| // Copyright (c) 2022, ETH Zurich and UNC Chapel Hill. | |
| // All rights reserved. | |
| // | |
| // Redistribution and use in source and binary forms, with or without | |
| // modification, are permitted provided that the following conditions are met: | |
| // | |
| // * Redistributions of source code must retain the above copyright | |
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| // | |
| // * Redistributions in binary form must reproduce the above copyright | |
| // notice, this list of conditions and the following disclaimer in the | |
| // documentation and/or other materials provided with the distribution. | |
| // | |
| // * Neither the name of ETH Zurich and UNC Chapel Hill nor the names of | |
| // its contributors may be used to endorse or promote products derived | |
| // from this software without specific prior written permission. | |
| // | |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
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| // | |
| // Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de) | |
| namespace colmap { | |
| namespace retrieval { | |
| // An inverted file entry. The template defines the dimensionality of the binary | |
| // string used to approximate the descriptor in the Hamming space. | |
| // This class is based on an original implementation by Torsten Sattler. | |
| template <int N> | |
| struct InvertedFileEntry { | |
| void Read(std::istream* ifs); | |
| void Write(std::ostream* ofs) const; | |
| // The identifier of the image this entry is associated with. | |
| int image_id = -1; | |
| // The index of the feature within the image's keypoints list. | |
| int feature_idx = -1; | |
| // The geometry of the feature, used for spatial verification. | |
| FeatureGeometry geometry; | |
| // The binary signature in the Hamming embedding. | |
| std::bitset<N> descriptor; | |
| }; | |
| //////////////////////////////////////////////////////////////////////////////// | |
| // Implementation | |
| //////////////////////////////////////////////////////////////////////////////// | |
| template <int N> | |
| void InvertedFileEntry<N>::Read(std::istream* ifs) { | |
| static_assert(N <= 64, "Dimensionality too large"); | |
| static_assert(sizeof(unsigned long long) >= 8, | |
| "Expected unsigned long to be at least 8 byte"); | |
| static_assert(sizeof(FeatureGeometry) == 16, "Geometry type size mismatch"); | |
| int32_t image_id_data = 0; | |
| ifs->read(reinterpret_cast<char*>(&image_id_data), sizeof(int32_t)); | |
| image_id = static_cast<int>(image_id_data); | |
| int32_t feature_idx_data = 0; | |
| ifs->read(reinterpret_cast<char*>(&feature_idx_data), sizeof(int32_t)); | |
| feature_idx = static_cast<int>(feature_idx_data); | |
| ifs->read(reinterpret_cast<char*>(&geometry), sizeof(FeatureGeometry)); | |
| uint64_t descriptor_data = 0; | |
| ifs->read(reinterpret_cast<char*>(&descriptor_data), sizeof(uint64_t)); | |
| descriptor = std::bitset<N>(descriptor_data); | |
| } | |
| template <int N> | |
| void InvertedFileEntry<N>::Write(std::ostream* ofs) const { | |
| static_assert(N <= 64, "Dimensionality too large"); | |
| static_assert(sizeof(unsigned long long) >= 8, | |
| "Expected unsigned long to be at least 8 byte"); | |
| static_assert(sizeof(FeatureGeometry) == 16, "Geometry type size mismatch"); | |
| const int32_t image_id_data = image_id; | |
| ofs->write(reinterpret_cast<const char*>(&image_id_data), sizeof(int32_t)); | |
| const int32_t feature_idx_data = feature_idx; | |
| ofs->write(reinterpret_cast<const char*>(&feature_idx_data), sizeof(int32_t)); | |
| ofs->write(reinterpret_cast<const char*>(&geometry), sizeof(FeatureGeometry)); | |
| const uint64_t descriptor_data = | |
| static_cast<uint64_t>(descriptor.to_ullong()); | |
| ofs->write(reinterpret_cast<const char*>(&descriptor_data), sizeof(uint64_t)); | |
| } | |
| } // namespace retrieval | |
| } // namespace colmap | |