pelorus 0.0.4

Pelorus - High Efficient Lidar Inertial Odometry

Pelorus Python Bindings

Python bindings for Pelorus - a LiDAR-Inertial Odometry system.

Installation

From source (requires Rust toolchain)

cd pelorus_py
pip install maturin
maturin develop --release

Or build a wheel:

maturin build --release
pip install target/wheels/pelorus-*.whl

Usage

Basic API

import pelorus
import numpy as np

# Create Pelorus instance
lio = pelorus.Handle()  # Uses embedded default config

# Or with custom config:
# lio = pelorus.Handle("path/to/config.rl")
#
# If you want to control PointCloud2 parsing (like `pelorus_create_with_options` in C):
# - device_specific_pointcloud2=True  (default)
# - device_specific_pointcloud2=False (generic parsing path)
# lio = pelorus.Handle("path/to/config.rl", device_specific_pointcloud2=False)

# Add IMU data
lio.add_imu(
    timestamp_sec=1000,
    timestamp_nanosec=0,
    orientation=[1.0, 0.0, 0.0, 0.0],  # w, x, y, z
    orientation_covariance=[0.01] + [0.0]*8,
    angular_velocity=[0.0, 0.0, 0.0],
    angular_velocity_covariance=[0.001] + [0.0]*8,
    linear_acceleration=[0.0, 0.0, 9.81],
    linear_acceleration_covariance=[0.01] + [0.0]*8,
)

# Add point cloud (recommended):
# - If you already have ROS2 messages, pass them directly:
#   lio.add_pointcloud2_ros(cloud_msg)
#
# - For non-ROS point sources, use numpy/list inputs:
# - Nx3: [x,y,z] (no per-point timing)
# - Nx4: [x,y,z,t] where t is uint32 nanosecond offset
# - Nx5: [x,y,z,intensity,t]
# For numpy/list inputs, you must also provide the scan header timestamp:
# lio.add_pointcloud(points_np, timestamp_sec=..., timestamp_nanosec=...)

# Try to receive odometry (non-blocking)
odom = lio.try_recv()
if odom:
    print(f"Position: {odom['position']}")
    print(f"Orientation: {odom['orientation']}")
    print(f"Linear velocity: {odom['linear_velocity']}")
    print(f"Points: {len(odom['points'])}")

# Or block until odometry is available
odom = lio.recv()


# Or receive odometry asynchronously via callback (like pelorus_c)
def on_odom(odom: dict) -> None:
    print("Odom:", odom["timestamp_sec"], odom["timestamp_nanosec"], odom["position"])

lio.set_callback(on_odom)
# ... feed IMU / pointclouds ...
lio.clear_callback()  # equivalent to lio.set_callback(None)

Using with MCAP Bagfiles

See examples/bagfile_example.py for a complete example using real sensor data from an MCAP bagfile.

python -m pip install mcap mcap-ros2-support

API Reference

Handle

Main interface to the Pelorus system.

Constructor

• Handle(config_path: str | None = None, device_specific_pointcloud2: bool = True): Create a new Pelorus instance

  device_specific_pointcloud2=False selects the generic parsing path for PointCloud2 inputs.

Methods

• add_imu(...): Add an IMU measurement
• add_odom(...): Add an odometry measurement
• add_pointcloud(cloud_dict): Add a point cloud (PointCloud2 format)
• add_pointcloud(cloud_np, timestamp_sec=..., timestamp_nanosec=...): Add a point cloud from numpy
• add_pointcloud2_ros(cloud_msg): Add a ROS2 sensor_msgs/msg/PointCloud2 message directly
• try_recv(): Try to receive odometry (non-blocking), returns None if no data
• recv(): Receive odometry (blocks until available)
• set_callback(callback): Deliver odometry via callback from a background thread; disables try_recv()/recv() queuing while enabled
• clear_callback(): Disable callback delivery (equivalent to set_callback(None))
• version(): Get library version (static method)

Timestamp semantics

Pelorus uses two timestamp levels:

1. IMU/Odom timestamps (timestamp_sec + timestamp_nanosec)

   • Absolute timestamps (typically epoch / ROS time) used for synchronization.

2. LiDAR timestamps

   • Scan header timestamp: absolute (sec/nanosec)
   • Per-point t field (if provided): uint32 nanoseconds offset, non-negative and forward in time relative to the scan header time.

The effective point time is:

point_time_abs = header_time_abs + (t * 1e-9)

Odometry outputs include timestamp_sec/timestamp_nanosec (and timestamp as float for convenience).

Development

# Install development dependencies
pip install maturin pytest black ruff

# Build and test
maturin develop
pytest

# Format code
black .
ruff check .

License

Dual-licensed under MIT or Apache-2.0, consistent with the Pelorus project.