Nikon Metrology

Understanding the metrology language for X-ray computed tomography

Computed tomography, Metrology CT, Technology Insight, X-ray and CT Inspection

When compared to CMMs, CT as a technique applied for industrial dimensional metrology is relatively new. In a recent article for Quality Magazine’s NDT special section, Herminso Villarraga-Gomez from Nikon Metrology looks to define the language and teminology used.


Interest is growing across many industries in the use of X-ray computed tomography (CT) for dimensional metrology in the pursuit of improved quality control. Currently, however, there exists a lack of agreement among governing bodies in metrology, research institutions, technology providers, and other organizations over standards dealing with verifying CT systems’ dimensional metrology performance and developing task-specific measurement uncertainty budgets.

The full article was published in the NDT special section for the Quality Magazine, and can be read, here.

Herminso Villarraga-Gomez is a CT metrology specialist at Nikon Metrology, read more of his work in this previous article – Rules of Micro-CT.



Did you know Nikon Metrology offers its in-house facilities and expertise for X-ray and CT inspection services? Find out more here…



Interesting to read…

To improve things, first we must define and better understand our terms and work forward to creating useful and needed standards. For example, how would you define accuracy? How does it differ from precision? In an interesting TEDEd talk , educator Matt Anicole says the distinction between these two terms is critical for many scientific endeavors, which certainly includes metrology and improved quality control.

Using the legendary story of William Tell being challenged to shoot an apple off his son’s head, Anicole defines accuracy as how close you can come to the correct result. Accuracy improves with the use of well-calibrated tools you are well-trained to operate.

Precision, on the other hand, is how consistently you can obtain that result using the same method. Precision improves with more finely incremented tools that require less estimation. Better equipment together with more detailed procedures equate to an acceptable level of uncertainty for any given project.

Watch the Accuracy vs Precision TEDEd talk video below…





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