Underwater computational ghost imaging LiDAR for multi-target detection with a super-low sampling ratio

Area of Science:

• Optics and Photonics
• Computational Imaging
• Oceanographic Technology

Background:

• Traditional underwater imaging systems struggle with low sampling ratios and turbid water conditions, leading to image elongation and reduced performance.
• Computational ghost imaging (CGI) offers a potential solution but requires efficient modulation pattern strategies for practical applications.

Purpose of the Study:

• To introduce and evaluate a novel wavelet transform-based Hadamard (WTH) ordering for underwater computational ghost imaging (UCGI) light detection and ranging (LiDAR) systems.
• To demonstrate the WTH ordering's ability to overcome limitations of traditional methods in terms of image quality and multi-target detection in challenging underwater environments.

Main Methods:

• Development of a novel wavelet transform-based Hadamard (WTH) ordering for modulation pattern selection in UCGI.
• Implementation of the WTH-ordered UCGI-LiDAR system for imaging and ranging experiments in simulated turbid water (Jerlov 9C).
• Comparative analysis of WTH ordering against traditional Sylvester Hadamard ordering using metrics like mean squared error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM).

Main Results:

• The WTH ordering achieves balanced information capture, mitigating image elongation issues common in traditional methods at low sampling ratios.
• In 10% sampling ratio conditions in Jerlov 9C water, WTH resulted in a 97.58% MSE reduction, 55.24% PSNR increase, and 528.92% SSIM enhancement compared to Sylvester Hadamard ordering.
• The system demonstrated ranging precision and accuracy exceeding 3.90 mm and 6.40 mm, respectively.

Conclusions:

• The WTH ordering provides a significant advancement for UCGI-LiDAR systems, enabling high-quality imaging and precise ranging in highly turbid underwater conditions.
• This novel approach offers a robust solution for high-speed imaging and ranging in dynamic underwater environments, overcoming previous limitations.
• WTH ordering is a promising technique for applications requiring efficient data acquisition and reliable performance in challenging aquatic settings.