我在QtGui-Application中使用自定义OpenCV VideoProcessor-Class。我的MainWindow有2个ViewerWidgets，用于显示VideoProcessor对象生成的输入和输出帧。 VideoProcessor-Object在这些ViewerWidgets上获取指针，用于在这些Widgets上显示已处理的帧。
当我启动应用程序时，GUI窗口中的所有内容都会响应用户输入。但是，当我开始处理时，它停止响应。我甚至无法关闭窗口或从应用程序菜单中选择一些东西。处理显示正确的输出并继续运行，但Window不再响应。
这是MainWindow的Slot开始处理：
void MainWindow::on_actionStart_Capture_triggered()
{
// Create instance
p = new VideoProcessor();
// Open video file
p->setInput(0);
// Declare a window to display the video
p->displayInput("Current Frame");
p->displayOutput("Output Frame");
// Play the video at the original frame rate
p->setDelay(1000./p->getFrameRate());
// Set the frame processor callback function
p->setFrameProcessor(canny);
// Start the process
p->run(cvWidgetIn, cvWidgetOut);
}
这就是VideoProcessor。文件来自OpenCV Cookbook，我更改了它，以便在下面代码末尾的run（）函数中指向我的ViewerWidgets。
#if !defined VPROCESSOR
#define VPROCESSOR
#include <iostream>
#include <iomanip>
#include <sstream>
#include <string>
#include <vector>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include "cvwidget.h"
// The frame processor interface
class FrameProcessor {
public:
// processing method
virtual void process(cv:: Mat &input, cv:: Mat &output)= 0;
};
class VideoProcessor {
private:
// the OpenCV video capture object
cv::VideoCapture capture;
// the callback function to be called
// for the processing of each frame
void (*process)(cv::Mat&, cv::Mat&);
// the pointer to the class implementing
// the FrameProcessor interface
FrameProcessor *frameProcessor;
// a bool to determine if the
// process callback will be called
bool callIt;
// Input display window name
std::string windowNameInput;
// Output display window name
std::string windowNameOutput;
// delay between each frame processing
int delay;
// number of processed frames
long fnumber;
// stop at this frame number
long frameToStop;
// to stop the processing
bool stop;
// vector of image filename to be used as input
std::vector<std::string> images;
// image vector iterator
std::vector<std::string>::const_iterator itImg;
// the OpenCV video writer object
cv::VideoWriter writer;
// output filename
std::string outputFile;
// current index for output images
int currentIndex;
// number of digits in output image filename
int digits;
// extension of output images
std::string extension;
// to get the next frame
// could be: video file; camera; vector of images
bool readNextFrame(cv::Mat& frame) {
if (images.size()==0)
return capture.read(frame);
else {
if (itImg != images.end()) {
frame= cv::imread(*itImg);
itImg++;
return frame.data != 0;
}
}
}
// to write the output frame
// could be: video file or images
void writeNextFrame(cv::Mat& frame) {
if (extension.length()) { // then we write images
std::stringstream ss;
ss << outputFile << std::setfill('0') << std::setw(digits) << currentIndex++ << extension;
cv::imwrite(ss.str(),frame);
} else { // then write video file
writer.write(frame);
}
}
public:
// Constructor setting the default values
VideoProcessor() : callIt(false), delay(-1),
fnumber(0), stop(false), digits(0), frameToStop(-1),
process(0), frameProcessor(0) {}
// set the name of the video file
bool setInput(std::string filename) {
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
images.clear();
// Open the video file
return capture.open(filename);
}
// set the camera ID
bool setInput(int id) {
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
images.clear();
// Open the video file
return capture.open(id);
}
// set the vector of input images
bool setInput(const std::vector<std::string>& imgs) {
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
// the input will be this vector of images
images= imgs;
itImg= images.begin();
return true;
}
// set the output video file
// by default the same parameters than input video will be used
bool setOutput(const std::string &filename, int codec=0, double framerate=0.0, bool isColor=true) {
outputFile= filename;
extension.clear();
if (framerate==0.0)
framerate= getFrameRate(); // same as input
char c[4];
// use same codec as input
if (codec==0) {
codec= getCodec(c);
}
// Open output video
return writer.open(outputFile, // filename
codec, // codec to be used
framerate, // frame rate of the video
getFrameSize(), // frame size
isColor); // color video?
}
// set the output as a series of image files
// extension must be ".jpg", ".bmp" ...
bool setOutput(const std::string &filename, // filename prefix
const std::string &ext, // image file extension
int numberOfDigits=3, // number of digits
int startIndex=0) { // start index
// number of digits must be positive
if (numberOfDigits<0)
return false;
// filenames and their common extension
outputFile= filename;
extension= ext;
// number of digits in the file numbering scheme
digits= numberOfDigits;
// start numbering at this index
currentIndex= startIndex;
return true;
}
// set the callback function that will be called for each frame
void setFrameProcessor(void (*frameProcessingCallback)(cv::Mat&, cv::Mat&)) {
// invalidate frame processor class instance
frameProcessor= 0;
// this is the frame processor function that will be called
process= frameProcessingCallback;
callProcess();
}
// set the instance of the class that implements the FrameProcessor interface
void setFrameProcessor(FrameProcessor* frameProcessorPtr) {
// invalidate callback function
process= 0;
// this is the frame processor instance that will be called
frameProcessor= frameProcessorPtr;
callProcess();
}
// stop streaming at this frame number
void stopAtFrameNo(long frame) {
frameToStop= frame;
}
// process callback to be called
void callProcess() {
callIt= true;
}
// do not call process callback
void dontCallProcess() {
callIt= false;
}
// to display the processed frames
void displayInput(std::string wn) {
windowNameInput= wn;
//cv::namedWindow(windowNameInput);
}
// to display the processed frames
void displayOutput(std::string wn) {
windowNameOutput= wn;
//cv::namedWindow(windowNameOutput);
}
// do not display the processed frames
void dontDisplay() {
cv::destroyWindow(windowNameInput);
cv::destroyWindow(windowNameOutput);
windowNameInput.clear();
windowNameOutput.clear();
}
// set a delay between each frame
// 0 means wait at each frame
// negative means no delay
void setDelay(int d) {
delay= d;
}
// a count is kept of the processed frames
long getNumberOfProcessedFrames() {
return fnumber;
}
// return the size of the video frame
cv::Size getFrameSize() {
if (images.size()==0) {
// get size of from the capture device
int w= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_WIDTH));
int h= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_HEIGHT));
return cv::Size(w,h);
} else { // if input is vector of images
cv::Mat tmp= cv::imread(images[0]);
if (!tmp.data) return cv::Size(0,0);
else return tmp.size();
}
}
// return the frame number of the next frame
long getFrameNumber() {
if (images.size()==0) {
// get info of from the capture device
long f= static_cast<long>(capture.get(CV_CAP_PROP_POS_FRAMES));
return f;
} else { // if input is vector of images
return static_cast<long>(itImg-images.begin());
}
}
// return the position in ms
double getPositionMS() {
// undefined for vector of images
if (images.size()!=0) return 0.0;
double t= capture.get(CV_CAP_PROP_POS_MSEC);
return t;
}
// return the frame rate
double getFrameRate() {
// undefined for vector of images
if (images.size()!=0) return 0;
double r= capture.get(CV_CAP_PROP_FPS);
return r;
}
// return the number of frames in video
long getTotalFrameCount() {
// for vector of images
if (images.size()!=0) return images.size();
long t= capture.get(CV_CAP_PROP_FRAME_COUNT);
return t;
}
// get the codec of input video
int getCodec(char codec[4]) {
// undefined for vector of images
if (images.size()!=0) return -1;
union {
int value;
char code[4]; } returned;
returned.value= static_cast<int>(capture.get(CV_CAP_PROP_FOURCC));
codec[0]= returned.code[0];
codec[1]= returned.code[1];
codec[2]= returned.code[2];
codec[3]= returned.code[3];
return returned.value;
}
// go to this frame number
bool setFrameNumber(long pos) {
// for vector of images
if (images.size()!=0) {
// move to position in vector
itImg= images.begin() + pos;
// is it a valid position?
if (pos < images.size())
return true;
else
return false;
} else { // if input is a capture device
return capture.set(CV_CAP_PROP_POS_FRAMES, pos);
}
}
// go to this position
bool setPositionMS(double pos) {
// not defined in vector of images
if (images.size()!=0)
return false;
else
return capture.set(CV_CAP_PROP_POS_MSEC, pos);
}
// go to this position expressed in fraction of total film length
bool setRelativePosition(double pos) {
// for vector of images
if (images.size()!=0) {
// move to position in vector
long posI= static_cast<long>(pos*images.size()+0.5);
itImg= images.begin() + posI;
// is it a valid position?
if (posI < images.size())
return true;
else
return false;
} else { // if input is a capture device
return capture.set(CV_CAP_PROP_POS_AVI_RATIO, pos);
}
}
// Stop the processing
void stopIt() {
stop= true;
}
// Is the process stopped?
bool isStopped() {
return stop;
}
// Is a capture device opened?
bool isOpened() {
return capture.isOpened() || !images.empty();
}
// to grab (and process) the frames of the sequence
void run(CVWidget *inputWidget, CVWidget *outputWidget) {
// current frame
cv::Mat frame;
// output frame
cv::Mat output;
// if no capture device has been set
if (!isOpened())
return;
stop= false;
while (!isStopped()) {
// read next frame if any
if (!readNextFrame(frame))
break;
// display input frame
if (windowNameInput.length()!=0)
// cv::imshow(windowNameInput,frame);
inputWidget->sendImage(&frame);
// calling the process function or method
if (callIt) {
// process the frame
if (process)
process(frame, output);
else if (frameProcessor)
frameProcessor->process(frame,output);
// increment frame number
fnumber++;
} else {
output= frame;
}
// write output sequence
if (outputFile.length()!=0)
writeNextFrame(output);
// display output frame
if (windowNameOutput.length()!=0)
//cv::imshow(windowNameOutput,output);
outputWidget->sendImage(&output);
// introduce a delay
if (delay>=0 && cv::waitKey(delay)>=0)
stopIt();
// check if we should stop
if (frameToStop>=0 && getFrameNumber()==frameToStop)
stopIt();
}
}
};
#endif
答案 0 :(得分：2)
虽然我无法找出问题的具体原因，但我终于找到了适合我的解决方案：
正如你所建议我摆脱了这个VideoProcessor-Utility类，并通过使用QTimer在每个帧之间延迟来实现处理循环以处理MainWindow中的frame-Sequences。
而不是我制作的VideoProcessor-Class“ProcessorWidget”。这个GUI-Widget提供了所有输入控件，用于参数化我到目前为止实现的每个Processor-Function。
所有OpenCV代码现在都在ProcessorWidget类中，并且它有一个公共插槽cv :: Mat进程（cv :: Mat输入），它只接受输入帧，然后解析来自的所有用户输入参数GUI并在内部处理正确的处理器和参数的选择。
MainWindow现在构建ViewerWidgets和ProcessorWidget并拥有Control和Timing。
处理和显示框架现在只是：
cvWidgetOut->sendImage(&processor->processFrame(input));
如果我想添加更多OpenCV功能，我不必更改我的MainWindow或GUI。这一切都在ProcessorWidget-Class中完成。
答案 1 :(得分：0)
openCV的highgui窗口处理它自己的事件循环 - 你不能（轻松地）将它与QMainWindows事件循环混合。
简单的方法是在openCV中抓取图像并使用Qimage和QPainter在Qt中显示 - QImage的24位RGB888格式与opencv的CV_8UC3兼容