DEVICE AND METHOD FOR RADAR-BASED MONITORING OF THE VASCULAR SYSTEM OF A HUMAN BODY

Abstract

A method and a corresponding device (100) for radar-based monitoring of the vascular system of a human body (110) are disclosed. The device (100) includes a radar device (120) for detecting superficial skin movements, wherein the radar device (120) is arranged at a distance from the body (110) so that the skin movements can be detected without contact. The radar device (120) is positioned at an angle of inclination α ≠ 90° to the longitudinal axis (130) of the body, so that radar waves (121) are emitted obliquely onto the body (110) to propagate from the head towards the feet or from the feet towards the head. An evaluation unit (140) determines a parameter of the vascular system based on skin movements detected by means of reflected radar waves.

Description

[0001] The innovative concept described herein relates to a device and a method for radar-based monitoring of the vascular system of a human body.

[0002] The vascular system of the human body, also known as the blood vessel system or circulatory system, consists of a network of blood vessels that transport blood throughout the body. It plays a central role in supplying the body with nutrients and oxygen and removing waste products. It can be divided into two main circulatory systems: the cardiopulmonary circulation (small circuit) and the systemic circulation (large circuit).

[0003] The vascular system comprises all blood vessels (arteries, arterioles, capillaries, venules, and veins) as well as the heart, which acts as the central pump. It is crucial for supplying the body with oxygen and nutrients and removing waste products. This network is also essential for regulating blood pressure and blood circulation in various organs and tissues.

[0004] Measuring blood pressure is a crucial part of preventative healthcare, as it provides information about the health of the cardiovascular system. Normal blood pressure is important for minimizing the risk of serious illnesses such as heart attack, stroke, and kidney damage. Abnormal blood pressure, whether high (hypertension) or low (hypotension), can lead to a variety of health problems. Hypertension can cause atherosclerosis, heart failure, and other complications, while hypotension can cause dizziness, fainting, and, in severe cases, shock. Regular blood pressure measurements are therefore essential for the early detection and prevention of such health risks.

[0005] Blood pressure is generated by the following factors: • Heartbeat: The heart pumps blood into the arteries. The pressure generated during heart contraction is called systolic blood pressure. • Vascular resistance: The resistance that blood encounters in the blood vessels affects blood pressure. Narrower or constricted vessels increase diastolic blood pressure (pressure in the arteries between heartbeats). • Blood volume: The total amount of blood circulating in the body also affects blood pressure. An increased blood volume can raise blood pressure. • Blood viscosity: Thicker blood can increase pressure, while thinner blood tends to lead to lower pressure.

[0006] Blood pressure is typically measured in healthcare settings as follows: The patient should sit quietly and relax. A sphygmomanometer (blood pressure cuff, manual or digital) is used, often in combination with a stethoscope for manual measurements. The patient's arm is positioned at heart level, and the cuff is placed about 2-3 cm above the elbow. The cuff is inflated until blood flow in the artery stops (typically to about 20-30 mmHg above the expected systolic value). Blood pressure is read as follows: Systolic pressure: The first audible pulse (Korotkoff sound) indicates the systolic pressure. Diastolic pressure: The last audible pulse indicates the diastolic pressure. Blood pressure is given in millimeters of mercury (mmHg), e.g., 120 / 80 mmHg.

[0007] It should be noted that this method has issues with the validity and variability of blood pressure measurements within a single individual (Mukkamala R. et al., 2021). The described method is used in practice, but it is not the gold standard.

[0008] Blood pressure can also be measured directly in the artery using an arterial access device, which is a very good option and essentially the gold standard (Saugel, 2020). However, this invasive method for continuous blood pressure monitoring is only used in hospital settings for critically ill patients. A catheter is inserted into an artery and connected to a pressure monitor. This method provides a more accurate measurement than non-invasive methods. Invasive blood pressure measurements are generally only used when medically necessary, as they carry a higher risk of complications.

[0009] From a medical perspective, regular blood pressure monitoring is beneficial for detecting and potentially preventing secondary illnesses. Due to the numerous factors influencing blood pressure, continuous measurement is desirable. However, this is difficult to achieve with current technology.

[0010] While the invasive catheter-based method is accurate and continuous, it poses too high a risk for widespread use outside of hospitals. Furthermore, blood pressure is only measured at a single point in the artery where the measurement is taken.

[0011] In contrast, blood pressure measurement via a cuff only allows for a purely point-in-time measurement, both spatially and temporally, and is also not as accurate as arterial blood pressure measurement. Furthermore, the pressure exerted by the cuff alters the patient's stress level (Mukkamala RG et al., 2022) and thus also their blood pressure.

[0012] It is also known to perform 24-hour ambulatory blood pressure monitoring using a blood pressure cuff. In this method, the patient wears a cuff continuously, which inflates at regular intervals (e.g., 15 minutes during the day, hourly at night) and automatically takes a measurement. Here, too, the measurement is noticeable to the patient and can lead to inaccuracies due to possible excitement or tension. Furthermore, the measurement significantly disrupts the patient's sleep.

[0013] There are already established approaches for continuous, contact-based blood pressure measurement. For example, a method for measuring the so-called pulse transit time (PTT) is used. The pulse transit time is the time it takes for a blood pulse to travel from one point in the circulatory system to another. It is a measure of the speed of the pulse wave as it propagates through the arteries with the blood flow. This time can serve as an indicator of arterial stiffness and blood pressure, as the PTT is strongly dependent on the elasticity of the arteries.

[0014] Nowadays, several manufacturers offer contact-based blood pressure measurement via smartwatch. However, the measurement is not continuous, but requires active initiation by the user. Furthermore, calibration using a blood pressure cuff measurement is necessary at regular intervals (e.g., every four weeks).

[0015] Both of the above-mentioned methods require contact-based measurement. The authors of this disclosure are not aware of any contactless measurement product. Furthermore, both of the above-mentioned methods only measure blood pressure locally at a single point.

[0016] In contrast, contactless solutions such as radar measurement systems, which continuously record blood pressure, are known from scientific publications. The following two methods are primarily used to correlate measurable skin movement with human blood pressure.

[0017] The first method is the previously mentioned pulse transit time (PTT). Using PTT, a person's blood pressure can be derived from skin movement detected by a radar device. PTT measures the time of heart contraction (emission of the pulse wave) and the time the pulse wave arrives at a distant body part (e.g., hand). If the blood pressure is higher, the pulse wave arrives at the distant body part (e.g., hand) sooner. If the blood pressure is lower, the pulse wave arrives there later.

[0018] The timing of the heartbeat and the arrival of the pulse wave are measured in various ways in radar literature. One possibility is to use an ECG to determine the heartbeat time, as well as to use radar directly on the skin to determine the arrival time of the pulse wave (Pour Ebrahim, 2019). Alternatively, several radars can be placed close to the skin surface, such as near the wrist (Singh, 2023).

[0019] The second method for radar-based blood pressure measurement is called pulse wave analysis (PWA). While in the conventional blood pressure cuff method the heart exerts pressure against the cuff via the vascular system, in PWA (without a cuff) the heart exerts pressure only on the arterial walls (as part of the vascular system). Higher blood pressure leads to a greater deflection of the arterial walls, and this deflection can be measured by radar on the skin surface. The detected skin movement can then be used to infer the individual's blood pressure.

[0020] In pulse wave analysis (PWA), properties of human skin movement are linked to information about blood pressure. One of these properties is the maximum skin displacement, represented by the height of the radar pulse signal peak. Other properties of the radar pulse signal that could contain information about blood pressure exist, such as the minimum signal value in a pulse interval or the time between these two extreme values ​​(Vysotskaya, 2023).

[0021] The relevant literature also describes methods in which PTT and PWA are combined (see Singh, Lovedeep, et al. “Remote Estimation of Blood Pressure Using Millimeter-Wave Frequency-Modulated Continuous-Wave Radar.” Sensors 23.14 (2023): 6517).

[0022] A key advantage of the contactless method is that skin movement during sleep can be recorded without disturbing the person. In the current state of the art, the radar device is positioned directly in front of or behind the person whose blood pressure is to be measured. If the person is in a horizontal position, for example, lying in bed, the radar device would therefore be positioned vertically above or below them. This is particularly advantageous for reliably detecting movement. For example, the chest rises and falls vertically during inhalation and exhalation. This movement thus exhibits a maximum deflection for the radar device positioned vertically above or below the person.

[0023] However, when the radar device is positioned vertically above or below a person lying horizontally, a problem arises: the person's body can only be divided into a few so-called distance bins, since the radar waves strike the body directly perpendicularly. This results in a multitude of overlapping signals due to various body movements (e.g., breathing, pulse, limb movement), which then have to be resolved into their individual signal components using complex algorithms. In practice, this has been shown to lead to poor signal quality and / or an excessively high signal-to-noise ratio (SNR).

[0024] The aim of the innovative concept described herein is therefore to improve existing devices for the contactless measurement of parameters relating to the vascular system of the human body in such a way as to reduce or eliminate the aforementioned disadvantages.

[0025] This objective is achieved by a device and a corresponding method for radar-based monitoring of the vascular system of the human body according to the independent claims.

[0026] The device according to the invention includes, among other things, a radar device for detecting superficial skin movements. The radar device can penetrate textile layers, such as clothing or bed linen, so that the human body can be measured, for example, during sleep. The radar device is positioned at a distance from the body, allowing skin movements to be detected without contact. This enables continuous measurements over extended periods, such as the entire duration of a person's sleep. Because the measurement using the radar device is contactless, the person's sleep is not disturbed by the measurements, as is the case, for example, with blood pressure cuffs. According to the invention, the radar device is positioned at an angle of inclination α ≠ 90° to the longitudinal axis of the body.

[0027] The tilt angle α corresponds to a vertical angle or elevation angle, or zenith angle. For a body lying horizontally, i.e., lying down, the tilt angle α would therefore correspond to the elevation angle known in engineering. This means the radar device could be positioned on an imaginary circular path extending vertically across the body from head to toe. In other words, an object moving along this vertical circular path would pass over the front (stomach) and back (back) of the person.

[0028] A horizontal circle arranged around a person lying down, however, describes the azimuth angle commonly used in engineering. This means the radar device could be positioned on a circular path extending laterally between the head and feet, i.e., sideways and parallel to the horizontal. In other words, an object moving along this horizontal circular path would pass over the left and right sides of the person's body.

[0029] The above discussion was purely illustrative, using a reclining body in a horizontal position as an example. However, the same applies, of course, to a standing person or any other person positioned in space. In every case, the reference axis is always the longitudinal axis of the body, extending between the head and feet; that is, the previously described azimuth and elevation angles must always be referenced to the longitudinal axis of the body.

[0030] Preferably, the radar device can be aligned exactly along the longitudinal axis of the body, corresponding to an azimuth angle of 0° or 180°. Alternatively, the radar device can be arranged along an imaginary line parallel to the longitudinal axis of the body. It is also conceivable that the radar device is not aligned exactly along or parallel to the longitudinal axis of the body, but offset laterally. This would be conceivable, for example, if one imagines a bedroom in which the person being monitored is lying in bed. The radar device could then be placed, for instance, on a bedside table next to the bed. The radar device would then be offset laterally to the longitudinal axis of the body, meaning the azimuth angle would be ≠ 0° or ≠ 180°. It is also conceivable that the radar device is preferably arranged within an azimuth angle range of ± 45° around the body.In principle, however, the azimuth angle is secondary in the device according to the invention.

[0031] The tilt angle α is of primary importance. As mentioned at the outset, according to the invention, the radar device is positioned at a tilt angle or elevation angle of α ≠ 90° to the longitudinal axis of the body. This means that the radar device is not directly perpendicular (α = 90°) or frontal to the person. Due to the tilt angle α ≠ 90°, the radar waves are emitted obliquely onto the body and propagate from the head towards the feet or from the feet towards the head.

[0032] This is significantly advantageous compared to arrangements where the radar device is positioned vertically (i.e., at an angle of inclination α = 90°) above (e.g., in the abdominal region) or below (e.g., in the back region) the person lying horizontally. Due to the oblique arrangement of the radar device according to the invention, at an angle of inclination α ≠ 90°, the radar waves propagate along the longitudinal axis of the body over the entire body, resulting in significantly more radar waves being reflected back to the radar device. Consequently, the radar device can divide the distance measurement performed using the reflected radar waves into significantly more distance bins, thus allowing the body to be divided into significantly more sections. This makes it possible to divide the body into the smallest possible sections and examine the individual sections for skin movements.Based on the skin movements detected by means of the reflected radar waves, an evaluation unit also belonging to the device according to the invention can then determine a parameter of the vascular system, such as blood pressure.

[0033] Further embodiments and advantageous aspects of this device and the corresponding method are mentioned in the respective dependent patent claims.

[0034] Some exemplary embodiments are shown in the drawing and are explained below. They show: Fig. 1 A schematic side view of a device for radar-based monitoring of the vascular system of a human body according to an embodiment, Fig. 2 a schematic side view of a device for radar-based detection of vital parameters of a human body according to the prior art, and Fig. 3 a schematic block diagram to illustrate a method a schematic side view of a device for radar-based monitoring of the vascular system of a human body according to an embodiment.

[0035] The following are examples of embodiments described in more detail with reference to the figures, whereby elements with the same or similar function are provided with the same reference numerals.

[0036] Process steps depicted or described in this disclosure may also be carried out in a different order than depicted or described. Furthermore, process steps relating to a specific feature of a device are interchangeable with that very feature of the device, and vice versa.

[0037] For clarity, blood pressure is described in this disclosure as a non-limiting example of a parameter of the vascular system that can be detected using the device according to the invention. In principle, however, all other parameters of the vascular system, such as pulse rate, heart rhythm, etc., can also be detected. In particular, all parameters of the vascular system that can be detected by means of superficial skin movements can be detected. These can be minimal skin movements in the range of only a few micrometers or millimeters, with the accuracy of the detection being limited only by the resolution of the radar device used.

[0038] Fig. Figure 1 shows an embodiment of a device 100 according to the invention for radar-based monitoring of the vascular system of a human body 110. The device 100 includes, among other things, a radar device 120. This radar device 120 serves to detect superficial skin movements. The radar device 120 is arranged at a distance from the body 110 so that the skin movements can be detected without contact. The person is not disturbed, as would be the case, for example, when wearing a cuff.

[0039] The longitudinal axis 130 of the body 110 runs through it. This axis extends straight through the body 110, specifically between the head and the foot of the body 110. The radar device 120 can be positioned along the longitudinal axis 130 of the body or along an imaginary line running parallel to the longitudinal axis 130. According to the invention, the radar device 120 is positioned at an angle of inclination α ≠ 90° to the longitudinal axis 130 of the body. This will be briefly explained below.

[0040] In Fig. Figure 1 shows a vertical line 131 extending at a 90° angle to the longitudinal axis 130 of the body. However, the radar device 120 is positioned outside this vertical line 131 at an angle α ≠ 90° to the longitudinal axis 130 of the body. For example, the radar device 120 can be positioned on an imaginary circular segment 133 that runs between the longitudinal axis 130 of the body (or an imaginary line parallel to it) and the vertical line 131, as shown schematically in Figure 1. Fig. 1 is indicated.

[0041] Fig. Figure 2, however, shows an arrangement as used in the prior art, where the radar device 120 is arranged directly above the body 110. That is, here the radar device 120 is positioned along the vertical 131, and thus at an angle α = 90° to the longitudinal axis 130 of the body.

[0042] When a person is lying down, the longitudinal axis of the body runs horizontally at 130 degrees. As can be seen in Fig. As shown in Figure 1, the radar device 120 is, according to the invention, not oriented vertically, i.e., at a 90° angle, to the horizontal longitudinal axis 130 of the body, but at an angle α other than 90°, i.e., α ≠ 90°. The radar device 120 is thus tilted or inclined relative to the vertical 131, which is why the described angle α can also be referred to as the angle of inclination. According to the invention, the radar device 120 therefore faces the body at an angle of inclination α ≠ 90°.

[0043] The positioning of the radar device 120 at an inclination angle α ≠ 90° is to be understood such that the radar waves (represented by the exit cone 121) are emitted at an elevation angle α ≠ 90° to the body's longitudinal axis 130 towards the body 110. Due to the oblique positioning of the radar device 120 relative to the body 110 according to the invention, the radar waves 121 emitted by the radar device 120 are thus emitted obliquely towards the body 110, so that the emitted radar waves 121 propagate along the body's longitudinal axis 130 (or parallel thereto) from the head towards the feet, or from the feet towards the head.If the radar device 120 is aligned at a certain azimuth angle relative to the body 110 (compare the example described above with the bedside table next to the bed), then the radar waves 121 emitted by the radar device 120 can also be emitted at this certain azimuth angle towards the body 110, so that the emitted radar waves 121 propagate from the head towards the feet, or from the feet towards the head.

[0044] In Fig. The radar unit 120 is shown in the upper right corner as a purely exemplary example. If one were to imagine a coordinate system in Fig. If we imagine the radar set 120 positioned in the first quadrant, this would correspond to its placement in the first quadrant. However, it would be equally advantageous for the radar set 120 to be located in the second quadrant (top left), the third quadrant (bottom left), or the fourth quadrant (bottom right). The crucial factor here is that the tilt angle α ≠ 90°. Depending on the counting method, this would correspond to a tilt angle α ≠ 270° in the case of the lower two quadrants, III and IV.

[0045] The device 100 according to the invention also includes an evaluation unit 140. The evaluation unit 140 can be integrated internally into the radar device 120 or connected externally to the radar device 120. The evaluation unit 140 can, for example, be designed in the form of a microcontroller, an integrated circuit, or the like.

[0046] According to the invention, the evaluation unit 140 is designed to determine a parameter of the vascular system based on skin movements detected by means of reflected radar waves. That is, the emitted radar waves 121 are reflected by the body 110 back towards the radar device 120. For the sake of clarity, the reflected waves are not explicitly shown here. Based on the reflected waves received by the radar device 120, the evaluation unit 140 can detect superficial skin movements.

[0047] The detectable skin movements can be in the millimeter or even micrometer range. This means that even the smallest superficial movements of the skin can be detected. For example, the pulse can be detected, which exerts pressure on the arterial walls as it travels through the arteries, resulting in a small superficial skin movement. These superficial skin movements are barely perceptible to the human eye. However, the radar device 120 according to the invention can detect these minute skin movements.

[0048] The evaluation unit 140 can determine one or more parameters of the vascular system based on the detected superficial skin movements. For this purpose, the recorded superficial skin movements can be converted into a corresponding parameter of the vascular system. It would be conceivable to perform the conversion of the detected signal properties, i.e., the recorded skin movement, into a parameter of the vascular system, such as blood pressure, using deep neural networks or machine learning approaches in general.

[0049] According to the invention, the radar device 120 is designed to divide a distance measured by means of reflected radar waves into discrete intervals, so-called distance bins 1211, ..., 121 n , to subdivide. Using these distance bins 1211, ..., 121 n The evaluation unit 140 can divide the body 110 into several sections S1, ..., S n, e.g., corresponding to the number of distance bins 1211, ..., 121 n subdivide. The individual distance bins can be 1211, ..., 121. n recorded skin movements in the individual sections S1, ..., S n of body 110.

[0050] Since the radar waves 121 strike the body 110 obliquely and propagate along the longitudinal axis 130 of the body, the body 110 can accordingly be divided into the several sections S1, ..., S n along the longitudinal axis of the body 130.

[0051] The individual sections S1, ..., S n They can have the same step size, i.e., be equidistant from each other. This may also correlate with the spacing between the reflected radar waves. Depending on the resolution of the radar system 120, the individual sections S1, ..., S nhave different sizes or surface areas. The smaller the individual sections S1, ..., S n The more precise or fine-grained the subdivision of body 110 can be, the more accurate or finer the subdivision can be.

[0052] Depending on the size of sections S1, ..., S n A specific body region can be captured within a single section. For example, a single section can be chosen to be large enough to capture the entire thigh. If the section is smaller, it can, for example, capture only a part of the thigh. Thus, depending on the size of the respective section, the entire body can be divided into several smaller body regions.

[0053] In other words, one or more sections S1, ..., S can therefore be used. nEach section represents a body region, i.e., a region of a specific body part, such as a thigh (or part thereof) or a lower leg (or part thereof). One or more body regions together can then be assigned to the respective entire body part, such as the entire left or right leg. Accordingly, the evaluation unit 140 can be configured to evaluate individual sections S1, ..., S n to assign to specific body regions (such as thighs). Evaluation unit 140 can also be configured to assign one or more body regions to an entire body part (such as left leg, right arm, torso, etc.).

[0054] In summary, it can therefore be stated that individual distance bins 1211, ..., 121 n a subdivision of body 110 into several individual sections S1, ..., S n enabled. The individual sections S1, ..., S nThese sections represent individual body regions, such as a thigh, or even just parts of it. The more fine-grained the subdivision of the individual sections S1, ..., S n The larger the area, the finer the subdivision of the individual body regions.

[0055] The number and size of sections S1, ..., S n This can depend, as mentioned at the beginning, on the step size of the distance bins 1211, ..., 121. n depend on the distance. Distance bins (also known as radar bins or range bins) are a concept used in radar systems to divide the distance to objects into discrete intervals. They essentially represent "divisions" of measured distances, where the radar measures the arrival of the reflected signal at different time intervals after transmission and then organizes these measurements into specific distance steps or "bins" (boundaries).

[0056] How distance bins work: 1. Signal output and reception: The radar 120 transmits a signal 121 (for example, a short pulse or a continuously modulated wave). When this signal 121 reaches the body 110, it is reflected and returns to the radar 120. The time it takes for the signal 121 to reach the body 110 and return to the radar 120 depends on the distance between the body 110 and the radar 120. 2. Measurement of the travel time: The radar device 120 measures the travel time of the signal 121 (i.e., the time the signal 121 takes to reach body 110 and return). This travel time is used to calculate the distance to body 110. The shorter the travel time, the closer body 110 is, and the longer the travel time, the farther away it is. 3. Subdivision into distance bins: To quantize the distance, the radar 120 divides the measured distance interval into small, discrete sections, which are called distance bins 1211, ..., 121. n be designated. Each Bin 1211, ..., 121 n corresponds to a specific distance, and all body regions that fall within a specific range. Bin 1211, ..., 121 n Falling objects are considered to lie at that distance level. This allows body 110 to be divided into individual sections S1, ..., S1. n can be subdivided. ◯ Example: Assume that radar set 120 has a maximum range of 10 meters and divides the distance range into 100 bins 1211, ..., 121 100 Then everyone would be 1211, ..., 121 100each bin represents a distance of 10 centimeters (10 meters / 100 bins = 10 centimeters per bin). This corresponds to the aforementioned step size. Therefore, if a body region is detected in a specific area of ​​radar 120, it will be represented in the corresponding distance bins 1211, ..., 121. n classified. Or, to put it another way, body 110 is divided into one hundred sections S1, ..., S 100 subdivided into 10 cm sections, with each section S1, ..., S 100 Each represents a different body region. 4. Using the distance bins: Bins 1211, ..., 121 n enable a precise subdivision of body 110 into individual sections or subsections S1, ..., S n This, in turn, helps to distinguish and precisely locate body regions from different distances in different areas. The finer the distance bins 1211, ..., 121 n The more accurately the radar device 120 can measure the distance.

[0057] The number of bins is 1211, ..., 121 n determined how many individual sections S1, ..., S n The body can be subdivided into 110 bins. A higher number of bins is 1211, ..., 121. n or sections S1, ..., S n This increases the number of measurement points and allows for a higher spatial resolution of the measured quantity. Multiplying the information, for example by summarizing several measurements, can also contribute to increasing the robustness and accuracy of the measurement results during evaluation. By combining information into a single result (e.g., by selecting the best / least noisy value), accuracy, reliability, and / or robustness (extending the time intervals in which results are delivered) can be increased.

[0058] Here, the radar unit 120 or the evaluation unit 140 processes the reflected signal to determine individual distance bins 1211, ..., 121. nto identify and thus divide body 110 into individual sections S1, ..., S n to subdivide. This enables fast and efficient signal processing and object detection.

[0059] Due to the previously described inclination angle α ≠ 90° according to the invention, in comparison to the in Fig. In the vertical positioning of the radar device 120 shown above or below the body 110, significantly more radar waves 121 are directed at the body 110. Accordingly, compared to the vertical arrangement ( Fig. 2) also significantly more distance bins 1211, ..., 121 n to be created, with the help of which the body 110 is divided into significantly more segments S1, ..., S n can be subdivided.

[0060] For example, the evaluation unit can divide body 110 into at least 20 different sections S1, ..., S n subdivide. In the vertical arrangement according to Fig. In case 2, this is not possible. Here, body 110 is only captured by two distance bins as a purely exemplary case.

[0061] A further advantage of the invention lies in the fact that, due to the inclined arrangement of the radar device 120 according to the invention at an angle of inclination α ≠ 90° to the longitudinal axis 130 of the body, a single radar device 120 is sufficient to divide the body 110 into the aforementioned several sections S1, ..., S n to be able to subdivide. The radar device 120 can have exactly one single sensor, e.g. in the form of exactly one single transmitting and receiving antenna.

[0062] An alternative embodiment of the invention may provide that, alternatively or additionally to the tilt angle α according to the invention, a radar device 120 is used which has several transmitting and receiving antennas. This radar device could then be configured to emit the radar waves 121 obliquely onto the body 110 by means of beamforming. Such a radar device 120 could theoretically be arranged vertically above the body 110, as is done in Fig. 2 is shown, whereby the radar waves 121 could then be emitted obliquely onto the body 110 by means of beamforming.

[0063] The advantage of beamforming and / or the deliberately chosen tilted or inclined positioning of the radar device 120 is that information about skin movements on multiple body parts can be obtained with just a single radar device 120, preferably simultaneously. This is made possible in particular because the oblique transmission of the electromagnetic waves 121 onto the body 110 results in a significantly higher number of distance bins 1211, ..., 121 (compared to the vertical arrangement without beamforming according to the prior art). n allowed.

[0064] This makes it possible to divide body 110 into several individual sections S1, ..., S n Individual body regions or body parts can be examined for the smallest skin movements, such as the heartbeat pulse.

[0065] One of several parameters of the vascular system that can be determined using the device 100 according to the invention based on superficial skin movements is blood pressure. This will be described below purely as an example of a possible parameter of the vascular system, whereby the applicability of the device according to the invention is not limited to blood pressure alone.

[0066] To determine blood pressure based on superficial skin movements, one of the aforementioned methods, i.e., PWA and / or PTT, can be used. According to one embodiment, the evaluation unit 140 can therefore be configured to determine blood pressure using at least one of the two methods: • Pulse wave analysis (PWA), whereby skin movements are based on at least one, locally on at least one distance-Bin 1211, ..., 121 n limited, pulse signal can be detected, • Pulse Transit Time (PTT), where skin movements are based on one, over several distance bins 1211, ..., 121 n Progressive pulse wave is detected.

[0067] It would also be conceivable to combine both methods. Both methods can detect superficial skin movements that can be attributed, for example, to pulse signals (heartbeat pulse).

[0068] In the context of blood pressure measurement, the pulse transit time is generally used as follows: 1. Arterial elasticity and stiffness: In healthy, elastic arteries, the PTT is usually shorter because the pulse wave propagates more quickly. With increasing age or in certain diseases (e.g., high blood pressure), the arteries can become stiffer, leading to a longer PTT. 2. Blood pressure relationship: The PTT is also inversely correlated with blood pressure (especially systolic blood pressure). Higher blood pressure leads to an increased pulse wave velocity, which can shorten the PTT. Conversely, a longer PTT may indicate lower blood pressure. 3. Non-invasive measurement: The pulse transit time can be used in the present invention to estimate blood pressure non-invasively. The radar device 120 and the evaluation unit 140 can measure the PTT between two points in the circulatory system (i.e., between two sections S1, ..., S1). n or body regions), such as between the thigh at the hip joint and the feet, to allow an approximate estimate of blood pressure.

[0069] In summary, pulse transit time is a suitable diagnostic tool that can reflect the elasticity of the blood vessels and thus indirectly the blood pressure.

[0070] Alternatively or additionally to PTT, pulse wave analysis (PWA) can be used. PWA is a method for measuring and analyzing a pulse wave propagated through the bloodstream. It can be used to obtain additional information about vascular health and blood pressure regulation.

[0071] Essentially, pulse wave analysis (PWA) involves examining the speed and shape of the pulse wave that travels through the body as blood is pumped from the heart into the arteries. PWA can provide information about arterial elasticity and the risk of cardiovascular disease.

[0072] The pulse wave is influenced by various factors, including arterial stiffness, blood pressure, and blood viscosity. By measuring pulse wave kinetics and their temporal evolution at different points in the circulatory system (i.e., at different sections S1, ..., S1), it is possible to determine the pulse wave's kinetic profile. nThe concept according to the invention can provide estimates of systolic and diastolic blood pressure as well as other cardiovascular parameters (e.g., body regions).

[0073] Some important aspects of the PWA: 1. Pulse wave velocity (PWV): This measures how quickly the pulse wave propagates through the arterial system. A higher velocity can indicate increased arterial stiffness, which is a risk factor for high blood pressure and cardiovascular disease. 2. Arterial elasticity: In healthy arteries, the pulse wave is slower and shows an elastic wall that expands and contracts with the pulse. However, when the arteries become stiff, the pulse wave accelerates, indicating a decrease in elasticity. 3. Blood pressure measurement: Based on the shape and speed of the pulse wave, the blood pressure can be determined or at least estimated using the concept according to the invention.

[0074] PWA is often regarded as less invasive and, to some extent, more precise in analyzing vascular health and blood pressure changes, primarily because it provides additional information about arterial structure that cannot be captured by conventional blood pressure measurements alone.

[0075] Regardless of which of the two methods mentioned above is used, a significant advantage of the concept according to the invention lies, among other things, in the fact that the evaluation unit can detect 140 minute skin movements in the individual sections S1, ..., S n can be recorded independently of each other. That is, the evaluation unit 140 can be used in each section S1, ..., S n , and thus detect skin movement, e.g. in the form of a pulse signal, separately in each body region.

[0076] Since the individual sections S1, ..., S nSince individual body regions can be represented, local blood pressure can be determined independently for each region. For example, a first local blood pressure measurement can be taken in one body region (e.g., thigh), and simultaneously a second local blood pressure measurement can be taken in a second body region (e.g., lower leg).

[0077] Since several body regions (e.g. lower leg, thigh) can belong to one entire body part (e.g. left leg), blood pressure can be measured in several sections along the respective body part.

[0078] Accordingly, the evaluation unit 140 could be used in the individual sections S1, ..., S n or body regions (e.g., upper and lower leg) are summarized and used to form a blood pressure value valid for the respective body part (e.g., entire leg).

[0079] Additionally, a blood pressure reading could be calculated for each body region (e.g., thigh and lower leg) to perform a plausibility check. Adjacent body regions (such as the upper and lower leg) should not show significantly different blood pressure readings.

[0080] Corresponding embodiments therefore provide that the evaluation unit 140 performs a plausibility check of two different sections S1, ..., S nThis method can be used to perform local blood pressure measurements. A local blood pressure measurement taken in a first section S1 or first body region (e.g., thigh) is compared with a local blood pressure measurement taken in an adjacent second section S2 or second body region (e.g., lower leg). The determination of the two local blood pressure measurements is only considered plausible if the comparison shows no deviation or only a deviation that is below a predefined threshold, i.e., if the two blood pressures differ only slightly.

[0081] This plausibility check is particularly advantageous when the PWA (pulse wave analysis) method is used. However, a plausibility check can also be performed when using the PTT (pulse transit time) method.

[0082] According to one possible configuration, the evaluation unit 140 can be designed to perform a plausibility check of the pulse transit time between two different sections S1 and S2, or body regions. The time interval between a detected skin movement at a starting point S1 and a detected skin movement at an endpoint S2 is determined. For example, the time interval between a skin movement detected in a first starting point section S1 or first starting point body region (e.g., thigh) and a skin movement detected in an adjacent second endpoint section S2 or second endpoint body region (e.g., lower leg) is measured. The measured pulse transit time is only considered plausible if the measured time interval is below a predefined threshold value. Between two adjacent sections or body regions (such as, for example, the lower leg)The pulse cannot have moved arbitrarily fast (in the upper and lower leg). Maximum pulse speeds known from medicine can be used here as plausibility limits.

[0083] The two plausibility checks mentioned above generally only make sense if the first section, S1, and the adjacent second section, S2, are located in the same body part. This means that both blood pressure measurements should be taken in the same extremity, for example, the right leg. As mentioned previously, adjacent body regions (such as the upper and lower leg) should not show significantly different blood pressure readings.

[0084] As mentioned at the beginning, body regions can also be subdivided into more finely granular sections. For example, the first section or starting point section S1 described above could be a small section of the thigh, while the second section or ending point section S2 described above could be an adjacent small section of the thigh. The distance between the two sections S1 and S2 can, in principle, be arbitrary; that is, they do not have to be two directly adjacent sections, but could also be separated by one or more other sections.

[0085] According to the invention, blood pressure can thus be recorded simultaneously in several body regions or body parts, and preferably at the same time (e.g., in a single measurement step). An advantageous embodiment of the device according to the invention provides that the evaluation unit 140 can create a complete body model based on the individual body regions, which indicates a distribution of blood pressure over the entire body 110.

[0086] For this purpose, the evaluation unit 140 can summarize the local blood pressure values ​​recorded in the individual body regions or body parts and use them to form a global blood pressure value valid for the entire body 110.

[0087] This whole-body model can be regularly updated using long-term measurements. Accordingly, the evaluation unit 140 could repeatedly take measurements to determine local blood pressure in one or more sections S1, ..., S over a specific period. n or perform the scans on specific body regions and then update the overall body model with the measured values ​​obtained.

[0088] A key advantage of the invention is that blood pressure can be measured independently at several different locations on the body, thus allowing conclusions to be drawn about the entire cardiovascular system. Regular measurements over years (especially due to the avoidance of sleep disturbances caused by the contactless operation) can also provide information about changes in the cardiovascular system over time, such as a reduction in elasticity. This data can then be used, for example, to assess risks, such as the narrowing of blood vessels due to plaque buildup.

[0089] The contactless blood pressure measurement according to the invention is also considered advantageous in many respects, as it does not affect the patient and thus makes the night during sleep possible as a measurement period. This measurement can therefore also be performed in other scenarios, such as while driving, and contribute to continuous monitoring.

[0090] The concept according to the invention thus significantly improves the validity of radar-based blood pressure measurement in everyday situations, in particular by determining a blood pressure value for several body segments and comparing them. Advantageously, a whole-body blood pressure model can be created from this, which can be updated over time by the local pulse signals of the respective body segments.

[0091] Furthermore, based on continuous measurement, time windows with little or no (disturbing) movement of the person and optimal position based on the body model can be identified in order to then carry out an optimal measurement.

[0092] Accordingly, the device 100 can, for example, continuously monitor the vascular system by having the radar device 120 first detect, using the reflected radar waves, whether the body 110 is at rest or in motion. Only when the body is detected as being at rest is a measurement triggered, in which the evaluation unit 140 determines the blood pressure.

[0093] Alternatively, the person could be asked to lie on their back with their legs extended for a short period and remain in that position so that their blood pressure can be measured. This is significantly less invasive than using a blood pressure cuff. Furthermore, suitable time intervals for such blood pressure measurements could be determined throughout the night. These intervals can be considerably more frequent than the 15-minute intervals required for blood pressure cuff measurements.

[0094] The vascular health of the entire body can be assessed from the blood pressure readings obtained over time and distributed across the body by comparing these values ​​and examining them for peculiarities. For example, if different body regions exhibit different pulse waves over time, this could indicate changes in blood flow in those regions.

[0095] Accordingly, the evaluation unit 140 can, for example, be designed to perform multiple measurements in a specific body region (e.g., the right forearm) over a certain period and to compare the blood pressure values ​​obtained there. This allows for a qualitative and / or quantitative assessment of whether long-term changes in blood pressure are present in this specific body region (e.g., the right forearm).

[0096] Alternatively or additionally, it would be conceivable to monitor not only individual body regions or parts over a longer period and check for changes, but the entire body. For this purpose, blood pressure readings taken in two or more body regions or parts (e.g., left arm, right leg) can be compared. If significant differences are found between them, this indicates a different distribution of blood pressure throughout the body. These differences can be detected with a single measurement. Trends in these differences can be recorded using long-term measurements.

[0097] The change in blood pressure values ​​over a night or based on long-term measurements over years could provide information about a person's blood pressure tendency as well as the health of the underlying arterial system, in order to observe the change in the vascular body model over time and to estimate a risk profile.

[0098] Since multiple skin movements, e.g., in the form of pulse waves, are detected in individual body regions or parts, these signals can also be used for dynamically adjusting filters to detect the pulse in other body regions, such as the torso, despite superimposed respiratory movements. This would allow multiple body parts to be used for pulse measurement, which could then be incorporated into the blood pressure model.

[0099] Accordingly, it would be conceivable that the evaluation unit 140 is designed to define a tolerance measurement range based on at least one skin movement detected in a first section S1 or body region, within which a detected skin movement is used to determine blood pressure. For example, a skin movement with a displacement of x µm could be detected in a first section S1 (e.g., on the right lower leg). Based on this, a tolerance range of, for example, x ± 20% could then be defined.

[0100] A movement detected in a different second section (S2) or body region is only used to determine blood pressure if it falls within the previously defined tolerance measurement range. For example, if a movement is detected in the torso that lies outside the tolerance range (e.g., ±20%), this movement is filtered out and not used to determine blood pressure. Particularly in the torso, respiratory movements overlay the superficial skin movements used to determine blood pressure. The rise and fall of the chest during breathing has a significantly larger amplitude than the superficial skin movements used to determine blood pressure. Therefore, respiratory movements fall outside the previously defined tolerance range and are filtered out and not used to determine blood pressure.

[0101] The aforementioned blood pressure model can also be optionally linked to other vital parameters, such as respiratory rates or pulse rates, or even to limb movements, all of which can be measured by the Radar 120 device. This linkage allows for the detection of multiple symptoms during screening.

[0102] As previously mentioned, radar-based determination of vascular system parameters, such as blood pressure, can be achieved using PWA and / or PTT methods, either individually or in combination. The application of these two methods within the framework of the inventive concept can lead to novel evaluations. These are listed again below in bullet points: PWA - Pulse wave analysis • The multiple pulse signals or skin movements along the individual body regions or body parts (such as legs) can be individually examined for signal properties in order to calculate a blood pressure value for the individual body regions (e.g. leg sections, such as upper and lower leg). • Additionally, a separate blood pressure value could be calculated for each body region (e.g., leg segment) to perform a plausibility check. Adjacent body regions (e.g., leg segments) should not show significantly different blood pressure values. • Another application would be a combination of all pulse signals along a body part (e.g. along the legs) to obtain a signal with an improved signal-to-noise ratio, from which the blood pressure can then be calculated. • Furthermore, individual body regions (e.g., leg segments) can be compared based on their pulse signal characteristics or their calculated blood pressure in the direction of the pulse wave towards another body region (e.g., towards the feet). The comparison between individual body regions (e.g., leg segments) can provide information about the propagation of the pulse wave across the entire body part (e.g., the legs). • Furthermore, pulse signal characteristics along a body part (e.g., along the legs) can be compared to go beyond the signal characteristics of a single pulse and summarize more information. For example, changes in maximum skin deflection along the entire body part (e.g., the entire legs) can be determined. Moreover, the blood pressure drop along the respective body part (e.g., along the legs) should also provide information about the blood pressure of the entire body. The blood pressure gradient from the hips to the feet can, in itself, represent novel clinical information. • Furthermore, information from multiple pulse waves along the body can be combined to determine the strength of the heartbeat / heart muscle. The pulse waves and their amplitude are caused by the force of the heartbeat. Multiple pulse waves combined with information about body size / weight could provide information about the heart. PTT - Pulse Transit Time • The concept according to the invention allows for the calculation of multiple transit times between different sections of individual body parts (e.g., the legs). For example, the pulse peak time could be determined at the base of the legs at the hip joint and at the feet. The time difference between these pulse peaks corresponds to the pulse transit time along the legs and correlates with blood pressure. • Other body regions (e.g., other leg segments) can be used as the endpoint for determining the pulse transit time instead of the feet. This allows for a plausibility test of the pulse transit time by comparing the distance traveled between the start and end points with the pulse transit time. The pulse cannot have moved arbitrarily fast between two adjacent body regions (e.g., leg segments). Maximum pulse velocities from medicine can be used here as plausibility limits. • Additionally, due to the multiple body regions (e.g., leg segments), it is not necessary to detect the pulse solely at the feet. If no pulse is detectable at the feet due to foot movements, another body region (e.g., another leg segment) with a detectable pulse signal can be selected as the endpoint for the pulse transit time. This increases the robustness of the method according to the invention. By measuring the distance to the radar device 120 and the time of the pulse peak for each distance bin 1211, ..., 121 n The pulse rate and its changes along a body part (e.g., along the legs) can be determined. This can provide information about the blood flow in that body part (e.g., the legs). • By combining pulse wave / blood pressure measurements along a body part (e.g., along the legs) with the relatively larger limb movements of the body, further symptoms can also be detected. An example would be circulatory disorders in the legs, which lead to leg movements (restless legs syndrome) in an attempt to stimulate blood flow. By measuring blood pressure and limb movement along the entire leg, a more valid assessment of such symptoms can be made (= combination of the blood pressure model of the leg with other measurable values ​​from the radar). • Pulse waves along the legs can also be used to define adaptive filters, for example, to locate the pulse on the torso. Since pulse measurement in the legs provides a clear indication of what to look for, the signal can be more easily identified in other body parts. This also allows for measuring a pulse wave closer to the heart than just on the thighs, thus improving the blood pressure measurement.

[0103] For the sake of clarity, the concept according to the invention has so far been described using the example of the legs. However, in the case of a person lying down, e.g., during sleep monitoring, the legs might not be lying straight in bed, but rather be bent or drawn up. In this case, skin movements or pulse signals could be detected at other parts of the body and evaluated in a similar way to how previously described using the legs as an example. If, for example, the PTT method is not used, but only the PWA method, then all detected skin movements or pulse signals could be converted into a blood pressure value. This would allow blood pressure to be determined simultaneously at different body positions.

[0104] Fig. Figure 3 shows a schematic block diagram illustrating a method 300 according to the invention for radar-based monitoring of the vascular system of a human body 110.

[0105] Block 301 involves the contactless detection of superficial skin movements using radar. The radar device 120 described above can be used for this purpose.

[0106] Block 302 includes a process step according to which the radar waves 121 are emitted obliquely, at an angle of inclination α ≠ 90° to the longitudinal axis of the body 130, in the direction of the body 110, so that the emitted radar waves 121 propagate along the longitudinal axis of the body 130 from the head towards the feet or from the feet towards the head.

[0107] Block 302 involves detecting skin movements using reflected radar waves and determining a parameter of the vascular system (e.g., the blood pressure described above) based on the detected skin movements.

[0108] The concept according to the invention and its advantages will be briefly summarized below: The invention essentially relates to a concept for contactless blood pressure measurement based on movements of the skin surface along the body based on distance measurements.

[0109] An important aspect of the invention lies, among other things, in the use of multiple skin movements or pulse signals along the body 110 for blood pressure determination using a single radar sensor 120, in order to measure blood pressure at many different body parts simultaneously and continuously. In this way, multiple pulse signals can be used to determine blood pressure. Furthermore, a blood pressure value can be determined for the different body parts for each heartbeat.

[0110] The concept according to the invention thus presents a technical solution for continuously, robustly, and accurately measuring 120 blood pressure values ​​at different body regions or body parts using only a single radar device. Additionally, these blood pressure values ​​can be converted into a whole-body blood pressure model 110.

[0111] Regarding the selection of the radar set 120, the use of a frequency-modulated continuous wave radar, or FMCW for short, is advantageous. An FMCW radar can divide a distance measurement into several individual distance bins 1211, ..., 121. n subdivide, thereby segmenting the entire body 110 (or parts thereof) into several individual body sections S1, ..., S n or body regions, e.g. according to the number of distance bins 1211, ..., 121 nThis makes it possible to examine individual body sections or regions for small skin movements, such as the heartbeat pulse.

[0112] The FMCW radar method is generally considered advantageous here because it can also image static objects, allowing a model of the body to be derived. This makes it possible to assign measurements to specific regions of the body. This can also be used as a plausibility test.

[0113] In principle, other radar methods could also be used (such as pulse radars). However, FMCW radar is considered advantageous here in order to relate the measurements to a body model and to be able to make the aforementioned derivations on this basis.

[0114] Regarding the positioning of the radar device 120, it is proposed that the radar device 120 be installed at an angle to the person 110 to be observed that differs from 90°, i.e. the radar device 120 is not installed vertically above or below (i.e. opposite the stomach or back) of the person 110, but preferably at the head or foot end.

[0115] This means that the radar device 120 is installed so that it is preferably aligned along the longitudinal axis of the body 130, i.e., from head to feet, or from feet to head. Thus, the radar waves 121 can also be emitted accordingly along the longitudinal axis of the body 130.

[0116] The concept according to the invention enables the continuous recording of blood pressure at various locations on the body. The concept according to the invention is considered technically advantageous because, with this measurement configuration, signal components (e.g., respiration and heartbeat) can be more clearly separated from one another during recording than with a vertical recording configuration according to the prior art (see Fig. 2).

[0117] For example, the legs are advantageous for detecting superficial skin movements (pulse extraction) because there is no respiratory movement there that could mask the pulse on the skin surface. Since the legs are closer to radar unit 120 in this radar position, more energy from the radar unit's electromagnetic wave will reach the legs than the distant upper body and be reflected back. This increases the signal-to-noise ratio and thus improves the detection of small pulse movements on the skin surface. Furthermore, the selected lateral recording configuration provides multiple pieces of information from different distance bins 1211, ..., 121. n , thus enabling an increase in the robustness of the derived values ​​and allowing statements about the entire vascular system.

[0118] Compared to the prior art for blood pressure cuffs, the concept according to the invention offers continuous and contactless measurement at multiple points on the body 110 without disturbing the person. This latter point also offers a decisive advantage over other contactless radar methods. Furthermore, multiple measurement points are available to validate a single measurement and make the result more robust against errors. In addition, a more complete picture of the blood pressure distribution in the body 110 is obtained, as well as information for assessing vascular risk, with only a single sensor (radar device 120) being sufficient.

[0119] The concept according to the invention also has the advantage of operating continuously and without contact, increasing the number of blood pressure readings along the body, improving the accuracy and robustness of the method, and enabling the derivation of novel information (cardiovascular assessment for specific body regions). As a result, the patient is no longer burdened by a pressure-increasing cuff in everyday life, and blood pressure is no longer influenced by routine blood pressure measurements. This creates the possibility of using continuous radar blood pressure measurement as a long-term monitoring tool for everyday life, allowing information to be derived for a health risk assessment.

[0120] A further advantage is that only a single radar device (transmitting and receiving antenna) 120 is used, yet multiple blood pressure readings along the body 110 can be recorded. This significantly reduces the complexity of the entire system 100, thereby considerably lowering both the cost and the physical component size of the entire system 100. Furthermore, the device 100 according to the invention can be used in several applications.

[0121] The most important advantages of the concept according to the invention are listed again in bullet points below: • Use of a single radar device / radar sensor 120 for contactless measurement of parameters of the vascular system, such as blood pressure, pulse, etc. • Possibility of validating contactless radar-based blood pressure measurements by combining multiple pulse signals based on PWA and / or PTT. • Possibility of plausibility tests by comparing adjacent body regions / sections (e.g., left thigh, left lower leg). • Changes in blood pressure along the limbs are detectable, which allows for the early diagnosis of circulatory diseases, for example. • Continuous blood pressure measurement of different body areas simultaneously instead of just one small body section, such as the arm above the elbow in a cuff measurement or just one small body section on which a radar device is directed according to the state of the art. • The ability to perform a time series of blood pressure measurements without the interference of contact sensors on the person being measured. This allows for long-term monitoring, e.g., for the early detection of health changes. • Ability to create a whole-body blood pressure model. This allows, in addition to increasing the validity, robustness, and / or accuracy of measurements, the identification of abnormalities in the cardiovascular system. • Ability to create and record blood pressure monitoring as part of sleep monitoring. • Ability to create and record blood pressure monitoring in various everyday scenarios (e.g. driving, at work, on the train, etc.) • Monitoring in the nursing sector for various diseases (e.g., bedriddenness, epilepsy, COPD) • Monitoring in the hospital • Home monitoring (outpatient or for personal health monitoring)

[0122] As mentioned previously, the solution proposed here uses a radar system to continuously and independently measure skin movement occurring in individual body regions or parts. For this purpose, a selected position of the radar device 120 can be used at an angle, i.e., at an inclination angle α ≠ 90° to the longitudinal axis 130 of the body. Alternatively or additionally, beamforming using multiple radar antennas can be employed.

[0123] Corresponding embodiments using beam forming provide for the following in this regard: A device 100 for radar-based monitoring of the vascular system of a human body 110, wherein the device 100 includes, among other things, a radar device 120 for detecting superficial skin movements, the radar device 120 being arranged at a distance from the body 110 so that the skin movements can be detected without contact. The radar device 120 is positioned along the longitudinal axis 130 of the body (e.g., at an angle α ≠ 90° or at an angle α = 90°). The radar device 120 can have several transmitting and receiving antennas so that radar waves 121 can be emitted obliquely onto the body 110 by means of beamforming, in order to propagate along the longitudinal axis 130 of the body from the head towards the feet or from the feet towards the head. The device 100 also includes an evaluation unit 140, which is designed to determine a parameter of the vascular system based on skin movements detected by means of reflected radar waves.

[0124] The embodiments described above merely illustrate the principles of the innovative concept described herein. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the concept described herein be limited only by the scope of protection set forth in the following patent claims and not by the specific details presented herein by way of description and explanation of the embodiments.

[0125] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device.

[0126] Some or all of the process steps can be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the key process steps can be performed by such an apparatus.

[0127] Depending on specific implementation requirements, exemplary embodiments can be implemented in hardware or software, or at least partially in hardware or at least partially in software. The implementation can be carried out using a digital storage medium, such as a floppy disk, DVD, Blu-ray disc, CD, ROM, PROM, EPROM, EEPROM, FLASH memory, hard disk, or other magnetic or optical storage medium, on which electronically readable control signals are stored. These signals can interact with, or interact with, a programmable computer system in such a way as to execute the respective method. Therefore, the digital storage medium can be computer-readable.

[0128] Some embodiments therefore include a data carrier that has electronically readable control signals capable of interacting with a programmable computer system in such a way as to carry out one of the methods described herein.

[0129] In general, embodiments can be implemented as a computer program product with a program code, wherein the program code is effective in carrying out one of the methods when the computer program product runs on a computer.

[0130] The program code can also be stored on a machine-readable medium, for example.

[0131] Other embodiments include a computer program for performing one of the methods described herein, wherein the computer program is stored on a machine-readable medium. In other words, an embodiment of the method described herein is a computer program that includes program code for performing one of the methods described herein when the computer program is executed on a computer.

[0132] Another embodiment of the method described herein is a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded. The data carrier, digital storage medium, or computer-readable medium is typically tangible and / or non-volatile.

[0133] Another embodiment of the method described herein is a data stream or a sequence of signals that represents the computer program for carrying out one of the methods described herein. The data stream or sequence of signals can be configured, for example, to be transferred via a data communication connection, such as the Internet.

[0134] Another embodiment comprises a processing device, for example a computer or a programmable logic device, which is configured or adapted to perform one of the methods described herein.

[0135] Another embodiment comprises a computer on which the computer program for performing one of the procedures described herein is installed.

[0136] Another embodiment comprises a device or system designed to transmit a computer program for carrying out at least one of the methods described herein to a receiver. The transmission can be, for example, electronic or optical. The receiver can be, for example, a computer, a mobile device, a storage device, or a similar device. The device or system can, for example, include a file server for transmitting the computer program to the receiver.

[0137] In some embodiments, a programmable logic device (for example, a field-programmable gate array, an FPGA) can be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array can interact with a microprocessor to perform one of the methods described herein. Generally, in some embodiments, the methods are performed by any hardware device. This can be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC. Bibliography Mukkamala, R. et al. (2021). Evaluation of the accuracy of cuffless blood pressure measurement devices: challenges and proposals. Hypertension 78.5, 1161-1167. Mukkamala, R. G. et al. (2022). Cuffless blood pressure measurement. Annual Review of Biomedical Engineering 24.1, 203-230. Pour Ebrahim, M. et al. (2019). Blood pressure estimation using on-body continuous wave radar and photoplethysmogram in various posture and exercise conditions. Scientific Reports 9.1., 16346. Saugel, B. et al. (2020). How to measure blood pressure using an arterial catheter: a systematic 5-step approach. Critical Care 24, 1-10. Singh, L. et al. (2023). Remote Estimation of Blood Pressure Using Millimeter-Wave Frequency-Modulated Continuous-Wave Radar. Sensors 23.14, 6517. Vysotskaya, N. et al. (2023). Continuous non-invasive blood pressure measurement using 60 GHz-radar-a feasibility study. Sensors 23.8, 4111. ZITATE ENTHALTEN IN DER BESCHREIBUNG

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] Mukkamala, R.G. et al. (2022). Cuffless blood pressure measurement. Annual Review of Biomedical Engineering 24.1, 203-230

[0137] Ebrahim, M. et al. (2019). Blood pressure estimation using on-body continuous wave radar and photoplethysmogram in various posture and exercise conditions. Scientific Reports 9.1., 16346

[0137] Saugel, B. et al. (2020). How to measure blood pressure using an arterial catheter: a systematic 5-step approach. Critical Care 24, 1-10

[0137] Singh, L. et al. (2023). Remote Estimation of Blood Pressure Using Millimeter-Wave Frequency-Modulated Continuous-Wave Radar. Sensors 23.14, 6517

[0137] Vysotskaya, N. et al. (2023). Continuous non-invasive blood pressure measurement using 60 GHz-radar-a feasibility study. Sensors 23.8, 4111

[0137]

Claims

[1] Device (100) for radar-based monitoring of the vascular system of a human body (110), wherein the device (100) comprises: a radar device (120) for detecting superficial skin movements, wherein the radar device (120) is arranged at a distance from the body (110) so that skin movements can be detected without contact, and wherein the radar device (120) is positioned at an inclination angle α ≠ 90° to the longitudinal axis (130) of the body, so that radar waves (121) are emitted obliquely onto the body (110) to propagate from the head towards the feet or from the feet towards the head, and an evaluation unit (140) designed to determine a parameter of the vascular system based on skin movements detected by means of reflected radar waves. [2] Device (100) according to claim 1, where the parameter of the vascular system is blood pressure. [3] Device (100) according to claim 1 or 2, wherein the radar device (120) is designed to convert a distance measured by means of reflected radar waves into discrete intervals, so-called distance bins (1211, ..., 121) n to subdivide, and wherein the evaluation unit (140) is designed to divide the body (110) into several sections (S1, ..., S n ) according to the number of distance bins (1211, ..., 121 n ) to subdivide, and the individual distance bins (1211, ..., 121 n ) recorded skin movements in the individual sections (S1, ..., S n ) of the body (110). [4] Device (100) according to claim 3, wherein the evaluation unit (140) is designed to divide the body (110) into at least 20 different sections (S1, ..., S n to subdivide. [5] Device (100) according to claim 3 or 4, where the body (110) is divided into several sections (S1, ..., S n ) along the longitudinal axis of the body (130). [6] Device (100) according to any one of claims 3 to 5, wherein the evaluation unit (140) is designed to evaluate individual sections (S1, ..., S n ) to be assigned to specific body regions. [7] Device (100) according to claim 6, wherein the evaluation unit (140) is designed to create an overall body model based on the individual body regions, which indicates a distribution of the parameter of the vascular system across the body (110). [8] Device (100) according to claim 6 or 7, wherein the evaluation unit (140) is designed to detect skin movements in the individual sections (S1, ..., S n) to record independently of each other, so that a local parameter of the vascular system can be determined independently of each other for the individual body regions. [9] Device (100) according to claim 8, wherein the evaluation unit (140) is designed to process the data in the individual sections (S1, ..., S n ) to summarize the recorded local parameters of the vascular system and from this to calculate an overall value valid for the respective body part for the parameter of the vascular system, and / or to form a global value valid for the entire body (110) for the parameter of the vascular system. [10] Device (100) according to claim 8 or 9, wherein the evaluation unit (140) is designed to perform multiple measurements over a specific period of time to determine the local parameters of the vascular system in one or more sections (S1, ..., S1). n) to execute and update a body model with the measured values ​​obtained. [11] Device according to any one of claims 6 to 10, wherein the evaluation unit (140) is designed to compare several local parameters of the vascular system recorded in different body regions, to obtain a qualitative and / or quantitative statement as to whether there are deviations between the different body regions with respect to the local parameter of the vascular system, which suggests a different distribution of the parameter of the vascular system in the body (110). [12] Device (100) according to any one of claims 6 to 11, wherein the evaluation unit (140) is designed to perform several measurements in a specific body region over a specific period of time and to compare the values ​​of the local parameter of the vascular system determined there with each other, to obtain a qualitative and / or quantitative statement about whether long-term changes in the local parameter of the vascular system are present in this one specific body region. [13] Device (100) according to any one of claims 3 to 12, wherein the evaluation unit (140) is designed to determine the parameter of the vascular system using at least one of the two methods: • Pulse wave analysis (PWA), where skin movements are based on one, or at least one, distance bin (1211, ..., 1211) n ) locally limited, pulse signal can be detected, • Pulse Transit Time (PTT), where skin movements are based on one, over several distance bins (1211, ..., 121) n ) progressing, pulse wave is detected, or both methods are combined. [14] Device (100) according to any one of claims 6 to 13, wherein the evaluation unit (140) is designed to perform a plausibility check of a pulse transit time between two different sections (S1, S2), by measuring the time interval between a skin movement detected in a first section (S1) and a skin movement detected in an adjacent second section (S2), and where the pulse transit time is considered plausible if the measured time span is below a predefined threshold. [15] Device (100) according to any one of claims 6 to 14, wherein the evaluation unit (140) is designed to perform a plausibility check of in two different sections (S1, ..., S n ) determined local parameters of the vascular system, by comparing a local parameter of the vascular system determined in a first section (S1) with a local parameter of the vascular system determined in an adjacent second section (S2), and The determination of the two local parameters of the vascular system is considered plausible if the comparison reveals no deviation or a deviation that is below a predefined threshold. [16] Device (100) according to claim 15, where the first section (S1) and the adjacent second section (S2) are assigned to the same body part. [17] Device (100) according to any one of the preceding claims, wherein the device (100) is designed to continuously monitor the vascular system, and wherein the radar device (120) is designed to detect, by means of reflected radar waves, whether the body (110) is at rest or in motion, and only when the body (110) is detected to be at rest, triggers a measurement in which the evaluation unit (140) determines the parameter of the vascular system. [18] Device (100) according to any one of the preceding claims, wherein the evaluation unit (140) is designed, to define a tolerance measurement range based on at least one skin movement detected in a first section (S1), within which a detected skin movement is used to determine the parameter of the vascular system, and A movement detected in a different second section (S2) should only be used to determine the parameter of the vascular system if the movement detected there is within the previously determined tolerance measurement range. [19] Device (100) according to any one of the preceding claims, wherein the radar device (120) has exactly one single transmitting and receiving antenna. [20] Device (100) according to any one of claims 1 to 18, wherein the radar device (120) has several transmitting and receiving antennas and is designed to emit the radar waves (121) obliquely onto the body (110) by means of beamforming. [21] Device (100) according to any one of the preceding claims, wherein the radar device (120) is designed in the form of an FMCW radar. [22] Method (300) for radar-based monitoring of the vascular system of a human body (110), wherein the method comprises the following steps: Non-contact detection of superficial skin movements using radar, wherein radar waves (121) are emitted obliquely, at an angle of inclination α ≠ 90° to the longitudinal axis of the body (130), in the direction of the body (110), so that the emitted radar waves (121) propagate from the head towards the feet or from the feet towards the head, and Detecting skin movements using reflected radar waves and determining a parameter of the vascular system based on the detected skin movements. [23] Computer-readable digital storage medium with program code stored thereon for carrying out the method according to claim 22 when the program runs on a computer.

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