IEEE J Biomed Health Inform. 2023 Aug;27(8):3710-3720. doi: 10.1109/JBHI.2023.3236631. Epub 2023 Aug 7.
Peripheral blood oxygen saturation (SpO ) is an essential indicator of respiratory functionality and received increasing attention during the COVID-19 pandemic. Clinical findings show that COVID-19 patients can have significantly low SpO before any obvious symptoms. Measuring an individual's SpO without having to come into contact with the person can lower the risk of cross contamination and blood circulation problems. The prevalence of smartphones has motivated researchers to investigate methods for monitoring SpO using smartphone cameras. Most prior schemes involving smartphones are contact-based: They require using a fingertip to cover the phone's camera and the nearby light source to capture reemitted light from the illuminated tissue. In this paper, we propose the first convolutional neural network based noncontact SpO estimation scheme using smartphone cameras. The scheme analyzes the videos of an individual's hand for physiological sensing, which is convenient and comfortable for users and can protect their privacy and allow for keeping face masks on. We design explainable neural network architectures inspired by the optophysiological models for SpO measurement and demonstrate the explainability by visualizing the weights for channel combination. Our proposed models outperform the state-of-the-art model that is designed for contact-based SpO measurement, showing the potential of the proposed method to contribute to public health. We also analyze the impact of skin type and the side of a hand on SpO estimation performance.
外周血氧饱和度（SpO ）是呼吸功能的重要指标，在 COVID-19 大流行期间受到越来越多的关注。临床研究表明，COVID-19 患者在出现明显症状之前，SpO 可能会显著降低。通过不与人体接触来测量个体的 SpO 可以降低交叉污染和血液循环问题的风险。智能手机的普及促使研究人员研究使用智能手机摄像头监测 SpO 的方法。大多数涉及智能手机的现有方案都是基于接触的：它们需要使用指尖覆盖手机的摄像头和附近的光源，以捕获来自被照亮组织的再发射光。在本文中，我们提出了第一个使用智能手机摄像头的基于卷积神经网络的非接触式 SpO 估计方案。该方案分析个体手部的视频进行生理感应，这对用户来说既方便又舒适，并且可以保护他们的隐私，允许他们戴口罩。我们设计了受 SpO 测量光学生理模型启发的可解释神经网络架构，并通过可视化通道组合的权重来证明其可解释性。我们提出的模型优于专为接触式 SpO 测量设计的最先进模型，表明该方法有可能为公共卫生做出贡献。我们还分析了皮肤类型和手部侧面对 SpO 估计性能的影响。
