Merge pull request #23388 from simonlynen:patch-2

asmorkalov · web-flow · commit 1af790ecc352 · 2023-03-23T16:18:29.000+03:00
Make LineSegmentDetector deterministic by using stable_sort
diff --git a/modules/imgproc/src/lsd.cpp b/modules/imgproc/src/lsd.cpp
@@ -592,8 +592,8 @@ void LineSegmentDetectorImpl::ll_angle(const double& threshold,
         }
     }
 
-    // Sort
-    std::sort(ordered_points.begin(), ordered_points.end(), compare_norm);
+    // Use stable sort to ensure deterministic region growing and thus overall LSD result determinism.
+    std::stable_sort(ordered_points.begin(), ordered_points.end(), compare_norm);
 }
 
 void LineSegmentDetectorImpl::region_grow(const Point2i& s, std::vector<RegionPoint>& reg,

Original file line number	Diff line number	Diff line change
`@@ -592,8 +592,8 @@ void LineSegmentDetectorImpl::ll_angle(const double& threshold,`
`592`	`592`	`}`
`593`	`593`	`}`
`594`	`594`
`595`		`- // Sort`
`596`		`- std::sort(ordered_points.begin(), ordered_points.end(), compare_norm);`
	`595`	`+ // Use stable sort to ensure deterministic region growing and thus overall LSD result determinism.`
	`596`	`+ std::stable_sort(ordered_points.begin(), ordered_points.end(), compare_norm);`
`597`	`597`	`}`
`598`	`598`
`599`	`599`	`void LineSegmentDetectorImpl::region_grow(const Point2i& s, std::vector<RegionPoint>& reg,`