Automatic length estimation of free-swimming fish using an underwater 3D range-gated camera
Petter Risholm, Ahmed Mohammed, Trine Kirkhus, Sigmund Clausen, Leonid Vasilyev, Ole Folkedal, Øistein Johnsen, Karl Henrik Haugholt, Jens T. Thielemann
Abstract
Camera estimation of fish size in aquaculture production and fisheries is crucial for enabling knowledge-based decision making. Automatic estimation of fish lengths on an individual and population basis are key steps to automate biomass estimation. We propose to use an underwater 3D range-gated camera for accurate fish-length estimation of free-swimming fish. The proposed algorithm requires no manual work or contact with the fish and is done in-situ. A robust algorithmic pipeline consisting of detection, tracking and fish length estimation stages is proposed. We show the accuracy of the proposed system on free-swimming fish, both in terms of individual fish lengths as well as the population distributions. The results show that the proposed system achieves length estimation errors in the order of 1% of manual-measured fish length.