National Physical Laboratory

Dimensional surface metrology

Most manufactured parts rely on some form of control of their surface characteristics, or dimensions of small functional surface features: bearing surfaces for automotive applications; local defects in solar cells; channel dimensions in microfluidic biosensors; and diffractive nanostructure security markings are just some examples. NPL supports fundamental uncertainty research, develops topography measurement good practice and calibration tools, and is leading collaborative research towards high-resolution, high-throughput inspection of small features on large area surfaces.

Ongoing research

Research themes for calibration, uncertainties and quantitative analysis include:

  • Development of calibration methods (and artefacts) for areal surface topography measurement and characterisation
  • Development of background theory and practical measurement methods for determining the spatial frequency response of an instrument
  • Development of software measurement standards for areal characterisation
  • Development of methods to aid an understanding and control of the function of a surface

Dimensional surface metrology #1 [587x249]

Research themes for in-process, high-dynamic range surface metrology include:

  • Advanced inline sensor development to significantly extend current capabilities on measurement throughput, range and resolution in the production environment
  • Calibration protocols and artefacts for in-process defect-detecting optical metrology, developing existing good practice to account for operational constraints
  • Good practice for correlating surface feature properties with global product function, enabling smarter, faster in-process measurement and better process control
  • Traceability support for global registration of features on large substrates, enabling substrate overlay and targeted correction of defects
  • Intelligent sampling and multi-sensor data fusion: non-standard methods for sampling and handling of data, such as online measurement strategy adaptation based on gathered data

Dimensional surface metrology #2 [602x249]

For more information on NPL's in-process dimensional metrology research, read about the EMPIR MetHPM project here

Research team

For more information on any aspect of the above, or for help with a specific metrology need, please contact

Recent publications


NPL Reports

Calibrations artefacts

Good Practice Guides



Last Updated: 8 Aug 2017
Created: 31 Jul 2017


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