3D Recon is a subsea stereo imaging system that delivers high-resolution, geospatially correct 3D models of subsea structures. Its compact subsea housing, rated for depths of up to 4000 meters, incorporates two high-resolution machine vision cameras and a very capable MEMS IMU. This integration of inertial technology with imaging sensors enables 3D Recon to create real-time sparse point clouds for navigation and quality control and generate high-density 3D model deliverables to inform engineers on how to make decisions on extending the life of subsea assets.

3D Recon Applications

3D Recon was initially developed for Integrity Management (IM) and Inspection, Repair, and Maintenance (IRM) purposes, but its versatility has led to its adaptation to various other applications, including:

• Jumper/Spool Metrology
• Mooring Chain Link Inspection
• Hull Inspection
• Pipeline Out-Of-Straightness (OSS) Surveys
• Pre-Install/As-Built Documentation
• Real-Time Relative-to-Structure Positioning

How 3D Recon Works

3D Recon leverages 3D reconstruction, advanced computer vision, and inertial navigation techniques to generate both sparse and high-density point clouds. Here's how it works:

1. Alignment: IMU data determines the sensor's orientation (heading, pitch, roll).
2. Feature Detection: Cameras capture images at 5-10Hz, and features are identified based on intensity variations.
3. Feature Matching: Descriptor vectors are computed for features and used for matching between stereo cameras and from frame to frame, creating a sparse point cloud (approximately 5-10cm pixel resolution).
4. Navigation Integration: The navigation engine integrates acceleration and angular velocity data to update navigation states (position, velocity, attitude).
5. Global Matching: Matching of features with existing ones in the map occurs.
6. Position Projection: Features are projected from the camera frame to the global frame.
7. Consistency Checks: Checks ensure alignment with the global map, utilizing RANSAC and optimization.
8. Navigation Update: Successful feature matches update the state and covariance; new features are added to the map.
9. Path Optimization: Data collection for map optimization involving keyframes triggered by specific events.
10. Dense Point Cloud Generation: High-density point clouds are generated using computed position and orientation.

3D Recon Key Features

• Linear, Angular, and Area Accuracy: Because of the tightly coupled inertial navigation solution, 3D Recon offers accurate spatial scaling within the dense delivered models. This precision ensures reliable data for measurement-based assessments.
• Change Detection: One of the key advantages of 3D Recon is its ability to automate change detection. Automated Change Detection is a powerful feature that becomes accessible through the utilization of models generated by 3D Recon. By comparing historical 3D models, operators can monitor structural changes over time for proactive IM decisions.
• Additional Sensor Integration: 3D Recon can integrate data from other sensors (Contactless CP, hydrocarbon sniffers, etc.), providing a comprehensive model or heat map for structural integrity analysis.

Deliverables of 3D Recon

The deliverables from 3D Recon include high-resolution geospatially correct 3D models with a submillimeter pixel resolution. These models are accurate and can be used for precise measurements to aid the subsea integrity community in making informed decisions on structural health over time. 3D Recon can integrate into existing workflows, providing high-resolution still images and conventional video as well as the 3D model.

Data Acquisition Requirements

We require a survey mux to integrate the 3D Recon spread. All power, serial communications, and image data are connected to the Mux/ROV through a single PBOF cable. It relies on one RS232 and one GB Ethernet port for configuration and data transmission. Power requirements are 24Vdc at 150W.

Product Specs

1. Type of Application – Marine
2. Year of Introduction – 2020
3. Length - 77.9 cm
4. Width - 59.4 cm
5. Depth - 30.0 cm
6. Weight in Air - 34Kg
7. Weight in Water - 23Kg
8. Power Requirement - 24VDC 6A / 150W
9. Serial Communications - RS232 (230400 bps)
10. Housing – Titanium
11. Rated - 4,000 m
12. Number of Cameras – 3
13. Sensor Type - Active Pixel CMOS, Global Shutter Resolution - 2028 x 2448
14. FoV Horizontal - 85°
15. FoV Vertical - 65°
16. Number of Frames Per Second - 5 - 10 fps Copper & 10 - 20 fps SM Fiber
17. Start Up Time - 0.02 s
18. Communication - 1 Gbps Ethernet Copper & 10 Gps
19. SM Fiber - Single Fiber Channel
20. Software – Included
21. Export Image Formats - Color palletized Mesh, Point Cloud *.ply (Binary)
22. Battery Type - No Battery

Contact Zupt today to learn more about 3D Recon and how it can enhance your subsea operations.