写了个程序，可在途图片，并切换成灰度图及伪彩图显示，主要代码如下：

#include "mainwindow.h"
#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);initRGBTable();//初始化颜色表
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_pushButton_2_clicked()//
{double fMax=0.0;double fMin=0.0;findMaxMin(m_vData,fMax,fMin);double fDifference = fMax - fMin;QVector<quint8> vnData;vnData.resize(m_vData.size());if(fDifference != 0){for(int i = 0;i<m_nHeight;i++){for(int j = 0;j<m_nWidth;j++){vnData[i*m_nWidth+j] = static_cast<int>((m_vData.value(i*m_nWidth+j)-fMin)*1.0f/fDifference*255);}}}QImage img((uchar*)(&vnData[0]),m_nWidth,m_nHeight,QImage::Format_Indexed8);img.setColorTable(m_vecGrayTable);ShowImg(img);
}
void MainWindow::findMaxMin(QVector<double> vData, double &fMax, double &fMin)
{if(vData.size()>1){fMax = vData.value(0);fMin = fMax;for(int i=1;i<vData.size();i++){if(fMax<vData.value(i)){fMax = vData.value(i);}if(fMin>vData.value(i)){fMin = vData.value(i);}}}
}void MainWindow::ShowImg(QImage img)
{QPixmap qPix = QPixmap::fromImage(img);qPix.scaled(ui->label->size(), Qt::KeepAspectRatio);ui->label->setPixmap(qPix);
}
void MainWindow::initRGBTable()
{//核心代码，请下载源码查看
}void MainWindow::on_pushButton_clicked()
{double fMax=0.0;double fMin=0.0;findMaxMin(m_vData,fMax,fMin);double fDifference = fMax - fMin;QVector<quint8> vnData;vnData.resize(m_vData.size());if(fDifference != 0){for(int i = 0;i<m_nHeight;i++){for(int j = 0;j<m_nWidth;j++){vnData[i*m_nWidth+j] = static_cast<int>((m_vData.value(i*m_nWidth+j)-fMin)*1.0f/fDifference*255);}}}QImage img((uchar*)(&vnData[0]),m_nWidth,m_nHeight,QImage::Format_Indexed8);img.setColorTable(m_vecColorTable);ShowImg(img);
}void MainWindow::on_pushButton_3_clicked()//打开图片
{QFileDialog *fileDlg = new QFileDialog(this);fileDlg->setWindowTitle("Choose Pictures");QStringList qstrFilters;qstrFilters<<"Any files (*)";fileDlg->setNameFilters(qstrFilters);//设置文件过滤器fileDlg->setFileMode(QFileDialog::ExistingFiles);//设置能选择多个文件，如果是单个文件就写成QFileDialog::ExistingFileif(fileDlg->exec() == QDialog::Accepted){QStringList strPathList = fileDlg->selectedFiles();if(strPathList.count()>0){qImg.load(strPathList.first());m_nWidth = qImg.width();m_nHeight = qImg.height();ShowImg(qImg);qImg = qImg.convertToFormat(QImage::Format_Grayscale8,Qt::AutoColor);m_vData.resize(m_nWidth*m_nHeight);unsigned char *ImgDataPtr = qImg.bits();for(int i = 0;i<m_nHeight;i++){for(int j = 0;j<m_nWidth;j++){m_vData[i*m_nWidth+j]=*ImgDataPtr;ImgDataPtr++;}}}}fileDlg->close();delete fileDlg;fileDlg = nullptr;
}

源码下载地址：https://download.csdn.net/download/weixin_43935474/88232145