Merge pull request #2231 from Saafke:dnn_superres_final_phase

* Add learning-based super-resolution module

Adds the module plus loading classes for SR data

Complete with docs, tutorials and tests.

* Fix typo

* Small commit to restart buildbot

* Change refs from arXiv to official

* Remove video string

* dnn_superres: update perf test code

* dnn_superres: test fixup

modules/datasets/samples/sr_div2k.cpp

@@ -0,0 +1,47 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "opencv2/datasets/sr_div2k.hpp"
+
+#include <opencv2/core.hpp>
+
+#include <cstdio>
+
+#include <string>
+#include <vector>
+
+using namespace std;
+using namespace cv;
+using namespace cv::datasets;
+
+int main(int argc, char *argv[])
+{
+    const char *keys =
+            "{ help h usage ? |    | show this message }"
+            "{ path p         |true| path to dataset (Div2k dataset folder containing the images) }";
+    CommandLineParser parser(argc, argv, keys);
+    string path(parser.get<string>("path"));
+    if (parser.has("help") || path=="true")
+    {
+        parser.printMessage();
+        return -1;
+    }
+
+    Ptr<SR_div2k> dataset = SR_div2k::create();
+    dataset->load(path);
+
+    // ***************
+    // Dataset contains all images.
+    // For example, let's output dataset size; first image name; and second image full path.
+    printf("dataset size: %u\n", (unsigned int)dataset->getTrain().size());
+
+    SR_div2kObj *example = static_cast<SR_div2kObj *>(dataset->getTrain()[0].get());
+    printf("first image name: %s\n", example->imageName.c_str());
+
+    SR_div2kObj *example2 = static_cast<SR_div2kObj *>(dataset->getTrain()[1].get());
+    string fullPath = path + "/" + example2->imageName.c_str();
+    printf("second image full path: %s\n", fullPath.c_str());
+
+    return 0;
+}