Function write_colmap_model

flowmap/export/colmap.py:174–214

(
    path: Path,
    extrinsics: Float[Tensor, "frame 4 4"],
    intrinsics: Float[Tensor, "frame 3 3"],
    image_names: list[str],
    image_shape: tuple[int, int],
)

def write_colmap_model(
    path: Path,
    extrinsics: Float[Tensor, "frame 4 4"],
    intrinsics: Float[Tensor, "frame 3 3"],
    image_names: list[str],
    image_shape: tuple[int, int],
) -> None:
    h, w = image_shape

    # Define the cameras (intrinsics).
    cameras = {}
    for index, k in enumerate(intrinsics):
        id = index + 1

        # Undo the normalization we apply to the intrinsics.
        k = k.detach().clone()
        k[0] *= w
        k[1] *= h

        # Extract the intrinsics' parameters.
        fx = k[0, 0]
        fy = k[1, 1]
        cx = k[0, 2]
        cy = k[1, 2]

        cameras[id] = Camera(id, "PINHOLE", w, h, (fx, fy, cx, cy))

    # Define the images (extrinsics and names).
    images = {}
    for index, (c2w, name) in enumerate(zip(extrinsics, image_names)):
        id = index + 1

        # Convert the extrinsics to COLMAP's format.
        w2c = c2w.inverse().detach().cpu().numpy()
        qx, qy, qz, qw = R.from_matrix(w2c[:3, :3]).as_quat()
        qvec = np.array((qw, qx, qy, qz))
        tvec = w2c[:3, 3]
        images[id] = Image(id, qvec, tvec, id, name, [], [])

    path.mkdir(exist_ok=True, parents=True)
    write_model(cameras, images, None, path)