Function BitmapToInputTensor

src/colmap/feature/aliked.cc:56–77

Convert bitmap to row-major [C, H, W] float tensor, normalized to [0, 1].

// Convert bitmap to row-major [C, H, W] float tensor, normalized to [0, 1].
std::vector<float> BitmapToInputTensor(const Bitmap& bitmap) {
  THROW_CHECK(bitmap.IsRGB());

  const int width = bitmap.Width();
  const int height = bitmap.Height();
  const int pitch = bitmap.Pitch();
  const int num_pixels = width * height;

  std::vector<float> input(num_pixels * 3);
  const std::vector<uint8_t>& data = bitmap.RowMajorData();
  for (int y = 0; y < height; ++y) {
    for (int x = 0; x < width; ++x) {
      for (int c = 0; c < 3; ++c) {
        constexpr float kImageNormalization = 1.0f / 255.0f;
        input[c * num_pixels + y * width + x] =
            kImageNormalization * data[y * pitch + 3 * x + c];
      }
    }
  }

  return input;
}

// Pads image dimensions to be divisible by a given factor.
struct InputPadder {