The calibration of laser-referenced underwater cameras for quantitative assessment of marine resources

Abstract

There is a growing need for cost-effective tools for quantitative assessment of marine resources in support of better future resource management. Video is one such tool being used by Australian researchers at CSIRO Marine Research (CMR) to enhance their understanding of benthic habitats and community dynamics. This paper discusses the challenge of obtaining accurate measurements from video images. The Monterey Bay Aquarium Research Institute (MBARI) has been developing quantitative video technology through its program of scientific remotely operated vehicle (ROV) development for a number of years-in particular, the use of laser-referenced imagery and associated software, named "Laser Measure@". Lasers located in a known configuration around the camera and projected into the field-of-view and onto a plane enable the image to be scaled. Recent collaboration between MBARI and CMR has enabled the developer of the "Laser Measure(C)" technology and CMR users to test the methodology and apply it to seafloor images from shelf to mid-slope depths off southeastern Australia, and also to apply aspects of the methodology to existing non-laser referenced imagery obtained in northern Australia. They use both fixed-mount referencing lasers and paired cameras, on a variety of platforms, to determine measurement scale in imagery.