Nirwan, J. S., Lou, S., Hussain, S., Nauman, M., Hussain, T., Conway, B. R., &; Ghori, M. U. (2022). Electrically tunable lens (ETL) - based variable focus imaging system for parametric surface texture analysis of materials. Micromachines. MDPI.https://doi.org/10.3390/mi13010017