arXiv:2412.00065eess.IVcs.CV2024-12中稿 · 18/04/2025 - Publi…被引 6

用连续时间事件取代离散帧,实现更高效高精度的动态断层成像。

DYRECT Computed Tomography: DYnamic Reconstruction of Events on a Continuous Timescale

  • 基于事件连续时间建模,用三个体积替代传统多帧数据
  • 在合成数据上实现低于1/10投影数的时序分辨率
  • 适合材料内部动态过程量化与低存储高效率场景

时间分辨高分辨率X射线断层扫描(4D μCT)可揭示不透明材料内部动态过程的演变。传统断层重建依赖一系列离散时间点的3D图像,受限于每次扫描所需时间,其时间分辨率低于动态射线照相实验,且导致数据量激增,需大量后处理计算,常忽略结构的时间相关性。本文提出的DYRECT方法,为样品中每个位置估计衰减演化曲线,构建新型内存高效的事件型表示:仅需三个图像体积——初始衰减、最终衰减及过渡时间。第三个体积以连续时间尺度表征局部事件,而非离散全局时间帧。我们提出一种迭代算法同步重建过渡时间和衰减体积。该方法在合成真实数据和实验数据上均得到验证,在合成数据中成功精确定位过渡时间,时间分辨率低于重建传统μCT时间帧所需投影数的十分之一。

原文摘要 · Abstract (English)

Time-resolved high-resolution X-ray Computed Tomography (4D $μ$CT) is an imaging technique that offers insight into the evolution of dynamic processes inside materials that are opaque to visible light. Conventional tomographic reconstruction techniques are based on recording a sequence of 3D images that represent the sample state at different moments in time. This frame-based approach limits the temporal resolution compared to dynamic radiography experiments due to the time needed to make CT scans. Moreover, it leads to an inflation of the amount of data and thus to costly post-processing computations to quantify the dynamic behaviour from the sequence of time frames, hereby often ignoring the temporal correlations of the sample structure. Our proposed 4D $μ$CT reconstruction technique, named DYRECT, estimates individual attenuation evolution profiles for each position in the sample. This leads to a novel memory-efficient event-based representation of the sample, using as little as three image volumes: its initial attenuation, its final attenuation and the transition times. This third volume represents local events on a continuous timescale instead of the discrete global time frames. We propose a method to iteratively reconstruct the transition times and the attenuation volumes. The dynamic reconstruction technique was validated on synthetic ground truth data and experimental data, and was found to effectively pinpoint the transition times in the synthetic dataset with a time resolution corresponding to less than a tenth of the amount of projections required to reconstruct traditional $μ$CT time frames.

断层成像动态重建事件相机连续时间

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