Influence of Ambient Factors on the Acquisition of 3-D Respiratory Motion Measurements in Infants

In recent decades, great progress has been made in the contactless detection of infant and child respiratory motion. Systematic camera errors and disturbing environmental influences can have a strong impact on the signal quality of depth cameras. The prevalence of respiratory diseases in children and the central role that respiratory activity plays in the treatment of these conditions necessitate a robust and nonintrusive way of quantifying nocturnal respiratory activity in children. The aim of our study was to assess the robustness of various depth cameras (Microsoft Kinect V2, photonic mixing device (PMD) CamBoard pico flexx, PMD CamBoard pico monstar, ORBBEC Astra Pro, Intel RealSense D435) regarding ambient factors typically found during the use in clinical and home settings. We investigated the influence of viewing angles, reflectivity, and infrared (IR) light on signal quality. By correlating depth images with respiratory—belt signals, our analyses show that three cameras achieved adequate performance and might be considered for use in the contactless assessment of infant or child respiration. Several cameras failed under some of the ambient conditions which are likely to be encountered in real-life settings. Therefore, a careful camera selection regarding environmental influences is pivotal.