Design And Implementation Of Noncontact Heart Rate Measurement System Based On A Camera

Heart rate is an important indicator for detection of human physiological parameters,and it has important reference value in personal daily health monitoring.Real-time monitoring of heart rate can effectively prevent and control the occurrence of cardiovascular diseases.Traditional medical heart rate detection methods are contact-type detection methods.This method relies on special electronic or optical sensors.The sensor needs to have direct physical contact with the skin,which often causes discomfort to the subject.In addition,this method has high safety and technical requirements in the measurement process,and is complicated in operation and is not convenient for detection in daily life.The non-contact heart rate detection method based on an imaging device overcomes the disadvantages of the conventional contact method and has a high performance-price ratio and is simple to operate.It is suitable for the advantages of large-scale group clinical and daily physiological signal detection.It has laid a good foundation for the development of smart medical in the Internet of Things and has become one of the research hotspots in the biomedical field.On the other hand,imaging devices such as web cameras,surveillance cameras and cell phone cameras are widely seen today.It makes it possible to popularize the application of heart rate detection technology based on imaging equipment in daily health monitoring and telemedicine.In this paper,the existing imaging heart rate detection technology to extract signal noise,weak signal and other issues related research.The work of this article is divided into four parts,as follows:The first part: Introduce the importance of heart rate detection and expound the necessity of non-contact heart rate detection.The development status of two non-contact heart rate detection techniques(imaging photoplethysmography and ballistocardiography)based on imaging devices at home and abroad are introduced.At the same time,it elaborated on its theoretical basis,system composition and working principle.The second part : The non-contact heart rate measurement method based on head movement was introduced in detail,and its technical method and detailed steps were described.A comparative experiment was designed to verify the feasibility of the method.Experiments have shown that the measurement method based on head movement has obvious advantages.This method is not limited to the naked skin and is visible in the face,and it is also effective even when it is completely invisible.Based on the above research,a centroid tracking method was used to achieve the heart rate measurement without skin exposure.A comparative experiment was set up to verify the reliability of the study.This method can improve the signal to noise ratio of the effective signalThe third part: For the problem that the head trajectory signal is weak and the noise is relatively large,an IBCG signal extraction method based on the principle of optical lever is proposed.Heart rate detection is realized by designing the system.The comparison experiment is set up,and the experiment proves that compared with the original method,the method improves the operation speed of the heart rate detection,and improves the signal-tonoise ratio and the accuracy of the heart rate of the signal.The fourth part: We propose a heart rate measurement method based on weighted average to improve signal-to-noise ratio of IPPG signal.The design and implementation of the heart rate measurement system based on this method are mainly described.Comparing with the previous methods,experiments show that this method can improve the signal-tonoise ratio of IPPG signal to a certain extent.