Imaging Photoplethysmography for Noninvasive Anastomotic Perfusion Assessment in Intestinal Surgery

Introduction: Anastomotic leakage after gastrointestinal surgery has a high impact on patient's quality of life and its origin is associated with inadequate perfusion. Imaging photoplethysmography (iPPG) is a noninvasive imaging technique that measures blood-volume changes in the microvascular tissue bed and detects changes in tissue...

Less Machine (=) More Vision: Approaches towards Practical and Efficient Machine Vision with Applications in Face Analysis

Machines that interact with humans can do so better if they can also visually understand us, but they have limited resources to do so. The main topic of this dissertation is contrasting the use of resources by machine vision systems against the accuracy obtained by them. This thesis focuses on reducing the need for data, memory, and computation...

Prediction of blood volume pulse waveform features using remote PPG

Contactless measurement of changes in blood volume by exploiting the color fluctuations in the face is a technique commonly referred to as remote photoplethysmography (rPPG). Recent developments show promising results for heart rate estimation from low-cost cameras, making applications in remote healthcare possible. Remote PPG applications in at...

Performance of the AOTF-based NO2 camera for urban pollution imaging

An instrument capable of imaging the field of NO2 in various open-air situations has been designed, manufactured, and tested. It is an improved version of the NO2 camera relying on an AOTF (acousto-optical tunable filter) which has demonstrated, amongst other things, its capability to quantify the NO2 released by power plant smokestacks. The...

Imaging PPG for In Vivo Human Tissue Perfusion Assessment during Surgery

Surgical excision is the golden standard for treatment of intestinal tumors. In this surgical procedure, inadequate perfusion of the anastomosis can lead to postoperative complications, such as anastomotic leakages. Imaging photoplethysmography (iPPG) can potentially provide objective and real-time feedback of the perfusion status of tissues....

An ECG- and PPG-Based Wearable Atrial Fibrillation Detection Device: Signal Acquisition

When symptoms of atrial fibrillation (AF), a common cardiac arrhythmia, are experienced, a Holter monitor or event recorder is used for official diagnosis. Apart from the fact that these devices are experienced as inconvenient, AF can already manifest damage in a pre-symptomatic phase. This thesis is aimed at developing a method for recording...

Classification Algorithm for Early Detection of Atrial Fibrillation: The Development of a Supervised Learning Method Using Photoplethysmography Signals for an ARM Processor

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia occurring in around 0.5% of the world population. AF is characterized by the rapid and irregular beating of the atrial chambers of the heart, which can cause lead to strokes and other heart-failures. To prevent these consequences the early detection of AF is paramount. Using...

Respiration and Heart Rate Monitoring of Neonates using Thermal Imaging

This project aims to explore the possibility of monitoring the vitals of the neonate remotely and without placing any sensors or electrodes on the subjects body using Thermal Imaging.

Adaptive Real-Time PPG Signal Qualification and Pulse Segmentation

Ever since its invention in the 1930s, photoplethysmography (PPG) is a wide-spread technique used for health-monitoring. Via illumination of the human skin with a light source and capturing the light, an estimate of important physiological properties such as the heart rate can be made. This is commonly done with dedicated medical equipment, but...

Real-Time Webcam Heart-Rate and Variability Estimation with Clean Ground Truth for Evaluation

Remote photo-plethysmography (rPPG) uses a camera to estimate a person’s heart rate (HR). Similar to how heart rate can provide useful information about a person’s vital signs, insights about the underlying physio/psychological conditions can be obtained from heart rate variability (HRV). HRV is a measure of the fine fluctuations in the...

The mental machine: Classifying mental workload state from unobtrusive heart rate-measures using machine learning

This paper investigates whether mental workload can be classified in an operator setting using unobtrusive psychophysiological measures. Having reliable predictions of workload using unobtrusive sensors can be useful for adaptive instructional systems, as knowledge of a trainee’s workload can then be used to provide appropriate training level...

Signal robustness dependency on sensor contact force in a novel photoplethysmography-based multi-purpose sensing device

A new photoplethysmography-based device called the Multiphotodiode Array (MPA) was validated to successfully measure the PWV in the vasculature of the distal phalanx of healthy subjects. It comprises an array of photodiodes and an array of opposing LEDs to detect blood volume changes due to the passing pressure pulse wave in the vasculature of...

Measuring pulse wave velocity with a novel, simple sensor on the finger tip: A feasibility study in healthy volunteers

Objective: The speed of pressure pulses traveling through the blood, the pulse wave velocity (PWV), is a metric that provides substantial information about the passive and active elasticity of the blood vessels. Therefore, PWV is a valuable parameter in the diagnosis of cardiovascular and vessel-related neurological diseases. The purpose of...

Design and functional testing of a novel blood pulse wave velocity sensor

The multiphotodiode array (MPA) is a novel transmission photoplethysmography (PPG) sensor to measure pulse wave velocity (PWV) in the finger. To validate the MPA, a setup was built to generate a red laser dot traveling over the MPA with known and constant scanning velocities. These scanning velocities were chosen to include speeds at least...

Increasing accuracy of pulse transit time measurements by automated elimination of distorted photoplethysmography waves

Photoplethysmography (PPG) is a widely available non-invasive optical technique to visualize pressure pulse waves (PWs). Pulse transit time (PTT) is a physiological parameter that is often derived from calculations on ECG and PPG signals and is based on tightly defined characteristics of the PW shape. PPG signals are sensitive to artefacts....

Heart rate measurement through PPG: Heartbeat measurement in a wireless headset

This thesis, assigned by Plantronics, proposes a solution to the motion artifacts that corrupt the results of PPG (Photo Plethysmo Graphic) signals and therefore the determined heart rate during physical exercises. An Infra-Red light emitting diode and phototransistor package was used to create a PPG signal that was amplified using an...