XClipGS: 用于医学体高斯溅射的精确半空间裁剪
XClipGS: Exact Half-Space Clipping for Medical Volume Gaussian Splatting
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中文总结 AI 辅助
本文提出XClipGS精确裁剪方法，通过闭式逐像素算子实现医学体高斯溅射的半空间精确裁剪，在8组CT/MRI数据集上，其PSNR、SSIM等指标均优于现有方法，渲染速度超650 FPS且泄漏量显著降低。
中文摘要 AI 辅助
高斯溅射代理可实现体医学扫描的交互式渲染，但裁剪平面会暴露未受外部视图训练约束的解剖结构，且与常规溅射只能整体保留或丢弃的基元相交。本文提出XClipGS（精确裁剪），将这些问题拆分为两个独立部分：渲染时的裁剪算子与隐藏内部的监督。在EWA溅射所用的局部仿射模型下，半空间受限高斯的光线积分可精确分解为其常规2D footprint（ footprint 即足迹）和一个条件高斯累积分布函数，该函数的自变量是像素坐标的仿射变换。由此得到的闭式逐像素算子无需引入学习到的裁剪参数或辅助网络，且对基元与平面保持可微性。我们使用具有不同裁剪平面轴和偏移的多距离参考视图，通过同一算子监督内部。我们还引入了配对的裁剪/未裁剪切面协议，采用差值参考的切面误差（CDE）和剔除侧泄漏（Leak），因为全局图像指标会稀释平面附近的误差。在8个体积CT和MRI（使用未用于训练的平面偏移）上，XClipGS在每个体积上均达到最高PSNR（33.56 dB，对比ClipGS的32.34 dB），同时渲染速度超过650 FPS，远超实时要求，而ClipGS为278 FPS。在体素轴切面视图上，其平均带SSIM从0.809提升至0.860，泄漏量减少约40倍；在任意法向量平面上，无需重新训练即可达到四项指标的最佳平均值；在固定内部时，其切面保真度与RaRa相当，泄漏量减少约16倍。项目页面：this https URL
英文摘要
Gaussian-splatting proxies enable interactive rendering of volumetric medical scans, but a clipping plane exposes anatomy not constrained by external-view training and intersects primitives that conventional splatting can only keep or drop whole. We present XClipGS (eXact Clipping), which treats these as two separate problems: the render-time clip operator and supervision of the hidden interior. Under the local affine model used by EWA splatting, the ray integral of a half-space-restricted Gaussian factorizes exactly into its ordinary 2D footprint and a conditional Gaussian CDF whose argument is affine in pixel coordinates. The resulting closed-form per-pixel operator introduces no learned clipping parameters or auxiliary network and remains differentiable with respect to the primitive and plane. We use multi-distance reference views with varied clipping-plane axes and offsets to supervise the interior through the same operator. We also introduce a paired clipped/unclipped cut-face protocol with difference-referenced cut error (CDE) and culled-side leakage (Leak), because global image metrics dilute errors near the plane. On eight CT and MRI volumes with plane offsets not used for training, XClipGS attains the highest PSNR on every volume (33.56 versus 32.34 dB for ClipGS) while rendering at over 650 FPS, far above real time, versus 278 FPS. On voxel-axis cut-face views, it raises average band SSIM from 0.809 to 0.860 and leaks roughly 40 times less. Without retraining, it also achieves the best average across all four metrics on arbitrary-normal planes; on a fixed interior, it matches RaRa's face fidelity with about 16 times less leakage. Project page: https://gaozhongpai.github.io/XClipGS/
