Dual-Radiance Universal Beta Splatting for RGB-Thermal Novel View Synthesis

We extend Universal Beta Splatting (UBS) to registered RGB-thermal novel-view synthesis with a dual-radiance primitive. Each primitive stores separate RGB and thermal three-channel radiance vectors, while positions, covariance, opacity, Beta parameters, and view-direction conditioning are shared. Two rendering passes swap only the color vector, leaving one primitive set and point cloud. On the ten-scene ThermoScenes benchmark (1, 100 paired frames), dual-radiance UBS reaches mean thermal PSNR, SSIM, and LPIPS of 35.72 dB, 0.981, and 0.055, with corresponding RGB means of 25.00 dB, 0.818, and 0.254. Comparisons with prior multimodal systems use native evaluators and are indicative. Under a shared evaluator, output radiance improves mean thermal and RGB PSNR by 3.05 and 1.39 dB over the tested modality-input UBS variant. Relative to RGB-only UBS, RGB PSNR is nearly unchanged (25.00 versus 24.97 dB), while LPIPS increases from 0.240 to 0.254. These results support output-radiance coupling within the tested UBS configurations; they do not isolate the Beta kernel's contribution from the rest of the representation.