Diff: include/opencv2/stitching/detail/motion_estimators.hpp

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+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
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+//
+//
+//                          License Agreement
+//                For Open Source Computer Vision Library
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+//M*/
+
+#ifndef OPENCV_STITCHING_MOTION_ESTIMATORS_HPP
+#define OPENCV_STITCHING_MOTION_ESTIMATORS_HPP
+
+#include "opencv2/core.hpp"
+#include "matchers.hpp"
+#include "util.hpp"
+#include "camera.hpp"
+
+namespace cv {
+namespace detail {
+
+//! @addtogroup stitching_rotation
+//! @{
+
+/** @brief Rotation estimator base class.
+
+It takes features of all images, pairwise matches between all images and estimates rotations of all
+cameras.
+
+@note The coordinate system origin is implementation-dependent, but you can always normalize the
+rotations in respect to the first camera, for instance. :
+ */
+class CV_EXPORTS Estimator
+{
+public:
+    virtual ~Estimator() {}
+
+    /** @brief Estimates camera parameters.
+
+    @param features Features of images
+    @param pairwise_matches Pairwise matches of images
+    @param cameras Estimated camera parameters
+    @return True in case of success, false otherwise
+     */
+    bool operator ()(const std::vector<ImageFeatures> &features,
+                     const std::vector<MatchesInfo> &pairwise_matches,
+                     std::vector<CameraParams> &cameras)
+        { return estimate(features, pairwise_matches, cameras); }
+
+protected:
+    /** @brief This method must implement camera parameters estimation logic in order to make the wrapper
+    detail::Estimator::operator()_ work.
+
+    @param features Features of images
+    @param pairwise_matches Pairwise matches of images
+    @param cameras Estimated camera parameters
+    @return True in case of success, false otherwise
+     */
+    virtual bool estimate(const std::vector<ImageFeatures> &features,
+                          const std::vector<MatchesInfo> &pairwise_matches,
+                          std::vector<CameraParams> &cameras) = 0;
+};
+
+/** @brief Homography based rotation estimator.
+ */
+class CV_EXPORTS HomographyBasedEstimator : public Estimator
+{
+public:
+    HomographyBasedEstimator(bool is_focals_estimated = false)
+        : is_focals_estimated_(is_focals_estimated) {}
+
+private:
+    virtual bool estimate(const std::vector<ImageFeatures> &features,
+                          const std::vector<MatchesInfo> &pairwise_matches,
+                          std::vector<CameraParams> &cameras);
+
+    bool is_focals_estimated_;
+};
+
+/** @brief Affine transformation based estimator.
+
+This estimator uses pairwise tranformations estimated by matcher to estimate
+final transformation for each camera.
+
+@sa cv::detail::HomographyBasedEstimator
+ */
+class CV_EXPORTS AffineBasedEstimator : public Estimator
+{
+private:
+    virtual bool estimate(const std::vector<ImageFeatures> &features,
+                          const std::vector<MatchesInfo> &pairwise_matches,
+                          std::vector<CameraParams> &cameras);
+};
+
+/** @brief Base class for all camera parameters refinement methods.
+ */
+class CV_EXPORTS BundleAdjusterBase : public Estimator
+{
+public:
+    const Mat refinementMask() const { return refinement_mask_.clone(); }
+    void setRefinementMask(const Mat &mask)
+    {
+        CV_Assert(mask.type() == CV_8U && mask.size() == Size(3, 3));
+        refinement_mask_ = mask.clone();
+    }
+
+    double confThresh() const { return conf_thresh_; }
+    void setConfThresh(double conf_thresh) { conf_thresh_ = conf_thresh; }
+
+    TermCriteria termCriteria() { return term_criteria_; }
+    void setTermCriteria(const TermCriteria& term_criteria) { term_criteria_ = term_criteria; }
+
+protected:
+    /** @brief Construct a bundle adjuster base instance.
+
+    @param num_params_per_cam Number of parameters per camera
+    @param num_errs_per_measurement Number of error terms (components) per match
+     */
+    BundleAdjusterBase(int num_params_per_cam, int num_errs_per_measurement)
+        : num_params_per_cam_(num_params_per_cam),
+          num_errs_per_measurement_(num_errs_per_measurement)
+    {
+        setRefinementMask(Mat::ones(3, 3, CV_8U));
+        setConfThresh(1.);
+        setTermCriteria(TermCriteria(TermCriteria::EPS + TermCriteria::COUNT, 1000, DBL_EPSILON));
+    }
+
+    // Runs bundle adjustment
+    virtual bool estimate(const std::vector<ImageFeatures> &features,
+                          const std::vector<MatchesInfo> &pairwise_matches,
+                          std::vector<CameraParams> &cameras);
+
+    /** @brief Sets initial camera parameter to refine.
+
+    @param cameras Camera parameters
+     */
+    virtual void setUpInitialCameraParams(const std::vector<CameraParams> &cameras) = 0;
+    /** @brief Gets the refined camera parameters.
+
+    @param cameras Refined camera parameters
+     */
+    virtual void obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const = 0;
+    /** @brief Calculates error vector.
+
+    @param err Error column-vector of length total_num_matches \* num_errs_per_measurement
+     */
+    virtual void calcError(Mat &err) = 0;
+    /** @brief Calculates the cost function jacobian.
+
+    @param jac Jacobian matrix of dimensions
+    (total_num_matches \* num_errs_per_measurement) x (num_images \* num_params_per_cam)
+     */
+    virtual void calcJacobian(Mat &jac) = 0;
+
+    // 3x3 8U mask, where 0 means don't refine respective parameter, != 0 means refine
+    Mat refinement_mask_;
+
+    int num_images_;
+    int total_num_matches_;
+
+    int num_params_per_cam_;
+    int num_errs_per_measurement_;
+
+    const ImageFeatures *features_;
+    const MatchesInfo *pairwise_matches_;
+
+    // Threshold to filter out poorly matched image pairs
+    double conf_thresh_;
+
+    //Levenberg–Marquardt algorithm termination criteria
+    TermCriteria term_criteria_;
+
+    // Camera parameters matrix (CV_64F)
+    Mat cam_params_;
+
+    // Connected images pairs
+    std::vector<std::pair<int,int> > edges_;
+};
+
+
+/** @brief Stub bundle adjuster that does nothing.
+ */
+class CV_EXPORTS NoBundleAdjuster : public BundleAdjusterBase
+{
+public:
+    NoBundleAdjuster() : BundleAdjusterBase(0, 0) {}
+
+private:
+    bool estimate(const std::vector<ImageFeatures> &, const std::vector<MatchesInfo> &,
+                  std::vector<CameraParams> &)
+    {
+        return true;
+    }
+    void setUpInitialCameraParams(const std::vector<CameraParams> &) {}
+    void obtainRefinedCameraParams(std::vector<CameraParams> &) const {}
+    void calcError(Mat &) {}
+    void calcJacobian(Mat &) {}
+};
+
+
+/** @brief Implementation of the camera parameters refinement algorithm which minimizes sum of the reprojection
+error squares
+
+It can estimate focal length, aspect ratio, principal point.
+You can affect only on them via the refinement mask.
+ */
+class CV_EXPORTS BundleAdjusterReproj : public BundleAdjusterBase
+{
+public:
+    BundleAdjusterReproj() : BundleAdjusterBase(7, 2) {}
+
+private:
+    void setUpInitialCameraParams(const std::vector<CameraParams> &cameras);
+    void obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const;
+    void calcError(Mat &err);
+    void calcJacobian(Mat &jac);
+
+    Mat err1_, err2_;
+};
+
+
+/** @brief Implementation of the camera parameters refinement algorithm which minimizes sum of the distances
+between the rays passing through the camera center and a feature. :
+
+It can estimate focal length. It ignores the refinement mask for now.
+ */
+class CV_EXPORTS BundleAdjusterRay : public BundleAdjusterBase
+{
+public:
+    BundleAdjusterRay() : BundleAdjusterBase(4, 3) {}
+
+private:
+    void setUpInitialCameraParams(const std::vector<CameraParams> &cameras);
+    void obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const;
+    void calcError(Mat &err);
+    void calcJacobian(Mat &jac);
+
+    Mat err1_, err2_;
+};
+
+
+/** @brief Bundle adjuster that expects affine transformation
+represented in homogeneous coordinates in R for each camera param. Implements
+camera parameters refinement algorithm which minimizes sum of the reprojection
+error squares
+
+It estimates all transformation parameters. Refinement mask is ignored.
+
+@sa AffineBasedEstimator AffineBestOf2NearestMatcher BundleAdjusterAffinePartial
+ */
+class CV_EXPORTS BundleAdjusterAffine : public BundleAdjusterBase
+{
+public:
+    BundleAdjusterAffine() : BundleAdjusterBase(6, 2) {}
+
+private:
+    void setUpInitialCameraParams(const std::vector<CameraParams> &cameras);
+    void obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const;
+    void calcError(Mat &err);
+    void calcJacobian(Mat &jac);
+
+    Mat err1_, err2_;
+};
+
+
+/** @brief Bundle adjuster that expects affine transformation with 4 DOF
+represented in homogeneous coordinates in R for each camera param. Implements
+camera parameters refinement algorithm which minimizes sum of the reprojection
+error squares
+
+It estimates all transformation parameters. Refinement mask is ignored.
+
+@sa AffineBasedEstimator AffineBestOf2NearestMatcher BundleAdjusterAffine
+ */
+class CV_EXPORTS BundleAdjusterAffinePartial : public BundleAdjusterBase
+{
+public:
+    BundleAdjusterAffinePartial() : BundleAdjusterBase(4, 2) {}
+
+private:
+    void setUpInitialCameraParams(const std::vector<CameraParams> &cameras);
+    void obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const;
+    void calcError(Mat &err);
+    void calcJacobian(Mat &jac);
+
+    Mat err1_, err2_;
+};
+
+
+enum WaveCorrectKind
+{
+    WAVE_CORRECT_HORIZ,
+    WAVE_CORRECT_VERT
+};
+
+/** @brief Tries to make panorama more horizontal (or vertical).
+
+@param rmats Camera rotation matrices.
+@param kind Correction kind, see detail::WaveCorrectKind.
+ */
+void CV_EXPORTS waveCorrect(std::vector<Mat> &rmats, WaveCorrectKind kind);
+
+
+//////////////////////////////////////////////////////////////////////////////
+// Auxiliary functions
+
+// Returns matches graph representation in DOT language
+String CV_EXPORTS matchesGraphAsString(std::vector<String> &pathes, std::vector<MatchesInfo> &pairwise_matches,
+                                            float conf_threshold);
+
+std::vector<int> CV_EXPORTS leaveBiggestComponent(
+        std::vector<ImageFeatures> &features,
+        std::vector<MatchesInfo> &pairwise_matches,
+        float conf_threshold);
+
+void CV_EXPORTS findMaxSpanningTree(
+        int num_images, const std::vector<MatchesInfo> &pairwise_matches,
+        Graph &span_tree, std::vector<int> &centers);
+
+//! @} stitching_rotation
+
+} // namespace detail
+} // namespace cv
+
+#endif // OPENCV_STITCHING_MOTION_ESTIMATORS_HPP