A Novel Algorithm for Sprial Large FOV Reconstruction

Cone-beam spiral Computed Tomography (CT) naturally extends longitudinal coverage, yet its transverse Field of View (FOV) remains constrained, causing projection truncation at high geometric magnification. We present an offset-spiral acquisition scheme paired with a Parker-weighted reconstruction algorithm that doubles the usable transverse FOV without modifying hardware. The one-sided lateral shift introduces projection redundancy, which is compensated by a tailored weighting function, allowing accurate recovery of truncated data through the standard Feldkamp-Davis-Kress (FDK) pipeline. Tests on simulated phantoms and real lithium-battery scans show that the proposed method preserves fine structural details and attains image quality comparable to conventional full-FOV reconstructions (mean PSNR ≈ 32 dB, SSIM ≈ 0.99, MSE < 0.014, FSIM and VIF<0.97). The technique is readily deployable in existing industrial CT systems and broadens the applicability of spiral FDK reconstruction to large, high-aspect-ratio objects.