Computed Tomography Helical Scanning for
Dimensional Metrology: Evaluation of Measurement
Publication: Publication Date: 1 July 2016Testing Method:
In industrial X-ray computed tomography, it is
frequently necessary to scan long objects that
exceed the dimensions of the detector, while
meeting dimensional accuracy requirements (for
example, in automotive and aerospace fields).
Conventional scans using circular trajectories face
limits when dealing with internal and complex
features on elongated work pieces. To this extent
helical scanning is a valuable solution that also
enables obtaining a strong improvement on image
quality, eliminating the cone beam artifacts that
characterize conventional scans. To use helical
scanning for dimensional quality control, the
assessment of metrological performances is
needed. In this work, metrological performances
for helical scanning are investigated and compared
with those of conventional circular scans.
Repeated helical scans are performed to investigate
the influence of main helical scans parameters
when performing dimensional measurements.
Experimental results show that helical scanning,
with appropriate scan parameters, performs better
than traditional circular scans with a strong
improvement on image quality.
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