content: import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.opencv.core.Core;
  import org.opencv.core.CvType;
  import org.opencv.core.Mat;
  import org.opencv.core.Scalar;
  import org.opencv.imgcodecs.Imgcodecs;
  import org.opencv.photo.CalibrateDebevec;
  import org.opencv.photo.MergeDebevec;
  import org.opencv.photo.MergeMertens;
  import org.opencv.photo.Photo;
  import org.opencv.photo.Tonemap;
  
  class HDRImaging {
      public void loadExposureSeq(String path, List<Mat> images, List<Float> times) {
          path += "/";
  
          List<String> lines;
          try {
              lines = Files.readAllLines(Paths.get(path + "list.txt"));
  
              for (String line : lines) {
                  String[] splitStr = line.split("\\s+");
                  if (splitStr.length == 2) {
                      String name = splitStr[0];
                      Mat img = Imgcodecs.imread(path + name);
                      images.add(img);
                      float val = Float.parseFloat(splitStr[1]);
                      times.add(1/ val);
                  }
              }
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  
      public void run(String[] args) {
          String path = args.length > 0 ? args[0] : "";
          if (path.isEmpty()) {
              System.out.println("Path is empty. Use the directory that contains images and exposure times.");
              System.exit(0);
          }
  
          //! [Load images and exposure times]
          List<Mat> images = new ArrayList<>();
          List<Float> times = new ArrayList<>();
          loadExposureSeq(path, images, times);
          //! [Load images and exposure times]
  
          //! [Estimate camera response]
          Mat response = new Mat();
          CalibrateDebevec calibrate = Photo.createCalibrateDebevec();
          Mat matTimes = new Mat(times.size(), 1, CvType.CV_32F);
          float[] arrayTimes = new float[(int) (matTimes.total()*matTimes.channels())];
          for (int i = 0; i < times.size(); i++) {
              arrayTimes[i] = times.get(i);
          }
          matTimes.put(0, 0, arrayTimes);
          calibrate.process(images, response, matTimes);
          //! [Estimate camera response]
  
          //! [Make HDR image]
          Mat hdr = new Mat();
          MergeDebevec mergeDebevec = Photo.createMergeDebevec();
          mergeDebevec.process(images, hdr, matTimes);
          //! [Make HDR image]
  
          //! [Tonemap HDR image]
          Mat ldr = new Mat();
          Tonemap tonemap = Photo.createTonemap(2.2f);
          tonemap.process(hdr, ldr);
          //! [Tonemap HDR image]
  
          //! [Perform exposure fusion]
          Mat fusion = new Mat();
          MergeMertens mergeMertens = Photo.createMergeMertens();
          mergeMertens.process(images, fusion);
          //! [Perform exposure fusion]
  
          //! [Write results]
          Core.multiply(fusion, new Scalar(255,255,255), fusion);
          Core.multiply(ldr, new Scalar(255,255,255), ldr);
          Imgcodecs.imwrite("fusion.png", fusion);
          Imgcodecs.imwrite("ldr.png", ldr);
          Imgcodecs.imwrite("hdr.hdr", hdr);
          //! [Write results]
  
          System.exit(0);
      }
  }
  
  public class HDRImagingDemo {
      public static void main(String[] args) {
          // Load the native OpenCV library
          System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
  
          new HDRImaging().run(args);
      }
  }
  