Waymo-Open Dataset#

The NCore Waymo tool converts data from the Waymo-Open format (.tfrecords) into NCore V4 format.

Conventions#

Waymo-Open’s data convention consists of 6 sensors:

Camera Sensors#

  1. Front Camera 50deg FOV (camera_front_50fov)

  2. Front Left Camera 50deg FOV (camera_front_left_50fov)

  3. Front Right Camera 50deg FOV (camera_front_right_50fov)

  4. Side Left Camera 50deg FOV (camera_side_left_50fov)

  5. Side Right Camera 50deg FOV (camera_side_right_50fov)

The camera intrinsics are compatible with the OpenCVPinholeCameraModelParameters model.

The Waymo camera frame convention is:

  • Principal axis along local camera’s +x axis

  • Local y-axis points left

  • Local z-axis points up

Note: The converter transforms this to NCore’s camera convention (principal axis +z, x-axis right, y-axis down).

Each camera provides panoptic segmentation data with 29 semantic classes.

LiDAR Sensors#

  1. Top Lidar (lidar_top)

LiDAR data includes point clouds with multi-return support (primary and secondary returns) and 3D bounding box labels for 5 classes: unknown, vehicle, pedestrian, sign, cyclist.

For more information, see the Waymo Open Dataset paper.

Conversion#

The converter uses NCore V4’s component-based architecture. Each sequence is parsed from .tfrecord files and written to NCore format via SequenceComponentGroupsWriter with specialized component writers for poses, intrinsics, lidar, cameras, masks, and 3D labels.

Usage#

Run the converter with Bazel from the repository root:

bazel run //tools/data_converter/waymo:convert -- \
    --root-dir <PATH_TO_TFRECORDS> \
    --output-dir <PATH_TO_OUTPUT> \
    waymo-v4

Base arguments (required):

Argument

Description

--root-dir PATH

Path to the directory containing .tfrecord sequence files

--output-dir PATH

Path where converted NCore V4 sequences will be written

Base arguments (optional):

Argument

Description

--no-cameras

Disable exporting all camera sensors

--camera-id ID

Export only the specified camera (repeatable; defaults to all cameras)

--no-lidars

Disable exporting all lidar sensors

--lidar-id ID

Export only the specified lidar (repeatable; defaults to all lidars)

--verbose

Enable debug-level logging

Subcommand arguments (waymo-v4):

Argument

Default

Description

--store-type {itar,directory}

itar

Output store format. itar produces an indexed tar archive; directory writes plain zarr directories

--profile {default,separate-sensors,separate-all}

default

Component group layout. default groups all sensors together; separate-sensors gives each sensor its own group; separate-all splits every component type into its own group

--sequence-meta / --no-sequence-meta

enabled

Whether to write a JSON metadata file alongside each converted sequence

For the complete implementation, see tools/data_converter/waymo/converter.py.

API Reference#

V4 Components (ncore.data.v4):

Data Converter (ncore.data_converter):

Sensor Models (ncore.data):