Non-contact detection of oxygen saturation based on visible light imaging device using ambient light

Abstract

A method that remotely measures blood oxygen saturation through two cameras under regular lighting is proposed and experimentally demonstrated. Two narrow-band filters with their visible wavelength of 660nm and 520nm are mounted to two cameras respectively, which are then used to capture two photoplethysmographic (PPG) from the subject simultaneously. The data gathered from this system, including both blood oxygen saturation and heart rate, is compared to the output of a traditional figure blood volume pulse (BVP) senor that was employed on the subject at the same time. Result of the comparison showed that the data from the new, non-contact system is consistent and comparable with the BVP senor. Compared to other camera-based measuring method, which requires additional close-up lighting, this new method is achievable under regular lighting condition, therefore more stable and easier to implement. This is the first demonstration of an accurate video-based method for non-contact oxygen saturation measurements by using ambient light with their respective visible wavelength of 660nm and 520nm which is free from interference of the light in other bands.

An evaluation study of vital parameter determination with RGB cameras in the field of ambient assisted living

“…A narrow band is to be preferred. The second setup consist of two cameras, which are equipped with narrow optical bandpass filters [24]. This approach is accurate in combination with the ratio-of-ratio approach.…”

Oxygen saturation detection aided with the theory of lock-in amplifier

“…The output signal 0 U is: Blood saturation is used to indicate the intensity of oxygen in blood [5] , which is defined as…”

Noncontact measurement of heart rate using facial video illuminated under natural light and signal weighted analysis

“…Currently, the methodologies have been investigated through analyzing the intensity of the diffuse reflection light on human face [14][15][16][17][18] based on the PPG technique. Wu, et al [14] amplified the diffuse reflection light intensity signal and measured the flow of blood as it fills the face using the videos illuminated in natural light.…”