2025 Valtchanov Gas Turbine Blade CAD CT Reconstruction

Non-destructive X-ray and computed tomography (CT) testing are essential for ensuring the dimensional accuracy of manufactured components with complex internal structures such as the cooling channels in gas turbine blades, which directly impact thermal performance and service life. This study presents a multi-part 3D-2D rigid registration approach for aligning CAD models to X-ray projections as an alternative to CT reconstruction for part inspection and measurement. A greedy registration algorithm is employed, sequentially aligning the blade’s exterior before registering internal components to maximize mutual information between simulated and scanned X-ray images. This stepwise approach significantly reduces problem complexity and improves alignment accuracy. View-angle optimization is performed using a greedy method, iteratively selecting angles to minimize dimensional deviation in measurements. Results indicate that a small number of oblique views provide the best accuracy, but a broad range of angles can yield acceptable results. The method achieves sub-pixel registration accuracy, with errors reduced to less than one-fifth of the (magnified) pixel pitch. Image noise and defects influence registration precision, but working in the projection space mitigates these effects compared to CT reconstruction. These findings indicate that the accuracy of the registration process is sensitive to X-ray image noise and defects but appropriate view optimization can mitigate these effects so that acceptable sub-pixel accuracy is achieved.