Effect of Visual Cognition on the Measurement of Particle Size Using ImageJ Software

Background: Nanoparticles are structures up to 100 nm in size. Estimation of their size is usually determined by assessing of images obtained from scanning electron microscopy (SEM) and/or transmission electron microscopy (TEM) techniques. Studies on the effect of visual cognition on the analysis of these types of images are limited. Objective: The aim of the research was to determine whether students’ visual cognition influences the identification, analysis, and measurement of nanoparticle size through SEM and TEM imaging using ImageJ software. Methods: The visual cognition of each participant was evaluated by recognizing individual nanoparticles and measuring their diameter using ImageJ software. Finally, the Kruskal Wallis test was performed for statistical analysis. Results: Participants applied or not four main identification criteria in order to identify individual nanoparticles: shape, high contrast, defined edges, and presence/absence of agglomerates, being “shape” the predominant parameter taken into account to measure the diameter using ImageJ. Average diameters, number of measured nanoparticles, and standard errors of measurements varied between groups in all analyzed images, evidencing the influence of visual cognition on the measurements. Conclusion: We conclude that there is an effect of visual cognition in the identification of nanoparticles and their diameter estimation. The user’s training, background, experience, perspective, and operational conditions of SEM/TEM play a fundamental role in estimating the size of nanoparticles measured in microphotographs using ImageJ.