International Refereed Journal of Engineering and Science (IRJES) ISSN (Online) 2319-183X, (Print) 2319-1821 Volume 6, Issue 7 (July 2017), PP.50-58 www.irjes.com 50 | Page Evaluation of Thresholding Based Noncontact Respiration Rate Monitoring using Thermal Imaging. * Abdulkadir Hamidu Alkali Department Of Computer Engineering.University Of Maiduguri, Borno State, Nigeria. Corresponding author: *Abdulkadir Hamidu Alkali Abstract: - A noncontact method for respiration rate monitoring using thermal imaging was developed and evaluated. Algorithms to capture images, detect the location of the face, locate the corners of the eyes from the detected face and thereafter locate the tip of the nose in each image were developed. The amount of emitted infrared radiation was then determined from the detected tip of the nose. Signal processing techniques were then utilised to obtain the respiration rate in real-time. The method was evaluated on 6 enrolled subjects after obtaining all ethical approvals. The evaluations were conducted against two existing contact based methods; thoracic and abdominal bands. Results showed a correlation coefficient of 0.9974 to 0.9999 depending on the location of the ROI relative to the detected tip of the nose. The main contributions of the work was the successful development and evaluation of the facial features tracking algorithms in thermal imagining, the evaluation of thermal imaging as a technology for respiration monitoring in a hospital environment against existing respiration monitoring systems as well as the real time nature of the method where the frame processing time was 40 ms from capture to respiration feature plotting. Keywords: - Image processing, Noncontact, Real-time, Respiration monitoring, Thermal imaging, Thresholding. INTRODUCTION Oxygen is a naturally occurring element in the atmosphere which the body uses as part of a process to obtain energy. Air-rich oxygen enters the lungs through inspiration from where oxygen goes into the blood stream via the capillaries and is transported all over the body. During expiration de-oxygenated air containing the produced carbon dioxide is returned to the atmosphere. The average number of breathes taken over a predefined period of time is respiration rate. Its value depends on several factors that include the person‟s age, gender and medical condition. It ranges between 12 to 60 cycles per minute in healthy adults and children. During respiration, a number of physiological effects take place that are the bases for respiration monitoring. These include variations in air flow as air is inhaled and exhaled, chest/abdomen movements, blood oxygen saturation variations, temperature changes in inhaled and exhaled air and variations in the amount of emitted infrared radiation from the skin surface centred on the nose and mouth. An uneven respiration rate is a good indicator of imbalance of the normal body condition [1] that studies [2-5] have shown to be a predictor of potential serious clinical events. Early detection and proactive intervention of the predicted condition can avert a potential serious harm [6,7]. Respiration rate therefore, needs to be accurately monitored to establish correct physiological operations in order to take the necessary clinical steps. Existing gold standard devices for monitoring respiratory rate make contact with the subject‟s body during monitoring and are therefore, referred to as contact based. They mostly require the subject to be constrained and thus disturb the sleep position which affects normal breathing. Since a natural sleep position does not alter breathing, it is therefore, critical that respiration monitoring does not alter it as well. In noncontact respiration monitoring, the device is not attached to the subject‟s body and therefore, a more reliable medical assessment can be obtained. Studies have reported that noncontact based methods for monitoring respiratory rate are better than contact based methods [8-11]. They attributed this to improved patient‟s comfort, improved accuracy due to elimination of distress as well as non-possibility of disruption of monitoring as a result of dislodgement of the sensing device. In this study, technique to facilitate noncontact respiration rate monitoring has been developed and its effectiveness was evaluated. The technique was based on measuring detecting the amount of emitted infrared radiation from the skin surface centred on the nose (thermal imaging method). This is based on a fact that during respiration, exhaled air is warmer than inhaled air. The air temperature variation during respiration results in temperature variation along the air flow path especially the area around the tip of the nose and upper lip regions thereby resulting in corresponding variation in the amount of emitted infrared radiation from those areas. These continuous variations in infrared emissions around the affected regions can be observed and processed by