Livox LVX2 to PLY Conversion and Visualization Tools

This repository provides Python tools for converting Livox LVX2 files to PLY format and visualizing point cloud data.

Overview

The toolset consists of four main components:

1. LVX2 to PLY Converter: Converts Livox LVX2 files to sequential PLY files
2. PLY Sequence Viewer: Visualizes a sequence of PLY files with options for looping and cumulative display
3. PLY Viewer: Simple viewer for a single PLY file
4. PLY Viewer Cumulative Frame: Visualizes accumulated point clouds from a specified range of frames

Requirements

Install the required dependencies:

pip install -r requirements.txt

Dependencies:

• numpy
• open3d
• laspy
• plyfile

Usage

LVX2 to PLY Converter

Convert Livox LVX2 files to sequential PLY files:

python convert_lvx2_to_ply.py -i input.lvx2 -o ./output_ply

Options:

• -i, --in_file: Input LVX2 file (required)
• -o, --out_dir: Output directory for PLY files (default: "output_ply")
• --prefix: Prefix for output filenames (default: "frame")
• --start: Start frame index (inclusive, default: 0)
• --end: End frame index (inclusive, -1 for all frames, default: -1)
• --step: Frame step (1 = every frame, 2 = every other, etc., default: 1)

Examples:

# Convert all frames in LVX2 file to PLY files
python convert_lvx2_to_ply.py -i data.lvx2 -o ./output_ply

# Convert only frames 10-50 with custom prefix
python convert_lvx2_to_ply.py -i data.lvx2 -o ./output_ply --prefix cloud --start 10 --end 50

# Convert every 5th frame
python convert_lvx2_to_ply.py -i data.lvx2 -o ./output_ply --step 5

PLY Sequence Viewer

Visualize a sequence of PLY files with options for looping and cumulative display:

python ply_sequence_viewer.py -i ./output_ply

Options:

• -i, --input-ply-dir: Directory containing PLY files (required)
• -l, --loop: Loop playback of point cloud sequence
• -c, --cumulative: Accumulate point clouds over time

Examples:

# Basic visualization of PLY sequence
python ply_sequence_viewer.py -i ./output_ply

# Loop the sequence
python ply_sequence_viewer.py -i ./output_ply -l

# Accumulate point clouds over time
python ply_sequence_viewer.py -i ./output_ply -c

# Loop and accumulate (accumulation resets after each loop)
python ply_sequence_viewer.py -i ./output_ply -l -c

PLY Viewer

Simple viewer for a single PLY file:

python ply_viewer.py -i ./output_ply/frame_000000.ply

Options:

• -i, --input-ply: Path to the input PLY file (required)

PLY Viewer Cumulative Frame

Visualize accumulated point clouds from a specified range of frames:

python ply_viewer_cumulative_frame.py -i ./output_ply

Options:

• -i, --input-ply-dir: Directory containing PLY files (required)
• --start: Start frame number (inclusive, default: 0)
• --end: End frame number (inclusive, -1 for all frames, default: -1)
• --jet-colormap: Use jet colormap for visualization

Examples:

# Visualize all frames with grayscale intensity
python ply_viewer_cumulative_frame.py -i ./output_ply

# Visualize frames 10-50 only
python ply_viewer_cumulative_frame.py -i ./output_ply --start 10 --end 50

# Visualize all frames with jet colormap
python ply_viewer_cumulative_frame.py -i ./output_ply --jet-colormap

A screenshot of the ply_viewer_cumulative_frame.py can be shown as below. .

Key Features

• Direct conversion from LVX2 to PLY without requiring ROS
• Support for reflectivity/intensity visualization
• Multiple visualization options (single frame, sequence, cumulative)
• Jet colormap visualization for better intensity discrimination
• Frame range selection for targeted analysis

Acknowledgments

The LVX2 file parsing code was inspired by lvx2_to_rosbag (BSD-3-Clause license).

References

• Livox LVX2 file format specifications: LVX2 Specifications.pdf