基于Qt的tcp客户端和服务器实现摄像头帧数据处理…

2018-07-22 05:46:41来源:博客园 阅读 ()

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  • 项目简述

  实现客户端调用摄像头,并以帧的形式将每一帧传输到服务端,服务端将图片进行某些处理后再返回给客户端。(客户端与服务端通信代码部分参考《Qt5 开发及实例》)

  • 项目步骤

  • 客户端的编写

  •   通过Qt Designer画出如下界面

  • 在客户端工程文件“client、pro”中加入 QT += network语句,并将环境路径配置好。
  • 在头文件“client.h”中加入如下代码:
     1 class Client : public QWidget
     2 {
     3     Q_OBJECT
     4 
     5 public:
     6     explicit Client(QWidget *parent = 0);
     7     ~Client();
     8 
     9 private slots:
    10     void slotEnter();
    11     void slotConnected();
    12     void slotDisconnected();
    13     void dataReceived();
    14     void slotSend();
    15     void nextFrame();
    16 signals:
    17     void connectedToServer(void);
    18 
    19 private:
    20     Ui::Client *ui;
    21     bool status;
    22     int port;
    23     QHostAddress *serverIP;
    24     QString userName;
    25     QTcpSocket *tcpSocket;
    26 
    27     qint64 receiveBlockSize;
    28 
    29     Mat frame;
    30     VideoCapture cap;
    31     QTimer* timer;
    32     QImage image;
    33 
    34     void ShowImage(QByteArray ba);
    35     QByteArray picToData(cv::Mat frame);
    36     QImage Mat2QImage(cv::Mat cvImg);
    37 };
    View Code

     

  • 在源文件“client.cpp”的构造函数中加入如下代码:
     1 Client::Client(QWidget *parent) :
     2     QWidget(parent),
     3     ui(new Ui::Client)
     4 {
     5     ui->setupUi(this);
     6 
     7     setWindowFlags(windowFlags()&~Qt::WindowMaximizeButtonHint);
     8     setFixedSize(this->width(),this->height());
     9 
    10     status=false;
    11     port=8010;
    12     ui->portLineEdit->setText(QString::number(port));
    13 
    14     serverIP=new QHostAddress();
    15     ui->serverIPLineEdit->setText("127.0.0.1");
    16     connect(ui->ConnectPushButton,SIGNAL(clicked(bool)),this,SLOT(slotEnter()));
    17 
    18     receiveBlockSize=0;
    19 
    20     timer=new QTimer(this);
    21     timer->start(30);
    22 
    23     cap.open(0);
    24     if(!cap.isOpened())
    25     {
    26         QMessageBox::information(this,tr("error"),tr("cam don't open"));
    27     }
    28 
    29     connect(timer,&QTimer::timeout,this,&Client::nextFrame);
    30 }
    View Code

     

槽函数nextFrame()通过调用openCV,实现获取每一帧图像:

 1 void Client::nextFrame()
 2 {
 3     cap>>frame;
 4     if (!frame.empty())
 5     {
 6         image = Mat2QImage(frame);
 7     
 8         //使图像适应label的大小
 9         QPixmap *pixmap = new QPixmap(QPixmap::fromImage(image));
10         pixmap->scaled(ui->capturedImage->size(), Qt::KeepAspectRatio);
11         ui->capturedImage->setScaledContents(true);
12         ui->capturedImage->setPixmap(*pixmap);
13         delete pixmap;//避免内存泄漏
14     }
15 }
View Code

 

函数Mat2QImage(cv::Mat cvImg)代码如下:

 1 QImage Client::Mat2QImage(cv::Mat cvImg)
 2 {
 3     QImage qImg;
 4     if(cvImg.channels()==3)                             //3 channels color image
 5     {
 6 
 7         cv::cvtColor(cvImg,cvImg,CV_BGR2RGB);
 8         qImg =QImage((const unsigned char*)(cvImg.data),
 9                      cvImg.cols, cvImg.rows,
10                      cvImg.cols*cvImg.channels(),
11                      QImage::Format_RGB888);
12     }
13     else if(cvImg.channels()==1)                    //grayscale image
14     {
15         qImg =QImage((const unsigned char*)(cvImg.data),
16                      cvImg.cols,cvImg.rows,
17                      cvImg.cols*cvImg.channels(),
18                      QImage::Format_Indexed8);
19     }
20     else
21     {
22         qImg =QImage((const unsigned char*)(cvImg.data),
23                      cvImg.cols,cvImg.rows,
24                      cvImg.cols*cvImg.channels(),
25                      QImage::Format_RGB888);
26     }
27     return qImg;
28 }
View Code

 

  以上代码中,槽函数slotEnter()实现连接和断开服务器功能(但现在断开后再连上数据传输有问题),代码如下:

 1 void Client::slotEnter()
 2 {
 3     if(!status)
 4     {
 5         QString ip=ui->serverIPLineEdit->text();
 6         if(!serverIP->setAddress(ip))
 7         {
 8             QMessageBox::information(this,tr("error"),
 9                                      tr("server ip address error"));
10             return;
11         }
12 
13         tcpSocket=new QTcpSocket(this);
14 
15         connect(tcpSocket,&QAbstractSocket::connected,this,&Client::slotConnected);
16 
17         connect(tcpSocket,&QAbstractSocket::disconnected,this,&Client::slotDisconnected);
18 
19         connect(tcpSocket,&QIODevice::readyRead,this,&Client::dataReceived);
20 
21         connect(this,&Client::connectedToServer,this,&Client::slotSend);
22 
23         tcpSocket->connectToHost(*serverIP,port);
24 
25 
26         status=true;
27     }
28     else
29     {
30 
31         tcpSocket->disconnectFromHost();
32 
33         status=false;
34     }
35 }
View Code

 

槽函数“slotConnected()”是connected()信号的响应槽,当与服务器连接成功后,客户端进行一些操作,具体代码如下:

1 void Client::slotConnected()
2 {
3     ui->handPushButton->setEnabled(true);
4     ui->facePushButton->setEnabled(true);
5     ui->ConnectPushButton->setText(tr("Leave"));
6     //ui->ConnectPushButton->setEnabled(false);
7     emit connectedToServer();
8 }
View Code

 

槽函数“slotDisconnected()”是disconnected()信号的响应槽,当与服务器断开连接时,进行如下操作:

1 void Client::slotDisconnected()
2 {
3     ui->handPushButton->setEnabled(false);
4     ui->facePushButton->setEnabled(false);
5     ui->ConnectPushButton->setText(tr("Enter"));
6 }
View Code

  

  当发出connectedToServer()信号后,槽函数slotSend()响应,具体代码如下:

 1 void Client::slotSend()
 2 {
 3     if(frame.empty())
 4         return;
 5 
 6     QByteArray byteArrayData=picToData(frame);
 7     QByteArray ba;
 8     QDataStream out(&ba,QIODevice::WriteOnly);
 9     out.setVersion(QDataStream::Qt_5_6);
10 
11     out<<(quint64)0;
12     out<<byteArrayData;
13     out.device()->seek(0);
14     out<<(quint64)(ba.size()-sizeof(quint64));
15     tcpSocket->write(ba);
16 }
View Code

 

  其中函数picToData(cv::Mat frame)代码如下:

 1 QByteArray Client::picToData(Mat frame)
 2 {
 3     QImage img((unsigned const char*)frame.data,frame.cols,frame.rows,QImage::Format_RGB888);
 4 
 5     QByteArray block;
 6     QBuffer buf(&block);
 7     img.save(&buf,"JPEG");//按照JPG解码保存数据
 8     QByteArray cc = qCompress(block,1);
 9     QByteArray hh;
10     hh=cc.toBase64();//base64数据
11     return hh;
12 }
View Code

 

  函数dataReceived()当客户端收到服务端数据时响应,代码如下:

 1 void Client::dataReceived()
 2 {
 3     ui->noteLabel->setText(tr("receive data"));
 4     QDataStream in(tcpSocket);
 5     QByteArray message;//存放从服务器接收到的字符串
 6     in.setVersion(QDataStream::Qt_5_6);
 7     if (receiveBlockSize==0)
 8     {
 9         //判断接收的数据是否有两字节(文件大小信息)
10         //如果有则保存到basize变量中,没有则返回,继续接收数据
11         if (tcpSocket->bytesAvailable()<(int)sizeof(quint64))
12         {
13             return;
14         }
15         in>>receiveBlockSize;
16     }
17     //如果没有得到全部数据,则返回继续接收数据
18     if (tcpSocket->bytesAvailable()<receiveBlockSize)
19     {
20         //qDebug()<<"tcpSocket->bytesAvailable()<receiveBlockSize";
21         return;
22     }
23     in>>message;//将接收到的数据存放到变量中
24     ShowImage(message);
25     receiveBlockSize=0;
26     emit connectedToServer();
27 }
View Code

  最后的emit connectedToServer();实现每次发送一次数据给服务端后,等待服务端响应后再发送数据,避免一直发数据,同时又接收数据而出现问题。

  最后,将处理后的图像显示,调用函数ShowImage(QByteArray ba)实现,代码如下:

 1 void Client::ShowImage(QByteArray ba)
 2 {
 3     QString ss=QString::fromLatin1(ba.data(),ba.size());
 4     QByteArray rc;
 5     rc=QByteArray::fromBase64(ss.toLatin1());
 6     QByteArray rdc=qUncompress(rc);
 7     QImage img;
 8     img.loadFromData(rdc);
 9     ui->processedImage->setPixmap(QPixmap::fromImage(img));
10     ui->processedImage->resize(img.size());
11     update();
12 }
View Code

  

  最后的最后,不要忘了调用析构函数:

1 Client::~Client()
2 {
3     delete ui;
4     delete tcpSocket;
5     delete timer;
6     delete serverIP;
7 }
View Code

 

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