Add Demo 5: Basic panorama stitching from a rotating camera in the homography tutorial.

samples/cpp/tutorial_code/features2D/Homography/panorama_stitching_rotating_camera.cpp

@@ -0,0 +1,88 @@
+#include <iostream>
+#include <opencv2/opencv.hpp>
+
+using namespace std;
+using namespace cv;
+
+namespace
+{
+void basicPanoramaStitching(const string &img1Path, const string &img2Path)
+{
+    Mat img1 = imread(img1Path);
+    Mat img2 = imread(img2Path);
+
+    //! [camera-pose-from-Blender-at-location-1]
+    Mat c1Mo = (Mat_<double>(4,4) << 0.9659258723258972, 0.2588190734386444, 0.0, 1.5529145002365112,
+                                     0.08852133899927139, -0.3303661346435547, -0.9396926164627075, -0.10281121730804443,
+                                     -0.24321036040782928, 0.9076734185218811, -0.342020183801651, 6.130080699920654,
+                                     0, 0, 0, 1);
+    //! [camera-pose-from-Blender-at-location-1]
+
+    //! [camera-pose-from-Blender-at-location-2]
+    Mat c2Mo = (Mat_<double>(4,4) << 0.9659258723258972, -0.2588190734386444, 0.0, -1.5529145002365112,
+                                     -0.08852133899927139, -0.3303661346435547, -0.9396926164627075, -0.10281121730804443,
+                                     0.24321036040782928, 0.9076734185218811, -0.342020183801651, 6.130080699920654,
+                                     0, 0, 0, 1);
+    //! [camera-pose-from-Blender-at-location-2]
+
+    //! [camera-intrinsics-from-Blender]
+    Mat cameraMatrix = (Mat_<double>(3,3) << 700.0, 0.0, 320.0,
+                                             0.0, 700.0, 240.0,
+                                             0, 0, 1);
+    //! [camera-intrinsics-from-Blender]
+
+    //! [extract-rotation]
+    Mat R1 = c1Mo(Range(0,3), Range(0,3));
+    Mat R2 = c2Mo(Range(0,3), Range(0,3));
+    //! [extract-rotation]
+
+    //! [compute-rotation-displacement]
+    //c1Mo * oMc2
+    Mat R_2to1 = R1*R2.t();
+    //! [compute-rotation-displacement]
+
+    //! [compute-homography]
+    Mat H = cameraMatrix * R_2to1 * cameraMatrix.inv();
+    H /= H.at<double>(2,2);
+    cout << "H:\n" << H << endl;
+    //! [compute-homography]
+
+    //! [stitch]
+    Mat img_stitch;
+    warpPerspective(img2, img_stitch, H, Size(img2.cols*2, img2.rows));
+    Mat half = img_stitch(Rect(0, 0, img1.cols, img1.rows));
+    img1.copyTo(half);
+    //! [stitch]
+
+    Mat img_compare;
+    Mat img_space = Mat::zeros(Size(50, img1.rows), CV_8UC3);
+    hconcat(img1, img_space, img_compare);
+    hconcat(img_compare, img2, img_compare);
+    imshow("Compare images", img_compare);
+
+    imshow("Panorama stitching", img_stitch);
+    waitKey();
+}
+
+const char* params
+    = "{ help h         |                              | print usage }"
+      "{ image1         | ../data/Blender_Suzanne1.jpg | path to the first Blender image }"
+      "{ image2         | ../data/Blender_Suzanne2.jpg | path to the second Blender image }";
+}
+
+int main(int argc, char *argv[])
+{
+    CommandLineParser parser(argc, argv, params);
+
+    if (parser.has("help"))
+    {
+        parser.about( "Code for homography tutorial.\n"
+                      "Example 5: basic panorama stitching from a rotating camera.\n" );
+        parser.printMessage();
+        return 0;
+    }
+
+    basicPanoramaStitching(parser.get<String>("image1"), parser.get<String>("image2"));
+
+    return 0;
+}

samples/cpp/tutorial_code/features2D/Homography/pose_from_homography.cpp

@@ -107,6 +107,14 @@ void poseEstimationFromCoplanarPoints(const string &imgPath, const string &intri
     }
     //! [pose-from-homography]
 
+    //! [polar-decomposition-of-the-rotation-matrix]
+    cout << "R (before polar decomposition):\n" << R << "\ndet(R): " << determinant(R) << endl;
+    Mat W, U, Vt;
+    SVDecomp(R, W, U, Vt);
+    R = U*Vt;
+    cout << "R (after polar decomposition):\n" << R << "\ndet(R): " << determinant(R) << endl;
+    //! [polar-decomposition-of-the-rotation-matrix]
+
     //! [display-pose]
     Mat rvec;
     Rodrigues(R, rvec);