Method Create

src/colmap/feature/sift.cc:565–672

  }

  static std::unique_ptr<FeatureExtractor> Create(
      const FeatureExtractionOptions& options) {
    // SiftGPU uses many global static state variables and the initialization
    // must be thread-safe in order to work correctly. This is enforced here.
    static std::mutex mutex;
    std::lock_guard<std::mutex> lock(mutex);

    std::vector<int> gpu_indices = CSVToVector<int>(options.gpu_index);
    THROW_CHECK_EQ(gpu_indices.size(), 1) << "SiftGPU can only run on one GPU";

    std::vector<std::string> sift_gpu_args;

    sift_gpu_args.push_back("./sift_gpu");

#if defined(COLMAP_CUDA_ENABLED)
    // Use CUDA version by default if darkness adaptivity is disabled.
    if (!options.sift->darkness_adaptivity && gpu_indices[0] < 0) {
      gpu_indices[0] = 0;
    }

    if (gpu_indices[0] >= 0) {
      sift_gpu_args.push_back("-cuda");
      sift_gpu_args.push_back(std::to_string(gpu_indices[0]));
    }
#endif  // COLMAP_CUDA_ENABLED

    // Darkness adaptivity (hidden feature). Significantly improves
    // distribution of features. Only available in GLSL version.
    if (options.sift->darkness_adaptivity) {
      if (gpu_indices[0] >= 0) {
        WarnDarknessAdaptivityNotAvailable();
      }
      sift_gpu_args.push_back("-da");
    }

    // No verbose logging.
    sift_gpu_args.push_back("-v");
    sift_gpu_args.push_back("0");

    // Set maximum image dimension.
    // Note the max dimension of SiftGPU is the maximum dimension of the
    // first octave in the pyramid (which is the 'first_octave').
    const int compensation_factor = 1
                                    << -std::min(0, options.sift->first_octave);
    sift_gpu_args.push_back("-maxd");
    sift_gpu_args.push_back(
        std::to_string(options.EffMaxImageSize() * compensation_factor));

    // Keep the highest level features.
    sift_gpu_args.push_back("-tc2");
    sift_gpu_args.push_back(std::to_string(options.sift->max_num_features));

    // First octave level.
    sift_gpu_args.push_back("-fo");
    sift_gpu_args.push_back(std::to_string(options.sift->first_octave));

    // Number of octave levels.
    sift_gpu_args.push_back("-d");