A Hierarchical Stabilization Control Method for a Three-Axis Gimbal Based on Sea-Sky-Line Detection

Area of Science:

• Robotics and Control Systems
• Image Processing and Computer Vision
• Marine Engineering

Background:

• Surface vehicles operating in heavy sea environments face significant challenges in obtaining stable video sequences due to severe motion disturbances.
• Existing image stabilization methods often struggle to cope with the extreme conditions encountered at sea, necessitating advanced solutions.

Purpose of the Study:

• To propose and evaluate a novel hierarchical image stabilization method for cameras mounted on surface vehicles.
• To enhance video stability in challenging marine environments by combining mechanical and electronic stabilization techniques.
• To leverage real-time sea-sky-line detection for effective motion compensation.

Main Methods:

• A hierarchical image stabilization approach integrating mechanical and electronic methods.
• Mechanical stabilization using a three-degrees-of-freedom (DOFs) gimbal with a robust controller for primary motion compensation.
• Electronic stabilization employing the Canny algorithm and Hough transform for real-time sea-sky-line detection, motion estimation, and compensation, coupled with an image-clipping strategy for efficiency.

Main Results:

• The proposed hierarchical method achieved significant vibration reduction.
• Mechanical stabilization reduced vibration by 74.2%.
• Electronic stabilization reduced vibration by 42.1%.

Conclusions:

• The developed hierarchical stabilization method effectively addresses the challenge of video instability in heavy sea environments.
• The combination of mechanical and electronic stabilization, particularly with real-time sea-sky-line detection, offers a robust solution for marine camera systems.
• The implemented image-clipping strategy enhances real-time performance and reduces equipment demands.