Experimental Study on Bottom-Up Detection of Underwater Targets Based on Polarization Imaging

Area of Science:

• Optics and Photonics
• Marine Technology

Background:

• Existing underwater polarization imaging primarily focuses on top-down detection.
• The effectiveness of bottom-up detection for underwater targets remains largely unexplored.

Purpose of the Study:

• To investigate the capability of bottom-up polarization imaging for detecting underwater targets.
• To evaluate the performance of an Underwater Polarization Imaging System (UPIS) for bottom-up detection.

Main Methods:

• Integrated a SALSA polarization camera and an attitude sensor into the UPIS.
• Conducted in situ experiments in Qiandao Lake with relatively clear water.
• Analyzed imaging performance using entropy, clarity, and contrast with varying radiation parameters.

Main Results:

• The angle of polarization was identified as the optimal parameter for bottom-up underwater target detection.
• This optimization is likely due to variations in the diffused reflectance of target surfaces relative to the linear polarization components of the Stokes vector.

Conclusions:

• Polarization imaging demonstrates significant potential for bottom-up underwater target detection.
• The angle of polarization is a critical factor for optimizing this detection method.