Dragonfish: Advance sensor for real-time detection of objects in ocean
Abstract
At present, there are two state of the art technologies for detecting man-made objects in the ocean: LIDAR and acoustic hydrophones. The LIDAR sensor has limitations in detecting objects which are near the surface of water due to strong glint issues produced because of the laser reflection from the water surface. The acoustic signal from plastics is weak and difficult to detect using acousticsensors. This limitation in technology makes it challenging to detect plastic objects which are located just beneath the ocean surface. With previous ONR funding we have successfully developed a fast fluorescence imaging sensor which detects objects made of plastic, clothes, paper, rubber, paint, epoxies, etc. in ocean water. The sensor provides real-time color video detection of objects in the ocean. The sensor also detects metals and air bubbles, which have no fluorescence signal, using color contrast as these objects appear dark due to the lack of fluorescence signal as shown in Figure 1. Thefluorescence sensor has filled a technology gap in LIDARand acoustic sonar for detecting plastic/metallic objects located near the water surface.The current fluorescence sensor uses a pulse laser for uniformly illuminating a wide-area in the water and utilizes a time-gated detection to capture fluorescence images of the targets. The sensor works both in daytime and nighttime conditions and has no glint issue because the sensor does not use laser photons as signal and laser reflection is completely blocked using an optical filter. The sensor was successfully field tested in the Pacific Ocean, validating the sensor concept and working principle.In this project, we propose to develop an advanced version of the fluorescence sensor, which will be more sensitive and cover a wider area than the existing sensor. Under the previous ONR project, it was realized that there is a tremendous need for detecting targets in a wider area in the ocean to look for objects made out of plastic and metals. In this proposal, we describe a novel approach for increasing the sensor capability by improving sensor sensitivity, area coverage and underwater depth penetration for detection. We will develop a complete system integrated into a remote-controlled boat platform (USV) to search for man-made objects in the ocean.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 15, 2024
- Source ID
- N000142412348
Entities
People
- Anupam K Misra
Organizations
- Office of Naval Research
- United States Navy
- University of Hawaiʻi System