اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدNon-contact transmittance photoplethysmographic imaging (PPGI) for long-distance cardiovascular monitoring
70
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Photoplethysmography (PPG) devices are widely used for monitoring cardiovascular function. However, these devices require skin contact, which restrict their use to at-rest short-term monitoring using single-point measurements. Photoplethysmographic imaging (PPGI) has been recently proposed as a non-contact monitoring alternative by measuring blood pulse signals across a spatial region of interest. Existing systems operate in reflectance mode, of which many are limited to short-distance monitoring and are prone to temporal changes in ambient illumination. This paper is the first study to investigate the feasibility of long-distance non-contact cardiovascular monitoring at the supermeter level using transmittance PPGI. For this purpose, a novel PPGI system was designed at the hardware and software level using ambient correction via temporally coded illumination (TCI) and signal processing for PPGI signal extraction. Experimental results show that the processing steps yield a substantially more pulsatile PPGI signal than the raw acquired signal, resulting in statistically significant increases in correlation to ground-truth PPG in both short- ($p in [<0.0001, 0.040]$) and long-distance ($p in [<0.0001, 0.056]$) monitoring. The results support the hypothesis that long-distance heart rate monitoring is feasible using transmittance PPGI, allowing for new possibilities of monitoring cardiovascular function in a non-contact manner.
قيم البحث
اقرأ أيضاً
We present a pair of optimized objective lenses with long working distances of 117~mm and 65~mm respectively that offer diffraction limited performance for both Cs and Rb wavelengths when imaging through standard vacuum windows. The designs utilise s
tandard catalog lens elements to provide a simple and cost-effective solution. Objective 1 provides $mathrm{NA}=0.175$ offering 3~$mu$m resolution whilst objective 2 is optimized for high collection efficiency with $mathrm{NA}=0.29$ and 1.8~$mu$m resolution. This flexible design can be further extended for use at shorter wavelengths by simply re-optimising the lens separations.
Multispectral imaging systems (MISs) have been used widely to analyze adulteration and toxin formation in oil, yet a dearth of attention has been tendered to oil reheating and reusing despite the consumption of such debased oil being deleterious. To
that end, the paper discusses the application of MISs to estimate the reheat cycle count classes (number of times an oil sample is recursively heated) and to identify critical classes at which substantial changes in the oil sample have materialized. The MIS captures the transmittance spectrum of the translucent specimen as opposed to other multispectral imaging research which often measures the reflected light from opaque solid samples. Firstly, the reheat cycle count class is estimated with Bhattacharyya distance between the reheated and a pure oil sample as the input. The classification was performed using a support vector machine classifier that resulted in an accuracy of 83.34 % for reheat cycle count identification. Subsequently, to distinguish critical classes under reheating, an unsupervised clustering procedure was introduced using a modified spectral clustering (SC) algorithm. In addition, laboratory experiments were performed to ascertain the ramifications of the reheating process with a chemical analysis. The chemical analysis of the coconut oil samples used in the experiment yielded that a statistically significant change (p < 0.05) had taken place in the chemical properties with reheating and the results of the proposed SC framework were deemed to coincide with the chemical analysis results.
We investigated the cause of optical transmittance degradation in tapered fibers. Degradation commences immediately after fabrication and it eventually reduces the transmittance to almost zero. It is a major problem that limits applications of tapere
d fibers. We systematically investigated the effect of the dust-particle density and the humidity on the degradation dynamics. The results clearly show that the degradation is mostly due to dust particles and that it is not related to the humidity. In a dust free environment it is possible to preserve the transmittance with a degradation of less than the noise (+/- ?0.02) over 1 week.
We present an IoT-based intelligent bed sensor system that collects and analyses respiration-associated signals for unobtrusive monitoring in the home, hospitals and care units. A contactless device is used, which contains four load sensors mounted u
nder the bed and one data processing unit (data logger). Various machine learning methods are applied to the data streamed from the data logger to detect the Respiratory Rate (RR). We have implemented Support Vector Machine (SVM) and also Neural Network (NN)-based pattern recognition methods, which are combined with either peak detection or Hilbert transform for robust RR calculation. Experimental results show that our methods could effectively extract RR using the data collected by contactless bed sensors. The proposed methods are robust to outliers and noise, which are caused by body movements. The monitoring system provides a flexible and scalable way for continuous and remote monitoring of sleep, movement and weight using the embedded sensors.
Synchronization is of great scientific interest due to the abundant applications in a wide range of systems. We propose a scheme to achieve the controllable long-distance synchronization of two dissimilar optomechanical systems, which are unidirectio
nally coupled through a fiber with light. Synchronization, unsynchronization, and the dependence of the synchronization on driving laser strength and intrinsic frequency mismatch are studied based on the numerical simulation. Taking the fiber attenuation into account, its shown that two mechanical resonators can be synchronized over a distance of tens of kilometers. In addition, we also analyze the unidirectional synchronization of three optomechanical systems, demonstrating the scalability of our scheme.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
