Designing and simulating realistic spatial frequency domain imaging systems using open-source 3D rendering software.
Designing and simulating realistic spatial frequency domain imaging systems using open-source 3D rendering software.
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DOI：
10.1364/boe.484286
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发表时间：
2023-06-01
影响因子：
3.4
通讯作者：
Gordon, George S. D.
中科院分区：
文献类型：
--
作者：
Crowley, Jane;Gordon, George S. D.
空间频域成像（SFDI）是一种低成本的成像技术，它可以映射吸收和降低散射系数，为重要的组织结构（如肿瘤）提供更好的对比度。实际的SFDI系统必须科普各种成像几何形状，包括离体成像平面样品，体内管腔内成像，例如用于内窥镜检查，以及测量不同形态的肿瘤或息肉。需要一种设计和仿真工具来加速新SFDI系统的设计，并在这些场景下仿真真实的性能。我们提出了这样一个系统，使用开源的3D设计和光线跟踪软件Blender，模拟介质与现实的吸收和散射在广泛的几何形状。通过使用Blender的Cycles光线跟踪引擎，我们的系统可以模拟各种效果，如不同的照明、折射率变化、非垂直入射、镜面反射和阴影，从而能够对新设计进行逼真的评估。我们首先证明了蒙特-卡罗模拟的吸收和减少散射系数与我们的Blender系统模拟的吸收系数和减少散射系数之间的定量一致性，实现了吸收系数和减少散射系数的差异。然而，我们然后表明，使用经验得出的查找表的错误分别减少到和。接下来，我们模拟SFDI映射的吸收，散射和形状模拟肿瘤球体，展示增强的对比度。最后，我们展示了一个管状管腔内的SFDI映射，这突出了一个重要的设计见解：必须为管腔的不同纵向截面生成自定义查找表。通过这种方法，我们获得了吸收误差和散射误差。我们预计我们的模拟系统将有助于设计新颖的SFDI系统的关键生物医学应用。
Spatial frequency domain imaging (SFDI) is a low-cost imaging technique that maps absorption and reduced scattering coefficients, offering improved contrast for important tissue structures such as tumours. Practical SFDI systems must cope with various imaging geometries including imaging planar samples ex vivo, imaging inside tubular lumen in vivo e.g. for endoscopy, and measuring tumours or polyps of varying morphology. There is a need for a design and simulation tool to accelerate design of new SFDI systems and simulate realistic performance under these scenarios. We present such a system implemented using open-source 3D design and ray-tracing software Blender that simulates media with realistic absorption and scattering in a wide range of geometries. By using Blender’s Cycles ray-tracing engine, our system simulates effects such as varying lighting, refractive index changes, non-normal incidence, specular reflections and shadows, enabling realistic evaluation of new designs. We first demonstrate quantitative agreement between Monte-Carlo simulated absorption and reduced scattering coefficients with those simulated from our Blender system, achieving discrepancy in absorption coefficient and in reduced scattering coefficient. However, we then show that using an empirically derived look-up table the errors reduce to and respectively. Next, we simulate SFDI mapping of absorption, scattering and shape for simulated tumour spheroids, demonstrating enhanced contrast. Finally we demonstrate SFDI mapping inside a tubular lumen, which highlighted a important design insight: custom look-up tables must be generated for different longitudinal sections of the lumen. With this approach we achieved absorption error and scattering error. We anticipate our simulation system will aid in the design of novel SFDI systems for key biomedical applications.