sl-perception 2a9b03dd76 feat(perception): depth-based obstacle size estimator (Issue #348)
Projects LIDAR clusters into the D435i depth image to estimate 3-D
obstacle width and height in metres.

- saltybot_scene_msgs/msg/ObstacleSize.msg      — new message
- saltybot_scene_msgs/msg/ObstacleSizeArray.msg — array wrapper
- saltybot_scene_msgs/CMakeLists.txt            — register new msgs
- saltybot_bringup/_obstacle_size.py            — pure-Python helper:
    CameraParams (intrinsics + LIDAR→camera extrinsics)
    ObstacleSizeEstimate (NamedTuple)
    lidar_to_camera()         LIDAR frame → camera frame transform
    project_to_pixel()        pinhole projection + bounds check
    sample_depth_median()     uint16 depth image window → median metres
    estimate_height()         vertical strip scan for row extent → height_m
    estimate_cluster_size()   full pipeline: cluster → size estimate
- saltybot_bringup/obstacle_size_node.py        — ROS2 node
    sub: /scan, /camera/depth/image_rect_raw, /camera/depth/camera_info
    pub: /saltybot/obstacle_sizes (ObstacleSizeArray)
    width from LIDAR bbox; height from depth strip back-projection;
    graceful fallback (LIDAR-only) when depth image unavailable;
    intrinsics latched from CameraInfo on first arrival
- test/test_obstacle_size.py                    — 33 tests, 33 passing
- setup.py                                      — add obstacle_size entry

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-03 13:32:41 -05:00
..

Jetson Nano — AI/SLAM Platform Setup

Self-balancing robot: Jetson Nano dev environment for ROS2 Humble + SLAM stack.

Stack

Component Version / Part
Platform Jetson Nano 4GB
JetPack 4.6 (L4T R32.6.1, CUDA 10.2)
ROS2 Humble Hawksbill
DDS CycloneDDS
SLAM slam_toolbox
Nav Nav2
Depth camera Intel RealSense D435i
LiDAR RPLIDAR A1M8
MCU bridge STM32F722 (USB CDC @ 921600)

Quick Start

# 1. Host setup (once, on fresh JetPack 4.6)
sudo bash scripts/setup-jetson.sh

# 2. Build Docker image
bash scripts/build-and-run.sh build

# 3. Start full stack
bash scripts/build-and-run.sh up

# 4. Open ROS2 shell
bash scripts/build-and-run.sh shell

Docs

Files

jetson/
├── Dockerfile              # L4T base + ROS2 Humble + SLAM packages
├── docker-compose.yml      # Multi-service stack (ROS2, RPLIDAR, D435i, STM32)
├── README.md               # This file
├── docs/
│   ├── pinout.md           # GPIO/I2C/UART pinout reference
│   └── power-budget.md     # Power budget analysis (10W envelope)
└── scripts/
    ├── entrypoint.sh       # Docker container entrypoint
    ├── setup-jetson.sh     # Host setup (udev, Docker, nvpmodel)
    └── build-and-run.sh    # Build/run helper

Power Budget (Summary)

Scenario Total
Idle 2.9W
Nominal (SLAM active) ~10.2W
Peak 15.4W

Target: 10W (MAXN nvpmodel). Use RPLIDAR standby + 640p D435i for compliance. See docs/power-budget.md for full analysis.