QT下调用摄像头(opencv2.4.4)

http://www.cnblogs.com/yuliyang/p/3525107.html

项目pro文件：

#-------------------------------------------------
#
# Project created by QtCreator 2014-01-18T14:39:58
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = opencv_vedio
TEMPLATE = app
INCLUDEPATH +=D:\program\opencv\build\includeINCLUDEPATH +D:\program\opencv\build\include\opencvINCLUDEPATH +=D:\program\opencv\build\include\opencv2
CONFIG(debug,debug|release) {
LIBS += -LD:\program\opencv\build\x86\vc10\lib     -lopencv_core244d     -lopencv_highgui244d     -lopencv_imgproc244d     -lopencv_features2d244d     -lopencv_calib3d244d
} else {
LIBS += -LD:\program\opencv\build\x86\vc10\lib     -lopencv_core244     -lopencv_highgui244     -lopencv_imgproc244     -lopencv_features2d244     -lopencv_calib3d244
}

SOURCES += main.cpp        dialog.cpp

HEADERS  += dialog.h

FORMS    += dialog.ui

dialog.h：

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <QTimer>
#include <QPixmap>
namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT

public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

private:
    Ui::Dialog *ui;
    CvCapture *capture; //highgui 里提供的一个专门处理摄像头图像的结构体
    IplImage *frame; //摄像头每次抓取的图像为一帧，使用该指针指向一帧图像的内存空间
    QTimer *timer; //定时器用于定时取帧，上面说的隔一段时间就去取就是用这个实现。
private slots:
    void getFrame(); //实现定时从摄像头取图并显示在label上的功能。

};

#endif // DIALOG_H

dialog.cpp：

#include "dialog.h"
#include "ui_dialog.h"
#include <QDebug>
Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
    timer = new QTimer(this);
    capture = cvCaptureFromCAM(0); //cvCaptureFromCAM其实是一个宏，就是cvCreateCameraCapture的别名，0代表第一个摄像头。-1代表默认摄像头。
    if(capture==NULL){
          qDebug()<<"error!";
        }
    timer->start(50); //1000为1秒，50毫秒去取一帧
    connect(timer,SIGNAL(timeout()),this,SLOT(getFrame())); //超时就去取
}

Dialog::~Dialog()
{
    timer->stop(); //停止取帧
    cvReleaseCapture(&capture); //释放资源是个好习惯
    delete ui;
}
void Dialog::getFrame(){
    frame = cvQueryFrame(capture); //从摄像头取帧
    QImage image = QImage((const uchar*)frame->imageData, frame->width, frame->height, QImage::Format_RGB888).rgbSwapped(); //简单地转换一下为Image对象，rgbSwapped是为了显示效果色彩好一些。
    ui->label->setPixmap(QPixmap::fromImage(image));
}

效果：