Effect of Vertical Camera Spacing on Novel-View Synthesis Quality in Multi-Height 360° Indoor Capture for 3D Gaussian Splatting

This study examines how the vertical spacing of a multi-height 360° camera array affects novel-view synthesis quality in indoor scenes reconstructed with 3D Gaussian splatting (3DGS). Although 3DGS enables high-quality real-time scene representation, its output depends on the geometric arrangement of the input views, which single-lens workflows secure through repeated captures at several heights. A rig of three vertically arranged 360° cameras was evaluated in four indoor spaces differing in ceiling height, structure, and capture path. Three spacing conditions were applied in each space, denoted as Set-L, Set-D, and Set-H. These are ordinal positions within the vertical range each space allows rather than fixed absolute distances, since an identical spacing sits differently in rooms of different scale. The 360° footage was stitched into equirectangular video and reframed into multi-view image sequences, yielding 120 datasets from four spaces × three conditions × ten repeated captures. Novel-view synthesis quality was measured with the PSNR, SSIM, and LPIPS on validation views withheld from training. Because normality and homogeneity of variance were not satisfied, a robust two-way factorial analysis of variance based on 20% trimmed means was used, with robust post hoc comparisons. Spacing, spatial characteristics, and their interaction were significant for all three metrics, so no single spacing was preferable across every space. The wide setting performed best in the low-ceiling repetitive space, the narrow setting in the open space, and the baseline setting in the largest space with variable ceiling height. In one space, comprising stepped, near-symmetric seating, no condition was distinguishable, and dispersion across repeated captures was an order of magnitude larger than elsewhere, indicating that, where a repetitive structure is extensive, the limiting factor is capture stability rather than the choice of spacing. The findings are consistent with a trade-off between vertical viewpoint separation and inter-view overlap, and provide exploratory, space-conditional reference points for indoor 3DGS capture rather than a standardized specification, with relevance to virtual exhibitions, architectural visualization, and digital-twin construction.