, dy+100), cvSize(20,35), 0, 0, 360, white, -1, 8, 0 );
cvEllipse( img, cvPoint(dx+273, dy+100), cvSize(20,35), 0, 0, 360, white, -1, 8, 0 );
}

cvNamedWindow( "image", 1 );
cvShowImage( "image", img );

cvFindContours( img, storage, &contours, sizeof(CvContour),
CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0) );

// comment this out if you do not want approximation
contours = cvApproxPoly( contours, sizeof(CvContour), storage, CV_POLY_APPROX_DP, 3, 1 );
cvNamedWindow( "contours", 1 );
cvCreateTrackbar( "levels+3", "contours", &levels, 7, on_trackbar );

 on_trackbar(0);
cvWaitKey(0);
cvReleaseMemStorage( &storage );
cvReleaseImage( &img );
return 0;

}
#ifdef _EiC
main(1,"");
#endif

五、图像旋转与缩放

//按Esc键退出
#include "cv.h"
#include "highgui.h"
#include "math.h"

int main (int argc, char **argv)
{
IplImage *src = 0;
IplImage *dst = 0;

/* the first command line parameter must be image file name */
src = cvLoadImage("../Lena.jpg", -1);

if (src != 0)
{
int delta = 1;
int angle = 0;
int opt = 0;	// 1： 旋转加缩放
// 0:  仅仅旋转

double factor;
dst = cvCloneImage (src);
cvNamedWindow ("src", 1);
cvShowImage ("src", src);

for (;;)
{
float m[6];

// Matrix m looks like:
//
// [ m0  m1  m2 ] ===>  [ A11  A12   b1 ]
// [ m3  m4  m5 ]       [ A21  A22   b2 ]
//
CvMat M = cvMat (2, 3, CV_32F, m);
int w = src->width;
int h = src->height;

if (opt)		// 旋转加缩放
factor = (cos (angle * CV_PI / 180.) + 1.0) * 2;
else			//  仅仅旋转
factor = 1;
m[0] = (float) (factor * cos (-angle * 2 * CV_PI / 180.));
m[1] = (float) (factor * sin (-angle * 2 * CV_PI / 180.));
m[3] = -m[1];
m[4] = m[0];

// 将旋转中心移至图像中间
m[2] = w * 0.5f;
m[5] = h * 0.5f;

//  dst(x,y) = A * src(x,y) + b
cvZero (dst);
cvGetQuadrangleSubPix (src, dst, &M);
cvNamedWindow ("dst", 1);
cvShowImage ("dst", dst);

if (cvWaitKey (1) == 27)	//ESC
break;
angle = (int) (angle + delta) % 360;
}			// for-loop
}
return 0;
}

六、读入视频文件及运动物体检测

#include <stdio.h>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>

int main( int argc, char** argv )
{
//声明IplImage指针
IplImage* pFrame = NULL;
IplImage* pFrImg = NULL;
IplImage* pBkImg = NULL;
CvMat* pFrameMat = NULL;
CvMat* pFrMat = NULL;
CvMat* pBkMat = NULL;
CvCapture* pCapture = NULL;
int nFrmNum = 0;

//创建窗口
cvNamedWindow("video", 1);
cvNamedWindow("background",1);
cvNamedWindow("foreground",1);

//使窗口有序排列
cvMoveWindow("video", 30, 0);
cvMoveWindow("background", 360, 0);
cvMoveWindow("foreground", 690, 0);

/*
if( argc > 2 )
{
fprintf(stderr, "Usage: bkgrd [video_file_name]\n");
return -1;
}
*/

//打开摄像头
// if (argc ==1)
if( !(pCapture = cvCaptureFromCAM(-1)))
{
fprintf(stderr, "Can not open camera.\n");
return -2;
}

//打开视频文件
/*
if(argc == 2)
if( !(pCapture = cvCaptureFromFile(argv[1])))
{
fprintf(stderr, "Can not open video file %s\n", argv[1]);
return -2;
}
*/

//逐帧读取视频
while(pFrame = cvQueryFrame( pCapture ))
{
nFrmNum++;
//如果是第一帧，需要申请内存，并初始化
if(nFrmNum == 1)
{
pBkImg = cvCreateImage(cvSize(pFrame->width, pFrame->height),  IPL_DEPTH_8U,1);
pFrImg = cvCreateImage(cvSize(pFrame->width, pFrame->height),  IPL_DEPTH_8U,1);
pBkMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);
pFrMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);
pFrameMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);

//转化成单通道图像再处理
cvCvtColor(pFrame, pBkImg, CV_BGR2GRAY);
cvCvtColor(pFrame, pFrImg, CV_BGR2GRAY);
cvConvert(pFrImg, pFrameMat);
cvConvert(pFrImg, pFrMat);
cvConvert(pFrImg, pBkMat);
}
else
{
cvCvtColor(pFrame, pFrImg, CV_BGR2GRAY);
cvConvert(pFrImg, pFrameMat);
//高斯滤波先，以平滑图像
//cvSmooth(pFrameMat, pFrameMat, CV_GAUSSIAN, 3, 0, 0);
//当前帧跟背景图相减
cvAbsDiff(pFrameMat, pBkMat, pFrMat);

//二值化前景图
cvThreshold(pFrMat, pFrImg, 60, 255.0, CV_THRESH_BINARY);
//进行形态学滤波，去掉噪音
//cvErode(pFrImg, pFrImg, 0, 1);
//cvDilate(pFrImg, pFrImg, 0, 1);

 //更新背景
cvRunningAvg(pFrameMat, pBkMat, 0.003, 0);
//将背景转化为图像格式，用以显示
cvConvert(pBkMat, pBkImg);

//显示图像
cvShowImage("video", pFrame);
cvShowImage("background", pBkImg);
cvShowImage("foreground", pFrImg);

//如果有按键事件，则跳出循环
//此等待也为cvShowImage函数提供时间完成显示
//等待时间可以根据CPU速度调整
if( cvWaitKey(2) >= 0 )
break;
}
}

//销毁窗口
cvDestroyWindow("video");
cvDestroyWindow("background");
cvDestroyWindow("foreground");

//释放图像和矩阵
cvReleaseImage(&pFrImg);
cvReleaseImage(&pBkImg);
cvReleaseMat(&pFrameMat);
cvReleaseMat(&pFrMat);
cvReleaseMat(&pBkMat);
cvReleaseCapture(&pCapture);
return 0;
}

七、Hougn线段检测

/* This is a standalone program. Pass an image name as a first parameter of the program.
Switch between standard and probabilistic Hough transform by changing "#if 1" to "#if 0" and back */
#include <cv.h>
#include <highgui.h>
#include <math.h>

int main(int argc, char** argv)
{
const char* filename = "../hough.png";
IplImage* src = cvLoadImage( filename, 0 );
IplImage* dst;
IplImage* color_dst;
CvMemStorage* storage = cvCreateMemStorage(0);
CvSeq* lines = 0;
int i;

if( !src )
return -1;

dst = cvCreateImage( cvGetSize(src), 8, 1 );
color_dst = cvCreateImage( cvGetSize(src), 8, 3 );

cvCanny( src, dst, 50, 200, 3 );
cvCvtColor( dst, color_dst, CV_GRAY2BGR );
#if 0
lines = cvHoughLines2( dst, storage, CV_HOUGH_STANDARD, 1, CV_PI/180, 100, 0, 0 );  // 标准型

for( i = 0; i < MIN(lines->total,100); i++ )
{
float* line = (float*)cvGetSeqElem(lines,i);
float rho = line[0];
float theta = line[1];
CvPoint pt1, pt2;
double a = cos(theta), b = sin(theta);
double x0 = a*rho, y0 = b*rho;
pt1.x = cvRound(x0 + 1000*(-b));
pt1.y = cvRound(y0 + 1000*(a));
pt2.x = cvRound(x0 - 1000*(-b));
pt2.y = cvRound(y0 - 1000*(a));
cvLine( color_dst, pt1, pt2, CV_RGB(255,0,0), 3, CV_AA, 0 );
}
#else
lines = cvHoughLines2( dst, storage, CV_HOUGH_PROBABILISTIC, 1, CV_PI/180, 50, 50, 10 ); //概率性
for( i = 0; i < lines->total; i++ )
{
CvPoint* line = (CvPoint*)cvGetSeqElem(lines,i);
cvLine( color_dst, line[0], line[1], CV_RGB(255,0,0), 3, CV_AA, 0 );
}
#endif
cvNamedWindow( "Source", 1 );
cvShowImage( "Source", src );

cvNamedWindow( "Hough", 1 );
cvShowImage( "Hough", color_dst );

cvWaitKey(0);

return 0;
}

八、鼠标绘图

#ifdef _CH_
#pragma package <opencv>
#endif

#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>

IplImage* inpaint_mask = 0;
IplImage* img0 = 0, *img = 0, *inpainted = 0;
CvPoint prev_pt = {-1,-1};

void on_mouse( int event, int x, int y, int flags, void* zhang)
{
if( !img )
return;

if( event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON) )
prev_pt = cvPoint(-1,-1);
else if( event == CV_EVENT_LBUTTONDOWN )
prev_pt = cvPoint(x,y);

else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON) )
{
CvPoint pt = cvPoint(x,y);

if( prev_pt.x < 0 )
prev_pt = pt;

cvLine( inpaint_mask, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
cvLine( img, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
prev_pt = pt;
cvShowImage( "image", img );
}
}

int main( int argc, char** argv )

{
char* filename = argc >= 2 ? argv[1] : (char*)"../Fruits.jpg";

if( (img0 = cvLoadImage(filename,-1)) == 0 )
return 0;

printf( "Hot keys: \n"
"\tESC - quit the program\n"
"\tr - restore the original image\n"
"\ti or ENTER - run inpainting algorithm\n"
"\t\t(before running it, paint something on the image)\n" );
cvNamedWindow( "image", 1 );
img = cvCloneImage( img0 );
inpainted = cvCloneImage( img0 );
inpaint_mask = cvCreateImage( cvGetSize(img), 8, 1 );
cvZero( inpaint_mask );
cvZero( inpainted );
cvShowImage( "image", img );
cvShowImage( "watershed transform", inpainted );
cvSetMouseCallback( "image", on_mouse, 0 );

for(;;)
{
int c = cvWaitKey(0);
if( (char)c == 27 )
break;
if( (char)c == 'r' )
{
cvZero( inpaint_mask );
cvCopy( img0, img,0 );
cvShowImage( "image", img );
}

if( (char)c == 'i' || (char)c == '\n' )
{
cvNamedWindow( "inpainted image", 1 );
cvInpaint( img, inpaint_mask, inpainted, 3, CV_INPAINT_TELEA );
cvShowImage( "inpainted image", inpainted );
}
}
return 1;
}

九、Yml文件读取与写入

/***********************************************************************

* OpenCV 2.1 example

***********************************************************************/
#include "cv.h"
#include "highgui.h"
#include <iostream>

using namespace cv; //下面的所有cv相关类型不用加上前缀了
using namespace std;

int main(int argc, char* argv[])

{
FileStorage fs("../test.yml", FileStorage::WRITE); //写的形式打开yml。当然也可以打开xml，主要看后缀

fs << "i" << 5 << "r" << 3.1 << "str" << "ABCDEFGH"; //存入整型、浮点型、字符串
Mat writeInImg = imread( "../lena.jpg" ); //载入Lena妞的图片载入
imshow( "Lena_from_jpg", writeInImg ); //看一看Lena妞是否健在

fs << "lena" << writeInImg; //将Lena妞的图片矩阵插入test.yml
fs.release();
FileStorage readfs("test.yml", FileStorage::READ); //读的形式打开yml。当然也可以打开xml，主要看后缀

if(readfs.isOpened() )
{
int i1 = (int)readfs["i"];
double r1 = (double)readfs["r"];
string str1 = (string)readfs["str"];
Mat readOutImg;

readfs["lena"] >> readOutImg; //把Lena从yml中取出
imshow( "Lena_from_yml", readOutImg ); //看看是不是跟之前放进去的是同一个人
std::cout<<"read out i:"<<i1<<std::endl<<"read out r:"<<r1<<std::endl<<"read out str:"<<str1<<std::endl;

}
readfs.release();
waitKey();

return 0;
}