article published yes Jorabar Singh Nirwan author Shan Lou author Saqib Hussain author Muhammad Nauman author 32c21954-2022-11eb-9d5f-af9f93c24e710000-0002-2111-4846 Tariq Hussain author Barbara R. Conway author Muhammad Usman Ghori author KiMo department Electrically tunable lenses (ETLs) are those with the ability to alter their optical power in response to an electric signal. This feature allows such systems to not only image the areas of interest but also obtain spatial depth perception (depth of field, DOF). The aim of the present study was to develop an ETL-based imaging system for quantitative surface analysis. Firstly, the system was calibrated to achieve high depth resolution, warranting the accurate measurement of the depth and to account for and correct any influences from external factors on the ETL. This was completed using the Tenengrad operator which effectively identified the plane of best focus as demonstrated by the linear relationship between the control current applied to the ETL and the height at which the optical system focuses. The system was then employed to measure amplitude, spatial, hybrid, and volume surface texture parameters of a model material (pharmaceutical dosage form) which were validated against the parameters obtained using a previously validated surface texture analysis technique, optical profilometry. There were no statistically significant differences between the surface texture parameters measured by the techniques, highlighting the potential application of ETL-based imaging systems as an easily adaptable and low-cost alternative surface texture analysis technique to conventional microscopy techniques https://research-explorer.ista.ac.at/download/10584/10601/2021_Micromachines_Singh.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ MDPI2022 eng surface textureelectrically tunable lensmaterialshypromellosesurface topographysurface roughnesspharmaceutical tabletvariable focus imaging 2072-666X 00075854720000110.3390/mi13010017 131 J.S. Nirwan, S. Lou, S. Hussain, M. Nauman, T. Hussain, B.R. Conway, M.U. Ghori, Micromachines 13 (2022). Nirwan, Jorabar Singh, Shan Lou, Saqib Hussain, Muhammad Nauman, Tariq Hussain, Barbara R. Conway, and Muhammad Usman Ghori. “Electrically Tunable Lens (ETL) - Based Variable Focus Imaging System for Parametric Surface Texture Analysis of Materials.” <i>Micromachines</i>. MDPI, 2022. <a href="https://doi.org/10.3390/mi13010017">https://doi.org/10.3390/mi13010017</a>. Nirwan JS, Lou S, Hussain S, Nauman M, Hussain T, Conway BR, Ghori MU. 2022. Electrically tunable lens (ETL) - based variable focus imaging system for parametric surface texture analysis of materials. Micromachines. 13(1), 17. Nirwan JS, Lou S, Hussain S, et al. Electrically tunable lens (ETL) - based variable focus imaging system for parametric surface texture analysis of materials. <i>Micromachines</i>. 2022;13(1). doi:<a href="https://doi.org/10.3390/mi13010017">10.3390/mi13010017</a> Nirwan, J. S., Lou, S., Hussain, S., Nauman, M., Hussain, T., Conway, B. R., &#38; Ghori, M. U. (2022). Electrically tunable lens (ETL) - based variable focus imaging system for parametric surface texture analysis of materials. <i>Micromachines</i>. MDPI. <a href="https://doi.org/10.3390/mi13010017">https://doi.org/10.3390/mi13010017</a> Nirwan, Jorabar Singh, et al. “Electrically Tunable Lens (ETL) - Based Variable Focus Imaging System for Parametric Surface Texture Analysis of Materials.” <i>Micromachines</i>, vol. 13, no. 1, 17, MDPI, 2022, doi:<a href="https://doi.org/10.3390/mi13010017">10.3390/mi13010017</a>. J. S. Nirwan <i>et al.</i>, “Electrically tunable lens (ETL) - based variable focus imaging system for parametric surface texture analysis of materials,” <i>Micromachines</i>, vol. 13, no. 1. MDPI, 2022. 105842022-01-02T23:01:33Z2023-08-09T10:16:10Z