Contactless blood pressure monitoring

Abstract

Method for contactless blood pressure monitoring of a patient (100), wherein the method comprises: Irradiation (202) of a patient's (100) blood vessel with infrared light, IR light through a blood pressure control system; Receiving (204) IR light reflected by the patient (100) via a polarization filter (108) through an IR camera (104) of the blood pressure monitoring system; Capturing (206), at a time based on a patient's heart rate (100), an initial IR image (208) of the patient's blood vessel (100) by the IR camera (204) of the blood pressure control system when the blood vessel is dilated; Determining (210) a maximum diameter of the blood vessel from the first image (208) by the blood pressure control system; Capturing (212), at a time based on the patient's heart rate (100), a second IR image (214) of the patient's blood vessel by the IR camera (104) of the non-contact blood pressure monitoring system when the blood vessel is constricted; Determining (216) a minimum diameter of the blood vessel from the second IR image (214) by the blood pressure control system; and Calculating (224) the patient's blood pressure as a function of the maximum and minimum diameters (218, 220) of the blood vessel by the blood pressure control system, where the calculation (224) of the patient's blood pressure further includes a reduction (702) of the influence of background radiation by a source separation algorithm.

Description

Field of invention

[0001] The field of the invention relates to methods, devices and products for contactless blood pressure monitoring of a patient. Description of the related technique

[0002] Current medical technology for measuring various blood-related parameters, such as blood pressure, heart rate, and blood flow rate, generally requires physical contact between a patient and the medical device. Blood pressure, for example, is generally measured using a sphygmomanometer (also called a blood pressure gauge or blood pressure monitor), which includes an inflatable cuff. When inflated, this cuff restricts blood flow through a patient's veins and contracts in a controlled manner to measure the blood pressure in the vein both when compressed and when not compressed. Such compression can be uncomfortable for many patients.

[0003] More advanced blood pressure measurement methods have already been described. For example, document US 2013 / 0322729A1 describes the use of video for contactless detection of cardiac function parameters using RGB and IR signals. Document US 5598842A also describes non-invasive blood analysis using light within a detection region of blood vessels and a corresponding detector. Furthermore, document US 2013 / 0274610A1 describes a method and a corresponding system for displaying waves of heartbeats in blood vessels. Optical detection is also used for this. Finally, document US 2015 / 0112214A1 describes a device for measuring blood pressure and a corresponding method. This method also partially relies on measuring the diameter of blood vessels.

[0004] Despite these advances already made, there is still a need to improve blood pressure measurement methods in such a way that fewer erroneous measurement results are produced. SUMMARY

[0005] This task is solved by the subject matter of the independent patent claims. Further details arise from the respective dependent patent claims.

[0006] This description discloses methods, devices, and products for non-contact blood pressure monitoring of a patient. According to one aspect, such non-contact blood pressure monitoring involves: irradiating a patient's blood vessel with infrared (IR) light by a blood pressure monitoring system; receiving IR light reflected by the patient through a polarizing filter by an IR camera of the blood pressure monitoring system; capturing, at a time based on the patient's heart rate, an initial IR image of the patient's blood vessel by the IR camera of the blood pressure monitoring system when the blood vessel is dilated; determining the maximum diameter of the blood vessel from the first image by the blood pressure monitoring system; capturing, at a time based on the patient's heart rate, a second IR image by the IR camera of the non-contact blood pressure monitoring system when the blood vessel is constricted.Determining the minimum diameter of the blood vessel from the second image using the blood pressure control system; and calculating the patient's blood pressure based on the maximum and minimum diameters of the blood vessel using the blood pressure control system.

[0007] The above and other objectives, features and advantages of the invention will become apparent from the following more detailed descriptions of exemplary embodiments of the invention, as illustrated in the accompanying drawings, in which identical reference numerals generally refer to identical parts of exemplary embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following describes embodiments of the invention with reference to the accompanying drawings, which are to be understood as merely exemplary and in which: Fig. 1 shows a block diagram of a system configured for contactless blood pressure monitoring of a patient according to embodiments of the present invention; Fig. 2 sets out a flow chart illustrating an exemplary procedure for contactless blood pressure monitoring of a patient according to embodiments of the present invention; Fig. 3 presents a representation of a patient's blood vessel; Fig. 4 sets out a flow chart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate; Fig. 5 sets out a flow chart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate; Fig. 6 presents another illustration of a patient's blood vessel; Fig. 7 sets out a flow chart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate. Detailed description

[0009] Exemplary methods, devices and products for contactless blood pressure monitoring of a patient according to the present invention are described with reference to the accompanying drawings, wherein with Fig. 1 is started. Fig. Figure 1 shows a block diagram of a system configured for contactless blood pressure monitoring of a patient according to embodiments of the present invention. The system consists of Fig. Figure 1 includes an example of a contactless blood pressure monitoring system according to various embodiments of the present invention. Such a blood pressure monitoring system can be implemented with an automated data processing mechanism in the form of a computer (152), a camera (104) and several light sources (106, 102).

[0010] The example computer (152) from Fig. 1 includes at least one computer processor (156) or “CPU” and one random access memory (RAM) (168) which is connected to the processor (156) and other components of the computer (152) via a high-speed memory bus (166) and a bus adapter (158).

[0011] A blood pressure control module (126), i.e., a module of computer program instructions for contactless blood pressure monitoring according to embodiments of the present invention, is stored in the RAM (168). For this purpose, the blood pressure control module (126) can irradiate one or more blood vessels of a patient (100) with IR light using the IR light source (102). In some embodiments of the present invention, irradiating the patient (100) with IR light can include irradiating the patient's face. The face contains many blood vessels in the form of veins, capillaries, and so on, as will be known to those skilled in the art. In the sense used in this description, a blood vessel can refer to a vein, a capillary, or an artery.

[0012] The blood pressure monitoring module (126) can also receive IR light reflected by the patient (100) via a polarization filter (108) using an IR camera (104). The camera (104) in the example from Fig. 1 can be implemented in various ways. For example, the camera can be a digital video camera configured to capture IR light, visible light, or both. In some embodiments, multiple cameras can be implemented. In such an embodiment, one camera can be an RGBA camera and another an IR camera. A polarizing filter generally prevents polarized light from passing through the filter. In the example system from Fig. 1. Different types of polarization filters can be used, e.g. a linear polarizer, a circular polarizer or a combination thereof.

[0013] The blood pressure control module (126) can also, at a time based on the patient's heart rate, capture an initial IR image of the patient's blood vessel via the camera (104) when the blood vessel is dilated, i.e., when it is fully expanded. It should be obvious to knowledgeable readers that such "capture" of an image can be performed by capturing many images, for example, by capturing a stream of full frames in a digital video, and by sampling the image data from these many images. Indeed, upon hearing the term "capture" in this description, knowledgeable readers should understand that the term can refer to capturing many images and sampling the image data from these images.

[0014] A heartbeat follows a cardiac cycle. The cardiac cycle begins with systole, during which the heart chambers contract and pump blood into the circulatory system. The cycle continues with a resting phase, followed by diastole, during which the heart chambers relax. As a result of the systolic phase of the cardiac cycle, the pressure in the blood vessels increases, and they expand. At this point, the blood pressure control module acquires an IR image of the blood vessel based on a known or calculated heart rate (described below). It should be obvious to knowledgeable readers that acquiring an IR image of a blood vessel generally refers to acquiring an image of a portion of the vessel rather than the entire vessel.

[0015] From the first IR image, the blood pressure control module (126) can determine a maximum diameter of the blood vessel. The diameter can be calculated based on image processing of the image, whereby vessel edges can be identified and the distance between the edges at the point of maximum dilation can be calculated in various ways.

[0016] The blood pressure monitoring module (126) can use the camera (104) to acquire a second infrared image of the patient's blood vessel at a specific time, based on the patient's heart rate, when the blood vessel is constricted. The same portion of the blood vessel that was previously captured in an infrared image when fully distended can be captured when the vessel is fully constricted, i.e., during the diastolic phase of the cardiac cycle. Accordingly, the blood pressure monitoring system can determine the minimum diameter of the blood vessel from this second infrared image.

[0017] From these maximum diameters, the blood pressure control module can then calculate the patient's blood pressure. Blood pressure is generally directly proportional to the product of the blood flow rate and the total peripheral resistance. The total peripheral resistance is highly variable based on the blood vessel radius. The blood pressure control module (126) can calculate the blood pressure in several ways. Blood pressure is generally measured during diastole and systole. In some embodiments, the blood pressure control module (126) can calculate the diastolic blood pressure by assuming or calculating a blood flow rate, estimating the total peripheral resistance based on the maximum diameter, and calculating the product of these values.The blood pressure control module (126) can also calculate the systolic blood pressure by assuming or calculating a blood flow rate, estimating the total peripheral resistance based on the minimum diameter, and calculating the product of these two values. Expert readers will know that this is just one of many ways to calculate blood pressure from the maximum and minimum diameters of a blood vessel. Each of these possible methods is within the scope of the present invention.

[0018] For knowledgeable readers, it should be obvious that this is in Fig. Figure 1 shows a blood pressure monitoring system, which includes the computer (152), the camera (104), and the light sources (102, 106). This system can be implemented in various ways. For example, it can be implemented in a kiosk where a user can access the kiosk, request a blood pressure check using user input devices, and receive the results on a display (180). Readers will also be aware that such monitoring can be dynamic and continuous. For instance, multiple cameras can be configured to capture 24 full frames per second, and the acquisition of the tracked IR images, the determination of the maximum and minimum vessel diameters, and the calculation of the blood pressure can be performed very frequently within a short period of time.

[0019] An operating system (154) is also stored in the RAM (168). Operating systems that are useful in computers configured for contactless blood pressure monitoring of a patient according to embodiments of the present invention include UNIX™, Linux™, Microsoft Windows™, AIX™, IBM's i™ operating system, and others, as should be obvious to those skilled in the art. Although the example from Fig. Figure 1 shows the operating system (154) and the blood pressure control module (126) in the RAM (168), but many components of such software are usually stored in non-volatile memory such as on a disk drive (170).

[0020] The computer (152) from Fig. 1 includes a disk drive adapter (172) which is connected to the processor (156) and other components of the computer (152) via an expansion bus (160) and the bus adapter (158). The disk drive adapter (172) connects the non-volatile memory to the computer (152) in the form of the disk drive (170). Disk drive adapters that are useful in computers configured for contactless blood pressure monitoring of a patient according to embodiments of the present invention include IDE (Integrated Drive Electronics) adapters, SCSI (Small Computer System Interface) adapters, and others, as should be obvious to those skilled in the art.Non-volatile computer memory can also be used for an optical disk drive, an electrically erasable programmable read-only memory (EEPROM or flash memory), RAM drives, and so on, as should be obvious to the person skilled in the art.

[0021] The example computer (152) from Fig. 1 includes one or more input / output adapters (I / O adapters) (178). I / O adapters use user-related inputs / outputs, for example via software drivers and computer hardware, to control outputs to display units such as computer display screens, as well as user inputs from user input units (181) such as keyboards and mice. The example computer (152) from Fig. 1 includes a video adapter (209), which is an example of an I / O adapter specifically designed for graphical output to a display unit (180) such as a display screen or computer monitor. The video adapter (209) is connected to the processor (156) via a high-speed video bus (164), the bus adapter (158), and the front-side bus (FSB) (162), which is also a high-speed bus.

[0022] The exemplary computer (152) from Fig. Figure 1 includes a data transmission adapter (167) for data transmissions with other computers and for data transmissions with a data transmission network (not shown here). As should be obvious to those skilled in the art, such data transmissions can be carried out serially via RS-232 connections, via external buses such as a Universal Serial Bus (USB), via data transmission networks such as IP data transmission networks, and in other ways. Data transmission adapters implement the hardware layer of data transmissions by which a computer sends data transmissions to another computer, either directly or via a data transmission network. Examples of data transmission adapters that are useful in computers configured for contactless blood pressure monitoring of a patient according to embodiments of the present invention include modems for wired dial-up connections, Ethernet (IEEE 802.11), and Ethernet (IEEE 802.11).3) Adapters for wired data transmissions and 802.11 adapters for wireless data transmissions.

[0023] The arrangement of computer components, cameras, and light sources that make up the in Fig. The illustrated systems in Figure 1 are intended as an explanation and not as a limitation. As should be obvious to those skilled in the art, data processing systems that are useful according to various embodiments of the present invention may include additional servers, routers, other units, and peer-to-peer architectures that are integrated into the system. Fig. Figure 1 is not shown. As should be obvious to those skilled in the art, networks in such data processing systems can support many data transmission protocols, including, for example, TCP (Transmission Control Protocol), IP (Internet Protocol), HTTP (Hypertext Transfer Protocol), WAP (Wireless Access Protocol), HDTP (Handheld Device Transport Protocol), and others. Various embodiments of the present invention can, in addition to those shown in Figure 1, support many data transmission protocols, including TCP (Transmission Control Protocol), IP (Internet Protocol), HTTP (Hypertext Transfer Protocol), WAP (Wireless Access Protocol), HDTP (Handheld Device Transport Protocol), and others. Fig. The platforms illustrated in 1 can be implemented in a variety of hardware platforms.

[0024] For further explanation, Fig. Figure 2 presents a flowchart illustrating an exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention. The example method from Fig. 2 can be carried out by a system similar to the one in the example from Fig. The system shown in 1 is.

[0025] The procedure from Fig. 2 involves irradiating (202) a patient's blood vessel with IR light by means of a blood pressure control system. The irradiation (202) of a blood vessel (or many blood vessels) can be carried out by directing IR light from an IR light source onto the face or other exposed area of ​​skin of a patient.

[0026] The procedure from Fig. 2 also includes receiving (204) IR light reflected by the patient via a polarization filter by an IR camera of the blood pressure monitoring system. The IR camera may include one or more lens filters to block incident light in the visible light spectrum while allowing IR light to reach a CCD (charge-coupled device) sensor or a CMOS (complementary metal oxide semiconductor) sensor.

[0027] The procedure from Fig. 2 also includes capturing (206) a first IR image (208) of the patient's blood vessel by the IR camera of the blood pressure monitoring system at a time based on the patient's heart rate, when the blood vessel is dilated. If, in one embodiment, the IR camera is a 24 FPS (frames per second) digital video camera, the first IR image can be captured by storing a stream of full frames for a certain period of time and identifying, based on the heart rate, a full frame that includes the vessel when fully dilated.

[0028] The procedure from Fig. 2 also includes determining (210) a maximum diameter (220) of the blood vessel from the first image (208) using the blood pressure control system. The diameter can be calculated by image processing, where edge detection is used to identify the vessel's edges. The distance between two points on opposite detected edges can be determined as the diameter.

[0029] The procedure from Fig. 2 also includes capturing (212), at a time based on the patient's heart rate, a second IR image (214) of the patient's blood vessel by the IR camera of the contactless blood pressure monitoring system when the blood vessel is constricted. The procedure from Fig. 2 also includes determining a minimum diameter (218) of the blood vessel from the second IR image by the blood pressure control system.

[0030] The procedure from Fig. 2 also includes a calculation (224) of the patient's blood pressure as a function of the maximum and minimum diameters of the blood vessel by the blood pressure control system. The calculation (224) of the blood pressure can be performed by calculating both the diastolic and systolic pressure, and such a calculation can be performed in various ways. In some embodiments, each diameter (220, 218) can be used to determine or assume a total peripheral resistance. Given a known or calculated blood flow rate, the calculation of the diastolic and systolic blood pressure can be performed by determining the product of the total peripheral resistance (at each diameter) and the blood flow rate.After calculation, the blood pressure can be displayed to the patient or otherwise made available, or provided electronically to a doctor (via email or other messaging).

[0031] For further explanation, Fig. Figure 3 shows a representation of a patient's blood vessel. For clarity, a patient's vessel (202) is shown enlarged. The blood vessel is shown at two time points: at t0, when the heart is in the diastolic phase and the vessel is contracting, and at t1, when the heart is in the systolic phase and the vessel is dilated. While the patient is irradiated with IR light, the blood pressure monitoring system can acquire an IR image at each time point that includes a relevant point (206). From the images, the blood pressure monitoring system can determine the minimum diameter (218) at the relevant point at t0 and the maximum diameter (220) at the relevant point at t1.

[0032] As mentioned above, the patient's heart rate, which can be used to determine the timing of IR images of the patient's blood vessel during dilation and contraction, can be assumed or calculated by other means. For this purpose, Fig. 4 presents a flow chart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate.

[0033] The procedure from Fig. 4 is similar to the procedure from Fig. 2, when the procedure from Fig. 4 also includes irradiating (202) a patient's blood vessel with IR light; receiving (204) IR light reflected by the patient; acquiring (206), at a time based on the patient's heart rate, a first IR image (208) of the patient's blood vessel when the blood vessel is dilated; determining (210) a maximum diameter (220) of the blood vessel; acquiring (212) a second IR image (214) of the patient's blood vessel when the blood vessel is constricted, at a time based on the patient's heart rate; determining (216) a minimum diameter (218) of the blood vessel; and calculating (224) a patient's blood pressure (226) as a function of the maximum and minimum diameters of the blood vessel.

[0034] The procedure from Fig. However, 4 differs from the procedure described above in that Fig. 2, when the procedure from Fig. 4 involves calculating (402) the patient's heart rate. The procedure consists of Fig. 4. The calculation (402) of the patient's heart rate is performed by: irradiating (404) the patient with IR light and visible light; capturing (406) a series of RGBA (Red, Green, Blue, Alpha) images while the patient is irradiated with the IR light; identifying (408) maximum RGBA intensity values ​​from the RGBA images; and determining (410) a frequency of repeatedly occurring maximum RGBA intensity values ​​over a period of time as the patient's heart rate.

[0035] When the heart beats, blood flows faster through the vessel, and the vessel expands. This causes the vessel's color to change. The change occurs periodically (or semi-periodically) based on the patient's regular, periodic heartbeat. Thus, the periodicity or frequency of the color change can be used to represent the heartbeat.

[0036] Each image in the series of images contains a plurality of pixels. Each pixel is defined by intensity values ​​for red, intensity values ​​for green, and intensity values ​​for blue. As the color of the vessel changes, the intensity values ​​of the pixel in each image also change. Thus, identifying (408) maximum RGBA intensity values ​​from the images can be done in several ways. In one example, the blood pressure monitoring system can calculate average intensity values ​​for each pixel from a number of pixels and for each color. The blood pressure monitoring system can then calculate a score based on the sum of the average color intensity values ​​and compare these sums with the sums of other images in the series. Those images with the highest intensity values ​​within a range they cover can be determined as the images with the highest RGBA intensity values.

[0037] Not only can the patient's heart rate be calculated for later use when capturing IR images for calculating blood pressure, but the heart rate can also be a diagnostic tool made available to the patient or doctor.

[0038] For further explanation, the procedure is interpreted Fig. Figure 5 presents a flowchart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate. The method from Fig. 5 is similar to the procedure from Fig. 2, when the procedure from Fig. 5 also includes irradiating (202) a patient's blood vessel with IR light; receiving (204) IR light reflected by the patient; acquiring (206) a first IR image (208) of the patient's blood vessel at a time based on the patient's heart rate when the blood vessel is dilated; determining (210) a maximum diameter (220) of the blood vessel; acquiring (212) a second IR image (214) of the patient's blood vessel at a time based on the patient's heart rate when the blood vessel is constricted; determining (216) a minimum diameter (220) of the blood vessel; and calculating (224) a patient's blood pressure (226) as a function of the maximum and minimum diameters of the blood vessel.

[0039] The procedure from Fig. However, 5 differs from the procedure described above in that Fig. 2, when the procedure from Fig. 5 involves calculating (502) a patient's blood flow rate. The procedure from Fig. 5. The calculation of the patient's blood flow rate is performed by: irradiating (504) the patient with IR light and visible light; acquiring (506) a series of RGBA images while the patient is irradiated with the IR light; identifying (508) a first image of a blood vessel from the series of RGBA images when a more upstream location in the blood vessel is stretched and a downstream location is not stretched; identifying (510) a second image of the blood vessel from the series of RGBA images when the downstream location is stretched; calculating (512) a time interval between the acquisition of the first and second images; and calculating (514) a blood flow rate based on the time interval.

[0040] Blood flow rate can be determined by measuring the time it takes for blood to flow from one point, an upstream location, to a second point, a downstream location. The blood pressure monitoring system can be configured to calculate the distance between the upstream and downstream locations and then identify in the images when blood flows through each location. The blood pressure monitoring system can identify the point at which blood flows through a location as the point at which the vessel dilates at that location. That is, at one point, blood flows through the upstream location, dilating the vessel at that point. Later, at a second point in time, blood flows through the downstream location, dilating the vessel at that location.The ratio of the time interval between the two stretches and the distance between the two points is the blood flow rate.

[0041] As mentioned above, the blood flow rate can be used to calculate blood pressure. For this purpose, the patient's blood pressure can be calculated (224) by calculating (516) the patient's blood pressure as a function of the blood flow rate and the maximum and minimum diameters of the blood vessel.

[0042] For further explanation, Fig. Figure 6 shows another representation of a patient's vessel. For clarity, a patient's vessel (602) is shown enlarged. The vessel (602) is shown at two time points: at t0, when an upstream portion (605) is stretched due to blood flow (618) (620), and at t1, when the downstream portion (606) of the vessel is stretched due to blood flow. During a period in which the patient is irradiated with IR light, the blood pressure monitoring system can acquire a series of IR images that include the vessel at t0 and t1. From these images, the blood pressure monitoring system can identify the image in which the upstream portion is stretched and the image in which the downstream portion is stretched. The blood pressure monitoring system can then calculate or determine the time interval between the acquisition of these images.Finally, the blood pressure monitoring system can divide the time interval by the distance between the two digits (605, 606).

[0043] For further explanation, the procedure is interpreted Fig. Figure 7 presents a flowchart illustrating a further exemplary method for contactless blood pressure monitoring of a patient according to embodiments of the present invention, which includes calculating the patient's heart rate. The method from Fig. 7 is similar to the procedure from Fig. 2, when the procedure from Fig. 7 also includes irradiating (202) a patient's blood vessel with IR light; receiving (204) IR light reflected by the patient; acquiring (206), at a time based on the patient's heart rate, a first IR image (208) of the patient's blood vessel when the blood vessel is dilated; determining (210) a maximum diameter (220) of the blood vessel; acquiring (212) a second IR image (214) of the patient's blood vessel when the blood vessel is constricted, at a time based on the patient's heart rate; determining (216) a minimum diameter (220) of the blood vessel; and calculating (224) a patient's blood pressure (226) as a function of the maximum and minimum diameters of the blood vessel.

[0044] The procedure from Fig. 7 differs from the procedure from Fig. 2, as in the procedure from Fig.2. The calculation (224) of the patient's blood pressure (226) also includes a reduction (702) of the influence of background radiation by means of a source separation algorithm. In some embodiments, scattered, ambient, or background radiation may reach the IR camera of the blood pressure control system. Such background radiation may include IR and RGBA sources other than those controlled by the blood pressure control system. For this purpose, a source separation algorithm may be applied to filter out some or all of the background radiation from the image data provided by the camera. A source separation algorithm attempts to identify uniquely distinguishable components that have been combined and to remove all components except the desired one.To support the source separation algorithm, the camera can capture images when no patient is present to identify any background radiation that is present and likely to be captured by the camera. When applying the source separation algorithm, the previously identified background radiation can then be taken into account by removing components that might be undesirable for blood pressure monitoring calculations. Additionally, multiple known light sources can be directed at the user to limit the amount of scattered radiation that can be received by the camera.

[0045] The present invention may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium (or media) on which computer-readable program instructions are stored to induce a processor to execute aspects of the present invention.

[0046] A computer-readable storage medium can be a physical unit capable of retaining and storing instructions for use by an instruction execution unit. For example, a computer-readable storage medium can be an electronic storage unit, a magnetic storage unit, an optical storage unit, an electromagnetic storage unit, a semiconductor storage unit, or any suitable combination thereof, without limitation. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), and erasable programmable read-only memory (EPROM).Flash memory), static random-access memory (SRAM), portable read-only compact disc (CD-ROM), DVD (Digital Versatile Disc), USB flash drive, floppy disk, a mechanically coded unit such as punched cards or raised structures in a groove on which instructions are stored, and any suitable combination thereof. A computer-readable storage medium shall not, in its use herein, be understood as volatile signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., light pulses guided by an optical fiber cable), or electrical signals transmitted by a wire.

[0047] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to individual data processing units or, via a network such as the internet, a local area network, a wide area network, and / or a wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission lines, wireless transmission, routing computers, firewalls, switching units, gateway computers, and / or edge servers. A network adapter card or network interface in each data processing unit receives computer-readable program instructions from the network and forwards them for storage on a computer-readable storage medium within the respective data processing unit.

[0048] Computer-readable program instructions for executing the steps of the present invention can be assembly instructions, ISA (Instruction Set Architecture) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., as well as conventional procedural programming languages ​​such as C or similar languages. The computer-readable program instructions can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server.In the latter case, the remotely located computer can be connected to the user's computer via any type of network, including a LAN or a WAN, or the connection can be established with an external computer (for example, via the Internet using an Internet service provider). In some embodiments, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), can execute computer-readable program instructions by using state information from the computer-readable program instructions to personalize the electronic circuits to perform aspects of the present invention.

[0049] Aspects of the present invention are described herein with reference to flowcharts and / or block diagrams or charts of methods, devices (systems), and computer program products according to embodiments of the invention. It is pointed out that each block of the flowcharts and / or block diagrams or charts, as well as combinations of blocks in the flowcharts and / or block diagrams or charts, can be executed by means of computer-readable program instructions.

[0050] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a specialized computer, or another programmable data processing device to create a machine, such that the instructions executed via the processor of the computer or other programmable data processing device generate a means of implementing the functions / steps specified in the block(s) of the flowcharts and / or block diagrams or charts.These computer-readable program instructions may also be stored on a computer-readable storage medium capable of controlling a computer, programmable data processing device, and / or other units to function in a particular manner, such that the computer-readable storage medium on which instructions are stored has a manufactured product, including instructions that implement aspects of the function / step specified in the block(s) of the flowchart and / or block diagrams or charts.

[0051] The computer-readable program instructions can also be loaded onto a computer, other programmable data processing device, or other unit to cause the execution of a series of process steps on the computer or other programmable device or other unit in order to generate a process executed on a computer, such that the instructions executed on the computer, other programmable device, or other unit implement the functions / steps specified in the block(s) of the flowcharts and / or block diagrams or charts.

[0052] The flowcharts and block diagrams or charts in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this context, each block in the flowcharts or block diagrams or charts can represent a module, segment, or part of instructions that includes one or more executable instructions for performing the specific logical function(s). In some alternative embodiments, the functions specified in the block may occur in a different order than shown in the figures. For example, two blocks shown consecutively may in reality be executed essentially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding functionality.It should also be noted that each block of the block diagrams or charts and / or flowcharts, as well as combinations of blocks in the block diagrams or charts and / or flowcharts, can be implemented by special hardware-based systems that perform the specified functions or steps, or execute combinations of special hardware and computer instructions.

[0053] It should be evident from the preceding description that various embodiments of the present invention can be modified and adapted without altering its essential conceptual content. The explanations in this description serve only for illustrative purposes and are not to be understood as limiting. The scope of the present invention is limited only by the wording of the following claims.

Claims

[1] Method for non-contact blood pressure monitoring of a patient (100) wherein the method comprises: Irradiation (202) of a patient's (100) blood vessel with infrared light, IR light through a blood pressure control system; Receiving (204) IR light reflected by the patient (100) via a polarization filter (108) through an IR camera (104) of the blood pressure monitoring system; Capturing (206), at a time based on a patient's heart rate (100), an initial IR image (208) of the patient's blood vessel (100) by the IR camera (204) of the blood pressure control system when the blood vessel is dilated; Determining (210) a maximum diameter of the blood vessel from the first image (208) by the blood pressure control system; Capturing (212), at a time based on the patient's heart rate (100), a second IR image (214) of the patient's blood vessel by the IR camera (104) of the non-contact blood pressure monitoring system when the blood vessel is constricted; Determining (216) a minimum diameter of the blood vessel from the second IR image (214) by the blood pressure control system; and Calculating (224) the patient's blood pressure as a function of the maximum and minimum diameters (218, 220) of the blood vessel by the blood pressure control system, where the calculation (224) of the patient's blood pressure further includes a reduction (702) of the influence of background radiation by a source separation algorithm. [2] The method of claim 1, further comprising a calculation of the patient's heart rate, comprising: Irradiation (404) of the patient (100) with IR light and visible light; Acquiring (406) a series of RGBA (Red, Green, Blue, Alpha) images while the patient (100) is irradiated with IR light; Identify (408) maximum RGBA intensity values ​​from the RGBA images; and Determine (410) a frequency of repeated maximum RGBA intensity values ​​over a period of time as the patient's heart rate (100). [3] The method of claim 1, further comprising a calculation of the patient's blood flow rate, comprising: Irradiation (202) of the patient (100) with IR light and visible light; Acquiring (506) a series of RGBA images (Red, Green, Blue, Alpha) while the patient (100) is irradiated with IR light; Identifying (508) a first image of a blood vessel from the series of RGBA images when an upstream area in the blood vessel is stretched and a downstream area is not stretched; Identifying (510) a second image of the blood vessel from the series of RGBA images when the upstream area in the blood vessel is stretched; Calculating (512) a time interval between the acquisition of the first and the second image; and Calculating (514) a blood flow rate based on the time interval. [4] Method according to claim 3, wherein the calculation of the patient's blood pressure further comprises calculating the patient's blood pressure as a function of the blood flow rate and the maximum and minimum diameters of the blood vessel. [5] Method according to claim 1, wherein the irradiation (516) of a blood vessel of the patient (100) with IR light further comprises irradiation of the face of the patient (100) with IR light. [6] Method according to claim 1, wherein the calculation of the blood pressure is updated periodically while the patient (100) is present. [7] Device for contactless blood pressure monitoring of a patient, the device comprising a computer processor (156) and a computer working memory (168) connected to the computer processor (156), wherein the computer working memory contains computer program instructions which, when executed by the computer processor (156), cause the device to perform the following steps: Irradiation of a patient's blood vessel with infrared light (IR light) by a blood pressure control system; Receiving (202) IR light reflected by the patient (100) via a polarization filter (108) through an IR camera (104) of the blood pressure monitoring system; Capturing (204), at a time based on a patient's heart rate (100), an initial IR image (208) of the patient's blood vessel (100) by the IR camera (104) of the blood pressure control system when the blood vessel is dilated; Determining (210) a maximum diameter of the blood vessel from the first image by the blood pressure control system; Capturing (212), at a time based on the patient's heart rate (100), a second IR image (214) of the patient's blood vessel by the IR camera (104) of the non-contact blood pressure monitoring system when the blood vessel is constricted; Determining (216) a minimum diameter of the blood vessel from the second IR image (214) by the blood pressure control system; and Calculating (224) the patient's blood pressure (100) depending on the maximum and minimum diameters (218, 220) of the blood vessel by the blood pressure control system, where calculating the patient's (100) blood pressure (224) further includes reducing (702) the influence of background radiation by means of a source separation algorithm. [8] Device according to claim 7, further comprising computer program instructions which, when executed by the computer processor (156), cause the device to perform the step of calculating the patient's heart rate (100), comprising: Irradiation (404) of the patient with IR light and visible light; Acquiring (406) a series of RGBA (Red, Green, Blue, Alpha) images while the patient (100) is irradiated with IR light; Identify (408) maximum RGBA intensity values ​​from the RGBA images; and Determine (410) a frequency of repeated maximum RGBA intensity values ​​over a period of time as the patient's heart rate (100). [9] Device according to claim 7, further comprising computer program instructions which, when executed by the computer processor (156), cause the device to perform the step of calculating a blood flow rate of the patient (100), comprising: Irradiation (504) of the patient (100) with IR light and visible light; Acquiring (506) a series of RGBA images (Red, Green, Blue, Alpha) while the patient (100) is irradiated with IR light; Identifying (508) a first image of a blood vessel from the series of RGBA images when an upstream area in the blood vessel is stretched and a downstream area is not stretched; Identifying (510) a second image of the blood vessel from the series of RGBA images when the upstream area in the blood vessel is stretched; Calculating (512) a time interval between the recording of the first and of the second image; and Calculating (514) a blood flow rate based on the time interval. [10] Device according to claim 9, wherein the calculation (516) of the patient's blood pressure (100) further comprises a calculation (516) of the patient's blood pressure depending on the blood flow rate and the maximum and minimum diameters of the blood vessel. [11] Device according to claim 7, wherein the irradiation (504) of a blood vessel of the patient (100) with IR light further comprises irradiation of the face of the patient (100) with IR light. [12] Device according to claim 7, wherein the calculation of the blood pressure (516) is updated periodically while the patient (100) is present. [13] Computer program product for contactless blood pressure monitoring of a patient, wherein the computer program product is present on a medium readable by a computer (152), wherein the computer program product includes computer program instructions which, when executed, cause a computer (152) to perform the following steps: Irradiation (202) of a patient's blood vessel with infrared light (IR light) by a blood pressure control system; Receiving (204) IR light reflected by the patient (100) via a polarization filter (108) through an IR camera (104) of the blood pressure monitoring system; Capturing (206), at a time based on a patient's heart rate (100), an initial IR image (208) of the patient's blood vessel (100) by the IR camera (104) of the blood pressure control system when the blood vessel is dilated; Determining (210) a maximum diameter of the blood vessel from the first image by the blood pressure control system; Capturing (212), at a time based on the patient's heart rate (100), a second IR image (214) of the patient's blood vessel by the IR camera (104) of the non-contact blood pressure monitoring system when the blood vessel is constricted; Determining (216) a minimum diameter of the blood vessel from the second IR image (214) by the blood pressure control system; and Calculating (224) the patient's blood pressure (100) depending on the maximum and minimum diameters (218, 220) of the blood vessel by the blood pressure control system, where the calculation (224) of the patient's blood pressure further includes a reduction (702) of the influence of background radiation by a source separation algorithm. [14] Computer program product according to claim 13, further comprising computer program instructions which, when executed, cause the computer (156) to perform the step of calculating the patient's heart rate, comprising: Irradiation (404) of the patient with IR light and visible light; Acquiring (406) a series of RGBA (Red, Green, Blue, Alpha) images while the patient (100) is irradiated with IR light; Identify (408) maximum RGBA intensity values ​​from the RGBA images; and Determine (410) a frequency of repeatedly occurring maximum RGBA intensity values ​​over a period of time as the patient's heartbeat (a). [15] Computer program product according to claim 13, further comprising computer program instructions which, when executed, cause the device to perform the step of calculating a patient's blood flow rate, comprising: Irradiation (202) of the patient (100) with IR light and visible light; Acquiring (506) a series of RGBA images (Red, Green, Blue, Alpha) while the patient (100) is irradiated with IR light; Identifying (508) a first image of a blood vessel from the series of RGBA images when an upstream area in the blood vessel is stretched and a downstream area is not stretched; Identifying (510) a second image of the blood vessel from the series of RGBA images when the upstream area in the blood vessel is stretched; Calculating (512) a time interval between the acquisition of the first and the second image; and Calculating (514) a blood flow rate based on the time interval. [16] Computer program product according to claim 15, wherein the calculation (516) of the patient's blood pressure (100) further comprises a calculation of the patient's blood pressure depending on the blood flow rate and the maximum and minimum diameters of the blood vessel. [17] Computer program product according to claim 13, wherein the irradiation (202) of a blood vessel of the patient (100) with IR light further comprises irradiation of the patient's face with IR light. [18] Computer program product according to claim 13, wherein the calculation of the blood pressure is updated periodically while the patient (100) is present. [19] Computer program product according to claim 13 wherein the blood vessel has a capillary vessel.

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