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NeptuNet Logo

NeptuNet

A Lightweight Vision-Based Perception Framework for Underwater Gas Pipeline Inspection

Embedded AI • Underwater Computer Vision • Resource-Aware Perception • Explainable Leak Monitoring

Python YOLOv8 ONNX INT8 NPU XAI License


Pipeline Perception  ·  ★ Bubble Monitoring  ·  ★ Leak Confirmation  ·  ★ Research PosterFramework SimulationC++ Runtime Skeleton


NeptuNet Research Poster

A research-oriented embedded perception framework for underwater gas pipeline inspection.


Overview

NeptuNet is a lightweight hierarchical vision-based perception framework for underwater gas pipeline inspection.

The framework connects three complementary perception levels:

Level Module Role Main Outputs
Level 1 Pipeline Geometric Perception Continuous infrastructure awareness Pipeline center, orientation, direction
Level 2 Bubble-Based Early Warning Lightweight temporal leak suspicion Suspicion score, temporal bubble descriptors, SHAP explanations
Level 3 Leak Confirmation Conditional gas plume analysis Plume mask, probable source, propagation direction

NeptuNet is designed around a resource-aware perception philosophy: instead of running all inspection models continuously, perception is organized according to inspection context. Pipeline perception remains continuously active, bubble analysis provides lightweight early warning, and leak confirmation is activated when suspicious activity is detected.

This repository serves as the central project hub for NeptuNet. Detailed source code, datasets, models, demos, and experiments are maintained inside the corresponding module repositories.


Research Motivation

Conventional subsea pipeline inspection remains costly, intermittent, and difficult to scale over long distances. Underwater visual perception is also affected by turbidity, scattering, illumination variation, low contrast, biofouling, and domain shifts between controlled and real underwater environments.

These constraints motivate embedded perception systems that can extract inspection-relevant information directly from underwater imagery while remaining lightweight enough for deployment-oriented robotic platforms.

NeptuNet addresses this challenge by combining:

  • segmentation-based pipeline geometry,
  • physics-inspired bubble plume monitoring,
  • explainable machine learning,
  • physics-guided gas plume representation,
  • lightweight instance segmentation,
  • ONNX and INT8 deployment workflows,
  • and CPU/NPU-aware perception organization.

The project positions underwater inspection as an embedded perception problem, not as a complete closed-loop AUV autonomy system.


Framework Architecture

NeptuNet Hierarchical Perception Architecture

NeptuNet follows a context-suspicion-confirmation structure:

Continuous Pipeline Monitoring
        ↓
Bubble-Based Suspicion
        ↓
Conditional Leak Confirmation

Each level answers a different inspection question:

Question NeptuNet Level
Where is the pipeline and how is it oriented? Level 1
Is there suspicious bubble activity near the inspection context? Level 2
Is there a visible gas plume and where is its probable source? Level 3

Level 1 — Pipeline Geometric Perception

Level 1 provides continuous pipeline-centered perception from monocular underwater imagery.

It estimates:

  • pipeline segmentation mask,
  • image-plane center offset,
  • dominant pipeline orientation,
  • directional alignment cue: LEFT, STRAIGHT, or RIGHT.

This module uses lightweight instance segmentation and PCA-based geometric extraction to transform segmentation masks into navigation-relevant geometric cues.

Pipeline Geometric Perception Demo

Core Methods

  • YOLOv8n-seg instance segmentation
  • ONNX deployment-oriented inference
  • prototype-mask reconstruction
  • bounding-box-guided mask cropping
  • PCA-based center and orientation estimation
  • INT8 NPU benchmarking

Repository

Underwater-Pipeline-Geometric-Perception

Datasets, model details, evaluation scripts, inference demos, and benchmark tables are provided inside the module repository.


Level 2 — Bubble-Based Early Warning

Level 2 analyzes temporal bubble plume behavior to identify leak-suspicious activity.

Instead of relying only on frame-level detection, this module encodes short-term bubble dynamics into physics-inspired descriptors. These descriptors capture density, temporal stability, vertical structure, and short-term persistence. A tree-based classifier then produces interpretable leak-suspicion predictions.

TUBLEX Bubble Monitoring Demo

Core Methods

  • adaptive underwater preprocessing
  • bubble candidate detection
  • spatial filtering
  • temporal windowing
  • physics-inspired feature extraction
  • Random Forest and XGBoost comparison
  • SHAP-based explainability

Main Outputs

  • bubble activity descriptor vector,
  • leak-suspicion score,
  • interpretable feature attributions,
  • lightweight early-warning signal.

Repository

TUBLEX-Bubble-Plume-Analysis

Datasets, windowing scripts, feature extraction code, trained classifiers, SHAP analysis, and evaluation details are provided inside the module repository.


Level 3 — Leak Confirmation

Level 3 performs conditional gas plume segmentation and geometric leak characterization.

This module uses Physics-Guided Diffuse-Texture Separation (PDTS) to enhance diffuse plume structures while suppressing high-frequency underwater background texture. The resulting representation is processed using a lightweight segmentation model, and the predicted mask is converted into geometric leak descriptors.

PDTS Leak Confirmation Demo

Core Methods

  • Physics-Guided Diffuse-Texture Separation
  • YOLOv8n-seg plume segmentation
  • ONNX deployment-oriented mask reconstruction
  • INT8 quantization
  • plume centroid estimation
  • probable image-plane source localization
  • plume direction estimation

Main Outputs

  • gas plume segmentation mask,
  • plume centroid,
  • probable leak source location,
  • dominant plume propagation direction.

Repository

Underwater-Leak-Geometric-Perception

Datasets, PDTS implementation, segmentation training, deployment evaluation, geometry extraction, and result analysis are provided inside the module repository.


Resource-Aware Operation

NeptuNet Resource-Aware Logic

NeptuNet is designed around conditional computational activation.

Normal Inspection
    ↓
Level 1 remains active for pipeline context
    ↓
Bubble activity is observed
    ↓
Level 2 evaluates temporal bubble behavior
    ↓
Suspicion score exceeds threshold
    ↓
Level 3 performs gas plume confirmation

This strategy avoids treating underwater inspection as a single monolithic detection problem. Instead, each level contributes a different type of information:

Level Information Type Computational Role
Level 1 Infrastructure geometry Continuous NPU-oriented perception
Level 2 Temporal bubble suspicion Lightweight CPU-oriented monitoring
Level 3 Spatial leak confirmation Conditional NPU-oriented segmentation

Framework Simulation Demo

NeptuNet includes a lightweight framework-level simulation demo that illustrates how the three perception levels interact during underwater inspection.

The demo uses predefined inspection scenarios to simulate module-level outputs and show how NeptuNet coordinates:

  • Level 1 — continuous pipeline geometric perception,
  • Level 2 — bubble-based early-warning analysis,
  • Level 3 — conditional leak confirmation.

This simulation is intentionally limited to perception-level coordination and does not claim full underwater robotic autonomy, closed-loop AUV control, underwater SLAM, or real-time onboard deployment.

Simulation Workflow

Scenario JSON files
        ↓
NeptuNet orchestrator
        ↓
Perception-level state decisions
        ↓
Notebook tables, timelines, and CSV outputs

The orchestrator follows the NeptuNet resource-aware logic:

Level 1 is always active
        ↓
If the pipeline is detected, Level 2 monitors bubble activity
        ↓
If bubble suspicion exceeds the threshold, Level 3 is activated
        ↓
The system reports normal monitoring, pipeline search, unconfirmed suspicion, or confirmed leak

Included Scenarios

Each scenario contains 10 inspection windows, representing approximately 10 seconds of inspection.

Scenario Purpose File
Normal inspection Pipeline visible, bubble monitoring active, no leak suspicion scenarios/scenario_01_normal_inspection.json
False anomaly return Suspicious bubbles activate leak confirmation, but no plume is confirmed scenarios/scenario_02_false_anomaly_return.json
Pipeline reacquisition Pipeline is initially not visible, then detected and monitoring resumes scenarios/scenario_03_pipeline_reacquisition.json
Confirmed leak event Bubble suspicion triggers leak confirmation and a plume is confirmed scenarios/scenario_04_confirmed_leak.json

Module Activation Timelines

The following plots summarize the activation behavior of the three NeptuNet levels across the four scenarios.

Scenario 1 Module Activation Timeline

Run the Simulation

Clone the repository and open the notebook:

git clone https://github.com/7amzaGH/NeptuNet-AUV-Intelligent-System.git
cd NeptuNet-AUV-Intelligent-System
jupyter notebook notebooks/01_neptunet_framework_simulation.ipynb

Or run one scenario directly from the command line:

python integration/neptunet_orchestrator.py \
  --scenario scenarios/scenario_04_confirmed_leak.json \
  --output outputs/scenario_04_confirmed_leak.json

The notebook generates structured CSV outputs in the outputs/ directory for documentation and further analysis.

Simulation Artifacts

Artifact Location
Orchestrator script integration/neptunet_orchestrator.py
Scenario JSON files scenarios/
Notebook demo notebooks/01_neptunet_framework_simulation.ipynb
CSV simulation outputs outputs/
Module activation screenshots assets/simulation/

Open the full simulation notebook: NeptuNet Framework Simulation Demo

This demo connects the independent NeptuNet modules at the framework level while keeping each module repository responsible for its own models, datasets, experiments, and evaluation.


C++ Embedded Runtime Skeleton

NeptuNet also includes a lightweight C++ embedded runtime skeleton that demonstrates how the framework-level coordination logic can be expressed in a deployment-oriented structure.

This component reproduces the same perception-level state machine used in the Python simulation:

CSV scenario input
        ↓
C++ NeptuNet state machine
        ↓
Level 1 / Level 2 / Level 3 activation logic
        ↓
Perception-level system state output

The C++ runtime does not perform neural network inference, underwater robot control, SLAM, underwater physics simulation, or full onboard AUV deployment. It is provided only as a clean embedded-style prototype for the NeptuNet coordination logic.

Included C++ Scenarios

Each CSV scenario contains 10 inspection windows, representing approximately 10 seconds of perception-level inspection behavior.

Scenario Purpose File
Normal inspection Pipeline visible, bubble monitoring active, no leak suspicion cpp_runtime/examples/scenario_01_normal_inspection.csv
False anomaly return Suspicious bubbles activate Level 3, but no plume is confirmed cpp_runtime/examples/scenario_02_false_anomaly_return.csv
Pipeline reacquisition Pipeline is initially not visible, then detected and monitoring resumes cpp_runtime/examples/scenario_03_pipeline_reacquisition.csv
Confirmed leak event Bubble suspicion activates Level 3 and a plume is confirmed cpp_runtime/examples/scenario_04_confirmed_leak.csv

Build and Run

cd cpp_runtime
mkdir build
cd build
cmake ..
cmake --build .

Run a scenario on Linux or Makefile-based builds as:

./neptunet_runtime ../examples/scenario_04_confirmed_leak.csv

Run with a custom suspicion threshold:

./neptunet_runtime ../examples/scenario_04_confirmed_leak.csv 0.75

C++ Runtime Files

Artifact Location
C++ runtime documentation cpp_runtime/README.md
CMake build file cpp_runtime/CMakeLists.txt
State-machine header cpp_runtime/include/neptunet_state_machine.hpp
State-machine implementation cpp_runtime/src/neptunet_state_machine.cpp
Runtime entry point cpp_runtime/src/main.cpp
Example CSV scenarios cpp_runtime/examples/

This C++ runtime skeleton complements the Python notebook demo by showing how NeptuNet’s perception coordination logic can be represented in a lightweight embedded-friendly form.


Key Contributions

1. NeptuNet Framework

A hierarchical embedded perception architecture for underwater gas pipeline inspection, combining infrastructure context, temporal anomaly suspicion, and spatial leak confirmation.

2. Pipeline Geometric Perception

A lightweight segmentation-based perception module that estimates image-plane pipeline center, orientation, and direction using YOLOv8n-seg and PCA-based geometry extraction.

3. Bubble-Based Early Warning

A physics-inspired temporal bubble monitoring module that uses structured descriptors, tree-based machine learning, and SHAP explainability to identify leak-suspicious bubble behavior.

4. Physics-Guided Leak Confirmation

A gas plume segmentation and localization module based on Physics-Guided Diffuse-Texture Separation and lightweight instance segmentation.

5. Embedded AI Deployment

A deployment-oriented evaluation workflow using ONNX export, INT8 quantization, post-processing analysis, and Qualcomm RB3 Gen 2 NPU benchmarking.

6. Open Research Resources

A connected research ecosystem including module repositories, public datasets, reproducible experiments, research papers, thesis material, and visual project documentation.


Results Summary

Pipeline Geometric Perception

Metric Result
Best mask mAP@0.5:0.95 0.946
Best center error 1.71 px
Best orientation error 0.54°
INT8 NPU latency 8.8 ms
Embedded throughput 113.6 FPS

Bubble-Based Early Warning

Metric Result
Main classifier Random Forest
F1-score 0.9888
ROC-AUC 0.9991
Runtime on embedded CPU 140 ms
Explainability method SHAP

Leak Confirmation

Metric Result
Main representation PDTS
Segmentation model YOLOv8n-seg
Mask mAP@0.5 on real ROV evaluation 0.993
INT8 NPU latency 10.7 ms
Embedded throughput 93.5 FPS

Embedded AI and Deployment

NeptuNet follows a deployment-oriented embedded AI workflow.

Model Training
    ↓
ONNX Export
    ↓
Deployment-Side Post-Processing
    ↓
INT8 Quantization
    ↓
NPU Benchmarking
    ↓
Framework-Level Integration Analysis

The framework separates tasks according to their computational profile:

Component Preferred Runtime Reason
Pipeline perception NPU Continuous segmentation and geometry extraction
Bubble monitoring CPU Lightweight structured features and tree-based inference
Leak confirmation NPU Conditional plume segmentation and geometry extraction

This CPU/NPU-aware organization is central to the NeptuNet design philosophy.


Datasets and Reproducibility

NeptuNet produced and organized multiple datasets for underwater pipeline perception, bubble plume monitoring, and gas plume leak analysis.

To keep this framework repository clean, datasets are documented and linked inside the corresponding module repositories:

Dataset Category Location
Pipeline training and external evaluation datasets Pipeline Perception Repository
Bubble plume temporal window datasets TUBLEX Bubble Monitoring Repository
Gas plume training and real evaluation datasets PDTS Leak Confirmation Repository

This organization avoids duplication and keeps each dataset connected to its code, experiments, and evaluation protocol.


Thesis and Research Outputs

NeptuNet was developed as a Master's thesis project and expanded into multiple research outputs.

Work Focus
Master Thesis Complete NeptuNet framework and system-level analysis
Pipeline Paper Lightweight underwater pipeline geometric perception
Bubble Paper Explainable physics-inspired bubble plume analysis
Leak Paper Embedded underwater gas leak segmentation using PDTS
NeptuNet Technical Supplement Framework-level technical magazine supplement

The thesis PDF is provided as a direct research reference:

NeptuNet Master Thesis

Publication links and paper-specific citation entries are maintained inside the related module repositories when public release is permitted.


Innovative Project Label

Innovative Project Label Badge      Ministerial Committee Logo

NeptuNet was awarded the Innovative Project Label in Algeria, recognizing its innovation potential in underwater AI, embedded perception, and intelligent inspection technologies.

This recognition was granted through the national innovation and startup support framework under the Ministry of Knowledge Economy, Startups and Micro-enterprises.

View Official Document

The label supports the project identity beyond the Master's thesis by positioning NeptuNet as both a research-oriented embedded perception framework and a potential applied technology direction for underwater infrastructure inspection.


Repository Structure

NeptuNet-AUV-Intelligent-System/
│
├── README.md
├── LICENSE
│
├── assets/<- Figures and media for this README
│
├── integration/
│   ├── neptunet_orchestrator.py
│   └── README.md
│
├── scenarios/
│   ├── scenario_01_normal_inspection.json
│   ├── scenario_02_false_anomaly_return.json
│   ├── scenario_03_pipeline_reacquisition.json
│   └── scenario_04_confirmed_leak.json
│
├── cpp_runtime/
│   ├── README.md
│   ├── CMakeLists.txt
│   ├── include/
│   │   └── neptunet_state_machine.hpp
│   ├── src/
│   │   ├── neptunet_state_machine.cpp
│   │   └── main.cpp
│   └── examples/ <- Scenarios csv files
│
├── notebooks/
│   └── neptunet_framework_simulation.ipynb
│
├── outputs/
│   ├── scenario_01_normal_inspection.csv
│   ├── scenario_02_false_anomaly_return.csv
│   ├── scenario_03_pipeline_reacquisition.csv
│   └── scenario_04_confirmed_leak.csv
│
├── poster/
│   ├── neptunet_poster.pdf
│   └── neptunet_poster.png
│   
└── docs/
    ├── NeptuNet_Master_Thesis.pdf
    ├── neptunet_innovative_project_label.pdf
    ├── neptunet_technical_magazinesupplement.pdf
    └── limitations.md

This repository intentionally remains lightweight. Detailed code, datasets, models, demos, and experiments are maintained inside the corresponding module repositories.


Research Scope

NeptuNet focuses on perception-side underwater inspection.

Validated Scope

  • underwater visual perception,
  • segmentation-based pipeline geometry extraction,
  • bubble temporal feature analysis,
  • explainable machine learning for leak suspicion,
  • gas plume segmentation,
  • image-plane source and direction estimation,
  • ONNX deployment workflow,
  • INT8 quantization,
  • NPU benchmarking,
  • cross-domain visual evaluation.
  • framework-level perception coordination simulation.
  • C++ embedded-style state-machine prototype for perception-level coordination.

Outside the Current Validated Scope

  • closed-loop AUV control,
  • underwater SLAM,
  • acoustic localization,
  • full mission autonomy,
  • hydrodynamic vehicle modeling,
  • long-duration offshore deployment,
  • complete onboard robotic system integration.

This distinction is intentional. NeptuNet is a perception framework and research foundation for future underwater robotic inspection systems.


Citation

If you use the NeptuNet framework, please cite the project and the corresponding module papers.

@software{ghitri2026neptunet, 
  title = {NeptuNet: A Lightweight Vision-Based Perception Framework for Underwater Gas Pipeline Inspection}, 
  author = {Ghitri, Hamza}, 
  year = {2026}, 
  url = {https://github.com/7amzaGH/NeptuNet-AUV-Intelligent-System}, 
  note = {Research-oriented embedded perception framework for underwater gas pipeline inspection} 
}

he original academic thesis that introduced the NeptuNet framework can be cited as:

@mastersthesis{ghitri2025neptunet_thesis, 
  title = {NeptuNet: A Lightweight Vision-Based Perception System for Underwater Gas Pipeline Inspection}, 
  author = {Ghitri, Hamza}, 
  school = {University of Ain Temouchent Belhadj Bouchaib}, 
  year = {2025}, 
  type = {Master's Thesis} 
}

For module-specific methods, datasets, or experiments, please cite the corresponding pipeline, bubble-monitoring, and leak-confirmation papers when they are available.


Acknowledgments

NeptuNet was developed as part of a Master's thesis in Cybersecurity and Artificial Intelligence at the University of Ain Temouchent Belhadj Bouchaib, where the thesis was awarded the full mark of 20/20.

The thesis was supervised by:

  • Dr. BELGRANA Fatima Zohra
  • Dr. BEMMOUSSAT Chemseddine

NeptuNet was also awarded the Innovative Startup Project Label under Ministerial Decision 1275 in Algeria.

  • EL HADJ MIMOUNE Mourad was part of the startup project team.

The project also benefited from research experience at the Silesian University of Technology and from open-source tools and datasets used for underwater computer vision, embedded AI, and explainable machine learning.


License

The source code in this repository is released under the MIT License.

Project documents, thesis material, posters, official recognition documents, logos, datasets, and third-party resources are not automatically covered by the MIT software license. Their reuse may require proper citation, permission, or respect of the license stated in the corresponding source.

See LICENSE for details.


NeptuNet : Lightweight embedded perception Framework for Underwater Gas Pipeline Inspection