Merge pull request #22329 from chinery:stitching-py-fixes

Fix stitching Python bindings (and one stitching_detailed.cpp bug)

modules/stitching/include/opencv2/stitching/detail/matchers.hpp

@@ -138,7 +138,7 @@ public:
     @sa detail::MatchesInfo
     */
     CV_WRAP_AS(apply2) void operator ()(const std::vector<ImageFeatures> &features, CV_OUT std::vector<MatchesInfo> &pairwise_matches,
-                     const cv::UMat &mask = cv::UMat());
+                                        const cv::UMat &mask = cv::UMat()) { match(features, pairwise_matches, mask); };
 
     /** @return True, if it's possible to use the same matcher instance in parallel, false otherwise
     */
@@ -161,6 +161,16 @@ protected:
     virtual void match(const ImageFeatures &features1, const ImageFeatures &features2,
                        MatchesInfo& matches_info) = 0;
 
+    /** @brief This method implements logic to match features between arbitrary number of features.
+    By default this checks every pair of inputs in the input, but the behaviour can be changed by subclasses.
+
+    @param features vector of image features
+    @param pairwise_matches found matches
+    @param mask (optional) mask indicating which image pairs should be matched
+     */
+    virtual void match(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
+                       const cv::UMat &mask = cv::UMat());
+
     bool is_thread_safe_;
 };
 
@@ -205,11 +215,12 @@ public:
     CV_WRAP BestOf2NearestRangeMatcher(int range_width = 5, bool try_use_gpu = false, float match_conf = 0.3f,
                             int num_matches_thresh1 = 6, int num_matches_thresh2 = 6);
 
-    void operator ()(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
-                     const cv::UMat &mask = cv::UMat());
-
-
 protected:
+    // indicate that we do not want to hide the base class match method with a different signature
+    using BestOf2NearestMatcher::match;
+    void match(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
+               const cv::UMat &mask = cv::UMat()) CV_OVERRIDE;
+
     int range_width_;
 };
 

modules/stitching/include/opencv2/stitching/detail/seam_finders.hpp

@@ -248,7 +248,7 @@ public:
     ~GraphCutSeamFinder();
 
     CV_WRAP void find(const std::vector<UMat> &src, const std::vector<Point> &corners,
-              std::vector<UMat> &masks) CV_OVERRIDE;
+                      CV_IN_OUT std::vector<UMat> &masks) CV_OVERRIDE;
 
 private:
     // To avoid GCGraph dependency

modules/stitching/misc/python/test/test_stitching.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 import cv2 as cv
+import numpy as np
 
 from tests_common import NewOpenCVTests
 
@@ -134,6 +135,47 @@ class stitching_matches_info_test(NewOpenCVTests):
         self.assertIsNotNone(matches_info.matches)
         self.assertIsNotNone(matches_info.inliers_mask)
 
+class stitching_range_matcher_test(NewOpenCVTests):
+
+    def test_simple(self):
+        images = [
+            self.get_sample('stitching/a1.png'),
+            self.get_sample('stitching/a2.png'),
+            self.get_sample('stitching/a3.png')
+        ]
+
+        orb = cv.ORB_create()
+
+        features = [cv.detail.computeImageFeatures2(orb, img) for img in images]
+
+        matcher = cv.detail_BestOf2NearestRangeMatcher(range_width=1)
+        matches = matcher.apply2(features)
+
+        # matches[1] is image 0 and image 1, should have non-zero confidence
+        self.assertNotEqual(matches[1].confidence, 0)
+
+        # matches[2] is image 0 and image 2, should have zero confidence due to range_width=1
+        self.assertEqual(matches[2].confidence, 0)
+
+
+class stitching_seam_finder_graph_cuts(NewOpenCVTests):
+
+    def test_simple(self):
+        images = [
+            self.get_sample('stitching/a1.png'),
+            self.get_sample('stitching/a2.png'),
+            self.get_sample('stitching/a3.png')
+        ]
+
+        images = [cv.resize(img, [100, 100]) for img in images]
+
+        finder = cv.detail_GraphCutSeamFinder('COST_COLOR_GRAD')
+        masks = [cv.UMat(255 * np.ones((img.shape[0], img.shape[1]), np.uint8)) for img in images]
+        images_f = [img.astype(np.float32) for img in images]
+        masks_warped = finder.find(images_f, [(0, 0), (75, 0), (150, 0)], masks)
+
+        self.assertIsNotNone(masks_warped)
+
 
 if __name__ == '__main__':
     NewOpenCVTests.bootstrap()

modules/stitching/src/matchers.cpp

@@ -335,8 +335,8 @@ MatchesInfo& MatchesInfo::operator =(const MatchesInfo &other)
 
 //////////////////////////////////////////////////////////////////////////////
 
-void FeaturesMatcher::operator ()(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
+void FeaturesMatcher::match(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
-                                  const UMat &mask)
+                            const UMat &mask)
 {
     const int num_images = static_cast<int>(features.size());
 
@@ -486,8 +486,8 @@ BestOf2NearestRangeMatcher::BestOf2NearestRangeMatcher(int range_width, bool try
 }
 
 
-void BestOf2NearestRangeMatcher::operator ()(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
+void BestOf2NearestRangeMatcher::match(const std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
-                                  const UMat &mask)
+                                       const UMat &mask)
 {
     const int num_images = static_cast<int>(features.size());
 

modules/stitching/test/test_matchers.cpp

@@ -114,4 +114,30 @@ TEST(ParallelFeaturesFinder, IsSameWithSerial)
     }
 }
 
+TEST(RangeMatcher, MatchesRangeOnly)
+{
+    Ptr<Feature2D> finder = ORB::create();
+
+    Mat img0 = imread(string(cvtest::TS::ptr()->get_data_path()) + "stitching/a1.png", IMREAD_GRAYSCALE);
+    Mat img1 = imread(string(cvtest::TS::ptr()->get_data_path()) + "stitching/a2.png", IMREAD_GRAYSCALE);
+    Mat img2 = imread(string(cvtest::TS::ptr()->get_data_path()) + "stitching/a3.png", IMREAD_GRAYSCALE);
+
+    vector<detail::ImageFeatures> features(3);
+
+    computeImageFeatures(finder, img0, features[0]);
+    computeImageFeatures(finder, img1, features[1]);
+    computeImageFeatures(finder, img2, features[2]);
+
+    vector<detail::MatchesInfo> pairwise_matches;
+    Ptr<detail::FeaturesMatcher> matcher = makePtr<detail::BestOf2NearestRangeMatcher>(1);
+
+    (*matcher)(features, pairwise_matches);
+
+    // matches[1] will be image 0 and image 1, should have non-zero confidence
+    EXPECT_NE(pairwise_matches[1].confidence, .0);
+
+    // matches[2] will be image 0 and image 2, should have zero confidence due to range_width=1
+    EXPECT_DOUBLE_EQ(pairwise_matches[2].confidence, .0);
+}
+
 }} // namespace