Practical geometric calibration for helical cone-beam industrial computed tomography

Area of Science:

• Industrial Computed Tomography (ICT)
• Image Reconstruction
• Geometric Calibration

Background:

• Mechanical misalignments in helical cone-beam ICT cause geometry artifacts.
• Artifacts degrade the quality of reconstructed images, impacting industrial applications.

Purpose of the Study:

• To develop a practical geometric calibration method for helical cone-beam ICT.
• To obtain artifact-free reconstruction images by addressing mechanical misalignments.

Main Methods:

• Adapted Noo's analytic geometric calibration method for circular scans to helical scans.
• Divided the helical path into segments and acquired circular scan projections at section points.
• Calculated geometry parameters using Noo's method and interpolated for intermediate projections.

Main Results:

• The method successfully determined high-precision geometry parameters for helical scans.
• Numerical simulations and real data experiments validated the method's effectiveness.
• Satisfactory artifact-free reconstruction images were achieved.

Conclusions:

• The proposed geometric calibration method is effective for helical cone-beam ICT.
• It provides a practical solution for improving image quality in industrial CT applications.
• Accurate geometry parameter estimation is crucial for artifact reduction.