Geospatial Imagery Viewer using GDAL, openCV, QT

[Kyeiv]

Hi all,
I am trying to achieve some simple image viewer for formats like nitf, geotif etc.
For now I can read some files and display them with QLabel and openCV's imshow().
The problem I stumbled upon is that some images are displayed corrupted when using QLabel while imshow() displays them correctly. Can someone pinpoint things that i am doing wrong?

SamplesLINK
For i_3004g the only good preview is opencv, for i_3301a the Qt is better.

Here is my code:

#include <QApplication>
#include <QFileDialog>
#include <QLabel>

#include <gdal/gdal.h>
#include <gdal/gdal_priv.h>

#include <opencv2/opencv.hpp>
#include <opencv2/imgproc/imgproc.hpp>

using namespace cv;

QSharedPointer<QLabel> create_preview(uchar* data, int cols, int rows, std::string title)
{
    QImage qt_image(data,
                     cols,
                     rows,
                     QImage::Format_RGB888);

    QVector<QRgb> colorTable;
    for(int i=0; i<256; ++i)
       colorTable << qRgb(i,i,i);

   qt_image.setColorTable(colorTable);
   QSharedPointer<QLabel> myLabel = QSharedPointer<QLabel>::create();
   myLabel->setPixmap(QPixmap::fromImage(qt_image));
   title += "Format_RGB888";
   QString displayable_title = QString::fromStdString(title);
   myLabel->setWindowTitle(displayable_title);
   return myLabel;
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QString imagePath = QFileDialog::getOpenFileName(Q_NULLPTR,"Open File","");

    const std::string imageName = imagePath.toStdString();
    const std::string output = "output_im.nitf";

    std::cout << "Reading png file: " << imageName << std::endl;
    Mat image2 = imread(imageName, cv::IMREAD_LOAD_GDAL | cv::IMREAD_COLOR );
    //cvtColor(image2, image2, CV_BGR2RGB);
    //NOTE: for some reason openCV's window displays in RGB but openCV Mat keeps data in BGR
    //NOTE using this with nor channels == 3 data causes runtime errors
    //imwrite(imageName, image2);

    std::cout << "Displaying png file: " << imageName << std::endl;
    namedWindow( imageName, WINDOW_AUTOSIZE );
    imshow( imageName, image2 );

    GDALAllRegister();

    GDALDataset * pOldDS, *pNewDS;
    GDALDriver *pDriverTiff;
    pDriverTiff = GetGDALDriverManager()->GetDriverByName("NITF");

    std::cout << "Reading gdal file: " << imageName << std::endl;
    pOldDS = (GDALDataset*) GDALOpen(imageName.c_str(), GA_ReadOnly);
    std::cout << "Saving to file: " << output << std::endl;
    pNewDS = pDriverTiff->CreateCopy(output.c_str(), pOldDS, FALSE, NULL, NULL, NULL);

    std::cout << "Closing datasets..." << std::endl;
    GDALClose(pNewDS);
    GDALClose(pOldDS);
    std::cout << "Completed!" << std::endl;

    std::cout << "Reading nitf file: " << output << std::endl;
    Mat image = imread(output, cv::IMREAD_LOAD_GDAL | cv::IMREAD_COLOR );
    //NOTE: for some reason openCV's window displays in RGB but openCV Mat keeps data in BGR
    //cvtColor(image, image, CV_BGR2RGB);

    std::cout << "Displaying nitf file: " << output << std::endl;
    namedWindow( output, WINDOW_AUTOSIZE );
    imshow( output, image );

    //============QT PREVIEWS============================================
    auto in_preview = create_preview(image2.data, image2.cols, image2.rows, "in_qt");
    auto ou_preview = create_preview(image.data, image.cols, image.rows, "ou_qt");

    in_preview->show();
    ou_preview->show();

    return a.exec();
}

Regards Kris

[SGaist]

Hi,

Can you show what you are getting ?

[Kyeiv]

@SGaist