Qt +Opencv 在ARM-A9上视频拍照

     OpenCV包含了大量的机器视觉处理算法，Qt是一个跨平台的C++图形用户界面库，一般通过OpenCV完成图像处理算法，用Qt实现人机交互接口。本文主要实现 Qt+Opencv在ARM-A9 4412上实现图像采集拍照的功能。

     Opencv移植到ARM上参考上篇博客   Ubuntu14.04 Opencv2.4.9交叉编译

     Qt4.7.1库采用讯为公司提供的，Qtcreator之前使用Qtcreator5.3.2，编译过程中出现各种奇葩的错误，也不知道为什么，后来使用Qtcreator2.6.1就基本没出现那
些奇怪的问题了。本人目前对Qt还不是很熟，出现这样问题留给以后解决…

     摄像头采用某宝上普通的USB摄像头。

     打开Qtcreator，新建一个Qt Gui工程，首先修改.pro文件，包含Opencv的头文件和库文件路径。

     

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = DIalogCam
TEMPLATE = app

UI_DIR=./UI

SOURCES += main.cpp\
        dialog.cpp

HEADERS  += dialog.h

FORMS    += dialog.ui


#INCLUDEPATH += /opt/qt-4.7.1/include
#INCLUDEPATH += /opt/qt-4.7.1/include/QtGui

#INCLUDEPATH += /usr/local/include
#INCLUDEPATH += /usr/local/include/opencv
#INCLUDEPATH += /usr/local/include/opencv2

#LIBS += /usr/local/lib/libopencv_highgui.so
#LIBS += /usr/local/lib/libopencv_legacy.so
#LIBS += /usr/local/lib/libopencv_imgproc.so
#LIBS += /usr/local/lib/libopencv_flann.so
#LIBS += /usr/local/lib/libopencv_ml.so
#LIBS += /usr/local/lib/libopencv_core.so
#LIBS += /usr/local/lib/libopencv_photo.so
#LIBS += /usr/local/lib/libopencv_contrib.so
#LIBS += /usr/local/lib/libopencv_video.so
#LIBS += /usr/local/lib/libopencv_objdetect.so
#LIBS += /usr/local/lib/libopencv_nonfree.so
#LIBS += /usr/local/lib/libopencv_calib3d.so
#LIBS += /usr/local/lib/libopencv_features2d.so

INCLUDEPATH += /usr/local/arm/opencv-install/include/
INCLUDEPATH += /usr/local/arm/opencv-install/include/opencv
INCLUDEPATH += /usr/local/arm/opencv-install/include/opencv2

LIBS += /usr/local/arm/opencv-install/lib/libopencv_highgui.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_legacy.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_imgproc.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_flann.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_ml.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_core.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_photo.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_contrib.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_video.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_objdetect.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_nonfree.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_calib3d.so
LIBS += /usr/local/arm/opencv-install/lib/libopencv_features2d.so

       上面Opencv路径是安装在ubuntu上x86架构opencv，下面是交叉编译的ARM架构opencv，在ubuntu上或者ARM上运行分别包含对应的路径。一般先在PC上调试，再在板子上运行。

       

       在dialog.ui加上一个lable和四个button

       dialog.cpp部分

       

#include "dialog.h"
#include "ui_dialog.h"
#include "switch.h"
#include "QtGui"

Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);

    cam     = NULL;
    timer   = new QTimer(this);
    imag    = new QImage();

    /*信号和槽*/
    connect(timer, SIGNAL(timeout()), this, SLOT(readFarme()));  // 时间到，读取当前摄像头信息
    connect(ui->openCam, SIGNAL(clicked()), this, SLOT(openCamara()));
    connect(ui->closeCam, SIGNAL(clicked()), this, SLOT(closeCamara()));
    connect(ui->savePic, SIGNAL(clicked()), this, SLOT(takingPictures()));
    connect(ui->openPic, SIGNAL(clicked()), this, SLOT(OpenPictures()));
}

void Dialog::openCamara()
{
    cam = cvCreateCameraCapture(204);//204
    timer->start(33);              // 开始计时，超时则发出timeout()信号
}

void Dialog::readFarme()
{
    frame = cvQueryFrame(cam);

    QImage image = QImage((const uchar*)frame->imageData, frame->width, frame->height,
                          QImage::Format_RGB888).rgbSwapped();
    ui->label->setPixmap(QPixmap::fromImage(image));
//    ui->label->resize(image.width(),image.height());
}

void Dialog::closeCamara()
{
    timer->stop();         // 停止读取数据。

    cvReleaseCapture(&cam);//释放内存；

    ui->label->setPixmap(NULL);
}

void Dialog::takingPictures()
{
    cvSaveImage("saveImage.jpg",frame);
}

void Dialog::OpenPictures()
{
    timer->stop();         // 停止读取数据。
    cvReleaseCapture(&cam);//释放内存；
    ui->label->setPixmap(NULL);

    QString filename;
    filename=QFileDialog::getOpenFileName(this,
                                          tr("Choose Picture"),
                                          "",
                                          tr("Images (*.png *.bmp *.jpg *.tif *.GIF )"));
    if(filename.isEmpty())
    {
         return ;
    }
    else
    {
        if(! ( imag->load(filename) ) ) //加载图像
        {
            return ;
        }
        ui->label->setPixmap(QPixmap::fromImage(*imag));
    }
}

Dialog::~Dialog()
{
    delete ui;
    delete timer;
    delete imag;
    delete frame;
}

        我的4412板子USB摄像头设备节点是/dev/video4，其中 cam =cvCreateCameraCapture(204) 部分，这个函数意思打开video4，网上讨论括号里参数可以是0 -1 202 ，需要根据自己实际情况修改，我在ubuntu运行 0 -1都可以。

       dialog.h部分

       

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QImage>
#include <QTimer>     // 设置采集数据的间隔时间

#include "highgui.h"  //包含opencv库头文件
#include "cv.h"

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT
    
public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

private slots:
    void openCamara();      // 打开摄像头
    void readFarme();       // 读取当前帧信息
    void closeCamara();     // 关闭摄像头
    void takingPictures();  // 拍照
    void OpenPictures();

private:
    Ui::Dialog *ui;
    QTimer    *timer;
    QImage    *imag;
    CvCapture *cam;// 视频获取结构， 用来作为视频获取函数的一个参数
    IplImage  *frame;//申请IplImage类型指针，就是申请内存空间来存放每一帧图像
};

#endif // DIALOG_H

使用qtcreator在release目录下生成可执行文件，通过file命令查看是x86-64架构，不能在ARM上运行。

root@ubuntu:/home/itop/Qtwork/DIalogCam/DIalogCam-build-Desktop-Release# file DIalogCam 
DIalogCam: ELF 64-bit LSB  executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=21ccf5af51609796c148650ece5a45903c4b99ac, not stripped

在工程目录下运行qt-4.7.1的qmake，生成makefile文件，最后再make生成ARM可运行文件
root@ubuntu:/home/itop/Qtwork/DIalogCam# /opt/qt-4.7.1/bin/qmake 
root@ubuntu:/home/itop/Qtwork/DIalogCam# make
root@ubuntu:/home/itop/Qtwork/DIalogCam# file DIalogCam
DIalogCam: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.14, not stripped
哈哈，至此就可以把生成可运行文件拷贝到板子上run了...

./DIalogCam -qws &
看下实际效果图