---
res:
  bibo_abstract:
  - 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@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Jorabar Singh
      foaf_name: Nirwan, Jorabar Singh
      foaf_surname: Nirwan
  - foaf_Person:
      foaf_givenName: Shan
      foaf_name: Lou, Shan
      foaf_surname: Lou
  - foaf_Person:
      foaf_givenName: Saqib
      foaf_name: Hussain, Saqib
      foaf_surname: Hussain
  - foaf_Person:
      foaf_givenName: Muhammad
      foaf_name: Nauman, Muhammad
      foaf_surname: Nauman
      foaf_workInfoHomepage: http://www.librecat.org/personId=32c21954-2022-11eb-9d5f-af9f93c24e71
    orcid: 0000-0002-2111-4846
  - foaf_Person:
      foaf_givenName: Tariq
      foaf_name: Hussain, Tariq
      foaf_surname: Hussain
  - foaf_Person:
      foaf_givenName: Barbara R.
      foaf_name: Conway, Barbara R.
      foaf_surname: Conway
  - foaf_Person:
      foaf_givenName: Muhammad Usman
      foaf_name: Ghori, Muhammad Usman
      foaf_surname: Ghori
  bibo_doi: 10.3390/mi13010017
  bibo_issue: '1'
  bibo_volume: 13
  dct_date: 2022^xs_gYear
  dct_identifier:
  - UT:000758547200001
  dct_isPartOf:
  - http://id.crossref.org/issn/2072-666X
  dct_language: eng
  dct_publisher: MDPI@
  dct_subject:
  - surface texture
  - electrically tunable lens
  - materials
  - hypromellose
  - surface topography
  - surface roughness
  - pharmaceutical tablet
  - variable focus imaging
  dct_title: Electrically tunable lens (ETL) - based variable focus imaging system
    for parametric surface texture analysis of materials@
...