QT+QT creator+OpenCV图像灰度化

#-------------------------------------------------
#
# Project created by QtCreator 2014-05-18T12:56:52
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = myQTDemo
TEMPLATE = app

SOURCES += main.cpp\
mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui
INCLUDEPATH+=d:\opencv249\include\opencv\
d:\opencv249\include\opencv2\
d:\opencv249\include

LIBS+=d:\opencv249\lib\libopencv_calib3d249.dll.a\
d:\opencv249\lib\libopencv_contrib249.dll.a\
d:\opencv249\lib\libopencv_core249.dll.a\
d:\opencv249\lib\libopencv_features2d249.dll.a\
d:\opencv249\lib\libopencv_flann249.dll.a\
d:\opencv249\lib\libopencv_gpu249.dll.a\
d:\opencv249\lib\libopencv_highgui249.dll.a\
d:\opencv249\lib\libopencv_imgproc249.dll.a\
d:\opencv249\lib\libopencv_legacy249.dll.a\
d:\opencv249\lib\libopencv_ml249.dll.a\
d:\opencv249\lib\libopencv_objdetect249.dll.a\
d:\opencv249\lib\libopencv_video249.dll.a

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
cv::Mat image,image2;
QImage img;

private slots:
void on_pushButton_clicked();

void on_pushButton_2_clicked();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QString>
#include <QFileDialog>
#include <QMessageBox>
#include <opencv/cv.h>
#include <QTextCodec>
using namespace cv;
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::on_pushButton_clicked()
{
QString filename = QFileDialog::getOpenFileName(this,tr("Open Image"),"",tr("Image File(*.bmp *.jpg *.jpeg *.png)"));
QTextCodec *code = QTextCodec::codecForName("gb18030");
std::string name = code->fromUnicode(filename).data();
image = cv::imread(name);

if(!image.data)
{
QMessageBox msgBox;
msgBox.setText(tr("image data is null"));
msgBox.exec();
}
else
{
cv::cvtColor(image,image2,CV_BGR2RGB);
img = QImage((const unsigned char*)(image2.data),image.cols,image.rows, image.step,  QImage::Format_RGB888);
ui->label->clear();
ui->label->setPixmap(QPixmap::fromImage(img));
//ui->processPushButton->setEnabled(true);
ui->label->resize(ui->label->pixmap()->size());
}
}

void MainWindow::on_pushButton_2_clicked()
{
// cv::flip(image,image,1);
Mat gray;

cvtColor(image,gray,CV_BGR2GRAY);
// cvtColor(gray,gray,CV_bg)
//  imshow("li",gray);

// cv::cvtColor(image,image,CV_BGR2RGB);
//      img = QImage((const unsigned char*)(image.data),image.cols,image.rows,image.cols*image.channels(),  QImage::Format_RGB888);
img = QImage((const unsigned char*)(gray.data),gray.cols,gray.rows,gray.step,  QImage::Format_Indexed8);

ui->label->setPixmap(QPixmap::fromImage(img));
}