Analytical review of technologies for contactless “weighing” fish

Abstract

The active development of aquaculture stimulates the emergence of new fish farming technologies, the de-velopment of which requires a lot of experiments. An important part of such experiments is the control of fish weight changes by regular weighing. Manual weighing of fish is a laborious process and causes severe stress in the experimental fish. A more modern alternative to manual weighing is automatic non-contact “weighing” using appropriate sensors and/or video cameras, which determines the linear dimensions of the fish and calculates the weight based on them. The emergence of new, increasingly compact, accurate, functional and inexpensive equipment stimulates the emergence of various approaches to contactless weighing, differing in the set of equipment used and the implementation of computer processing. An analytical review of approaches to the creation of contactless weighing devices is presented based on the analysis of 72 scientific papers with a publication date no earlier than 2012. Some devices have a fairly wide range of applications, but we focus on weighing fish in laboratory conditions. Installations based on sensors, sonars, video cameras and their combinations are described. Special attention is paid to installations based on video cameras due to their wide distribution and suitable characteristics for solving the problem of non-contact weighing. Both systems with a single video camera and those using synchronized stereo pairs or orthogonal cameras are considered. A qualitative comparison of equipment of various types and configurations is provided. A general basic algorithm for contactless weighing based on images that can be obtained by both video cameras and other devices is presented. The algorithm includes detection, isolation, measurement and calculation of fish weight.