Remote sensing of the reflectance photoplethysmogram using a video camera typically positioned 1 m away from the patient's face is a promising method for monitoring the vital signs of patients without attaching any electrodes or sensors to them. Most of the papers in the literature on non-contact vital sign monitoring report results on human volunteers in controlled environments. We have been able to obtain estimates of heart rate and respiratory rate and preliminary results on changes in oxygen saturation from double-monitored patients undergoing haemodialysis in the Oxford Kidney Unit. To achieve this, we have devised a novel method of cancelling out aliased frequency components caused by artificial light flicker, using auto-regressive (AR) modelling and pole cancellation. Secondly, we have been able to construct accurate maps of the spatial distribution of heart rate and respiratory rate information from the coefficients of the AR model. In stable sections with minimal patient motion, the mean absolute error between the camera-derived estimate of heart rate and the reference value from a pulse oximeter is similar to the mean absolute error between two pulse oximeter measurements at different sites (finger and earlobe). The activities of daily living affect the respiratory rate, but the camera-derived estimates of this parameter are at least as accurate as those derived from a thoracic expansion sensor (chest belt). During a period of obstructive sleep apnoea, we tracked changes in oxygen saturation using the ratio of normalized reflectance changes in two colour channels (red and blue), but this required calibration against the reference data from a pulse oximeter.

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Non-contact video-based vital sign monitoring using ambient light and auto-regressive models

Recent studies in computer vision have shown that, while practically invisible to a human observer, skin color changes due to blood flow can be captured on face videos and, surprisingly, be used to estimate the heart rate (HR). While considerable progress has been made in the last few years, still many issues remain open. In particular, state of-the-art approaches are not robust enough to operate in natural conditions (e.g. in case of spontaneous movements, facial expressions, or illumination changes). Opposite to previous approaches that estimate the HR by processing all the skin pixels inside a fixed region of interest, we introduce a strategy to dynamically select face regions useful for robust HR estimation. Our approach, inspired by recent advances on matrix completion theory, allows us to predict the HR while simultaneously discover the best regions of the face to be used for estimation. Thorough experimental evaluation conducted on public benchmarks suggests that the proposed approach significantly outperforms state-of the-art HR estimation methods in naturalistic conditions.

/pdf/self-adaptive-matrix-completion-for-heart-rate-estimation-34gc3nht50.pdf

Self-Adaptive Matrix Completion for Heart Rate Estimation from Face Videos under Realistic Conditions

A display panel and a display device are provided. The display panel comprises a central region and peripheral regions. The peripheral regions are provided at two opposite ends of the display panel and have a first curvature; the central region is provided between the two opposite ends of the display panel and has a second curvature; and the second curvature of the central region is smaller than the first curvature of the peripheral regions.

Display panel and display device

The present invention relates to a device and a method for extracting information from detected characteristic signals. A data stream (76, 78, 80, 82) derivable from electromagnetic radiation (14) emitted or reflected by an object (11) is received and a plurality of characteristic index elements (50) varying over time can be extracted therefrom. The index elements (50) comprise physiological information (48) indicative of at least one at least partially periodic vital signal (12), and a disturbing signal component (58). For eliminating the disturbing signal component (58) to a great extent, the characteristic index elements (50) can be projected to a disturbance-reduced index element (64) having a distinct orientation in relation to a presumed orientation of the disturbing signal component (58). The disturbance-reduced index element (64) is chosen so as to reflect a dominant main orientation and length of the disturbing signal component (58) over time. Consequently, the mainly genuine physiological information (48) extracted from the data stream (76, 78, 80, 82) in this way can be utilized for determining the at least one at least partially periodic vital signal (12).

/pdf/device-and-method-for-extracting-information-from-w9n5x93vtn.pdf

Device and method for extracting information from characteristic signals

A method of remote monitoring of vital signs by detecting the PPG signal in an image of a subject taken by a video camera such as a webcam. The PPG signal is identified by auto-regressive analysis of ambient light reflected from a region of interest on the subject's skin. Frequency components of the ambient light and aliasing artefacts resulting from the frame rate of the video camera are cancelled by auto-regressive analysis of ambient light reflected from a region of interest not on the subject's skin, e.g. in the background. This reveals the spectral content of the ambient light allowing identification of the subject's PPG signal. Heart rate, oxygen saturation and breathing rate are obtained from the PPG signal. The values can be combined into a wellness index based on a statistical analysis of the values.

Remote monitoring of vital signs

A method of processing images of at least one living being, includes obtaining a sequence (19) of digital images taken at consecutive points in time. At least one measurement zone (26) comprising a plurality of image points is selected. For each measurement zone (26), a signal (28,30) representative of at least variations in a time- varying value of a combination of pixel values at at least a number of the image points for use in determining at least one of a presence and a frequency value of at least one peak in a spectrum of the signal (28,30) corresponding to a frequency of a periodic physiological phenomenon is obtained. The step (25) of selecting at least one measurement zone (26) includes analyzing information based on pixel data of a plurality of image parts in at least one of the images (19), each image part including at least one image point, and selecting each measurement zone (26) from contiguous parts determined to have similar characteristics.

Processing images of at least one living being

A liquid crystal display comprising first and second liquid crystal display panel (1, 3), each defining an array of picture elements (13, 15). The resolution of the image displayed on the second liquid crystal display panel (3) is lower than that of the image displayed on the first liquid crystal display panel (1). The picture elements (15) of the second liquid crystal display panel (3), located between the first liquid crystal display panel (1) and backlighting means (2) may be relatively large and preferably partially overlap at least in one direction. A charge is selectively applied to the picture elements (15) of the second liquid crystal display panel (3) corresponding to the relatively darker portions of the image to be displayed on the first liquid crystal panel (1), so as to at least limit the amount of light reaching these portions of the first liquid crystal display panel (1) and thereby increasing the contrast trio of the device. In an alternative embodiment, the image displayed on the second liquid crystal display panel (3) may be blurred relative to the image displayed on the first liquid crystal display panel (1) and/or the image displayed on the first liquid crystal display panel (1) may be sharpened relative to the image displayed on the second liquid crystal display panel (3 ) .

High contrast liquid crystal display device

A display (1) for displaying an image and a method for driving such display is proposed. Therein, the display comprises: a background light (31), a first LCD panel (3) defining an array of pixel elements (13), a second LCD panel (5) defining an arrayofpixel elements (29) and a control unit(37) for driving the first and second LCD panels (3, 5). The second LCD panel (5) is a color display and is arranged between the first LCD panel (3) and the background light (31). The control unit (37) is adapted to controlthe second LCD panel (5) such that a white color point of the display (1) may be adjusted. Preferably, a diffuser (33) is arranged between the first display (3) and the second display (5). Accordingly, on the one hand, such display shows enhanced displaying properties such as an increased contrast and viewing angle, while, on the other hand, the white color point of the display can be adjusted as desired by using the controlunit(37) for correspondingly controlling the second LCD panel (5) being preferably a low resolution color display.

High contrast liquid crystal display with adjustable white color point

A fragrance apparatus comprising a fragrance dispensing unit having a plurality of fragrance dispensers being refillable, the fragrance dispensing unit being disposed in a modular housing unit and a control unit disposed in the modular housing unit, the control unit configured to control the fragrance apparatus such that the fragrance dispensing unit generates a spatio-temporal pattern of fragrance and/or removes the generated spatio-temporal pattern of fragrance is disclosed. The disclosed fragrance apparatus is useful in atmosphere creation.

Modular fragrance apparatus

The invention relates to a sleep element (1) like a heating blanket for improving the sleep of a person. The sleep element comprises a property determination unit (2, 5) for determining a property of a person, a thermal energy unit (3) for transferring thermal energy to or away from the person, and a thermal energy control unit (4) for controlling the thermal energy unit depending on the determined property of the person. Since the sleep element comprises the property determination unit, the thermal energy unit, and the thermal energy control unit, the temperature of the person can be controlled depending on a determined property of the person, while the person is sleeping, such that the sleep of the person is improved. Moreover, the temperature control can simply be used within a bed by placing the sleep element in the bed. The handling of the temperature control is therefore very simple.

Dmitri Chestakov

Papers

Processing images of at least one living being

High contrast liquid crystal display device

High contrast liquid crystal display with adjustable white color point

Modular fragrance apparatus

Sleep element for improving the sleep of a person