created by Dejavu
你们有过这样的经历吗？当在多线程中使用opencv的imshow和waitkey方法，不知道该如何下手，因为waitkey是管理按键事件和图像刷新的，imshow则是用来更新对应窗口的图像，如果这两者在多线程的程序中滥用，会导致很多致命的错误，大部分是以栈错误为主，在这里我有一个比较好的解决多线程中管理opencv图像显示的办法，就是将所有的对图像显示和按键事件操作放入到一个单独的线程中，在这个线程，要做的是仅仅是收集外部处理过后的图像
- 以下代码，是针对与linux系统编写的
该类的使用方法
#include "imgManager.h"
int main() {
//输入源，按照具体项目而定
cv::VideoCapture cap(0);
cv::Mat src;cap>>src;
ImgManager iMag(cap);
int src_id = iMag.add(src,"tracker");
while(!iMag.isSignalLoss) {
src = cv::Scalar(iMag.vMin,iMag.vMax,iMag.sMin);
iMag.update(src_id,src);
//iMag.remove(src_id)
}
}
要用到的头文件
#include <iostream>
#include <vector>
#include <cmath>
#include <pthread.h>
#include <opencv2/opencv.hpp>
#include <sys/time.h>
#include <unistd.h>
using namespace std;
线程锁类
class Mutex {
private:
pthread_mutex_t m_mutex;
public:
Mutex() {pthread_mutex_init(&m_mutex, NULL);}
void lock() {pthread_mutex_lock(&m_mutex);}
void unlock() {pthread_mutex_unlock(&m_mutex);}
class ScopedLock {
private:
Mutex &_mutex;
public:
ScopedLock(Mutex &mutex) : _mutex(mutex) {_mutex.lock();}
~ScopedLock() {_mutex.unlock();}
};
};
外部输出输入数据类，包括orb特征算子的描述符im，和关键点集kp
class DataSet{
public:
cv::Mat color;
std::vector<cv::KeyPoint> kp;
cv::Mat im;
void set(DataSet dataSet);
void operator=(DataSet &dataSet);
};
图像管理类，这里我用了VideoCapture类作为主要输入源，具体输入源，需符合项目要求即可
class ImgManager : public DataSet {
private:
bool isSelect,isShowInfo,isCopyOperation;
//输入源按照具体项目而定
cv::VideoCapture ∩
int sq;
int pause_time;
bool write_flag;
bool getData();
static void* getPthreadImg(void*);
void run_thread();
public:
enum {Exec,Roi,Dest,Next};
Mutex imgLock;
bool isSignalLoss;
bool isCalcFeature;
int order;
std::list<VisImg> visImg;
int vMin,vMax,sMin;
ImgManager(cv::VideoCapture &c) : isSignalLoss(false),vMin(30),vMax(200),sMin(5),
cap(c),order(-1),write_flag(false),pause_time(1),sq(0),
isSelect(false),isShowInfo(false),isCopyOperation(false) {
run_thread();
}
~ImgManager() {isSignalLoss = true;}
bool calc_feature();
DataSet copy();
cv::Mat clone();
int add(cv::Mat &src,std::string name);
bool update(int index,cv::Mat& src);
bool remove(int index,int pauseTime=1,int orderType=-1);
bool show();
};
cpp文件 类中函数的实现
#include "imgManager.h"
//different memory manager
//i defined in main function those data no need to delete i use &dataSet
void DataSet::operator=(DataSet &dataSet) {
color = dataSet.color.clone();
im = dataSet.im.clone();
if(kp.size() > 1) kp.clear();
for(int i=0;i<dataSet.kp.size();i++) kp.push_back(dataSet.kp[i]);
}
//function return dataSet will generator a lot of useless data
//those data need to delete so..... just use dataSet
void DataSet::set(DataSet dataSet) {
color = dataSet.color.clone();
im = dataSet.im.clone();
if(kp.size() > 1) kp.clear();
for(int i=0;i<dataSet.kp.size();i++) kp.push_back(dataSet.kp[i]);
}
DataSet ImgManager::copy() {
isCopyOperation = true;
Mutex::ScopedLock lock(imgLock);
DataSet dataSet;
dataSet.color = color.clone();
if(isCalcFeature) {
dataSet.im = im.clone();
for(int i=0;i<kp.size();i++) dataSet.kp.push_back(kp[i]);
}
isCopyOperation = false;
return dataSet;
}
cv::Mat ImgManager::clone() {
isCopyOperation = true;
Mutex::ScopedLock lock(imgLock);
cv::Mat data = color.clone();
isCopyOperation = false;
return data;
}
bool ImgManager::calc_feature() {
cv::OrbFeatureDetector ofd;
cv::OrbDescriptorExtractor ode;
cv::Mat src = color.clone();
cv::Mat gray = src.clone();
cv::blur(src,src,cv::Size(3,3));
cv::cvtColor(src,gray,CV_BGR2GRAY);
ofd.detect(gray,kp);
ode.compute(gray,kp,im);
if(im.empty() || src.empty()) return false;
return true;
}
// ------------------------show Unit -------------------
int ImgManager::add(cv::Mat &src,std::string name) {
VisImg tmp;
tmp.name = name;
std::cout << src.size() << std::endl;
tmp.src = src.clone();
tmp.index = sq;
visImg.push_back(tmp);
if(name == "tracker") {
cv::namedWindow("tracker");
cv::createTrackbar("vMin", "tracker", &vMin, 255, 0);
cv::createTrackbar("vMax", "tracker", &vMax, 255, 0);
cv::createTrackbar("sMin", "tracker", &sMin, 255, 0);
usleep(1e5);
}
std::cout << tmp.src.size() << std::endl;
return (sq++);
}
bool ImgManager::remove(int index,int pauseTime,int orderType) {
if(visImg.size() < 1) return false;
for(std::list<VisImg>::iterator it = visImg.begin();it!=visImg.end();) {
if(it->index == index) {
cv::destroyWindow(it->name);
it = visImg.erase(it);
break;
}
else it++;
}
pause_time = pauseTime;
if(order == Next) {
order = -1;
return true;
}
else if(orderType == order) {
order = -1;
return true;
}
return false;
}
bool ImgManager::update(int index,cv::Mat& src) {
if(!write_flag) write_flag = true;
for(std::list<VisImg>::iterator it = visImg.begin();it!=visImg.end();it++) if(index == it->index) {
it->src = src.clone();
}
write_flag = false;
return (pause_time == 0);
}
bool ImgManager::getData() {
if(isCopyOperation) return true;
Mutex::ScopedLock lock(imgLock);
cap >> color;
if(isCalcFeature) calc_feature();
cv::imshow("src",color);
for(std::list<VisImg>::iterator it = visImg.begin();it!=visImg.end();it++) {
if(!write_flag) {
if(it->src.empty()) continue;
cv::imshow(it->name,it->src);
}
}
char key = char(cv::waitKey(pause_time));
switch(key) {
case 27:return false;break;
case 'n': order = Next;break;
case 'r': order = Roi;break;
case 'd': order = Dest;break;
case 'c': order = Exec;break;
}
if(pause_time == 0) pause_time = 1;
return true;
}
void* ImgManager::getPthreadImg( void* __this ) {
ImgManager* _this = (ImgManager*) __this;
while(true) {
if(!_this->getData()) {
_this->isSignalLoss = true;
cv::destroyWindow("src");
for(std::list<VisImg>::iterator it = _this->visImg.begin();it!=_this->visImg.end();it++) cv::destroyWindow(it->name);
_this->visImg.clear();
pthread_exit(NULL);
}
}
}
void ImgManager::run_thread() {
pthread_t id;
pthread_create(&id,NULL,getPthreadImg,(void*)this);
}
编译用到的makefile参考
OPENCV = $(shell pkg-config --cflags opencv) $(shell pkg-config --libs opencv)
LINK_ALL = $(OPENCV)
SRC = $(CAMERASHIFT) $(GUIDENCE) imgManager.cpp exec.cpp
TAR = exec
$(TAR):$(SRC)
g++ -o $(TAR) $(SRC) $(LINK_ALL) -z execstack -fno-stack-protector -g
clean:
rm $(OBJ) $(TAR)
%.o:%.cpp
g++ -I $(LINK_ALL) -o $@ -c $<
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