| // Copyright (c) 2022, ETH Zurich and UNC Chapel Hill. | |
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| // | |
| // Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de) | |
| namespace colmap { | |
| // Scene clustering approach using normalized cuts on the scene graph. The scene | |
| // is hierarchically partitioned into overlapping clusters until a maximum | |
| // number of images is in a leaf node. | |
| class SceneClustering { | |
| public: | |
| struct Options { | |
| // Flag for hierarchical vs flat clustering | |
| bool is_hierarchical = true; | |
| // The branching factor of the hierarchical clustering. | |
| int branching = 2; | |
| // The number of overlapping images between child clusters. | |
| int image_overlap = 50; | |
| // The max related images matches to look for in a flat cluster | |
| int num_image_matches = 20; | |
| // The maximum number of images in a leaf node cluster, otherwise the | |
| // cluster is further partitioned using the given branching factor. Note | |
| // that a cluster leaf node will have at most `leaf_max_num_images + | |
| // overlap` images to satisfy the overlap constraint. | |
| int leaf_max_num_images = 500; | |
| bool Check() const; | |
| }; | |
| struct Cluster { | |
| std::vector<image_t> image_ids; | |
| std::vector<Cluster> child_clusters; | |
| }; | |
| SceneClustering(const Options& options); | |
| void Partition(const std::vector<std::pair<image_t, image_t>>& image_pairs, | |
| const std::vector<int>& num_inliers); | |
| const Cluster* GetRootCluster() const; | |
| std::vector<const Cluster*> GetLeafClusters() const; | |
| static SceneClustering Create(const Options& options, | |
| const Database& database); | |
| private: | |
| void PartitionHierarchicalCluster( | |
| const std::vector<std::pair<int, int>>& edges, | |
| const std::vector<int>& weights, Cluster* cluster); | |
| void PartitionFlatCluster(const std::vector<std::pair<int, int>>& edges, | |
| const std::vector<int>& weights); | |
| const Options options_; | |
| std::unique_ptr<Cluster> root_cluster_; | |
| }; | |
| } // namespace colmap | |