System and method for extracting physiological information from remotely detected electromagnetic radiation

Abstract

The present invention relates to a device and a method for extracting physiological information indicative of at least one health symptom from remotely detected electromagnetic radiation. The device comprises an interface (20) for receiving a data stream comprising remotely detected image data representing an observed region comprising at least one subject of interest (12), wherein the image data comprises wavelength-dependent image information, wherein the wavelength-dependent image information is composed of at least two color channels (96, 98, 100) representative of respective wavelength portions; an image processor (22) for detecting channel signal strength information for at least two of the at least two color channels (96, 98, 100); and a data comparison unit (24) for comparing detected channel signal strengths with respective reference values.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a system and a method for extracting physiological information indicative of at least one health symptom from remotely detected electromagnetic radiation. More particularly, the present invention may contribute in analyzing vital signs information indicative of vital parameters, physiological parameters or, more generally, health parameters. The electromagnetic radiation may be considered as radiation in the visible wavelength band re-emitted by a subject of interest. As used herein, visible radiation may relate to radiation in a particular wavelength range which is visible to a human eye, or, at least to a sensing device. Even more specifically, the present invention may relate to (visible) image capturing and processing systems and corresponding methods for detecting and monitoring vital parameters and / or symptom-indicative information which may be applied, for instance, in the field of remote monitoring, such as remote ...

AI Technical Summary

Benefits of technology

[0022]More particularly, it would be advantageous to provide a device and a corresponding method being capable of adequately processing remote PPG information without requiring multiple signal transformation steps. In other words, it would be beneficial to provide a method and a system for extracting physiological information that are particularly adapted to remotely detected image data which generally may comprise enormous disturbances and noise-affected portions.

[0034]According to another aspect, the at least two color channels are associated with a color model, the color model being based on a color model convention allocating respective wavelength portions to the at least two color channels. Basically, a color model may provide sufficient information allowing for digitization of originally analogous image information. In other words, under consideration of the color model, real colors may be transferred into “bits and bites”.

[0035]According to yet another aspect, the color model is color space based on a color space mapping convention, wherein respective wavelength portions are assigned to respective axes of the color space. Basically the color model may provide a mathematical model describing a digital representation of colors. The color space, however, may be considered as an appropriate color representation based on the respective color model. Such a means may be beneficial since in this way color properties may be presented by geometric entities, such as vectors, which may facilitate handling and processing the respective data.

[0037]By way of example, given the exemplary RGB-color space embodiment, a blue to red ratio (B / R) or a red to green and blue ratio (R / (G+B)) may be indicative of respective health symptoms. Comparing such a ratio with a respective reference ratio may reveal significant deviations. In case a deviation-representative value exceeds a predefined threshold, a clear indication of an occurrence of a symptom may be provided. According to a further embodiment the symptom analyzer is configured for detecting a level of serum bilirubin in the subject's circulating blood under consideration of detected channel strength fluctuations. An increased level of serum bilirubin may be considered as a strong indicator for jaundice. Neonatal jaundice is a yellowing of the skin and other tissues of a new born infant. Jaundice may also occur among adults. The color change is attributed to an increased level of bilirubin. Management and treatment of jaundiced subjects typically requires assessing and monitoring the level of serum bilirubin. According to the above aspect, the system may provide for a long-term unobtrusive bilirubin measurement. In this way, blood sampling and further obtrusive measurement methods can be avoided, at least to a great extend.

[0039]In a jaundiced subject, an increased bilirubin level may be present in the subject's circulating blood. However, due to diffusion, bilirubin may also accumulate in the subject's skin tissue. Both bilirubin concentrations in the blood and in the skin may affect the image data from which the desired health information may be obtained. It may be thus beneficial to determine and assess an increase of the bilirubin level in the blood and an increase of the bilirubin level in the skin tissue of the subject. It has been further observed that during treatment of jaundice the level of bilirubin in the skin tissue may be reduced faster than the level of bilirubin in the blood. Consequently, the ability of detecting the level of bilirubin in the blood and the level of bilirubin in the skin tissue allows for the determination of further health-indicative values which may be utilized, for instance, for managing and controlling the treatment of jaundice.

[0042]According to a preferred embodiment, the system further comprises an image sensor for remotely recording video data, the image sensor comprising a responsivity (or: sensitivity) adapted to capture electromagnetic radiation in at least two wavelength portions corresponding to the at least two color channels. In this way, consistent image data encoding and processing may be ensured. When the system also incorporates the image sensor, such as an RGB-camera, a high level of signal integration may be achieved. As indicated above, rather conventional consumer level video cameras may be utilized. It is even further preferred that the camera, the image processor and further components of the system basically apply the same color model. The sensitivity of the image sensor may cover, at least, a considerable portion of visible radiation. However, in some embodiments, the sensitivity of the image sensor may further cover at least a portion of infrared radiation and / or ultraviolet radiation.

Problems solved by technology

This may be experienced as being considerably unpleasant.

Since reflection mechanisms in the subject's skin are rather complex and multi-dependent on factors such as wavelengths, penetration, depth, skin composition, vascular system structure, and further influencing parameters, terms such as “emitted”, “transmitted” and “reflected” shall not be understood in a limited way.

In many cases, this is considered unpleasant, particularly for long-term monitoring.

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