Department of AI & Informatics, Graduate School, Sangmyung University, Seoul 03016, Korea.
Department of Human-Centered Artificial Intelligence, Sangmyung University, Seoul 03016, Korea.
Sensors (Basel). 2021 Sep 12;21(18):6120. doi: 10.3390/s21186120.
Oxygen saturation (SPO) is an important indicator of health, and is usually measured by placing a pulse oximeter in contact with a finger or earlobe. However, this method has a problem in that the skin and the sensor must be in contact, and an additional light source is required. To solve these problems, we propose a non-contact oxygen saturation measurement technique that uses a single RGB camera in an ambient light environment. Utilizing the fact that oxygenated and deoxygenated hemoglobin have opposite absorption coefficients at green and red wavelengths, the color space of photoplethysmographic (PPG) signals recorded from the faces of study participants were converted to the YCgCr color space. Substituting the peaks and valleys extracted from the converted Cg and Cr PPG signals into the Beer-Lambert law yields the SPO via a linear equation. When the non-contact SPO measurement value was evaluated based on the reference SPO measured with a pulse oximeter, the mean absolute error was 0.537, the root mean square error was 0.692, the Pearson correlation coefficient was 0.86, the cosine similarity was 0.99, and the intraclass correlation coefficient was 0.922. These results confirm the feasibility of non-contact SPO measurements.
血氧饱和度（SPO）是健康的重要指标，通常通过将脉搏血氧仪放置在手指或耳垂上来测量。然而，这种方法存在一个问题，即皮肤和传感器必须接触，并且需要额外的光源。为了解决这些问题，我们提出了一种非接触式血氧饱和度测量技术，该技术在环境光下使用单个 RGB 相机。利用含氧和去氧血红蛋白在绿光和红光波长处具有相反的吸收系数这一事实，将从研究参与者面部记录的光体积描记（PPG）信号的颜色空间转换为 YCgCr 颜色空间。将从转换后的 Cg 和 Cr PPG 信号中提取的峰和谷代入比尔-朗伯定律，通过线性方程得到 SPO。当根据脉搏血氧仪测量的参考 SPO 评估非接触式 SPO 测量值时，平均绝对误差为 0.537，均方根误差为 0.692，皮尔逊相关系数为 0.86，余弦相似度为 0.99，组内相关系数为 0.922。这些结果证实了非接触式 SPO 测量的可行性。
