Thermal image processing for real‐time non‐contact respiration rate monitoring

Abstract

A real-time thermal imaging based, non-contact respiration rate monitoring method was developed. It measured the respiration related skin surface temperature changes under the tip of the nose. Facial tracking was required as head movements caused the face to appear in different locations in the recorded images over time. The algorithm detected the tip of the nose and then, a region just under it was selected. The pixel values in this region in successive images were processed to determine respiration rate. The segmentation method, used as part of the facial tracking, was evaluated on 55,000 thermal images recorded from 14 subjects with different extent of head movements. It separated the face from image background in all images. However, in 11.7% of the images, a section of the neck was also included, but this did not cause an error in determining respiration rate. The method was further evaluated on 15 adults, against two contact respiration rate monitoring methods that tracked thoracic and abdominal movements. The three methods gave close respiration rates in 12 subjects but in 3 subjects, where there were very large head movements, the respiration rates did not match.

Pencil‐drawn Paper‐based Non‐invasive and Wearable Capacitive Respiration Sensor

“…In addition, the movement of the patient dislodge the sensor and errors are introduced in the final measurement. The non‐contact methods to measure breath pattern include thermal imaging and Doppler radar sensors . These sensors require expensive hardware and strict positional requirements and it is very difficult to fulfil all these requirements.…”

Development of a High-Resolution Infrared Thermographic Imaging Method as a Diagnostic Tool for Acute Undifferentiated Limp in Young Children.

“…However, issues including the camera's optimum focus, zoom and practicalities such as ensuring an adequate distance from the child to avoid disturbing him/her limit the closeness of the camera to the subject. In our previous studies involving thermal imaging from children, a distance of 1 m proved effective [10]. Instead of recording a single image, a 20-s video recording was obtained, repeated with the patient in four different positions, i.e.…”

“…In children, previous studies have shown IRT to be an effective tool in respiratory monitoring, using nasal temperature differentials determined through image tracking systems [10][11][12][13]. Additionally, IRT has been successfully applied to the diagnosis of varying degrees of paediatric skin burn, with a reported sensitivity and specificity often greater than that of clinical assessment [14,15].…”

An Implementation of Non-Contact Respiratory Monitoring System with Advanced Nasal-Mandible Tracking Algorithm with Roi

“…George B. Moody, et al developed a contact modality in which numerous Electrocardiogram (ECG) electrodes and sensors are attached to the subject [1]. The principle of operation is based on the fact that the heart rate is typically modulated by breathing, a phenomenon known as sinus arrhythmia [2]. Therefore, a signal corresponding to the heart function contains breath information, which is filtered out using bandpass filters.…”

“…Respiratory inductance plethysmography is a non-invasive technique whereby two bands measure the respiration rate, the thoracic band which is placed around the rib cage and the abdominal band which is placed over the abdomen at the level of the umbilicus. The bands are made from an extendible/deformable conducting material, either a very fine wire or thin foil such that the conductivity can be maintained during the stretching process [2,5]. The principle of the strain gauge sensor is based on increase in the resistance of a conductor when the area of the conductor is increased during the respiration process.…”