SE2130200A1

SE2130200A1 - A sensing arrangement for obtaining data from a body part

Info

Publication number: SE2130200A1
Application number: SE2130200A
Authority: SE
Inventors: Fredrik Malmsten; Lars Carlsson; Roy Forslund; Thomas Petig; Tommy Hansson
Original assignee: Rths Ab
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-17
Also published as: WO2023285087A1

Abstract

A sensing arrangement (100) for obtaining data from captured light reflected by and/or transmitted through a body part (110). The sensing arrangement comprises illumination means (120) comprising one or more emitters (121) arranged to illuminate at least a portion of the body part (110). The illumination means is arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions (B1;...;B6) from the one or more emitters to the body part (110). The sensing arrangement further comprises optical sensing means (130) arranged to capture light reflected by and/or transmitted through the body part (110). The optical sensing means is arranged at a distance from at least one emitter (121). The optical sensing means is arranged facing the body part and is arranged on a line (S1) between the optical sensing means (130) and the body part (110). The line (S1) is arranged at a non-zero angle with respect to an extension directions of at least one transmit beam (B1;...;B6).

Description

TITLE A SENSING ARRANGEMENT FOR OBTAINING DATA FROM A BODY PART TECHNICAL FIELD The present disclosure relates to sensing arrangements for obtaining data from captured light reflected by and/or transmitted through a body part. The data may comprise biometric identification data and/or vital data. The sensing arrangements may be used in a control system for allowing ingress to a person.

BACKGROUND Considering recent pandemic and epidemic spreads of infectious diseases like SARS, MERS, and COVID-19, finding ways of limiting the spread is crucial. Since symptoms of disease may not be detected by the infected individual before he or she has become contagious, one viable option is to automatically scan vital signs of people entering locations where people move, meet, and gather, such as offices, airports, and arenas, and denying entry to people showing any signs of infectious disease and sickness. Automatic scanning, however, faces many challenges regarding accuracy, speed, and cost.

Vital data comprising various vital parameters may be obtained from captured light reflected by and/or transmitted through a body part. Sensing arrangements for obtaining such data may also be used for obtaining biometric identification data. Checking the identity of a person entering the locations mentioned above can be a required compliment to checking vital signs.

Existing sensing arrangements typically only provide accurate data for certain skin types, which means that they cannot be used accurately on all people. Therefore, there is a need for improved sensing arrangements.

SUMMARY lt is an object of the present disclosure to provide improved sensing arrangements, which, i.a., offer improved sensing performance for wide range of different skin types.

This object is at least in part obtained by a sensing arrangement for obtaining data from captured light reflected by and/or transmitted through a body part. The sensing arrangement comprises illumination means comprising one or more emitters arranged to illuminate at least a portion of the body part. The illumination means is arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions from the one or more emitters to the body part. The sensing arrangement further comprising optical sensing means arranged to capture light reflected by and/or transmitted through the body part. The optical sensing means is arranged at a distance from at least one emitter, The optical sensing means is arranged facing the body part and is arranged on a line between the optical sensing means and the body part. The line is arranged at a non-zero angle with respect to an extension direction of at least one transmit beam.

The disclosed sensing arrangement improves signal to noise ratio (SNR) by emitting and sensing at least three different discrete wavelengths. This enables data to be obtained from a comparison of captured light of at least two different wavelengths even if the captured light of one wavelength has poor SNR. lf more than three wavelengths are used, this robustness increases further. Here poor SNR means that the captured light does not yield data with sufficient accuracy. lf one of the emitted discrete wavelengths is absorbed to a large amount by the body part, reflected and/or transmitted light will be weak, i.e., have a low intensity. This results in a poor SNR for that the captured light of that particular wavelength. Using at least three wavelengths thus enables data acquisition with high accuracy for many different skin types.

A non-zero angle with respect to a transmit beam means that the one or more sensors of the optical sensing means are not arranged directly in the extension direction of that beam. Such direct path is undesired since light from the illumination means that has not been reflected and/or transmitted through the body part does not comprise any information of the body part. The non-zero angle results in the undesired light emitted from a direct path between the illumination means to the sensing means is avoided. Thus, the non-zero angle improves SNR.

According to aspects, the optical sensing means is arranged in a separate housing from the illumination means. This can provide additional shielding from undesired light from the illumination means from a direct path. Furthermore, undesired light that has been reflected can also be reduced, i.e., light not lightfrom the illumination means that has not been reflected and/or transmitted through the body part but has been reflected on a wall or such. This way, SNR is improved further.

According to aspects, the illumination means comprises a respective emitter for each Wavelength. This is a cost-effective Way of providing a plurality of different discrete Wavelengths.

According to aspects, wherein the optical sensing means comprises a respective sensor for each wavelength. This way, all wavelengths may illuminate the body part simultaneously and all wavelengths can be captured simultaneously. This provides fast measurements and improved accuracy since all wavelengths comprise data of the same time instance.

According to aspects, wherein the extension directions of a least t\No transmit beams are parallel.

According to aspects, the illumination means is distributed to transmit at least two beams from different locations. This Way, redundancy is introduced. lf one emitter illuminates the body part such that little light is captured by the optical sensing means, another emitter at another location may provide light giving better data.

According to aspects, the sensing arrangement comprises ranging means arranged to obtain a distance between the body part and the optical sensing means. This way, accurate measurements of relative movement of the body part or sections of the body part can be obtained, such as the movement resulting from the heartbeat, breathing etc..

According to aspects, the ranging means comprise the optical sensing means and a laser arranged in proximity to the optical sensing means. lt is beneficial to reuse the optical sensing means for this purpose since it saves costs and space.

According to aspects, wherein the data comprises biometric identification data and/or vital data.

According to aspects, wherein the optical sensing means comprises one or more CameFaS.

According to aspects, the body part is a hand and/or a wrist. These body parts provide accurate data and a non-intrusive way of obtaining data.

According to aspects, wherein the illumination means is arranged to illuminate the body part with six discrete wavelengths. This provides more robustness against if one or more wavelengths present poor SNR. Furthermore, different data can be revealed since different wavelengths penetrate body parts at different levels.

According to aspects, at least one wavelength is within any of the visible spectrum, the infrared spectrum, and the ultraviolet spectrum. According to further aspects, at least one wavelength is between 600-700 nm, preferably between 640-680 nm, and more preferably about 660 nm, and at least another wavelength is between 800-1000 nm, preferably between 850-890 nm, and more preferably about 870 nm. Light comprising wavelengths within the red/green spectrum is typically reflected at the surface of human skin. This reflection can therefore be used to reveal skin pattern, such as palm print, i.e. principal lines, secondary lines (wrinkles), and epidermal ridges. lnfrared light on the other hand, tends to penetrate into the skin a few millimeters before it is reflected. Therefore, infrared reflections can be used to reveal blood vessel patterns, i.e. arteries, arterioles, capillaries, venules, and veins. Using different specific wavelengths that penetrate the skin differently can therefore provide data for different layers of the body part. Such data can, e.g., be used as unique identification means for a person.

According to aspects, the sensing arrangement further comprises a control unit arranged to obtain a blood oxygen saturation from magnitudes of at least two of the discrete wavelengths of the captured light. A low oxygen saturation could be a symptom of a contagious condition, e.g., a COVID -19 infection or other infections.

According to aspects, the sensing arrangement further comprises a control unit arranged to obtain a heart rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light. An increased pulse and heart rate are common findings in infectious diseases.

According to aspects, the sensing arrangement further comprises a control unit arranged to obtain a breathing rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light. An increased breathing frequency could be a symptom of an ongoing infection like COVID-19.

According to aspects, the sensing arrangement further comprises a control unit arranged to obtain a blood pressure from a comparison of variations over time of the magnitude of at least one of the wavelengths of the captured light at different locations of the illuminated body part. A high blood pressure is quite common but can be a symptom in an infected subject.

According to aspects, at least one of the at least three discrete wavelengths emitted by the illumination means is arranged to excite a marker administered (e.g., injected) in the blood flowing through the body part. This Way, additional information can be obtained from the body part, e.g., the presence or concentration of an anti-body.

There is also disclosed herein a method for obtaining data from captured light reflected by and/or transmitted through a body part. The method comprises illuminating at least a portion of the body part With illumination means comprising one or more emitters, Where the illumination means is arranged to transmit at least three discrete wavelengths of light With respective transmit beams extending along respective extension directions from the one or more emitters to the body part, and capturing light reflected by and/or transmitted through the body part With optical sensing means, wherein the optical sensing means is arranged at a distance from at least one emitter, and wherein the optical sensing means is arranged facing the body part and is arranged on a line between the optical sensing means and the body part, wherein the line is arranged at a non-zero angle With respect to an extension direction of at least one transmit beam.

According to aspects, the data comprises biometric identification data and/or vital data.

According to aspects, the vital data comprises any of the following vital parameters: heart rate, blood oxygen saturation, pulse, and blood pressure.

According to aspects, the optical sensing means is arranged in a separate housing from the illumination means.

According to aspects, the method comprises obtaining data from the body part at a plurality of occasions. This Way, information can be obtained from analyzing a value of deviation instead of the absolute value of a parameter. Furthermore, this can be used to establish individual base values of a parameter.

According to aspects, the method comprises illuminating the body part with at least one discrete wavelength arranged a to excite a marker administered in the blood flowing through the body part. This way, additional data can be obtained, such as the presence of antibodies.

The methods disclosed herein are associated with the same advantages as discussed above in connection to the different apparatuses. There is also disclosed herein computer programs, computer program products, and control units associated with the above-mentioned advantages.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated othenNise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will now be described in more detail with reference to the appended drawings, where Figures 1-2 illustrate example sensing arrangements, Figure 3 is a flow chart illustrating methods, Figure 4 schematically illustrates a control unit, Figure 5 shows a computer program product, and Figures 6A-6C show different views of an example sensing arrangement.

DETAILED DESCRIPTION Aspects of the present disclosure will now be described more fully with reference to the accompanying drawings. The different devices and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for describing aspects of the disclosure only and is not intended to limit the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates othenNise.

There is herein disclosed a sensing arrangement 100 for obtaining data from an illuminated body part 110 of a person. Figures 1, 2 and 6A-6C show different embodiments of the sensing arrangement 100. The sensing arrangement comprises illumination means 120 arranged to illuminate at least a portion of the body part 110, and optical sensing means 130 arranged to capture light reflected by and/or transmitted through the body part 110. The optical sensing means may comprise one or more cameras. The data may comprise biometric identification data and/or vital data, although other types of data may also be extracted from the body part. Data may also include presence and/or concentrations of molecules, antibodies, drugs, alcohol, proteins etc. present in the blood flowing through the body part. The body part 110 preferably is a hand and/or a wrist. ln that case, the illumination means may be arranged to illuminate the whole hand or a section of it, such as a 3 cm by 3 m square in the palm. The illumination means may be arranged to emit beams intersecting in a point on or in the body part. The body part may be other parts of a body, such as the earlobe, nose, foot etc. lt may further be a large portion of a body, such as the torso with or without arms, or the whole body.

The sensing arrangement 100 may be arranged in any location where people move, meet, and gather. The sensing arrangement 100 can increase the safety for people and also increase the feeling of being safe for the people on the location. lt will make people more relaxed and able to enjoy the event, the game, the trip, the food, or sight, instead of worrying about their surroundings. A few example locations are museums, sporting, events, malls, education, travel, restaurants, concerts, conferences, and parliaments.

The sensing arrangement may be used in access control system for allowing access to a person deemed free from infectious disease and sickness and/or passing an authorization check. The access control system may comprise a gate or the like to temporarily block ingress. Alternatively, or in combination of, the access control system may comprise a light arranged to indicate if a person should be allowed access. The light can, e.g., switch between a green and red light to indicate ifa person should be allowed access or not.

The identification check may comprise a set of biometric identification data values of persons authorized for access. Such authorized person can be a person that is allowed to enter, as in an office building. lt can also mean anyone except people explicitly not allowed to enter, as in a passport control or an arena.

The disclosed sensing arrangement 100 can be used as a real time health scanner using automated scanning with no surface touch. The system enables a safer way for people to meet, travel, and enjoy things together. The system can e.g. detect symptoms of COVID-19 and other possible infections in just a few seconds or less. A symptom can be abnormal vital parameters. According to some aspects, the disclosed sensing arrangement can measure the five following vital parameters of a person for a highly sensitive and accurate measurement of symptoms of disease.

- Breathing rate. An increased breathing frequency could be a symptom of an ongoing infection like COVID-19.

- Oxygen Saturation. A low oxygen saturation could be a symptom of a COVID -19 infection or other infections.

- Body Temperature. An above normal body temperature can be symptoms of many infections.

- Heart rate. An increased pulse and heart rate are common findings in infectious diseases.

- Blood pressure. A high blood pressure is quite common but can be a symptom in an infected subject.

As mentioned, the disclosed sensing arrangement 100 can obtain biometric identification data of the person for determining the identity of the person. The biometric identification data may comprise any of vein pattern, artery pattern, and skin pattern. Other data extracted from the illuminated body part may also be used as biometric identification data. The biometric identification data may be used for an identification check, which comprises comparing obtained biometric identification data to a pre-determined set of biometric identification data values. The set of biometric identification data values can, e.g., comprise previously scanned vein patterns of a number of people, such as all employees in an office building.

Although identity cards, near-field communication tags, passwords etc. can be used for determining the identity of the person, their level of security is limited since they can be lost or stolen. Identification means using biometric data, on the other hand, can be intrinsically more secure. Biometric data commonly used for identification are fingerprints, iris scans, and facial recognition. Fingerprint scanning, however, often require physical contact between the finger and the scanner. This is unhygienic and is counterproductive to the prevention of contagion. This can be alleviated by using disinfectants, which may not be able to guarantee total disinfection and is an inconvenience and expense. lris scanning is inconvenient and facial recognition may require extensive computational effort and computational training. Facial recognition may further feel invasive to the person.

The vital data may be used for a health test, which comprises comparing obtained vital data to a pre-determined set of vital data values. The set of vital data values in the health test can comprise ranges of allowable values. For example, the comparison of body temperature can comprise checking if the obtained value is within 36.5-37.5 °C. lfthe obtained body temperature is within this range, the person passes the health test, or at least partly if more vital parameters are observed.

To summarize, there is disclosed herein a sensing arrangement 100 for obtaining data from captured light reflected by and/or transmitted through a body part 110. The sensing arrangement comprises illumination means 120 comprising one or more emitters arranged to illuminate at least a portion of the body part 110. The illumination means is arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions B1;...;B6 from the one or more emitters to the body part 110. The sensing arrangement 100 also comprises optical sensing means 130 arranged to capture light reflected by and/or transmitted through the body part 110. The optical sensing means is arranged at a distance from at least one emitter 121. The optical sensing means is arranged facing the body part and is arranged on a line S1 between the optical sensing means 130 and the body part 110. The line S1 is arranged at a non-zero angle with respect to an extension direction of at least one transmit beam B1;...;B6.

Different wavelengths penetrate human skin at different levels, which can reveal different data. Furthermore, a specific wavelength is absorbed by different amounts for different skin types. One factor affecting absorption for a wavelength is melanin concentration. Vital data, such as blood oxygen saturation, can be obtained by analyzing light reflected and/or transmitted through the body part for two different discrete wavelengths. Other vital parameters and other data can also be obtained by comparing captured light at two different discrete wavelengths. lt is also possible to use three or more discrete wavelengths. According to aspects, each of the discrete wavelengths are separated from each other by a distance in the spectrum, e.g., by 100 nm. lf one of the emitted discrete wavelengths is absorbed to a large amount, reflected and/or transmitted light will be weak, i.e., have a low intensity. This results in a poor signal to noise ratio (SNR) for that the captured light of that particular wavelength. This means the ratio of the desired signal, i.e., the reflected and/or transmitted light, over undesired sources, such as ambient light from the sun or lighting arrangements. Undesired light can also be light from the illumination means 120 that has not been reflected and/or transmitted through the body part 110 since such light does not comprise any information of the body part. Such light can be emitted from a direct path between the illumination means 120 to the optical sensing means 130 or via a reflection from a wall or the like. lf the body part is hand, a direct path can occur, e.g., between the fingers or at the edges of the hand. Preferably, the light illuminating the body part has passed through or has been reflected by blood. That way, various vital parameters can be obtained accurately. As such, light only passing through the edge of a body part, without hitting blood, may also be undesired.

Other noise will also degrade SNR, such as noise added by the equipment, such as thermal noise and shot noise. lf the absorption of a wavelength is large, increasing the intensity of the emitted light of that wavelength may not be sufficient to improve SNR.

The disclosed sensing arrangement improves SNR by emitting and sensing at least three different discrete wavelengths. According to aspects, the illumination means 120 is arranged to illuminate the body part 110 with six discrete wavelengths. Using, e.g., three different wavelengths enables data to be obtained from a comparison of captured light of two different wavelengths even ifthe captured light at one wavelength has poor SNR. Here poor SNR means that the captured light does not yield data with sufficient accuracy. Using multiple wavelengths thus enables data acquisition with high accuracy for many different skin types. The inventors of the present disclosure have realized that six different wavelengths result in reliable data for a vast number of different skin types.

According to aspects, a vital parameter is calculated using captured light at the two wavelengths presenting the best SNR out of all of the emitted wavelengths. However, light captured at one or more wavelengths with poor SNR are not necessarily ignored. These signals may be used to some extent when calculating vital parameters, e.g., blood oxygen saturation. ln that case, these signals may be used with some weighting to decrease their influence on the obtained vital parameters.

Preferably, at least one discrete wavelength is within any of the visible spectrum, the infrared spectrum, and the ultraviolet spectrum. Even more preferably, at least one 11 wavelength is within the blue/green spectrum and at least another wavelength is within the infrared spectrum. According to aspects, at least one wavelength is between 600-700 nm, preferably between 640-680 nm, and more preferably about 660 nm, and at least another wavelength is between 800-1000 nm, preferably between 850-890 nm, and more preferably about 870 nm.

Light comprising discrete wavelengths within the red/green spectrum is typically reflected at the surface of human skin. This reflection can therefore be used to reveal skin pattern, such as palm print, i.e. principal lines, secondary lines (wrinkles), and epidermal ridges. lnfrared light on the other hand, tends to penetrate into the skin a few millimeters before it is reflected. Therefore, infrared reflections can be used to reveal blood vessel patterns, i.e. arteries, arterioles, capillaries, venules, and veins. Using different specific wavelengths that penetrate the skin differently can therefore provide biometric data for different layers of the body part. Such biometric data can be used as unique identification means for a person.

The optical sensing means is arranged facing the body part and is arranged on a line S1 between the optical sensing means 130 and the body part 110. lf the optical sensing means 130 comprises a single sensor (e.g., a camera) arranged in a housing, a normal direction of the housing is parallel to the line, i.e., the camera faces the body part, and the body part is arranged centrally in a picture captured by the camera. Normally, the optical sensing means 130 comprises a single housing, as is shown in Figures 1 and 2. This housing may comprise a single sensor, as is shown in Figure 1, or a plurality of sensors, as is shown in Figure 2.

As mentioned, the optical sensing means 130 is arranged at a distance from one or more emitters 121. This way, undesired leakage of light not reflected or passing through the body part can be reduced, which improves SNR. Preferably, the optical sensing means 130 is arranged at a distance from all emitters 121 of the illumination means 120. According to aspects, the distance between the optical sensing means 130 and the one or more emitters 121 is larger than the half the distance between the optical sensing means 130 and the body part. According to other aspects, the distance is at least 10 cm. According to further aspects, the distance is larger than a diameter of the illuminated area of the body part.

According to aspects, the optical sensing means is arranged in a separate housing from at least one emitter 121. A housing encapsulates at least a part of the optical sensing means. lf the optical sensing means comprises a camera, the housing can 12 be a camera housing. The housing can provide additional shielding from undesired light from the illumination means 120 from a direct path. Furthermore, undesired light that has been reflected can also be reduced, i.e., light from the illumination means that has not been reflected and/or transmitted through the body part but has been reflected on a Wall or such. This Way, SNR is improved further. lt is typically only relevant to capture light that has been reflected by or passed through the body part. Therefore, the optical sensing means may be arranged to capture light parallel With the line S1. This can be achieved With lenses, shielding, reflectors or the like. ln other words, light not parallel to the line S1 is not captured, or at least such light is captured to a less extent compared to the parallel light. Here, to be parallel to the line S1 includes substantially parallel light as Well, since the same technical effect is still obtained to some extent. According to aspects, parallel here means within plus- minus 20 degrees.

As mentioned, the line S1 is arranged at a non-zero angle With respect to an extension direction of at least one transmit beam B1;...;B6. ln Figure 1, the line S1 is arranged at a non-zero angle With respect to the respective extension directions of the transmit beams B1, B2, and B3. ln Figure 2, the line S1 is arranged at a non-zero angle With respect to the respective extension directions of the transmit beams B1, B2, B3, B4, B5, and B6. A non-zero angle With respect to a transmit beam means that the one or more sensors of the optical sensing means 130 are not arranged directly in the extension direction of that beam. This Way, the undesired light emitted from a direct path bet\Neen the illumination means 120 to the optical sensing means 130 is avoided.

When light hits the illuminated body part, a portion of the light is scattered. This scattered light is then reflected by and/or transmitted through the body part. Arranging the optical sensing arrangement 130 With the line S1 With a non-zero angle can therefore capture light comprising data of the body part.

Thus, the non-zero angle improves SNR. Furthermore, the non-zero angle reduces pixel blooming if the optical sensor comprises a digital camera, which further improves SNR.

Preferably, the non-zero angle is at least 10 degrees, and more preferably, the non- zero angle is at least 20 degrees, and even more preferably, the non-zero angle is at least 30 degrees. The non-zero angle may be a different angle with respect to different beams. Preferably, the line S1 is arranged at a non-zero angle With respect to the respective extension directions of all transmit beams B1;...;B6. However, if different 13 sensors are used for respective wavelengths, it may be sufficient that each sensor is arranged at a non-zero angle with respect to the respective extension direction of the transmit beam of the corresponding wavelength.

As mentioned, the sensing arrangement comprises illumination means 120 comprising one or more emitters arranged to illuminate at least a portion of the body part 110. An emitter is a light source arranged to transmit one or more beams, i.e., directed light. The illumination means 120 may comprise a respective emitter 121 for each wavelength. Alternatively, an emitter may emit a plurality or all discrete wavelengths. Multiple beams from one emitter may be overlapping. An emitter can comprise a plurality of light sources, such as LEDs, that can be grouped together. An emitter can be similar to an LED flashlight which comprises a plurality of LEDs and a ref|ector arranged to emit a beam. lf an emitter is arranged to transmit a plurality of different discrete wavelengths, it may comprise a plurality of interleaved light sources emitting different wavelengths.

Herein, to emit a single discrete wavelength means to emit light with a narrow bandwidth, such as the light from a light emitting diode (LED) or laser. Generally, the illumination means 120 herein comprise one or more emitters arranged to emit one or more beams of light, where each beam is associated with a beam width. For example, each such emitter may comprise a laser and/or an LED. A laser emits beam with monochromatic light, or rather light with a narrow linewidth, that is coherent. An LED emits light with a relatively low bandwidth, e.g., in the order 25 nm. An LED typically emits light as point source where a beam can be obtained using reflectors and/or lenses. Any light sources used in the emitter may utilize reflectors and/or lenses.

Preferably, a section of the body part is illuminated by the illumination means. This section has an area of preferably a few centimeters squared.

A beam typically has a peak intensity along an axis where the intensity drops symmetrically away from that axis. Arranging the optical sensing means 130 on a line S1 arranged at a non-zero angle with respect to an extension directions of at least one transmit beam B1;...;B6 therefore improves SNR. Preferably, the optical sensing means is arranged such that less than 10 percent of the light emitted by the illumination means 120 hits the optical sensing arrangement directly when no body part is arranged between the illumination means 120 and optical sensing means 130.

Even more preferably, that amount light is less than 1 percent. 14 The illumination means 120 may alternatively, or in combination of, comprise a wideband emitter, such as an incandescent light bulb, in conjunction with one or more filters to emit one or more discrete wavelengths with narrow bandwidths, e.g., similar to an LED. One or more filters may also be used in conjunction with narrowband sources as well.

The optical sensing means 130 may comprise a respective sensor 131 for each wavelength. Each sensor may comprise a filter arranged for a single wavelength. The optical sensing means 130 may alternatively comprise a single sensor for a plurality or even all wavelengths. ln that case, different filters may be arranged in front of the sensor at different times to capture light of different wavelengths. Capturing one wavelength at a time or using filters or timing enables the use of black and white cameras as a sensor(s). For example, if only a single specific wavelength is transmitted at a time, there is no need to sort the light received by the camera sensor by wavelength in the camera sensor or the camera sensor output in order to extract the desired wavelength. Thus, a black and white camera may be used. An example resolution of the camera is 640 by 480 pixels. However, it is also possible to use other types of cameras and later distinguish different wavelengths using softvvare or the like.

Having a respective sensor for each wavelength results in that all wavelengths can illuminate the body part simultaneously and all wavelengths can be captured simultaneously. This provides fast measurements and improved accuracy since all wavelengths comprise data of the same time instance. This significantly reduces problems introduced by movement of the body part. For example, it the data is analyzed by comparing absorption of two different wavelengths, it is preferable that the two different wavelengths are measured under as similar conditions as possible. ln case the optical sensing means comprises multiple sensors, the sensors are preferably spaced closely together so that they capture as similar images as possible. As mentioned, it may be preferable that the different wavelengths are measured under as similar conditions as possible. ln an example embodiment, the optical sensing means 130 comprises a camera arranged to capture an image at a rate of 600 Hz. Six discrete wavelengths are used, and the illumination means 120 is arranged to cycle through each of the six wavelengths at a rate of 600 Hz. Consequently, a picture of one of the wavelengths is captured at a rate of 100 Hz. Each wavelength is transmitted as a square pulse with a duration 0.28 milliseconds. Consequently, the illumination means is transmitting light at duty cycle of 25%, i.e. no light is emitted during 75% of the time, and each specific wavelength has a duty cycle of 4.2%. Furthermore, the camera is triggered to capture an image during a pulse. This way, high illumination for each specific wavelength can be obtained while keeping heating effects at a minimum. Other pu|se durations and repetition rates are also possible. Constant illumination is also possible, one specific wavelength at a time or all at once. ln another example embodiment, the illumination means 120 emits six different discrete wavelengths at the same time and the optical sensing means 130 comprises six different sensors arranged to capture respective wavelengths. Each sensor is a camera arranged to capture an image at a rate of 100 Hz. All of the wavelengths are transmitted as respective square pu|se with a duration 0.625 milliseconds. Consequently, the illumination means is transmitting light at duty cycle of 25%, i.e. no light is emitted during 75% of the time. Furthermore, all cameras are triggered to capture an image during the pulses.

As is shown in Figure 1, the extension directions of the transmit beams B1, B2, and B3 are parallel. More generally, the extension directions of a least two transmit beams B1;...;B6 may be parallel. ln Figure 1, the illumination means 120 comprises three different emitters 121 in a single housing. ln Figure 2, however, the illumination means is distributed across different housings. ln other words, the illumination means 120 is distributed to transmit at least two beams from different locations. More specifically, the at least two emitters 121 are arranged at a different physical location in relation to the body part compared to another emitter. This way, redundancy is introduced. lf one emitter illuminates the body part such that little light is captured by the optical sensing means, another emitter at another location may provide light giving better data.

As mentioned, the illumination means 120 is arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions (B1;...;B6) from the one or more emitters to the body part (110). According to aspects, one or more of the wavelengths may be transmitted with a plurality of beams. For example, a single wavelength may be transmitted both from the left housing and the right housing in Figure 2. This may provide additional redundancy.

According to aspects, the sensing arrangement 100 comprises ranging means arranged to obtain a distance between the body part 110 and the optical sensing 16 means 130. Knowing the distance between the optical sensing means and the body part is desired to be able to measure relative movements of the body part or sections of the body part, such as movement resulting from heart beats. The ranging means may comprise the optical sensing means 130 and a laser 140 arranged in proximity to the optical sensing means 130. lt is beneficial to reuse the optical sensing means for this purpose since it saves costs and space. Furthermore, such arrangement can use constant illumination during the off time in an arrangement with illumination means 120 with a duty cycle. Arranging the laser in proximity to the optical sensing means can mean that they are in the same housing. According to aspects, the laser comprises a beam extending in a normal direction of a housing comprising the optical sensing means. ln an example embodiment, the laser 140 is parallel with the line S1, and the distance between the body part and the optical sensing arrangement is obtained from where the position of a dot of the laser on the body part is in the frame of a camera in the optical sensing arrangement. This way, complicated timing and triggering can be avoided. According to aspects, t\No or more lasers 140 are used for redundancy purposes. ln some cases, the body part may have a shape where one of the ranging laser beams is reflected in an undesired dissection.

The ranging means may, however, also comprise any of a time of flight camera, a laser telemeter, an ultrasonic distance sensor, a radar sensor, or a stereo camera.

As mentioned, the sensing arrangement 100, can, according to aspects, measure blood oxygen saturation. ln that case, the sensing arrangement further comprising a control unit 150 arranged to obtain a blood oxygen saturation from magnitudes of at least two of the discrete wavelengths of the captured light. The magnitudes of at least two wavelengths in the reflected light and/or transmitted light are then compared to an absorption spectrum of hemoglobin with and without oxygen to determine the blood oxygen saturation. ln other words, the measured magnitudes are compared to expected magnitudes arising from a specific saturation of blood oxygen. Preferably, this measurement is averaged over a few seconds to capture accurate data. As mentioned, using captured light at the two wavelengths presenting the best SNR out of all of the emitted wavelengths may be used to obtain the blood oxygen saturation. Furthermore, wavelengths with different SNR can be assigned different weights to adjust their influence when obtaining the blood oxygen saturation. According two 17 aspects, the illumination means arranged to transmit at least two discrete wavelengths of light with different absorption levels in blood.

According to aspects, the sensing arrangement 100 further comprising a control unit 150 arranged to obtain a heart rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light. The heartbeat of a person causes many kinds of motion with a cyclical nature, such as the slight movement at the point on the wrist where pulse can be measured by touch. Such cyclical movement has a period commonly bet\Neen 0.5 and 2 seconds. Relative movement of blood through a vein, e.g., can be indicated as amplitude variations of the reflected light at a single specific wavelength. A plurality of wavelengths can also be averaged. Analyzing the cyclical nature of the amplitude variations can therefore provide the heart rate of the person. Preferably, this measurement is captured over a few seconds to capture accurate data. captured light at the wavelengths presenting the best SNR out of all of the emitted wavelengths may be used to obtain the heart rate. Furthermore, wavelengths with different SNR can be assigned different weights to adjust their influence when obtaining the heart rate.

According to aspects, the sensing arrangement 100 further comprises a control unit 150 arranged to obtain a breathing rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light. Similar to the heart rate, the breathing rate can be obtained by analyzing amplitude variations of the reflected light of one or more specific wavelengths. The breathing rate can reveal itself by cyclical motion with a period commonly between 2 and 10 seconds. Using captured light at the wavelengths presenting the best SNR out of all of the emitted wavelengths may be used to the breathing rate. Furthermore, wavelengths with different SNR can be assigned different weights to adjust their influence when obtaining the breathing rate.

According to aspects, the sensing arrangement 100 further comprises a control unit 150 arranged to obtain a blood pressure from a comparison of variations over time of the magnitude of at least one of the wavelengths of the captured light at different locations of the illuminated body part 110. Monitoring any type of variation over time for different parts of the body part allows for obtaining a time delay between a propagation of a movement, e.g. a pulse propagation of a blood arising from a heartbeat. This time delay can be used to analyze how much blood has been passed through a certain section during a certain time, which can give the blood pressure of 18 the person. Using captured light at the wavelengths presenting the best SNR out of all of the emitted wavelengths may be used to the blood pressure. Furthermore, wavelengths with different SNR can be assigned different weights to adjust their influence when obtaining the blood pressure.

The sensing arrangement 100 can read out biometric identification data from the same sensor that can be used for other data, such as the vital data. This simplifies the arrangement and saves costs. Furthermore, any of the body temperature, heart rate, breathing rate, blood oxygen saturation, and blood pressure can be used to determine if the person is alive. This adds another layer of security when biometric identification alone is not be secure enough. For example, fingerprints may be replicated or be detached, and it may be possible to mold a replication of a face.

According to aspects, the sensing arrangement 100 further comprises a thermal camera. ln that case, the sensing arrangement may obtain body temperature. Furthermore, if the thermal camera is aimed at the face, the breathing rate can be obtained from measuring temperature differences of the face resulting from inhaled and/or exhaled air. The thermal camera is used to observe the colder and hotter skin areas, compared to the environment, preferably skin areas around the mouth and/or nose. This way of obtaining the breathing rate can be used as an alternative to or a combination with the way described above. A weighted average between the two different measurements may, e.g., be used. lt is also possible to obtain the breathing rate from measurements of hot and cold air resulting from respiration and from measurements of relative movement of face. These two ways can be a compliment or alternative. lf the thermal camera is pointed at the face of the person, the blood pressure can be obtained using the optical sensing means 130 together with the thermal camera. ln that case, the thermal camera is directed to body part different from the illuminated body part 110. The blood pressure is obtained from a measured time delay between an observation of a movement by the thermal camera and an observation of a movement by the optical sensing means 130. Both movements are movements of respective body parts resulting from the same heartbeat. Movement related to the heartbeat in the face can be observed by the thermal camera. Monitoring any type of variation over time in the signals received by the optical sensing arrangement can be correlated to the movement observed by the thermal camera. The time delay bet\Neen the observations can then provide the blood pressure. This way of obtaining the blood 19 pressure can be used as an alternative to or in combination with the way described above. A weighted average between the two different measurements may, e.g., be used.

The sensing arrangement 100 may comprise a temperature reference device arranged to provide a reference temperature to the therma| camera. The reference device can, e.g., be a heat plate arranged to provide a constant surface temperature. The reference device is used for calibrating the therma| camera. Therefore, the reference device may be arranged such that it is in the field of view of therma| camera, e.g. at all times or when there is no person using the access control system. Calibration can, e.g., occur once a minute, between every person using the system or something similar.

The sensing arrangement100 may comprise a display means arranged to show a live feed of the person and to show guiding means arranged guide to the person to an optimal distance between the person and the therma| camera. The guiding means can for example comprise a rectangle around the displayed face of the person that changes color to indicate distance. Green can indicate optimal distances and red can indicate incorrect distances. Optimal distances are distances allowing reliable sensor observations. The display means may comprise a monitor, like a television monitor, but it can also be a light strip or something similar.

The display means may alternatively, or in combination of, be arranged to show guiding means arranged to guide the person to an optimal distance between the illuminated body part of the person and the optical sensing means 130. The sensing arrangement 100 may comprise ranging means arranged to obtain a distance between the person and the therma| camera. This ranging means may comprises a time-of-flight camera arrangement. According to aspects, this ranging means may also comprise any of a laser telemeter, an ultrasonic distance sensor, a radar sensor, or a stereo camera.

The sensing arrangement 100 may comprise guiding means comprising two or more lasers with visible light, where the all the beams of these lasers intersect on point at a desired distance from the optical sensing means 130. This way, these laser beams present different dots on the body part 110 when it is at an incorrect distance from the optical sensing means 130 and show up as a single dot on the body part (i.e., a plurality of overlapping dots) when it is at the desired distance from the optical sensing means 130. These lasers may also be used to detect if a body part is present.

According to aspects, the illumination means 120 comprises a reflector arranged to direct the light from the illumination means towards the illuminated body part. The reflector can facilitate equal illumination of the illuminated body part for the specific wavelengths, from the point of view of the optical sensing arrangement. The number of emitters 121 and their placement can be optimized in conjunction with a reflector plate. The optimization tries to achieve evenly distributed illumination of the illuminated body part for the different wavelengths, from the point of view of the optical sensing means. There may be different amounts of diodes for one wavelength compared to another wavelength since the different diodes may have different intensities.

The sensing arrangement 100 may comprise a radar arranged to measure movement of a body part of the person. This movement measurement may replace other measurements using relative movements of the body or complement them, such as measurements obtaining a breathing rate of the person, obtaining heart rate of the person, and/or obtaining blood pressure of the person. The radar measurements can also be used in combination with other measurements.

A radar will in general perform measurements by transmitting radio waves which are ref|ected by objects in the environment. The ref|ected radio waves are then received by the radar and signal processing methods are applied to determine the location and velocity of the objects. As an example, the radar may measure the distance to a body part by measuring the time between transmission of radio waves and reception of the ref|ected radio waves. A movement of a body part may then be detected through measuring the distance to the body part at different points in time. As another example, the radar may measure the movement of a body part by measuring the Doppler shift of the ref|ected radio waves.

According to aspects, at least one of the at least three discrete wavelengths emitted by the illumination means 120 is arranged to excite a marker administered (e.g., injected) in the blood flowing through the body part 110. The marker, if binding to a specific molecular structure present in the blood, for example an antibody, will emit fluorescent light at a known and by the device detectable wavelength. Other structures can be alcohol, drugs, proteins, or molecules in general.

Figures 6A-6C show different views of an example sensing arrangement 100, where Figure 6A shows an overview, Figure 6B shows details of the illumination means 120, and Figure 6C shows details of the sensing arrangement 130. An RFID arrangement 21 620 is arranged adjacent to the illumination means 120. This can be used as an alternative or complement to identification. ln general, the RFID arrangement may be replaced by identification means using keys, QR codes etc.

Two guiding lasers with respective beams 610 are arranged adjacent to the illumination means. These beams intersect at point which has an optimal distance to the optical sensing arrangement 130. When the body part is placed between the optical sensing means 130 and the illumination means 120, these lasers will appear as a single dot on the body part when the body part is at an optimal distance from the optical sensing means 130, and as t\No dots for other distances.

The illumination means 120 comprises an emitter 121 with a plurality of sockets for LEDs. Different LEDs for a total of six different wavelengths are interleaved in this arrangement. The LEDs have viewing angles (related to beam width) of about 5-25 degrees for the various wavelengths. Note that other viewing angles are possible and that all wavelengths may have LEDs with the same viewing angle. All LEDs are aimed at the intersection point of the beams 610 of the guiding lasers.

The optical sensing means 130 comprise six sensors 131 with respective filters for six different wavelengths. Each sensor is arranged in recess with roughly a rectangular shape. Respective beams of tvvo ranging lasers 140 emerges from tvvo locations between the two rows of sensors.

Figure 3 is a flowchart illustrating methods. There is illustrated a method for obtaining data from captured light reflected by and/or transmitted through a body part 110. The method comprises illuminating Sx1 at least a portion of the body part 110 with illumination means 120 comprising one or more emitters 121, where the illumination means is arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions B1;...;B6 from the one or more emitters to the body part 110, and capturing Sx2 light reflected by and/or transmitted through the body part 110 with optical sensing means 130, wherein the optical sensing means is arranged at a distance from at least one emitter 121, and wherein the optical sensing means is arranged facing the body part and is arranged on a line S1 between the optical sensing means 130 and the body part 110, wherein the line S1 is arranged at a non- 22 zero angle with respect to an extension direction of at least one transmit beam B1;...;B6.

Thus, the method describes aspects of the above disclosed techniques for obtaining data from an illuminated body part.

According to aspects, the data comprises biometric identification data and/or vital data. The vital data may comprise any of the following vital parameters: heart rate, blood oxygen saturation, pulse, and blood pressure.

According to aspects, the optical sensing means 130 is arranged in a separate housing from at least one emitter 121.

According to aspects, the method comprises obtaining Sx3 data from the body part at a plurality of occasions. The data may, e.g., be captured every day over several months. Other intervals are also possible. Multiple measurements at multiple occasions makes it possible to establish individual base values of vital parameters. That way, deviations from the base values can be detected, which may indicate a condition. This can enable more accurate analysis of various vital parameters compared to looking at deviations from a nominal value for a group of people.

Furthermore, a base values can decrease accuracy requirements on measuring absolute values. ln a new measurement, it may be more relevant to measure the value of a deviation itself rather than the absolute value ofthe new measurement comprising the deviation. lfthe requirements on measuring exact absolute values can be relaxed, calibration procedures can be relaxed.

According to aspects, the method comprises illuminating Sx11 the body part 110 with at least one discrete wavelength arranged a to excite a marker administered (i.e., depleted or injected) in the blood flowing through the body part.

Figure 4 schematically illustrates, in terms of a number of functional units, the general components of a control unit 150 which may be part of the sensing arrangement 100. Processing circuitry 410 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium 430. The processing circuitry 410 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA. 23 Particularly, the processing circuitry 410 is configured to cause the sensing arrangement 100 to perform a set of operations, or steps, such as the methods discussed in connection to Figure 3 and the discussions above, and also to set operating parameters of the system according to the discussions above. For example, the storage medium 430 may store the set of operations, and the processing circuitry 410 may be configured to retrieve the set of operations from the storage medium 430 to cause the device to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 410 is thereby arranged to execute methods as herein disclosed.

The storage medium 430 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. This storage medium may be configured to store one or more sets of configuration settings for the sensing arrangement 100.

The control unit 150 may further comprise an interface 420 for communications With at least one external device. As such the interface 420 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for Wireline or Wireless communication.

The processing circuitry 410 controls the general operation of the control unit 150, e.g., by sending data and control signals to the interface 420 and the storage medium 430, by receiving data and reports from the interface 420, and by retrieving data and instructions from the storage medium 430.

Figure 5 illustrates a computer readable medium 510 carrying a computer program comprising program code means 520 for performing the methods illustrated in Figure 3 and/or for executing the various functions discussed above, when said program product is run on a computer. The computer readable medium and the code means may together form a computer program product 500. This computer program product may comprise one or more sets of configurations for controlling the sensing arrangement 100 discussed above to perform the methods disclosed herein.

Claims

1. A sensing arrangement (100) for obtaining data from captured light reflected by and/or transmitted through a body part (110), the sensing arrangement comprising illumination means (120) comprising one or more emitters (121 ) arranged to illuminate at least a portion of the body part (110), the illumination means arranged to transmit at least three discrete wavelengths of light with respective transmit beams extending along respective extension directions (B1;...;B6) from the one or more emitters to the body part (110), and optical sensing means (130) arranged to capture light reflected by and/or transmitted through the body part (110), wherein the optical sensing means is arranged at a distance from at least one emitter (121), and wherein the optical sensing means is arranged facing the body part and is arranged on a line (S1) between the optical sensing means (130) and the body part (110), wherein the line (S1) is arranged at a non-zero angle with respect to an extension direction of at least one transmit beam (B1;...;B6).

2. The sensing arrangement (100) according to claim 1, wherein the optical sensing means (130) is arranged in a separate housing from at least one emitter (121).

3. The sensing arrangement (100) according to any previous claim, wherein the illumination means (120) comprises a respective emitter (121) for each wavelength.

4. The sensing arrangement (100) according to any previous claim, wherein the optical sensing means (130) comprises a respective sensor (131) for each wavelength.

5. The sensing arrangement (100) according to any previous claim, wherein the extension directions of a least two transmit beams (B1;...;B6) are parallel.

6. The sensing arrangement (100) according to any previous claim, wherein the illumination means (120) is distributed to transmit at least two beams from different locations.

7. The sensing arrangement (100) according to any previous claim, comprising ranging means arranged to obtain a distance between the body part (110) and the optical sensing means (130).

8. The sensing arrangement (100) according to claim 7, wherein the ranging means comprise the optical sensing means (130) and a laser (140) arranged in proximity to the optical sensing means (130).

9. The sensing arrangement (100) according to any previous claim, wherein the data comprises biometric identification data and/or vital data.

10. The sensing arrangement (100) according to any previous claim, wherein the optical sensing means (130) comprises one or more cameras.

11. The sensing arrangement (100) according to any previous claim, wherein the body part (110) is a hand and/or a wrist.

12. The sensing arrangement (100) according to any previous claim, wherein the illumination means (120) is arranged to illuminate the body part (1 10) with six discrete wavelengths.

13. The sensing arrangement (100) according to any previous claim, wherein at least one wavelength is within any of the visible spectrum, the infrared spectrum, and the ultraviolet spectrum.

14. The sensing arrangement (100) according to any previous claim, wherein at least one wavelength is between 600-700 nm, preferably between 640-680 nm, and more preferably about 660 nm, and at least another wavelength is between 800-nm, preferably between 850-890 nm, and more preferably about 870 nm.

15. The sensing arrangement (100) according to any previous claim, further comprising a control unit (150) arranged to obtain a blood oxygen saturation from magnitudes of at least two of the discrete wavelengths of the captured light.

16. The sensing arrangement (100) according to any previous claim, further comprising a control unit (150) arranged to obtain a heart rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light.

17. The sensing arrangement (100) according to any previous claim, further comprising a control unit (150) arranged to obtain a breathing rate from variations over time of the magnitude of at least one of the discrete wavelengths of the captured light.

18. The sensing arrangement (100) according to any previous claim, further comprising a control unit (150) arranged to obtain a blood pressure from a comparison of variations over time of the magnitude of at least one of the Wavelengths of the captured light at different locations of the illuminated body part (110).

19. The sensing arrangement (100) according to any previous claim, wherein at least one of the at least three discrete Wavelengths is arranged to excite a marker administered in the blood flowing through the body part (110).

20. A method for obtaining data from captured light reflected by and/or transmitted through a body part (110), the method comprising llluminating (Sx1) at least a portion of the body part (110) With illumination means (120) comprising one or more emitters (121), Where the illumination means is arranged to transmit at least three discrete Wavelengths of light With respective transmit beams extending along respective extension directions (B1;...;B6) from the one or more emitters to the body part (110), and capturing (Sx2) light reflected by and/or transmitted through the body part (110) with optical sensing means (130), wherein the optical sensing means is arranged at a distance from at least one emitter (121), and wherein the optical sensing means is arranged facing the body part and is arranged on a line (S1) between the optical sensing means (130) and the body part (110), wherein the line (S1) is arranged at a non-zero angle With respect to a extension direction of the at least one transmit beam (B1;...;B6).

21. The method according to claim 20, wherein the data comprises biometric identification data.

22. The method according to any of claims 20-21, wherein the data comprises vital data.

23. The method according to claim 22, wherein the vital data comprises any of the following vital parameters: heart rate, blood oxygen saturation, pulse, and blood pressure.

24. The method according to any of claims 20-23, wherein the optical sensing means (130) is arranged in a separate housing from at least one emitter (121 ).

25. The method according to any of claims 20-24, comprising obtaining data from the body part at a plurality of occasions.

26. The method according to any of claims 20-25, comprising illuminating (Sx11) the body part (110) with at least one discrete wavelength arranged a to excite a marker administered in the blood flowing through the body part.