Pathway Project Multibeam Imaging Sonar Data Analysis

Vessel Mount Data Sets

Overview

As part of the OERA Pathway Program, SOAR is conducting research to help evaluate the effectiveness of multibeam imaging sonars for monitoring marine animals in tidal channels. This information will help inform DFO, tidal energy developers, and other stakeholders in the design and implementation of effective monitoring systems for tidal energy projects in the Bay of Fundy, and beyond.

Multibeam imaging sonars are essentially the closest technology to echolocation used by marine animals including dolphins and porpoises. The sonars send out pings (from multiple beams) and process the time and intensity of the returns (backscatter) as images of the subsea environment.

Two imaging sonars are being tested:

Tritech Gemini with 720 kHz frequency, 50 m range, 120 degree field of view, and 20 degree vertical beam spread.
Teledyne BlueView with 2250 kHz frequency, 10 m range, 130 degrees field of view, and 20 degree vertical beam spread.

These 2 sonars are world class technologies, and were selected to test the ability of the BlueView to identify and track targets at close ranges (less than 10m) and the Gemini to detect and track targets at relatively further ranges (out to 50m).

The sonars were mounted near surface to a pole (Figure 1) on research vessel Grand Adventure, which was anchored in Grand Passage. The targets were suspended beneath the SciBoard (Figure 2), which was towed behind the Grand Adventure (Figure 3). The targets are man made, including a 1 inch metal sphere, 1 lb lead fishing weight, fist sized basalt rock in a lobster bait bag, and the DOT V-Wing (Figure 4).

Algorithms are in development for automated data analysis, but they are not yet validated or reliable. They also require site (data set) specific training. So, we are basing the evaluation on manual analysis of the data files including YOUR INPUT! Throughout this analysis you are not being tested. The evaluation is on the ability of these sonars to detect and track the targets, as determined by a group of human observers.

THANK YOU FOR PARTICIPATING IN DEVELOPMENT OF EFFECTIVE ENVIRONMENTAL MONITORING SYSTEMS FOR TIDAL TURBINES!

Figure 1: Pole mounted sonars and optical camera (raised position)

Figure 2: SciBoard

Figure 3: Experiment setup

Figure 4: Targets, including 1) 1 inch tungsten carbide sphere, 2) 1 lb lead fishing weight, 3) fist sized basalt rock in a lobster bait bag, and 4) DOT V-Wing.

Note, the squid jig was used in initial testing with a 1 lb lead weight inside. It exhibited interesting behaviour, but for the purpose of this experiment the increased drag made it difficult to handle while being very acoustically similar to target 2. As such, it was removed from further analysis.

Data Analysis Instructions

Data are provided below in video format, which you can pause and replay as you wish. The data playback speed is set to twice as fast as real time to increase efficiency.
All videos should be viewed full screen at 1920 x 1080 resolution.
You will watch a training data set for each sonar, where the target type is provided and the target is marked with a red circle that follows/tracks it through each example. Following the training data, you then watch sets of files in the test data sets and record your observations in the spreadsheet provided.
After each “file” included in the video, hit pause and enter your observations into the spreadsheet.
Your observations will be quantitative, but subjective. You will provide:
- Yes/no as to if there is a target included in the data file
  - If yes, your best interpretation of the target type in comparison to those in the training data set along with a ranking of 1 (low) to 5 (high) on your certainty.
- The range over which you viewed the target (min and max)
- Scoring on ability to detect and track the target from 1 (low) to 5 (high)
- Notes on the track of the target. For example, does it follow a straight line, stop at points, etc. Anything you think useful for describing the trajectory of the target.

Optional (but useful!) - Sign up for a free Vimeo account to enable video review with time coded notes. This allows you to click directly on targets at different locations in space and time throughout the test videos and attach your notes directly to the data. If you do this, please email us and we will send you a link to a private (just for you to use) review page for each of the test data sets.

To start, please have a look at the spreadsheet then watch this video showing the experiment setup including the general configuration and the target types.