Application of Optical CT to Estimate the Mass of Macroalgae in a Tank of Water

Abstract

This thesis develops and tests a mass estimation system for macroalgae using optical computed tomography. The system consists of a table with a fixed camera and backlighting, which rotates around a container of macroalgae to collect images from various points. The images capture the translucency along various light paths through the container. From the translucency measurements, computed tomography techniques are used to reconstruct the optical density at points on the interior of the container. The mass of the macroalgae is determined as a function of the total optical density. The system was evaluated in several tests which controlled optical densities using "mock algae" consisting of a number of paper strips within the container. Experiments found a linear relationship between the total optical density and the number of mock algae strips. However, the relationship was inconsistent across experimental trials, and the reconstructed volumes were blurry and inaccurate. Despite several tests and analyses, these difficulties remain unexplained at this time. While the system has some potential due to the strong linearity within sets, the inconsistencies and inaccuracies must be resolved before it can be considered a viable tool for estimating the mass of real algae in an acrylic hollow cylinder.