多孔径PPG与MAPIS：空间光学与时间相干场
Multi-Aperture PPG with MAPIS: Spatial Optical and Temporal Coherence Fields
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中文总结 AI 辅助
本研究通过MAPIS多孔径PPG揭示了光学强度、搏动敏感性与波形相干性的空间关系，为理解光子路径机制奠定基础。
中文摘要 AI 辅助
传统反射式光电容积描记法（PPG）通常将组织光学响应减少到一个或几个探测器通道。矩阵针孔图像传感（MAPIS）则同时采样多个孔径相关的光学信号。我们分析了来自单个MAPIS设备的44段各30秒的记录，以表征DC强度、搏动性AC、灌注指数（PI）以及红和红外通道间时间相干性的空间关系。AC在两种波长下均随DC呈亚线性增加，导致在较低DC孔径处PI更高，这与一阶相对路径敏感性解释一致。第二个反直觉的空间趋势出现在时间相干性中：较低DC和较低AC的孔径表现出更高的自相关性和更大的心周期频谱集中度。红外信号还表现出比相应红信号一致更高的时间相干性。这些观察表明，多孔径PPG解析了光学强度、分数搏动敏感性和波形相干性之间可重复的空间关系，而这些在传统单通道PPG中大多被平均化。本研究建立了设备内关系，并推动了对底层光子路径机制的受控研究。
英文摘要
Conventional reflectance photoplethysmography (PPG) typically reduces tissue optical responses to one or a few detector channels. Matrix Pinhole Image Sensing (MAPIS) instead simultaneously samples multiple aperture-dependent optical signals. We analyzed 44 recordings of 30 seconds each from a single MAPIS device to characterize the spatial relationships among DC intensity, pulsatile AC, perfusion index (PI), and temporal coherence across Red and infrared channels. AC increased sublinearly with DC at both wavelengths, resulting in higher PI toward lower-DC apertures, consistent with a first-order relative path-sensitivity interpretation. A second counterintuitive spatial trend was observed in temporal coherence: lower-DC and lower-AC apertures exhibited higher autocorrelation and greater cardiac-periodic spectral concentration. IR signals also showed consistently higher temporal coherence than corresponding Red signals. These observations demonstrate that multi-aperture PPG resolves reproducible spatial relationships among optical intensity, fractional pulsatile sensitivity, and waveform coherence that are largely averaged together in conventional single-channel PPG. The present study establishes within-device relationships and motivates controlled studies of the underlying photon-path mechanisms.
