A comparative analysis of 2D, visible light imaging technologies for describing the physical properties of micro- and mesoplastics (0.5 to 50 mm).

This study evaluates three visible-light imaging methods; ImageJ, the Saturna Imaging System (Ocean Diagnostics), and the Segmentation Model (The Ocean Cleanup), for characterizing 2D properties of micro- and mesoplastics (0.5-50 mm) collected from the North Pacific Garbage Patch. Their performance was compared with traditional manual counting in terms of accuracy, efficiency, and cost. Manual analysis remains the most accurate for particle counts and type classification but is highly labor-intensive, requiring twice the processing time of imaging systems and providing only broad size-class information. In contrast, 2D imaging technologies offer rapid, user-friendly, and adaptable workflows that generate detailed measurements of particle size, shape and color. These systems reduce human error and provide harmonized outputs. The incorporation of 2D imaging technologies can support future research projects, reduce intensive work in the lab, and provide detailed information about the properties of plastic particles' actual size and shape distribution.