Blood pressure measuring device and use method thereof

Abstract

The invention discloses a blood pressure measuring device and a using method thereof. An apparatus and method for blood pressure measurement using an electro-acoustic transducer in combination with a piezoelectric ultrasonic transducer are provided. The device and method can provide continuous and non-invasive blood pressure monitoring.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 2021800245223 (PCT / US2021 / 015324), filed on January 27, 2021, entitled “Blood Pressure Measuring Device and Method of Using Therewith”.

[0002] Cross-references

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 966,927, filed January 28, 2020, which is incorporated herein by reference. Background Technology

[0004] Blood pressure is a fundamental vital sign routinely used to manage patient care. Methods for measuring blood pressure are often complex and cumbersome. Typical methods have several limitations, including sensitivity to ambient noise, patient discomfort, and the inability to obtain continuous blood pressure measurements. Another method is invasive blood pressure measurement. While this provides higher quality data than external cuffs, its invasiveness also introduces higher risks, including infection, bleeding, or ischemia. There is a strong need for alternative, non-invasive methods for measuring blood pressure, especially as hypertension has become an increasingly prevalent medical problem in the United States and other parts of the world. Summary of the Invention

[0005] This document provides an embodiment of a blood pressure measuring device comprising: a first transducer configured to direct sound waves to a blood vessel; and a second transducer configured to direct ultrasound waves to the blood vessel, receive ultrasound waves reflected from the echo boundary of the blood vessel, and measure the radius and wall thickness of a cross-section of the blood vessel. The first transducer may be an electroacoustic transducer and / or the second transducer may be a piezoelectric ultrasonic transducer. The device may further include an audio signal generator coupled to the first transducer. In some embodiments, the audio signal generator includes at least a variable resistor for adjusting the frequency of the sound waves. The variable resistor may be a potentiometer. In some embodiments, the audio signal generator displays the frequency of the sound waves. The second transducer may monitor vibrations of the cross-section of the blood vessel. In some embodiments, the second transducer monitors vibrations of the cross-section of the blood vessel, and wherein the piezoelectric ultrasonic transducer records the frequency of the vibrations of the cross-section and determines its resonant frequency. The resonant frequency may be determined when the vibrations of the cross-section of the blood vessel are at their maximum. In some embodiments, the frequency of the sound waves varies in the range of 1 Hz to 3000 Hz. In some embodiments, the frequency of the sound waves varies in the range of 670 Hz to 2300 Hz. An electroacoustic transducer can be an audio speaker, and an audio speaker can be a tweeter. A blood vessel can be an artery or a vein.

[0006] This document further provides an embodiment of a method for measuring blood pressure, the method comprising: determining the radius and thickness of a cross-section of a blood vessel; directing sound waves to the blood vessel; varying the frequency of the sound waves; detecting the maximum resonance of the cross-section of the blood vessel to determine the resonant frequency of the blood vessel; and calculating blood pressure in the blood vessel based on the determined resonant frequency. Varying the frequency of the sound waves may include varying the frequency of the sound waves in the range of 1 Hz to 3000 Hz. In some embodiments, varying the frequency of the sound waves includes varying the frequency of the sound waves in the range of 670 Hz to 2300 Hz. The resonant frequency can be determined by using a piezoelectric ultrasonic transducer for detecting the maximum resonance. The piezoelectric ultrasonic transducer may include a sampling rate of at least 3 kHz. In some embodiments, determining the radius and thickness of the blood vessel includes directing ultrasound waves to the blood vessel and receiving reflected ultrasound waves reflected from the echo boundary of the blood vessel. In some embodiments, the method may further include measuring the Doppler shift of the reflected ultrasound waves and calculating the wave velocity of the blood vessel. The Doppler shift can be measured using a piezoelectric ultrasonic transducer. The blood vessel may be an artery or a vein.

[0007] This document provides an embodiment of a blood pressure measuring device, comprising: a first transducer configured to emit multiple sound waves having multiple frequencies, the sound waves being configured to vibrate a blood vessel of a subject; a second transducer configured to capture one or more ultrasound images of the blood vessel; and a processing device configured to: determine the resonant frequency of the blood vessel based on the one or more captured ultrasound images; and calculate the blood pressure of the blood vessel or the subject based on the wall thickness of the blood vessel, the radius or diameter of the blood vessel, and the determined resonant frequency.

[0008] In some embodiments, one or more captured ultrasound images are used to measure the wall thickness and radius or diameter of the blood vessel. In some embodiments, the one or more captured ultrasound images include multiple ultrasound images, wherein determining the resonant frequency of the blood vessel includes: determining a frequency among multiple frequencies that maximizes the vibration of the blood vessel based on the multiple ultrasound images; and selecting the frequency as the resonant frequency. In some embodiments, the device further includes: an audio signal generator electrically coupled to a first transducer, the audio signal generator being configured to adjust the frequency of sound waves emitted by the first transducer. In some embodiments, the audio signal generator includes at least one variable resistor that adjusts the frequency of the sound waves emitted by the first transducer. In some embodiments, each frequency is between 1 Hz and 3000 Hz. In some embodiments, each frequency is between 670 Hz and 2300 Hz.

[0009] In some embodiments, the blood vessel is the subject's carotid artery. In some embodiments, the first transducer is an audio speaker. In some embodiments, the device further includes a substrate, wherein the substrate includes an adhesive surface for adhesion to the subject's skin, wherein the first transducer and the second transducer are incorporated into the substrate. In some embodiments, the substrate is adhered near the blood vessel. In some embodiments, the blood vessel is the carotid artery. In some embodiments, the substrate includes alignment lines. In some embodiments, the substrate includes a transparent window.

[0010] In some embodiments, the device further includes a third transducer configured to capture a second set of one or more ultrasound images of a blood vessel. In some embodiments, the second and third transducers each have a corresponding resonant frequency, and the second transducer includes a frequency response that partially overlaps with the frequency response of the third transducer; and the processing device processes the measurements performed by the first and second transducers. In some embodiments, the processing of the measurements performed by the first and second transducers includes normalizing the first and second frequency responses.

[0011] In some embodiments, the device further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessel. In some embodiments, the device further includes a substrate, wherein the substrate includes an adhesive surface for adhesion to the skin of a subject, wherein the first, second, and third transducers are incorporated into the substrate. In some embodiments, the substrate is adhered near the blood vessel. In some embodiments, the blood vessel is the carotid artery. In some embodiments, the substrate includes alignment lines. In some embodiments, the substrate further includes a transparent window.

[0012] In some embodiments, the device further includes a fourth transducer configured to capture a third set of one or more ultrasound images of a blood vessel. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency response of the second transducer. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency response of a third transducer. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency responses of both the second and third transducers.

[0013] In some embodiments, the device further includes a substrate, wherein the substrate includes an adhesive surface for adhesion to the skin of a subject, wherein a first transducer, a second transducer, and a third transducer are incorporated into the substrate. In some embodiments, the substrate is adhered near a blood vessel. In some embodiments, the blood vessel is a carotid artery. In some embodiments, the substrate includes alignment lines. In some embodiments, the substrate further includes a transparent window.

[0014] In some embodiments, the device further includes a third transducer configured to capture a second set of one or more ultrasound images of a blood vessel. In some embodiments, the second and third transducers each have a corresponding resonant frequency, and the second transducer includes a frequency response that partially overlaps with the frequency response of the third transducer; and a processing device processes the measurements performed by the first and second transducers. In some embodiments, the processing of the measurements performed by the first and second transducers includes normalizing the first and second frequency responses.

[0015] In some embodiments, the device further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessel. In some embodiments, the device further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessel. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency response of the second transducer. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency response of the third transducer. In some embodiments, the fourth transducer includes a frequency response that partially overlaps with the frequency responses of both the second and third transducers.

[0016] According to some embodiments, this document provides a non-transitory computer-readable storage medium storing instructions executable by a processor, wherein execution of the instructions causes a blood pressure measuring device to perform operations including: emitting multiple sound waves of multiple frequencies using a first transducer near a blood vessel of a subject, the sound waves causing vibration of the subject's blood vessel; determining the resonant frequency of the blood vessel based on the vibration response of the blood vessel to the multiple sound waves; determining the wall thickness and radius or diameter of the blood vessel using a second transducer that emits ultrasound waves; and calculating the subject's blood pressure based on the resonant frequency, the wall thickness of the blood vessel, and the radius or diameter of the blood vessel.

[0017] In some embodiments, the operation further includes: capturing multiple ultrasound images of the blood vessel as it vibrates in response to sound waves using a second transducer, wherein determining the resonant frequency of the blood vessel includes: determining the resonant frequency of the blood vessel based on the ultrasound images. In some embodiments, determining the wall thickness and radius of the blood vessel includes: directing ultrasound waves to the blood vessel using the second transducer; and receiving ultrasound waves reflected from the echo boundary of the blood vessel using the second transducer. In some embodiments, after calculating blood pressure, the operation further includes: determining the updated radius of the blood vessel and the updated velocity of blood flow through the blood vessel using a first transducer and a second transducer; and calculating updated blood pressure based on the updated radius and the updated velocity.

[0018] In some embodiments, the frequencies of the multiple sound waves are between 1 Hz and 3000 Hz. In some embodiments, the frequencies of the multiple sound waves are between 670 Hz and 2300 Hz. In some embodiments, the first transducer is an audio loudspeaker.

[0019] In some embodiments, the operation further includes capturing a first set of ultrasound images of the blood vessel using a third transducer. In some embodiments, the operation further includes capturing a second set of ultrasound images of the blood vessel using a second transducer. In some embodiments, the operation further includes normalizing the second set of ultrasound images using the first set of ultrasound images.

[0020] In some embodiments, the operation further includes capturing a third set of ultrasound images of the blood vessel using a fourth transducer. In some embodiments, the operation further includes normalizing the second set of ultrasound images using the first set of ultrasound images. In some embodiments, the operation further includes normalizing the second set of ultrasound images using the third set of ultrasound images.

[0021] According to some embodiments, this document provides a method comprising: emitting multiple sound waves of multiple frequencies using a first transducer located near a blood vessel of a subject, the sound waves causing the blood vessel of the subject to vibrate; determining the resonant frequency of the blood vessel based on the vibration response of the blood vessel to the sound waves; determining the wall thickness and radius or diameter of the blood vessel using a second transducer that emits ultrasound waves; and calculating the blood pressure of the subject based on the resonant frequency, the wall thickness of the blood vessel, and the radius or diameter of the blood vessel.

[0022] In some embodiments, the method further includes: capturing multiple ultrasound images of the blood vessel as it vibrates in response to sound waves using a second transducer, wherein determining the resonant frequency of the blood vessel includes: determining the resonant frequency of the blood vessel based on the ultrasound images. In some embodiments, determining the wall thickness and radius of the blood vessel includes: directing ultrasound waves to the blood vessel using the second transducer; and receiving ultrasound waves reflected from the echo boundary of the blood vessel using the second transducer.

[0023] In some embodiments, the method for calculating blood pressure further includes: determining the radius of a new blood vessel and the rate of blood flow through the vessel using a first transducer and a second transducer; and calculating the updated blood pressure based on the updated radius and the updated rate of flow. In some embodiments, each frequency is between 670 Hz and 2300 Hz.

[0024] In some embodiments, the method further includes using a third transducer to capture a second set of multiple ultrasound images of the blood vessel as the blood vessel vibrates in response to sound waves. In some embodiments, the method further includes normalizing multiple ultrasound images of the blood vessel captured by a second transducer with the second set of multiple ultrasound images of the blood vessel captured by the third transducer.

[0025] In some embodiments, the method further includes capturing a third set of multiple ultrasound images of the blood vessel as the blood vessel vibrates in response to sound waves using a fourth transducer. In some embodiments, the method further includes normalizing multiple ultrasound images of the blood vessel captured by a second transducer with a second set of multiple ultrasound images of the blood vessel captured by the third transducer. In some embodiments, the method further includes normalizing multiple ultrasound images of the blood vessel captured by the second transducer with a third set of multiple ultrasound images of the blood vessel captured by the fourth transducer.

[0026] According to some embodiments, this document provides a blood pressure measuring device comprising: a first transducer configured to direct sound waves to a blood vessel; and a second transducer configured to direct ultrasound waves to a blood vessel, receive ultrasound waves reflected from the echo boundary of the blood vessel, measure the diameter or radius of a cross-section of the blood vessel, and measure the wall thickness of the cross-section of the blood vessel.

[0027] In some embodiments, the first transducer is an electroacoustic transducer and the second transducer is a piezoelectric ultrasonic transducer. In some embodiments, the device further includes an audio signal generator coupled to the first transducer. In some embodiments, the audio signal generator is configured to change the frequency of the sound wave. In some embodiments, the device further includes a display. In some embodiments, the display shows the frequency of the sound wave.

[0028] In some embodiments, the second transducer monitors the vibration of the cross-section of the blood vessel. In some embodiments, the second transducer monitors the vibration of the cross-section of the blood vessel, and wherein the second transducer records the frequency of the vibration of the cross-section and determines its resonant frequency. In some embodiments, the resonant frequency is determined when the vibration of the cross-section of the blood vessel is at its maximum value.

[0029] In some embodiments, the frequency of the sound waves varies in the range of 1 Hz to 3000 Hz. In some embodiments, the frequency of the sound waves varies in the range of 670 Hz to 2300 Hz. In some embodiments, the electroacoustic transducer is an audio loudspeaker. In some embodiments, the audio loudspeaker is a tweeter.

[0030] In some embodiments, the blood vessel is an artery or vein. In some embodiments, a first transducer and a second transducer are coupled to a substrate, wherein the substrate includes an adhesive backing. In some embodiments, the substrate is adhered near the blood vessel. In some embodiments, the blood vessel is a carotid artery. In some embodiments, the substrate includes alignment lines. In some embodiments, the substrate includes alignment lines and a transparent window.

[0031] According to some embodiments, this document provides a method for measuring blood pressure, the method comprising: determining the radius and wall thickness of a cross-section of a blood vessel; directing sound waves to the blood vessel; changing the frequency of the sound waves; detecting the maximum resonance of the cross-section of the blood vessel to determine the resonant frequency of the blood vessel; and calculating the blood pressure within the blood vessel based on the determined resonant frequency, radius, and wall thickness of the blood vessel.

[0032] In some embodiments, changing the frequency of a sound wave includes changing the frequency of the sound wave within the range of 1 Hz to 3000 Hz. In some embodiments, changing the frequency of a sound wave includes changing the frequency of the sound wave within the range of 670 Hz to 2300 Hz.

[0033] In some embodiments, a resonant frequency is determined using a piezoelectric ultrasonic transducer for detecting maximum resonance. In some embodiments, the piezoelectric ultrasonic transducer includes a sampling rate of at least 3 kHz. In some embodiments, the steps of determining the radius and wall thickness of the blood vessel include directing ultrasound waves to the blood vessel and receiving reflected ultrasound waves reflected from the echo boundary of the blood vessel. In some embodiments, the method further includes measuring the Doppler shift of the reflected ultrasound waves and calculating the wave velocity of the blood vessel. In some embodiments, the Doppler shift is measured by a piezoelectric ultrasonic transducer.

[0034] In some embodiments, the blood vessel is an artery or a vein. In some embodiments, the method further includes directing a first set of transmitted ultrasound waves toward the blood vessel and capturing a first set of reflected ultrasound waves from the blood vessel. In some embodiments, the steps of directing the first set of transmitted ultrasound waves toward the blood vessel and capturing the first set of reflected ultrasound waves from the blood vessel are performed by a single ultrasound transducer.

[0035] In some embodiments, the method further includes using a first ultrasound transducer to guide a first set of transmitted ultrasound waves toward a blood vessel, and using a second ultrasound transducer to capture a first set of reflected ultrasound waves from the blood vessel. In some embodiments, the method further includes using a first ultrasound transducer to guide the first set of transmitted ultrasound waves toward a blood vessel, and using both a first ultrasound transducer and a second ultrasound transducer to capture a first set of reflected ultrasound waves from the blood vessel. In some embodiments, the method further includes using a first ultrasound transducer to guide the first set of transmitted ultrasound signals toward a blood vessel, and using the first ultrasound transducer to capture a first reflected ultrasound signal from the blood vessel.

[0036] In some embodiments, the method further includes capturing a second reflected ultrasound signal from a blood vessel using a second ultrasound transducer. In some embodiments, the method further includes normalizing a first reflected ultrasound signal using the second reflected ultrasound signal.

[0037] In some embodiments, the method further includes capturing a third reflected ultrasound signal from the blood vessel using a third ultrasound transducer. In some embodiments, the method further includes normalizing the first reflected ultrasound signal with the third reflected ultrasound signal. In some embodiments, the blood vessel is a carotid artery.

[0038] According to some embodiments, this document provides a system for transmitting and receiving ultrasonic signals, the system comprising: a software-defined radio including one or more outputs and one or more inputs; an ultrasonic signal processing circuit electrically coupled to the software-defined radio; and one or more ultrasonic transducers electrically coupled to the ultrasonic signal processing circuit, wherein the ultrasonic signal processing circuit processes one or more ultrasonic transmission signals from one or more outputs of the software-defined radio and transmits the processed ultrasonic transmission signals to the one or more ultrasonic transducers to generate ultrasonic waves, and wherein a signal processing unit processes one or more received ultrasonic signals from the one or more ultrasonic transducers and transmits the processed received ultrasonic signals to one or more inputs of the software-defined radio.

[0039] In some embodiments, the ultrasonic processing circuitry includes at least one high-voltage amplifier to amplify one or more ultrasonic transmitted signals from one or more outputs of a software-defined radio. In some embodiments, the ultrasonic processing circuitry includes at least one variable-gain amplifier to amplify one or more received ultrasonic signals from one or more ultrasonic transducers.

[0040] In some embodiments, the ultrasonic processing circuitry includes at least one variable gain amplifier to amplify one or more received ultrasonic signals from one or more ultrasonic transducers. In some embodiments, the output of the software-defined radio includes a gain ramp and a transmission pulse. In some embodiments, the ultrasonic processing circuitry includes a high-voltage amplifier for amplifying the transmission pulse.

[0041] In some embodiments, the ultrasonic processing circuitry includes a variable gain amplifier to amplify one or more received ultrasonic signals from one or more ultrasonic transducers based on a gain ramp defined by a software-defined radio transmission. In some embodiments, the amplification rate of the ramp signal corresponds to the time since the initial pulse of the software-defined radio transmission ramp signal.

[0042] In some embodiments, the ultrasonic transducer includes a first pixel group and a second pixel group. In some embodiments, the first pixel group and the second pixel group each include 16 pixels. In some embodiments, the first pixel group is configured to receive processed ultrasonic transmission signals. In some embodiments, only the first pixel group receives the processed ultrasonic transmission signals.

[0043] In some embodiments, one or more received ultrasonic signals are received by a first pixel group and a second pixel group and transmitted to an ultrasonic processing circuit. In some embodiments, the variable gain amplifier is a low-noise, single-ended, linear, general-purpose variable gain amplifier.

[0044] In some embodiments, the ultrasonic transducer includes a first pixel group and a second pixel group. In some embodiments, the first pixel group is configured to receive a processed ultrasonic transmission signal.

[0045] In some embodiments, the system further includes a computing device connected to the software-defined radio, such that the computing device controls one or more outputs of the software-defined radio. In some embodiments, the computing device includes a display that displays data received from one or more inputs of the software-defined radio. In some embodiments, the display displays one or more ultrasound images obtained from one or more ultrasound transducers.

[0046] In some embodiments, the system further includes a computing device connected to the software-defined radio, such that the computing device controls one or more outputs of the software-defined radio. In some embodiments, the computing device includes a display that displays data received from one or more inputs of the software-defined radio.

[0047] The system described in 123 includes a display showing one or more ultrasonic images obtained by one or more ultrasonic transducers.

[0048] According to some embodiments, this document provides a method for modulating one or more ultrasonic signals, the method comprising: receiving a first transmitted signal from a software-defined radio; amplifying the first transmitted signal to form an amplified transmitted signal; forwarding the amplified transmitted signal to one or more ultrasonic transducers using a first multiplexer; receiving one or more received ultrasonic signals from the one or more ultrasonic transducers using the first multiplexer; and amplifying the one or more received ultrasonic signals to form one or more amplified received ultrasonic signals.

[0049] In some embodiments, amplification of one or more received ultrasound signals is based on a gain ramp defined by a software-defined radio transmission. In some embodiments, the amplification is time-dependent. In some embodiments, amplification of one or more received ultrasound signals is performed by one or more low-noise, single-ended, linear, general-purpose variable gain amplifiers. In some embodiments, amplification of one or more received ultrasound signals is performed by one or more low-noise, single-ended, linear, general-purpose variable gain amplifiers.

[0050] In some embodiments, the method further includes emitting one or more ultrasonic waves toward at least one object, wherein at least one object reflects one or more ultrasonic waves, and wherein the reflected ultrasonic waves are detected by one or more ultrasonic transducers and form one or more received ultrasonic signals.

[0051] In some embodiments, amplification of one or more received ultrasonic signals is based on a gain ramp defined by a software-defined radio transmission. In some embodiments, the amplification is time-dependent. In some embodiments, amplification of one or more received ultrasonic signals is performed by one or more low-noise, single-ended, linear, general-purpose variable gain amplifiers.

[0052] In some embodiments, at least one object is a blood vessel of the subject. In some embodiments, the blood vessel is the carotid artery. Attached Figure Description

[0053] The novel features of the invention are particularly set forth in the appended claims. A better understanding and advantage of the features of the invention will be obtained by referring to the following detailed description illustrating illustrative embodiments (in which the principles of the invention are utilized) and the drawings (also referred to herein as “drawings” and “figures”), in which:

[0054] Figure 1 Forces acting on the arterial membrane according to some embodiments are described;

[0055] Figure 2 Vibration of the arterial wall at a resonant frequency according to some embodiments is depicted;

[0056] Figure 3 This is a block diagram illustrating some components of a continuous blood pressure measurement device according to some embodiments of the present disclosure;

[0057] Figure 4 The echo boundaries of the arterial wall according to some embodiments are depicted;

[0058] Figure 5 An adhesive patch comprising an integrated continuous blood pressure measurement device is described according to some embodiments;

[0059] Figure 6 This is an operational flowchart illustrating an example method for measuring the blood pressure of a subject, based on some embodiments.

[0060] Figures 7A-7B The frequency response of three ultrasonic sensors in a continuous ultrasonic measurement apparatus according to some embodiments is described;

[0061] Figures 8A-8D The technique for cross-correlation in ultrasonic measuring equipment is described;

[0062] Figure 9A block diagram of an illustrative example system according to some embodiments is depicted;

[0063] Figure 10 This describes computer systems that are programmed or otherwise configured to implement the methods provided herein, according to some embodiments;

[0064] Figure 11 A method for forming an ultrasound image from a plurality of ultrasound transducers according to some embodiments is shown; and

[0065] Figure 12 Example chipsets that can be used to implement architectures and methods according to various embodiments of this disclosure are described. Detailed Implementation

[0066] This document provides a device capable of continuous, non-invasive blood pressure measurement. In some embodiments, the device includes one or more ultrasonic transducers. In some embodiments, the device presented herein eliminates the need for calibration steps and provides continuous, non-invasive blood pressure monitoring capabilities in an inexpensive and easy-to-use manner.

[0067] According to some embodiments, the techniques disclosed herein pertain to blood pressure measuring devices capable of continuous, non-invasive blood pressure measurement using acoustic and ultrasonic transducers. In some embodiments, an electroacoustic transducer is used to generate an audio signal that stimulates vibrations in an artery. By varying the frequency of the acoustic signal, the resonant frequency at which the artery vibrates most intensely can be determined. This resonant frequency can be combined with a measurement of the artery radius to calculate absolute blood pressure. In some embodiments, the radius of the artery is measured by one or more ultrasonic transducers using an ultrasound imaging method. Methods for measuring blood pressure using acoustic stimulation eliminate the need for separate calibration steps and provide blood pressure monitoring in an inexpensive and easy-to-use manner.

[0068] To understand the basic principles of the technology described in this article, it is helpful to consider the potential forces of blood flow through arteries. Figure 1 An arterial wall 110 is depicted, which can be represented as a tube made of an elastic material. The dynamics of the arterial wall 110 are governed by the balance between the blood pressure 120 that pushes the wall out and the tension 130 that holds the wall together. Laplace's law states that for a fluid flowing through a cylindrical elastic membrane with a constant radius R, the fluid pressure P and the tension T in the membrane are related to the equation T = RP.

[0069] One or more ultrasound devices can be used to measure the radius of an artery. Therefore, the remaining task for determining the fluid pressure P is to measure the tension in the arterial wall. In some embodiments, the tension can be determined by measuring how the arterial wall responds to pulses from an acoustic stimulus. Figure 2This process is described. In some embodiments, acoustic stimulation 240 generated by electroacoustic transducer 250 is used to induce measurable perturbations in the arterial wall 210. This method can utilize acoustic stimulation emitted at sound intensities well below the sound intensity limits specified by FDA guidelines. By focusing on vibrational patterns around the artery, particularly the lowest energy vibrations that can be excited in the surrounding area, tension can be estimated as follows.

[0070] The lowest energy vibration has a wavelength of λ = πR. The mechanical properties of the arterial wall also govern the velocity ν. ω The vibration propagates along the circumference of the wall at this speed. The wave speed and wavelength combine to produce the resonant frequency f = ν. ω / λ. If an external stimulus (such as a sound wave) is applied at frequency f, the wall will vibrate very strongly, but if the frequency of the stimulus changes away from f, the amplitude of the vibration will decrease. Therefore, f can be determined by applying an acoustic stimulus within a frequency range and finding the frequency at which the artery vibrates most strongly. In turn, this will tell us the wave velocity v. w =λf = πRf. In an elastic material under tension, with a bulk density of ρ and a thickness of h, the wave velocity is related to the tension by the following equation: T = ρhv w 2 The volume density of the arterial wall is almost constant among patients and the wall thickness can be measured from ultrasound images in the same manner as R. Using this information, pressure can be determined based on equation (1):

[0071] P = T / R = ρhv w 2 / R=π 2 πhRf 2 (1)

[0072] Therefore, measuring h and R via standard ultrasound imaging and determining the resonance point through the arterial vibration response to measure f will allow for the calculation of blood pressure.

[0073] I. Feasibility Analysis.

[0074] To illustrate the feasibility of the continuous blood pressure measurement technique described herein, the following factors can be considered. First, to demonstrate the practicality of this blood pressure measurement method, it can be ensured that the resonant frequency f is taken as a reasonable value in typical patients. In the common carotid artery, the measured values ​​are typically: P is approximately 100 mmHg, R is 2.5 mm, h is 0.3 mm, and p is 1 g / mL. Substituting these values ​​into equation (1) yields a predicted resonant frequency of approximately 1.3 kHz. Therefore, to detect this vibration, sampling at least ~3 kHz may be required to exceed the Nyquist rate. Currently available ultrasound instruments can produce imaging rates of at least 8 kHz, far exceeding the minimum sampling rate. 1.3 kHz is also much higher than the heart rate, which even under extreme conditions, does not exceed 5 Hz in human patients. Because the frequency at which resonance occurs is much higher than the rate of pressure change of the heartbeat, blood pressure (and the resulting tension) can be assumed to be constant during the duration of each vibration cycle, greatly simplifying the analysis. Furthermore, 1.3kHz falls comfortably within the range of currently available loudspeakers, so no special hardware is needed to produce a tone with sufficient amplitude and frequency to stimulate arterial vibrations.

[0075] Secondly, another metric for feasibility is the frequency range that the electroacoustic transducer might need to operate in. In extreme conditions, a patient's blood pressure could be as low as 25 mmHg or as high as 300 mmHg. Using the artery dimensions given above, this corresponds to a resonant frequency range of 670 Hz to 2.3 kHz, still within the acoustic range produced by commercially available loudspeakers.

[0076] Third, the required frequency resolution level for achieving a useful level of accuracy in pressure measurement should also be considered. To be comparable to the current clinical gold standard for continuous blood pressure measurement, the blood pressure measuring device should be able to measure pressure with an accuracy of at least ±5 mmHg. Based on the arterial dimensions given above, this magnitude of blood pressure fluctuation would result in a change in the resonant frequency of ±34 Hz, or approximately 2.5%. This level of accuracy can also be readily obtained from commercially available loudspeakers.

[0077] Figure 3This is a block diagram illustrating some components of a continuous blood pressure measurement device 300 according to some embodiments of the present disclosure. As shown, the device 300 includes an audio signal generator 305, an electroacoustic transducer 310, at least one ultrasonic sensor 320, at least one processing device 330, at least one machine-readable medium 340, a wireless transmitter 315, and optionally, one or more non-ultrasonic sensors 360. The electrical components of the device 300 may be powered by a battery 301 connected to a power supply circuit 302 for distributing power. The battery 301 may be rechargeable (e.g., via a USB port and / or an AC / DC converter). Although the battery 301 is shown in this example, it should be understood that any suitable battery or power technology can be used to power the components of the device 300. For example, lithium-ion batteries, single-cell batteries, piezoelectric or vibration energy harvesters, photovoltaic cells, AC / DC sources, or other similar devices may be used.

[0078] The electroacoustic transducer 310 can be implemented as an audio loudspeaker that can output sound waves within a suitable frequency range (e.g., to find the resonant frequency of a blood vessel). For example, the loudspeaker can be implemented as a woofer, a midrange loudspeaker, and / or a tweeter (e.g., a high-frequency loudspeaker). In some embodiments, a combination of loudspeakers can be used to output sound within a suitable frequency range. An audio signal generator 305 for adjusting the frequency of the sound waves can be coupled to the transducer 310. In some embodiments, the audio signal generator includes at least a variable resistor for adjusting the frequency of the sound waves. The variable resistor can be a potentiometer. In some embodiments, the blood pressure measuring device 300 can display the frequency of the sound waves. In some embodiments, the audio signal generator 305 is a component of the processing device 330.

[0079] In some embodiments, the sound waves output by the electroacoustic transducer 310 can be configured to vary within a frequency range from about 100 Hz to about 3,500 Hz. In one embodiment, the frequency range of the electroacoustic transducer 310 varies within the following ranges: about 100 Hz to about 500 Hz, about 100 Hz to about 1,000 Hz, about 100 Hz to about 1,500 Hz, about 100 Hz to about 2,000 Hz, about 100 Hz to about 2,500 Hz, about 100 Hz to about 3,000 Hz, about 500 Hz to about 1,000 Hz, about 500 Hz to about 1,500 Hz, about 500 Hz to about 2,000 Hz, about 500 Hz to about 2,500 Hz, about 500 Hz to about 3,000 Hz, about 500 Hz to about 3,500 Hz, and about 1,000 Hz to about 1,500 Hz. Approximately 1,000 Hz to approximately 2,000 Hz, approximately 1,000 Hz to approximately 2,500 Hz, approximately 1,000 Hz to approximately 3,000 Hz, approximately 1,000 Hz to approximately 3,500 Hz, approximately 1,500 Hz to approximately 2,000 Hz, approximately 1,500 Hz to approximately 2,500 Hz, approximately 1,500 Hz to approximately 3,000 Hz, approximately 1,500 Hz to approximately 3,500 Hz, approximately 2,000 Hz to approximately 2,500 Hz, approximately 2,000 Hz to approximately 3,000 Hz, approximately 2,500 Hz to approximately 3,500 Hz, or approximately 3,000 Hz to approximately 3,500 Hz. In some embodiments, the frequency range of the electroacoustic transducer 310 varies within the following frequencies: approximately 100 Hz, approximately 500 Hz, approximately 1,000 Hz, approximately 1,500 Hz, approximately 2,000 Hz, approximately 2,500 Hz, approximately 3,000 Hz, or approximately 3,500 Hz. In some embodiments, the frequency range of the electroacoustic transducer 310 varies within the following frequencies: at least approximately 100 Hz, approximately 500 Hz, approximately 1,000 Hz, approximately 1,500 Hz, approximately 2,000 Hz, approximately 2,500 Hz, or approximately 3,000 Hz. In some embodiments, the frequency range of the electroacoustic transducer 310 varies at most within the following frequencies: approximately 500 Hz, approximately 1,000 Hz, approximately 1,500 Hz, approximately 2,000 Hz, approximately 2,500 Hz, approximately 3,000 Hz, or approximately 3,500 Hz.

[0080] In some embodiments, the audio signal generator 305 can be configured to adjust the frequency of the sound wave output by the transducer 310 in appropriate increments to search for the resonant frequency of the vibration with sufficient accuracy. For example, the frequency can be adjusted in increments between 1 Hz and 500 Hz (such as 1 Hz, 5 Hz, 10 Hz, 25 Hz, 50 Hz, 100 Hz, 200 Hz, 500 Hz, etc.). The accuracy of the estimated resonant frequency can be improved by decreasing the size of each increment. Conversely, the time spent determining the resonant frequency can be improved by increasing the size of each increment.

[0081] One or more ultrasound sensors 320 (referred to individually as "ultrasound sensor 320") are configured to collect imaging data of a subject (e.g., a blood vessel of the subject). The imaging data can be used to measure the wall thickness and radius of the blood vessel. The blood vessel can be an artery or a vein. Additionally, the imaging data can be used to determine the resonant frequency of the blood vessel's vibrations, which vibrates in response to sound waves output from an electroacoustic transducer 310. Each ultrasound sensor 320 includes a transducer configured to convert electricity into ultrasound and vice versa. For example, the transducer can be a piezoelectric transducer that oscillates and generates ultrasonic pulses when an alternating current voltage is applied. Alternatively, the transducer can be a capacitive transducer that uses an electrostatic field between a conductive diaphragm and a backplate to generate ultrasound waves. The ultrasound waves can be generated at frequencies greater than or equal to about 20 kHz (KHz). In some embodiments, the transducer of the ultrasound sensor 320 can generate ultrasound at any frequency between 2 MHz (MHz) and 20 MHz. When the transducer receives the reflected ultrasound signal (i.e., "echo"), an electrical signal can be generated by the ultrasound sensor 120 and used to determine the distance to the subject being imaged. In some embodiments, the transducer can generate ultrasound at frequencies between 7 MHz and 11 MHz.

[0082] In some embodiments, ultrasound measurements are performed using only a single piezoelectric element. Ultrasound waves within the body are primarily reflected by sharp boundaries between regions of different densities. Many arteries (including the carotid artery) are embedded in soft tissue of relatively homogeneous density; therefore, the only significant source of echo is the boundary 460 formed by the inner and outer edges of the arterial wall 410, such as... Figure 4 As depicted. By measuring the delay between the echoes received from these different boundaries, the arterial radius and wall thickness can be accurately determined from a single piezoelectric ultrasonic transducer element 450.

[0083] like Figure 2As depicted, when acoustic stimulus 240 (e.g., using a tweeter) is applied to an artery, the resulting vibrations will cause the artery diameter, as observed using ultrasound imaging, to sinusoidally oscillate as it expands and contracts along an axis perpendicular to the incident sound wave. If the stimulus power remains constant, this oscillation will have maximum amplitude when the stimulus is applied at a frequency matching the resonant frequency of the arterial wall 210. Therefore, the resonant frequency can be determined by applying acoustic stimulation across different frequency ranges and identifying the point of maximum observed oscillation amplitude via ultrasound imaging. Using this setup, the wall velocity can also be determined independently of its location by measuring the Doppler shift of the returned echo. Since the wall velocity is also maximized at resonance, velocity measurements will provide an orthogonal method for determining the resonance point, thus improving accuracy.

[0084] In another embodiment, accuracy can be increased by increasing the number of ultrasonic piezoelectric elements. In some embodiments, four piezoelectric elements may be used. One piezoelectric element generates an ultrasonic signal, while the other three listen for the echo, thereby performing triangulation on the echo when it is received. This embodiment can allow for better elimination of spurious echoes, thus providing better isolation of echoes generated by the arterial wall.

[0085] Ultrasound entering tissue can be transmitted, attenuated, or reflected. While higher frequency ultrasound can provide higher resolution signals, it can provide poorer depth penetration into the imaged tissue. Conversely, while lower frequency ultrasound can provide lower resolution signals, it can provide better depth penetration into the imaged tissue. To overcome these limitations, some embodiments may use multiple ultrasound sensors 320, each with a transducer configured with a unique resonant frequency. Specifically, the ultrasound transducers may be selected such that their acoustic responses do not overlap. By actuating the transducers in a time-staggered manner, each sensor can be used to image the surface of the sample at a unique depth. Furthermore, each transducer may be simultaneously actuated in combination with other transducers to generate higher harmonics that allow for subpixel feature resolution. In some embodiments, ultrasound sensor transducers that partially overlap in frequency response and in frequency response may be selected, thereby allowing normalization of measurements from any pair of sensors, reducing system noise sources and significantly improving signal integrity. Furthermore, transducers with different resonant frequencies may be used to simultaneously interrogate the surface to generate super-resolution ultrasound images. In some embodiments, the frequency overlap between sensors may be configured to be about 200 kHz or less. In some embodiments, frequency overlap between sensors can be configured such that the frequency response range of one ultrasonic sensor does not overlap with the resonant frequency of another ultrasonic sensor, wherein the resonant frequency of the ultrasonic sensor may refer to the operating frequency at which the transducer most efficiently converts electrical energy into mechanical energy.

[0086] Processing device 330 can be configured to control the operation of components of device 300, including an audio signal generator 305 (a component of processing device 130 in some embodiments), an electroacoustic transducer 310, one or more ultrasonic sensors 320, and one or more non-ultrasonic sensors 360 (discussed further below). For example, processing device 330 can be configured to cause electroacoustic transducer 310 to emit sound at a specific frequency or frequency range. Furthermore, processing device 330 can be configured to cause ultrasonic sensor 320 and / or one or more non-ultrasonic sensors 360 to perform image acquisition. Additionally, processing device 330 can receive, store (e.g., in machine-readable medium 340), and / or process signal measurements received from ultrasonic sensor 320 and / or non-ultrasonic sensor 360. In some embodiments, processing device 330 can also be configured to continuously measure blood pressure in arteries or other blood vessels using signal measurements received from ultrasonic sensor 320. Processing device 330 can apply the above methods by executing instructions stored on machine-readable medium 340. In one embodiment, the processing device 330 may be implemented as a single integrated circuit (IC) microcontroller, which includes memory (e.g., machine-readable medium 340) for storing program information and data.

[0087] As described above, the continuous blood pressure measurement device 300 can accurately determine blood pressure based solely on arterial radius, wall thickness, and resonant frequency. However, these three values ​​are not the only information that can be determined. In some embodiments, additional information can be obtained during the measurement of the arterial vibration response within a certain frequency range, including: the intensity and width of the resonance peaks, the baseline excitation level at low frequencies, and / or the excitation level of high-energy vibrational modes. Changes in these parameters can also be observed during the heartbeat as blood pressure and tension levels change. Ultrasound imaging of the arteries can also produce information about the echo intensity of the arterial wall, which can provide insight into the level of calcification and plaque buildup. All this additional information can be used for refined calculations, to achieve better accuracy, and / or to provide additional information about the patient's overall health.

[0088] In some embodiments, the continuous blood pressure measurement device 300 may include one or more non-ultrasound sensors 360 to allow multimodal measurements of health indicators other than blood pressure. For example, an LED light source and photodiode receiver may be integrated into a wireless platform to measure blood oxygenation via a pulse oximeter. Other example sensors that may be implemented include sensors for detecting fluid status, cardiac ejection fraction, or other vital signs may be integrated into the hardware / sensor package. In some embodiments, measurements using the non-ultrasound sensor 360 may be correlated and normalized with ultrasound measurements used to calculate blood pressure. The accuracy of the device 300 may be improved by using additional modalities to measure blood pressure in addition to the ultrasound sensor 320.

[0089] exist Figure 3 In the example, the continuous blood pressure measurement device 300 includes a wireless transmitter 315 (e.g., a transceiver) configured to transmit ultrasound measurement data to a wireless receiver 355 (e.g., a transceiver) of the display system 350. Depending on the ultrasound imaging application, the received ultrasound measurement data may be processed using a processing device 352 of the display system 355 (e.g., in a format suitable for display) and / or displayed using a display 354. Instructions for formatting may be stored on a machine-readable medium 356. For example, the display 354 may be a component of a cardiac monitor, a mobile device (e.g., a smartphone or head-mounted display), or some other suitable display device. The display 354 may also display the frequency of sound waves, which are transmitted by an electroacoustic transducer 310 (e.g., via an audio signal generator 305). The wireless communication link between the wireless transmitter 315 and the wireless receiver 355 may be a radio frequency link, such as... or Low-energy (LE) links, The data transfer between the device 300 and the display system 350 may be achieved using a wired transmitter or other suitable wired interface. For example, a USB-C connector, a USB 2.x or 3.x connector, a micro USB connector, a THUNDERBOLT connector, an Ethernet cable, etc., may be used to transfer data.

[0090] In some embodiments, the functionality of the display 354 and / or display system 350 may be integrated into the continuous blood pressure measurement device 300. In some embodiments, the continuous blood pressure measurement device 300 may still retain the transmitter 315 to transmit historical or current blood pressure measurement data to an external device (such as a smartphone).

[0091] Figure 6This is a flowchart illustrating an example method 600 for measuring the blood pressure of a subject, according to some embodiments of the present disclosure. In some embodiments, method 600 may be implemented using a continuous blood pressure measurement device 300 as described above.

[0092] At operation 610, the ultrasonic transducer and electroacoustic transducer are brought near the subject's blood vessels. For example, a continuous blood pressure measurement device 300, including an electroacoustic transducer 310 and an ultrasonic sensor 320, can be brought near the patient's artery (e.g., the carotid or brachial artery). In some embodiments, a substrate 500 including the device 300 can be aligned with and subsequently adhered to the subject's artery. For example, the substrate 500 can be adhered near the brachial artery in the patient's arm. Alternatively, the substrate can be adhered near the carotid artery in the patient's neck. In some embodiments, the positions of the ultrasonic transducer and electroacoustic transducer (e.g., device 300 or substrate 500) can be adjusted to maximize the amplitude and / or signal-to-noise ratio of the measured signal.

[0093] At operation 620, the electroacoustic transducer is actuated to emit multiple sound waves having multiple frequencies. For example, the audio signal generator 305 can be configured to cause the electroacoustic transducer 310 to emit sound waves at multiple different frequencies. The sound waves can generate a vibration response in the blood vessel (e.g., in the cross-section of the blood vessel to which the sound wave is directed). The vibration response can have an amplitude that varies according to the frequency of the sound wave.

[0094] In some embodiments, the frequency of each sound wave may be between 1 Hz and 3000 Hz. In some embodiments, the frequency of each sound wave may be between 670 Hz and 2300 Hz. In some embodiments, the frequency of each sound wave is from about 300 Hz to about 3,000 Hz. In some embodiments, the frequency of each sound wave is from about 1 Hz to about 3,000 Hz. In some embodiments, the frequency of each sound wave is about 1 Hz to about 300 Hz, about 1 Hz to about 500 Hz, about 1 Hz to about 750 Hz, about 1 Hz to about 1,000 Hz, about 1 Hz to about 1,500 Hz, about 1 Hz to about 2,000 Hz, about 1 Hz to about 2,500 Hz, about 1 Hz to about 3,000 Hz, about 300 Hz to about 500 Hz, about 300 Hz to about 750 Hz, about 300 Hz to about 1,000 Hz, about 300 Hz to about 1,500 Hz, about 300 Hz to about 2,000 Hz, about 300 Hz to about 2,500 Hz, about 300 Hz to about 3,000 Hz, about 500 Hz to about 750 Hz, about 500 Hz to about 1,000 Hz, about 500 Hz to about 1,500 Hz, about 500 Hz to about 2,000 Hz. Approximately 500 Hz to approximately 2,500 Hz, approximately 500 Hz to approximately 3,000 Hz, approximately 750 Hz to approximately 1,000 Hz, approximately 750 Hz to approximately 1,500 Hz, approximately 750 Hz to approximately 2,000 Hz, approximately 750 Hz to approximately 2,500 Hz, approximately 750 Hz to approximately 3,000 Hz, approximately 1,000 Hz to approximately 1,500 Hz, approximately 1,000 Hz to approximately 2,000 Hz, approximately 1,000 Hz to approximately 2,500 Hz, approximately 1,000 Hz to approximately 3,000 Hz, approximately 1,500 Hz to approximately 2,000 Hz, approximately 1,500 Hz to approximately 2,500 Hz, approximately 2,000 Hz to approximately 3,000 Hz, or approximately 2,500 Hz to approximately 3,000 Hz. In some embodiments, the frequency of each sound wave is about 1 Hz, about 300 Hz, about 500 Hz, about 750 Hz, about 1,000 Hz, about 1,500 Hz, about 2,000 Hz, about 2,500 Hz, or about 3,000 Hz. In some embodiments, the frequency of each sound wave is at least about 1 Hz, about 300 Hz, about 500 Hz, about 750 Hz, about 1,000 Hz, about 1,500 Hz, about 2,000 Hz, or about 2,500 Hz. In some embodiments, the frequency of each sound wave is at most about 300 Hz, about 500 Hz, about 750 Hz, about 1,000 Hz, about 1,500 Hz, about 2,000 Hz, about 2,500 Hz, or about 3,000 Hz.

[0095] In some embodiments, the frequency of each sound wave is from about 1 kHz to about 3,000 kHz. In some embodiments, the frequency of each sound wave is from about 1 kHz to about 3,000 kHz. In some embodiments, the frequency of each sound wave is from about 1 kHz to about 250 kHz, from about 1 kHz to about 750 kHz, from about 1 kHz to about 1,000 kHz, from about 1 kHz to about 1,250 kHz, from about 1 kHz to about 1,500 kHz, from about 1 kHz to about 1,750 kHz, from about 1 kHz to about 2,000 kHz, from about 1 kHz to about 2,250 kHz, from about 1 kHz to about 2,500 kHz, from about 1 kHz to about 2,750 kHz, from about 1 kHz to about 3,000 kHz, from about 250 kHz to about 750 kHz, from about 250 kHz to about 1,000 kHz, from about 250 kHz to about 1,000 kHz. 250kHz, approximately 250kHz to approximately 1,500kHz, approximately 250kHz to approximately 1,750kHz, approximately 250kHz to approximately 2,000kHz, approximately 250kHz to approximately 2,250kHz, approximately 250kHz to approximately 2,500kHz, approximately 250kHz to approximately 2,750kHz, approximately 250kHz to approximately 3,000kHz, approximately 750kHz to approximately 1,000kHz, approximately 750kHz to approximately 1,250kHz, approximately 750kHz to approximately 1,500kHz, approximately 750kHz to approximately 1,750kHz, approximately 750kHz to approximately 2,000kHz, approximately 750kHz to approximately 2,250 kHz, approximately 750 kHz to 2,500 kHz, approximately 750 kHz to approximately 2,750 kHz, approximately 750 kHz to approximately 3,000 kHz, approximately 1,000 kHz to approximately 1,250 kHz, approximately 1,000 kHz to approximately 1,500 kHz, approximately 1,000 kHz to approximately 1,750 kHz, approximately 1,000 kHz to approximately 2,000 kHz, approximately 1,000 kHz to approximately 2,250 kHz, approximately 1,000 kHz to approximately 2,500 kHz, approximately 1,000 kHz to approximately 2,750 kHz, approximately 1,000 kHz to approximately 3,000 kHz, approximately 1,250 kHz to Approximately 1,500 kHz, approximately 1,250 kHz to approximately 1,750 kHz, approximately 1,250 kHz to approximately 2,000 kHz, approximately 1,250 kHz to approximately 2,250 kHz, approximately 1,250 kHz to approximately 2,500 kHz, approximately 1,250 kHz to approximately 2,750 kHz, approximately 1,250 kHz to approximately 3,000 kHz, approximately 1,500 kHz to approximately 1,750 kHz, approximately 1,500 kHz to approximately 2,000 kHz, approximately 1,500 kHz to approximately 2,250 kHz, approximately 1,500 kHz to approximately 2,500 kHz, approximately 1,500 kHz to approximately 2,750 kHz, approximately 1,500kHz to approximately 3,000kHz, approximately 1,750kHz to approximately 2,000kHz, approximately 1,750kHz to approximately 2,250kHz, approximately 1,750kHz to approximately 2,500kHz, approximately 1,750kHz to approximately 2,750kHz, approximately 1,750kHz to approximately 3,000kHz, approximately 2,000kHz to approximately 2,250kHz, approximately 2,000kHz to approximately 2,500kHz, approximately 2, The frequencies of each sound wave are approximately 1 kHz to about 2,750 kHz, approximately 2,000 kHz to about 3,000 kHz, approximately 2,250 kHz to about 2,500 kHz, approximately 2,250 kHz to about 2,750 kHz, approximately 2,250 kHz to about 3,000 kHz, approximately 2,500 kHz to about 2,750 kHz, approximately 2,500 kHz to about 3,000 kHz, or approximately 2,750 kHz to about 3,000 kHz. In some embodiments, the frequency of each sound wave is approximately 1 kHz, approximately 250 kHz, approximately 750 kHz, approximately 1,000 kHz, approximately 1,250 kHz, approximately 1,500 kHz, approximately 1,750 kHz, approximately 2,000 kHz, approximately 2,250 kHz, approximately 2,500 kHz, approximately 2,750 kHz, or approximately 3,000 kHz. In some embodiments, the frequency of each sound wave is at least about 1 kHz, about 250 kHz, about 750 kHz, about 1,000 kHz, about 1,250 kHz, about 1,500 kHz, about 1,750 kHz, about 2,000 kHz, about 2,250 kHz, about 2,500 kHz, or about 2,750 kHz. In some embodiments, the frequency of each sound wave is at most about 250 kHz, about 750 kHz, about 1,000 kHz, about 1,250 kHz, about 1,500 kHz, about 1,750 kHz, about 2,000 kHz, about 2,250 kHz, about 2,500 kHz, about 2,750 kHz, or about 3,000 kHz.

[0096] At operation 630, based on the blood vessel's vibrational response to sound waves of each of a plurality of different frequencies, the resonant frequency of the blood vessel's vibration can be determined (e.g., based on the frequency that produces the maximum response amplitude). In some embodiments, the resonant frequency may be held briefly and then recorded in memory (e.g., in computer-readable medium 340).

[0097] In some embodiments, an ultrasound sensor is used to detect resonant frequencies by capturing images of a blood vessel (e.g., a cross-section) as the vessel vibrates in response to different applied frequencies. The frequency that produces the highest vibration amplitude can be selected as the resonant frequency (e.g., via a processing device communicatively coupled to the sensor). In some embodiments, the ultrasound transducer has a sampling rate of at least 3 kHz.

[0098] In some embodiments, the electroacoustic transducer and the ultrasonic sensor can be placed adjacent to each other and driven synchronously. For example, a small speaker can be placed on either side of the ultrasonic sensor, and the two devices / components can be driven synchronously.

[0099] In some embodiments of operations 620 and 630, to improve the speed of finding the resonant frequency, an optimized search algorithm can be used to adjust the frequency of the sound waves output by the electroacoustic transducer between measurements. The search algorithm can utilize suitable boundary conditions (e.g., maximum frequency, minimum frequency, frequency adjustment rate, etc.). The search algorithm can begin with a wide frequency scan over a large frequency range, using large frequency variations between measurements to find a narrower frequency range where the resonance peak is located, and then transition to a narrow frequency scan within this narrower frequency range to find the resonant frequency. In some embodiments, the resonant frequency can be held briefly and then recorded in memory (e.g., in computer-readable medium 340).

[0100] At operation 640, the wall thickness and radius of the blood vessel (e.g., for a cross-section) are determined. These parameters can be determined from ultrasound images captured using ultrasound sensor 320. For example, echo-mode ultrasound examination can be used to determine the wall thickness and radius. Ultrasound waves can be directed to the blood vessel and ultrasound waves reflected from the echo boundaries of the blood vessel can be received. The Doppler shift of the reflected ultrasound waves can be measured using the ultrasound sensor, and the wave velocity of the blood vessel can be calculated based on this Doppler shift. In some embodiments, multiple ultrasound transducers can be used to improve imaging accuracy and / or speed. For example, one transducer can generate an ultrasound signal while three other transducers listen for echoes, thereby performing triangulation on the echoes upon receipt.

[0101] At operation 650, blood pressure is calculated based on resonant frequency, wall thickness, and radius. The calculated blood pressure establishes a baseline diastolic pressure. Once the absolute diastolic pressure is established, the change in blood pressure over time can be measured using one or more ultrasound sensors (e.g., using Doppler ultrasound imaging) to extract a continuous waveform. When employing this type of differential measurement, a small but persistent inaccurate drift can coalesce into a large drift over many heartbeats. Therefore, it may be necessary to periodically reset the baseline to maintain accuracy for long-term patient monitoring. This demonstrates another advantage of the proposed method; while other baseline techniques would require repeated application of an external pressure cuff or force probe, using the method presented herein, baseline setting can be performed automatically at periodic intervals using an electroacoustic transducer and the same ultrasound hardware employed to perform continuous monitoring.

[0102] In some embodiments, the device 300 or the external display system 350 may display the calculated blood pressure over time. In some embodiments, the processing device 330 of the continuous blood pressure measurement device 300 may perform the necessary DSP and calculations to obtain the patient's blood pressure.

[0103] In some embodiments, the electroacoustic transducer can be omitted, and acoustic signals of different frequencies can be generated by pulses applied to the ultrasound sensor at different frequencies to deliver energy to the blood vessel. This alternative design may have the advantage of using a single sensor to generate a resonant response and capture ultrasound imaging data.

[0104] In some embodiments, the system includes an ultrasonic platform for driving one or more ultrasonic transducers. In some embodiments, the ultrasonic platform processes and / or modulates signals received by one or more ultrasonic transducers.

[0105] II. Adhesive Patch Monitoring Equipment

[0106] In some embodiments, by Figure 5 The depicted continuous blood pressure measurement device 500 can be incorporated into a substrate 510. As shown, the device 500 may include one or more alignment lines 565 or other markings for aligning one or more sensors or transducers 520, 530, 540, 550 of the device 500 with the patient's artery before actuation transducer 310 and ultrasound measurement. In some embodiments, a transparent window 575 is provided for aligning one or more sensors or transducers 520, 530, 540, 550 of the device 500 with the patient's artery before actuation transducer 310 and ultrasound measurement. In some embodiments, the device may include a transparent window 575 for viewing the artery behind the substrate during placement. The combination of the transparent window and alignment markings can further facilitate device placement.

[0107] Additionally, substrate 510 may include an adhesive for holding the substrate in place and aligning it with the patient's artery. During application, the adhesive can be exposed by peeling off the paper backing. The adhesive may include a rubber, acrylic, or acrylic blend adhesive. In some embodiments, the device may be placed on the patient's neck to measure blood pressure via the carotid artery. Similar measurements can be performed on the radial or ulnar artery. With some embodiments, blood pressure measurement can be non-invasive, reliable, rapid, and provides continuous measurement, thus taking into account stroke-by-stroke variations. As described above, these continuous variations can be presented to the user on display system 350.

[0108] In some embodiments, the sensor and transducer of device 500 include at least one ultrasonic transducer and at least one electroacoustic transducer. Including more than one ultrasonic transducer can allow for increased resolution as described herein. In some embodiments, the device includes two ultrasonic transducers and one electroacoustic transducer. In some embodiments, the patch includes three ultrasonic transducers and one electroacoustic transducer. In some embodiments, the patch includes four ultrasonic transducers. Each transducer 520, 530, 540, 550 can be configured as a transmitter, a receiver, or both (transceiver). In some embodiments, transducer 520 is configured as a transmitter and transducer 540 is configured as a receiver. In some embodiments, transducer 520 is configured as a transmitter and transducer 530 is configured as a receiver. In some embodiments, transducer 520 is configured as a transmitter and transducer 550 is configured as a receiver. In some embodiments, transducer 530 is configured as a transmitter and transducer 520 is configured as a receiver. In some embodiments, transducer 530 is configured as a transmitter and transducer 540 is configured as a receiver. In some embodiments, transducer 530 is configured as a transmitter and transducer 550 is configured as a receiver. In some embodiments, transducers 520 and 530 are configured as transmitters and transducers 540 and 550 are configured as receivers. In some embodiments, transducers 530 and 540 are configured as transmitters and transducers 520 and 550 are configured as receivers. In some embodiments, transducers 520 and 550 are configured as transmitters and transducers 530 and 540 are configured as receivers. In some embodiments, transducers 520 and 540 are configured as transmitters and transducers 530 and 550 are configured as receivers. In some embodiments, transducer 520 is configured as a transmitter and transducers 530 and 540 are configured as receivers. In some embodiments, transducer 530 is configured as a transmitter and transducers 550 and 540 are configured as receivers.

[0109] In some embodiments, one or more transducers are incorporated into a wearable device. The wearable device may include a wristband or watch, wherein one or more transducers are directed to the brachial artery to determine mean arterial pressure. In some embodiments, a substrate including one or more transducers is incorporated into the wearable device. The wearable device may wirelessly communicate with an external computing device to display or record data.

[0110] In some embodiments, the device includes four ultrasonic transducers and one electroacoustic transducer or loudspeaker. In some embodiments, images or signals captured by the ultrasonic transducers are input into a rotation matrix. Rotation and / or skew matrices can be applied to properly orient the received signal for convolution, deconvolution, or normalization. As disclosed herein, normalization can be applied to the received signal. In some embodiments, skew parameters are applied to the rotation matrix.

[0111] Each of a plurality of ultrasonic transducers can be configured to transmit a transmitted ultrasonic imaging signal to an object. Each of the plurality of ultrasonic transducers can be configured to transmit a transmitted ultrasonic imaging signal having a frequency of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, approximately 11 MHz, approximately 15 MHz, approximately 20 MHz, approximately 25 MHz, or approximately 30 MHz. Each of the plurality of ultrasonic transducers can be configured to transmit a transmitted ultrasonic imaging signal having a frequency within a range defined by any two of the foregoing values.

[0112] Each of a plurality of ultrasonic transducers can be configured to receive a received ultrasonic imaging signal from an object. Each of the plurality of ultrasonic transducers can be configured to receive the received ultrasonic imaging signal having a frequency of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, approximately 11 MHz, approximately 15 MHz, approximately 20 MHz, approximately 25 MHz, or approximately 30 MHz. Each of the plurality of ultrasonic transducers can be configured to receive the received ultrasonic imaging signal having a frequency within a range defined by any two of the foregoing values.

[0113] Each of a plurality of ultrasonic transducers can be configured to transmit and receive. Each of the plurality of ultrasonic transducers can be configured to transmit a transmitted ultrasound imaging signal or receive a received ultrasound imaging signal at one or more of the same frequencies as those transmitted or received by another ultrasonic transducer. Each of the plurality of ultrasonic transducers can be configured to transmit a transmitted ultrasound imaging signal or receive a received ultrasound imaging signal at a frequency different from all frequencies transmitted or received by all other ultrasonic transducers. Each of the plurality of ultrasonic transducers can be configured to transmit or receive simultaneously with one or more other ultrasonic transducers.

[0114] For example, the imaging signal transmitted first by the first ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, or approximately 11 MHz. The imaging signal transmitted second by the second ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency in the range of approximately 0.5 MHz to approximately 30 MHz. The first received imaging signal of the first ultrasonic transducer of the plurality of ultrasonic transducers may have a frequency of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, or approximately 11 MHz. The second received imaging signal of the second ultrasonic transducer of the plurality of ultrasonic transducers may have a frequency in the range of approximately 0.5 MHz to approximately 30 MHz.

[0115] In another example, the first transmitted imaging signal of a first ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency in the range of about 0.5 MHz to about 30 MHz. The second transmitted imaging signal of a second ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency in the range of about 0.5 MHz to about 30 MHz, but this frequency differs from the frequency of the first transmitted imaging signal. The first received imaging signal of the first ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency in the range of about 0.5 MHz to about 30 MHz. The second received imaging signal of the second ultrasonic transducer of a plurality of ultrasonic transducers may have a frequency in the range of about 0.5 MHz to about 30 MHz, but this frequency differs from the frequency of the first received imaging signal.

[0116] The imaging signals transmitted by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers may have frequencies of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, or approximately 11 MHz, respectively. The imaging signals transmitted by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers may have frequencies within the range described by any two of the foregoing values. The imaging signals transmitted in the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth series may have values ​​in the range of about 0.5 MHz to about 30 MHz. The imaging signals transmitted in the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth series may have frequencies different from one or more of the frequencies of the imaging signals transmitted in the first and second series.

[0117] The imaging signals received by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers may have frequencies of approximately 100 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, approximately 500 kHz, approximately 650 kHz, approximately 700 kHz, approximately 800 kHz, approximately 850 kHz, approximately 900 kHz, approximately 1 MHz, approximately 2 MHz, approximately 3 MHz, approximately 5.5 MHz, approximately 6 MHz, approximately 8 MHz, or approximately 11 MHz, respectively. The imaging signals received by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers may have frequencies within the range described by any two of the foregoing values. The imaging signals received by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth may have values ​​in the range of about 0.5 MHz to about 30 MHz. The frequencies of the imaging signals received by the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, thirteenth, fourteenth, fifteenth, or sixteenth may have frequencies different from one or more of the frequencies of the first and second transmitted imaging signals.

[0118] Each of the multiple transducers can transmit transmitted ultrasound imaging signals or receive received ultrasound imaging signals within a bandwidth. A first ultrasound transducer may have a first bandwidth and a second ultrasound transducer may have a second bandwidth. The first and second bandwidths may overlap. The first and second bandwidths may partially overlap. The first and second bandwidths may not overlap. Similarly, a third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasound transducer may each have a third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth bandwidth. Any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth bandwidths may overlap with each other. Any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth bandwidths may partially overlap with each other. None of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth bandwidths can overlap with each other.

[0119] The received imaging signals can be subject to preprocessing operations. For example, the first received imaging signal can form the basis for normalizing other received imaging signals. The second received imaging signal can be normalized using the first received imaging signal. The third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth received imaging signals can be normalized using the first received imaging signal.

[0120] The system may include a transmission (Tx) generator. The transmission generator may include a host computer, software-defined radio, and ultrasound signal processing circuitry (USPC) as disclosed herein. The Tx generator may be a Tx beamformer. The Tx generator may be configured to operate any one of the ultrasound transducers to transmit first, second, third, or fourth transmitted ultrasound imaging signals, respectively. The Tx generator may operate any two or more of the first, second, third, or fourth ultrasound imaging transducers simultaneously. The system may also include an image synthesis module. The image synthesis module may include a receive (Rx) beamformer. The Rx beamformer may be configured to operate any one of the ultrasound transducers to receive first, second, third, or fourth received ultrasound imaging signals, respectively. The image synthesis module may perform ultrasound image reconstruction operations on the received ultrasound imaging signals. For example, the image synthesis module may perform delay and summation operations on the received ultrasound imaging signals. The image synthesis module may perform any ultrasound image reconstruction operation on the received ultrasound imaging signals. The Tx generator can be configured to operate the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers to transmit the ultrasonic imaging signals transmitted by the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth transducers, respectively. The Tx generator can simultaneously operate any two or more of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic imaging transducers. Similarly, the Rx beamformer can be configured to operate the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers to transmit the ultrasonic imaging signals transmitted by the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth transducers, respectively.

[0121] The Tx generator can be configured to operate any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, or sixteenth ultrasonic transducers for sequential transmission.

[0122] Figure 11A method for forming an ultrasound image from multiple ultrasound transducers is illustrated schematically. This method can utilize measurements from multiple ultrasound imaging sensors. It can utilize single-pixel and multi-pixel image processing techniques. In the single-pixel case, the nth ultrasound imaging measurement (where n is a positive integer) can be input to a signal processing unit. The signal processing unit can apply any ultrasound signal processing program to the nth ultrasound imaging measurement. The signal processing unit can output the measurement results of the signal processing to an image processing unit and a single-pixel feature extraction unit. The image processing unit can apply any ultrasound image processing program. The single-pixel feature extraction unit can apply any ultrasound single-pixel feature extraction program. The single-pixel feature extraction unit can output the extracted features to the operator.

[0123] In the multi-pixel case, the m-th and (m+1)-th (where m and m+1 are positive integers) ultrasound imaging measurements can be input to the multi-pixel image synthesis unit and the multi-pixel feature extraction unit. The image synthesis unit can apply any ultrasound image synthesis program. The multi-pixel feature extraction unit can apply any ultrasound multi-pixel feature extraction program. The multi-pixel feature extraction unit can output the extracted features to the operator. Multi-pixel extraction can be used to construct 3D pixels (i.e., voxels).

[0124] In multi-pixel cases, image processing methods such as two-dimensional smoothing filters, Haar filters, Gaussian filters, and integrators can be used to improve the recorded image. Furthermore, each pixel can be filtered in the time domain to highlight signal features. Single or multiple Butterworth, Chebyshev, and elliptic filters can be used to suppress noise and enhance feature extraction.

[0125] The device's sensors may also include temperature sensors, optical sensors, electrical sensors, chemical sensors, and electrochemical sensors. In some embodiments, additional sensors allow for the measurement of body temperature, respiratory rate, blood pressure level, and blood oxygen saturation (spO2) level.

[0126] A stethoscope device may include a first ultrasonic transducer, a light source, and a photodetector. The stethoscope device may optionally include a second ultrasonic transducer. The first ultrasonic transducer may operate in Tx mode. The second ultrasonic transducer may operate in receive mode. The stethoscope device may be placed on the skin of a subject (such as the skin in the subject's arm). As a blood bolus travels through an artery under the subject's skin, the stethoscope device may transmit an ultrasonic signal from the first ultrasonic transducer and an optical signal from the light source. The ultrasonic or optical signal may be scattered, dispersed, or reflected from the bolus. The scattered, dispersed, or reflected ultrasonic or optical signals may be detected by the second ultrasonic transducer or the photodetector, respectively. The intensity of the scattered, dispersed, or reflected ultrasonic or optical signals may be compared to the intensity of the transmitted ultrasonic or optical signal, respectively. These measurements may produce the velocity of the blood bolus as measured by the ultrasonic imaging signal and the optical signal, respectively. The velocity of the blood bolus, as measured by the ultrasonic imaging signal, may be normalized by the velocity of the blood bolus, as measured by the optical signal, or vice versa. These values ​​can be synthesized and correlated to determine one or more physiological parameters of a subject, such as the subject's heart rate, blood pressure, or respiration.

[0127] III. Methods to Improve Ultrasonic Resolution

[0128] Ultrasound tissue imaging can be hampered by poor optical and acoustic transmittance and beam scattering. To overcome these difficulties and improve resolution, multi-wavelength ultrasound imaging can be employed, utilizing information collected from multiple ultrasound sensors, each with an ultrasound transducer having a unique resonant frequency. Through the resonant physiology of multiple ultrasound sensors operating at different resonant frequencies, ultrasound emitted by multiple transducers can simultaneously penetrate different depths within a given cross-sectional region of physiology (e.g., tissue). In particular, ultrasound sensors with acoustic responses can be actuated in a time-staggered manner, allowing each sensor to be used to image the physiological surface at a single depth. This enables high-resolution tomography without increasing the gain or number of ultrasound imaging sensors. Furthermore, each sensor can be simultaneously actuated in combination with other sensors to generate higher harmonics that allow for subpixel feature resolution (i.e., super-resolution imaging).

[0129] As used in this article to refer to transducers, the term "resonant frequency" generally refers to the operating frequency at which the transducer most efficiently converts electrical energy into mechanical energy. For example, in the context of piezoelectric transducers, the term resonant frequency can refer to the operating frequency at which the piezoelectric material vibrates most readily and most efficiently converts electrical energy into mechanical energy.

[0130] Ultrasound waves entering tissue can be transmitted, attenuated, or reflected. While higher frequency ultrasound can provide higher resolution signals, it can also provide poorer depth penetration into the imaged tissue. Conversely, while lower frequency ultrasound can provide lower resolution signals, it can provide better depth penetration into the imaged tissue. To overcome these limitations of conventional ultrasound imaging systems, each ultrasound sensor can have a transducer configured with a unique resonant frequency. Specifically, ultrasound transducers can be selected such that their acoustic responses do not overlap. By actuating the transducers in a time-staggered manner, each sensor can be used to image the surface of a sample at a single depth. Furthermore, each transducer can be simultaneously actuated in combination with other transducers to generate higher harmonics that allow for subpixel feature resolution.

[0131] like Figure 7A As shown, selecting transducers 711, 712, and 713 with partially overlapping frequencies allows for signal self-normalization and cross-correlation. In some embodiments, by selecting sensor transducers that are adjacent and partially overlapping in their frequency responses, measurements from any pair of sensors can be normalized, thereby reducing system noise sources and significantly improving signal integrity. Furthermore, transducers with different resonant frequencies can be used to simultaneously interrogate the surface to generate super-resolution ultrasonic images of object 700. In some embodiments, the frequency overlap between sensors 711, 712, and 713 can be configured to be about 200 kHz or lower. In some embodiments, the frequency overlap between sensors can be configured such that the frequency response range of one sensor does not overlap with the resonant frequency of another sensor. For example, as... Figure 7B As depicted, the first sensor 711 with a resonant frequency 721 and the second sensor 712 with a resonant frequency 722 partially overlap in their frequency responses. Furthermore, the second sensor 712 and the third sensor 713 with a resonant frequency 723 also partially overlap in their frequency responses.

[0132] In some embodiments, the frequency overlap between sensors is from about 10 kHz to about 500 kHz. In some embodiments, the frequency overlap between sensors is from about 10 kHz to about 20 kHz, from about 10 kHz to about 30 kHz, from about 10 kHz to about 40 kHz, from about 10 kHz to about 50 kHz, from about 10 kHz to about 75 kHz, from about 10 kHz to about 100 kHz, from about 10 kHz to about 150 kHz, from about 10 kHz to about 200 kHz, from about 10 kHz to about 300 kHz, from about 10 kHz to about 400 kHz, from about 10 kHz to about 500 kHz, from about 20 kHz to about 30 kHz, from about 20 kHz to about 40 kHz, from about 20 kHz to about 50 kHz, from about 20 kHz to about 75 kHz, and from about 20 kHz. z to approximately 100kHz, approximately 20kHz to approximately 150kHz, approximately 20kHz to approximately 200kHz, approximately 20kHz to approximately 300kHz, approximately 20kHz to approximately 400kHz, approximately 20kHz to approximately 500kHz, approximately 30kHz to approximately 40kHz, approximately 30kHz to approximately 50kHz, approximately 30kHz to approximately 75kHz, approximately 30kHz to approximately 100kHz, approximately 30kHz to approximately 150kHz, approximately 30kHz to approximately 200kHz, approximately 30kHz to approximately 300kHz, approximately 30kHz to approximately 400kHz, approximately 30kHz to approximately 500kHz, approximately 40kHz to approximately 50kHz, approximately 40kHz to approximately 75kHz 5kHz, approximately 40kHz to approximately 100kHz, approximately 40kHz to approximately 150kHz, approximately 40kHz to approximately 200kHz, approximately 40kHz to approximately 300kHz, approximately 40kHz to approximately 400kHz, approximately 40kHz to approximately 500kHz, approximately 50kHz to approximately 75kHz, approximately 50kHz to approximately 100kHz, approximately 50kHz to approximately 150kHz, approximately 50kHz to approximately 200kHz, approximately 50kHz to approximately 300kHz, approximately 50kHz to approximately 400kHz, approximately 50kHz to approximately 500kHz, approximately 75kHz to approximately 100kHz, approximately 75kHz to approximately 150kHz, approximately 75kHz to approximately 200kHz kHz, approximately 75kHz to 300kHz, approximately 75kHz to 400kHz, approximately 75kHz to 500kHz, approximately 100kHz to 150kHz, approximately 100kHz to 200kHz, approximately 100kHz to 300kHz, approximately 100kHz to 400kHz, approximately 100kHz to 500kHz, approximately 150kHz to 200kHz, approximately 150kHz to 300kHz, approximately 150kHz to 400kHz, approximately 150kHz to 500kHz, approximately 200kHz to 300kHz, approximately 200kHz to 400kHz, approximately 200kHz to 500kHzThe frequency overlap between the sensors is approximately 300 kHz to approximately 400 kHz, approximately 300 kHz to approximately 500 kHz, or approximately 400 kHz to approximately 500 kHz. In some embodiments, the frequency overlap between the sensors is approximately 10 kHz, approximately 20 kHz, approximately 30 kHz, approximately 40 kHz, approximately 50 kHz, approximately 75 kHz, approximately 100 kHz, approximately 150 kHz, approximately 200 kHz, approximately 300 kHz, approximately 400 kHz, or approximately 500 kHz. In some embodiments, the frequency overlap between the sensors is at least approximately 10 kHz, approximately 20 kHz, approximately 30 kHz, approximately 40 kHz, approximately 50 kHz, approximately 75 kHz, approximately 100 kHz, approximately 150 kHz, approximately 200 kHz, approximately 300 kHz, or approximately 400 kHz. In some embodiments, the frequency overlap between sensors is at most about 20 kHz, about 30 kHz, about 40 kHz, about 50 kHz, about 75 kHz, about 100 kHz, about 150 kHz, about 200 kHz, about 300 kHz, about 400 kHz, or about 500 kHz.

[0133] Figures 8A-8D A cross-correlation technique for use in ultrasonic measurement equipment is described. As depicted, the cross-correlation of signals from any pair of sensors 811, 812, 813 with overlapping frequency responses allows for redundant measurements of voxels. Specifically, the transducers of the sensors can be actuated in a time-staggered manner. For each actuation (e.g., actuation of sensor 812), a signal is transmitted to object 800, and the received echo can be obtained by... Figure 8B Measurements were taken at all three transducers 811, 812, and 812, and the results obtained at all three transducers were as follows: Figure 8C The received signals 821, 822, and 823 are depicted. By examining the correlation of the received signals from all three sensors, the signals can be normalized. Figure 8C This describes an event where the actuated echo from the second sensor 812 is measured by all three sensors. In some embodiments, the frequency responses of the first sensor 811 and the second sensor 812 are convolved with the received echo waveform in the frequency domain. During deconvolution, at step 805, the measurement from the third sensor can be correlated with the measurement from the second sensor, while the measurement from the first sensor is used to normalize the measurement from the second sensor. Figure 8D As described, sharper peaks were obtained in the signal monitored by the second sensor, and these sharper peaks could be achieved through the aforementioned cross-frequency normalization.

[0134] IV. Signal Generation, Transmission and Reception

[0135] In some embodiments, circuitry is used to process ultrasonic signals. Figure 9A processing circuitry (USPC) 950 according to some embodiments is depicted, configured to process and / or modulate ultrasonic signals transmitted between one or more ultrasonic transducers 930 and a software-defined radio system 920. Systems for generating and receiving ultrasonic signals, such as... Figure 9 As shown, this can correspond to a transmit (Tx) generator and / or receive (Rx) beamformer as described herein. One or more signals transmitted by a software-defined radio system can be referred to as the output of the software-defined radio system. One or more signals transmitted by a software-defined radio system can be referred to as the input of the software-defined radio system.

[0136] In some embodiments, the software-defined radio system 920 transmits one or more signals 922, 924 to an ultrasonic signal processing circuit (USPC) 950. In some embodiments, the first transmitted signal 922 includes a transmitted pulse or a reference clock. In some embodiments, the second transmitted signal 924 includes a gain ramp. In some embodiments, the transmitted pulse 922 is a low-voltage transmitted pulse. In some embodiments, the transmitted pulse 922 is a + / - 4 volt signal.

[0137] In some embodiments, a first transmission signal 922 is received by a high-voltage amplifier 952. In some embodiments, a transmission pulse or reference clock is input to the high-voltage amplifier 952. In some embodiments, the amplified signal from the high-voltage amplifier 952 passes through a diode 954. In some embodiments, the first transmission signal 922 is then transmitted to a first multiplexer 982. In some embodiments, the first transmission signal 922 is a transmission pulse or reference clock transmitted to the first multiplexer 982. In some embodiments, the diode 954 is an anti-parallel diode configured to block signals received from the ultrasonic transducer 930 or the multiplexer 982 to the high-voltage amplifier 952. The high-voltage amplifier may be a discrete amplifier. In some embodiments, the output signal of the high-voltage amplifier is a + / -100 volt amplifier. In some embodiments, the high-voltage amplifier 952 generates a + / -100 volt device signal from the low-voltage output of a software-defined radio 920.

[0138] In some embodiments, the output from the first multiplexer 928 is transmitted to one or more ultrasonic transducers 930. In some embodiments, the output from the first multiplexer 928 is received by a first pixel group of the ultrasonic transducer 930. The ultrasonic transducer 930 can then transmit the ultrasonic signal from the first pixel group to an object. The object can then reflect the transmitted ultrasonic signal, and the ultrasonic transducer 930 can receive the reflected signal. In some embodiments, the reflected signal is received as part of the first pixel group. In some embodiments, the reflected signal is received as part of a second pixel group. In some embodiments, the reflected signal forms both the first pixel group and the second pixel group. The ultrasonic transducer 930 can then transmit the received reflected signal as an electrical signal. The reflected signal received from the first pixel group can be considered a first received signal. In some embodiments, the first received signal can be received from the transducer 930 by a first multiplexer 982. The reflected signal received from the second pixel group can be considered a second received signal. In some embodiments, the second received signal can be received from the transducer 930 by a second multiplexer 984. In some embodiments, signals are wirelessly transmitted between multiplexers 982, 984 and one or more ultrasonic transducers 930. The wireless communication link between multiplexers 982, 984 and ultrasonic transducers 930 can be in a wireless mode, such as... or Low-energy (LE) links, The link may be a ZigBee link or some other suitable wireless communication link. In some embodiments, the wired communication link between the multiplexers 982, 984 and the ultrasonic transducer 930 may be implemented using a wired transmitter or other suitable wired interface. For example, data may be transmitted using a USB-C connector, a USB 2.x or 3.x connector, a micro USB connector, a THUNDERBOLT connector, an Ethernet cable, etc.

[0139] One or more signals transmitted to an ultrasonic transducer can be referred to as the input of the ultrasonic transducer. One or more signals transmitted by the ultrasonic transducer can be referred to as the output of the ultrasonic transducer. The output of the ultrasonic transducer can correspond to the reflected ultrasonic signal measured or detected by the ultrasonic transducer.

[0140] In some embodiments, a first multiplexer 982 transmits a first received signal from a first pixel group to a first low-noise amplifier 964. In some embodiments, the first received signal passes through a high-voltage blocker 966. The high-voltage blocker 966 can prevent signals from the high-voltage amplifier 952 from being transmitted to the first low-noise amplifier. The blocker 966 can be a high-voltage protected transmit / receive switch (T / R switch), such as an MD0100. In some embodiments, the first low-noise amplifier 964 is a low-noise, single-ended, dB-level linear, general-purpose variable gain amplifier, such as an AD8336. In some embodiments, the first received signal is then received by a first variable gain amplifier 962. In some embodiments, the variable gain amplifier 962 is a low-noise, single-ended, dB-level linear, general-purpose variable gain amplifier, such as an AD8336. In some embodiments, the first low-noise amplifier 964 and the first variable gain amplifier 962 utilize the same chip type.

[0141] In some embodiments, the second multiplexer 984 transmits the first received signal from the second pixel group to the second low-noise amplifier 974. In some embodiments, a diode 976 prevents the transmitted signal from being output to the second multiplexer 984. In some embodiments, the diode 976 is an anti-parallel diode. In some embodiments, the second low-noise amplifier 974 is a low-noise, single-ended, dB-level linear, general-purpose variable gain amplifier, such as the AD8336. In some embodiments, the second received signal is then received by the second variable gain amplifier 972. In some embodiments, the variable gain amplifier 972 is a low-noise, single-ended, dB-level linear, general-purpose variable gain amplifier, such as the AD8336. In some embodiments, the first low-noise amplifier 964, the first variable gain amplifier 962, the second low-noise amplifier 974, and the second variable gain amplifier 972 utilize the same chip type. In some embodiments, amplifiers 962, 964, 972, and 974 receive weak return pulses and amplify them according to a gain ramp signal. In some embodiments, 962, 964, 972, 974 receive weak return pulses and amplify them according to a second transmission signal 924, which is a gain ramp signal. In some embodiments, the amplification of the ramp signal corresponds to the time since the input pulse. In some embodiments, the amplification rate or ratio is determined by the time since the initial pulse of the transmitted gain ramp signal. In some embodiments, the return pulse is the received signal.

[0142] In some embodiments, the second transmission 924 signal is transmitted to the first variable gain amplifier 962. In some embodiments, the signal output by the first variable gain amplifier 962 is received by the first receive channel 926 of the software-defined radio system 920 and the second variable gain amplifier 972. In some embodiments, the signal output by the second variable gain amplifier 972 is received by the second receive channel 928 of the software-defined radio system 920.

[0143] In some embodiments, the first multiplexer 982 is a 16-channel multiplexer. In some embodiments, the second multiplexer 984 is a 16-channel multiplexer. In some embodiments, the first pixel group comprises 16 pixels. In some embodiments, the second pixel group comprises 16 pixels. In some embodiments, the first pixel group serves as a transmit and receive (transceiver) group. In some embodiments, the second pixel group serves as a receive-only group. In some embodiments, the system resolution is 14 bits. In some embodiments, the system resolution is 16 bits. In some embodiments, the system is modular and the number of channels can be increased using additional hardware. In some embodiments, the system may include 16 to 2,048 channels. In some embodiments, the system may include 16 to 32 channels, 16 to 64 channels, 16 to 128 channels, 16 to 256 channels, 16 to 512 channels, 16 to 1,024 channels, 16 to 2,048 channels, 32 to 64 channels, 32 to 128 channels, 32 to 256 channels, 32 to 512 channels, 32 to 1,024 channels, 32 to 2,048 channels, 64 to 128 channels, 64 to 2 The system may include 56 channels, 64 to 512 channels, 64 to 1,024 channels, 64 to 2,048 channels, 128 to 256 channels, 128 to 512 channels, 128 to 1,024 channels, 128 to 2,048 channels, 256 to 512 channels, 256 to 1,024 channels, 256 to 2,048 channels, 512 to 1,024 channels, 512 to 2,048 channels, or 1,024 to 2,048 channels. In some embodiments, the system may include 16 channels, 32 channels, 64 channels, 128 channels, 256 channels, 512 channels, 1,024 channels, or 2,048 channels. In some embodiments, the system may include at least 16 channels, 32 channels, 64 channels, 128 channels, 256 channels, 512 channels, or 1,024 channels. In some embodiments, the system may include up to 32 channels, 64 channels, 128 channels, 256 channels, 512 channels, 1,024 channels, or 2,048 channels.

[0144] In some embodiments, the software-defined radio system 920 is a general-purpose software-defined radio peripheral (USRP), such as the National Instruments USRP N210. In some embodiments, the software-defined radio system 920 is connected to a host computer 910. In some embodiments, the radio system 920 is connected to the computer 910 via a high-speed link. In some embodiments, the high-speed link includes an Ethernet connection. In some embodiments, the Ethernet connection is a gigabit Ethernet connection, which can allow sampling rates up to 50 MS / s (megasamples per second). In some embodiments, host-based software is loaded onto the computer 910 and used to control the radio system hardware and transmit / receive data. In some embodiments, the general functionality of the host computer is implemented in the radio system 920, which has an embedded processor that allows the radio system 920 to operate independently.

[0145] In some embodiments, the connection to computer 910 includes a Universal Serial Bus (USB) connection, a fiber optic connection, a Peripheral Component Interconnect (PCIe) connection, or other suitable connections. In some embodiments, the connection to computer 910 may allow the system to utilize the computer's Fast Access Memory (RAM). In some embodiments, the embedded processor may include a RAM buffer. In some embodiments, the RAM buffer may include 4, 8, 16, 32, 64, 80, 128, or 256 gigabytes (GB).

[0146] In some embodiments, the software-defined radio system 920 includes a motherboard. The motherboard may provide subsystems such as clock generation and synchronization, a field-programmable gate array (FPGA), one or more analog-to-digital converters (ADCs), one or more digital-to-analog converters (DACs), a host processor interface, and power conditioning. In some embodiments, a modular front-end or daughterboard is used for analog operation, such as up / down conversion, filtering, and other signal conditioning. This modularity allows the software-defined radio system 920 to serve applications operating between DC and 6 GHz. In some embodiments, the system operates between DC and 5 MHz. In some embodiments, the system operates only down to 1 MHz, which can be considered the limit of normal ultrasonic signals. In some embodiments, the system operates at frequencies from approximately 1 Hz to 3000 Hz to generate resonant mode sound waves.

[0147] In some embodiments, the signal received by the first receive channel 926 or the second receive channel 928 of the software-defined radio system 920 can be adjusted to provide a received signal gain of approximately -14 dB to +60 dB.

[0148] In some embodiments, the transmitter daughterboard module is configured to modulate the output signal to a higher frequency. In some embodiments, the receiver daughterboard module is configured to acquire RF signals and convert them to baseband. In some embodiments, the transceiver daughterboard module is configured to combine the functions of a transmitter and a receiver.

[0149] In some embodiments, the FPGA of the software-defined radio system 920 performs several digital signal processing (DSP) operations. In some embodiments, the DSP operations performed by the FPGA provide a transformation from a real signal in the analog domain to a lower-rate, complex baseband signal in the digital domain. In some embodiments, these complex samples are fed to / from applications running on the main processor, which perform the DSP operations.

[0150] In some embodiments, the hardware driver for the software-defined radio system 920 supports operating systems such as Linux, macOS, and Windows platforms. In some embodiments, several frameworks, including GNU Radio, LabVIEW, MATLAB, and Simulink, can use the hardware driver. The functionality provided by the hardware driver can also be directly accessed through the hardware driver application programming interface (API). In some embodiments, the API provides native support for C++ or any other language that can import C++ functions.

[0151] According to some embodiments, this disclosure provides a computer system programmed to implement the methods of this disclosure. Figure 10 A computer system 1001 is illustrated, which is programmed or otherwise configured to, for example, implement the methods disclosed herein. The computer system 1001 may be a user's electronic device or a computer system remotely located relative to an electronic device. The electronic device may be a mobile electronic device.

[0152] Computer system 1001 includes a central processing unit (CPU, also referred to herein as a "processor" and "computer processor") 1005, which may be a single-core or multi-core processor, or multiple processors for parallel processing. Computer system 1001 also includes memory or memory locations 1010 (e.g., random access memory, read-only memory, flash memory), electronic storage units 1015 (e.g., hard disks), a communication interface 1020 for communicating with one or more other systems (e.g., a network adapter), and peripheral devices 1025 (such as caches, other memories, data storage devices, and / or electronic display adapters). Memory 1010, storage units 1015, interface 1020, and peripheral devices 1025 communicate with CPU 1005 via a communication bus (solid line) such as a motherboard. Storage unit 1015 may be a data storage unit (or data warehouse) for storing data. Computer system 1001 may be operatively coupled to computer network ("network") 1030 with the aid of communication interface 1020. Network 1030 may be the Internet, an Internet and / or an extranet, or an intranet and / or extranet communicating with the Internet. In some cases, network 1030 is a telecommunications and / or data network. Network 1030 may include one or more computer servers that can enable distributed computing, such as cloud computing. In some cases, with the assistance of computer system 1001, network 1030 may implement a peer-to-peer network, which allows devices coupled to computer system 1001 to act as clients or servers.

[0153] CPU 1005 can execute a series of machine-readable instructions, which can be embodied in a program or software. The instructions can be stored in a memory location (such as memory 1010). The instructions can be directed to CPU 1005, which can then be programmed or otherwise configured to implement the methods of this disclosure. Examples of operations performed by CPU 1005 may include fetching, decoding, executing, and writing back.

[0154] CPU 1005 may be part of a circuit, such as an integrated circuit. One or more other components of system 1001 may be included in the circuit. In some cases, the circuit is an application-specific integrated circuit (ASIC).

[0155] Storage unit 1015 may store files, such as drivers, libraries, and saved programs. Storage unit 1015 may store user data, such as user preferences and user programs. In some cases, computer system 1001 may include one or more additional data storage units external to computer system 1001, such as those located on a remote server communicating with computer system 1001 via an intranet or the Internet.

[0156] Computer system 1001 can communicate with one or more remote computer systems via network 1030. For example, computer system 1001 can communicate with a user's remote computer system (e.g., a smartphone, laptop computer). Examples of remote computer systems include personal computers (e.g., portable PCs), tablet computers, or tablet PCs (e.g., tablet PCs). iPad Galaxy Tab), phone, smartphone (e.g.) iPhone, Android-compatible devices (or personal digital assistant). Users can access computer system 1001 via network 1030.

[0157] The methods described herein can be implemented by a machine (e.g., a computer processor) storing executable code on an electronic storage location (such as, for example, memory 1010 or electronic storage unit 1015) in computer system 1001. The machine-executable or machine-readable code may be provided in the form of software. During use, the code may be executed by processor 1005. In some cases, the code may be retrieved from storage unit 1015 and stored in memory 1010 for rapid access by processor 1005. In some cases, electronic storage unit 1015 may be excluded, and machine-executable instructions may be stored on memory 1010.

[0158] The code can be pre-compiled and configured for use with machines having processors suitable for executing the code, or it can be compiled at runtime. The code can be supplied in a selectable programming language so that it can be executed either pre-compiled or compiled.

[0159] Aspects of the systems and methods provided herein (such as computer system 1001) can be embodied in programming. These aspects of the technology can be considered as “products” or “articles of art” typically in the form of machine (or processor) executable code and / or related data carried or embodied on a type of machine-readable medium. Machine-executable code can be stored on electronic storage units such as memory (e.g., read-only memory, random access memory, flash memory) or hard disks. “Storage” type media can include any or all tangible memory of a computer, processor, or the like, or related modules thereof, such as various semiconductor memories, magnetic tape drives, disk drives, and the like, which can provide non-transitory storage for software programming at any time. All or part of the software can sometimes be communicated via the Internet or various other remote communication networks. For example, such communication can enable the loading of software from one computer or processor to another, such as from a management server or host computer to a computer platform for an application server. Therefore, another type of medium that can carry software elements includes light waves, radio waves, and electromagnetic waves (such as physical interfaces between local devices, via wired and optical ground networks, and via various air links). The physical elements carrying such waves (such as wired or wireless links, optical links, or the like) can also be considered as the medium carrying software. As used herein, unless limited to non-transitory, tangible "storage" media, terms such as "computer or machine-readable medium" refer to any medium that participates in providing instructions to the processor for execution.

[0160] Therefore, machine-readable media (such as computer-executable code) can take many forms, including but not limited to tangible storage media, carrier media, or physical transmission media. Non-volatile storage media include, for example, optical discs or disks, any storage device such as any computer(s) or the like, such as a database that can be used to implement the figures shown. Volatile storage media include dynamic memory, such as the main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wires and optical fibers, including wires that form a bus within a computer system. Carrier transmission media can take the form of electrical or electromagnetic signals, or sound waves or light waves (e.g., sound waves or light waves generated during radio frequency (RF) and infrared (IR) data communications). Therefore, common forms of computer-readable media include, for example: floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs or DVD-ROMs, any other optical media, punched cardstock magnetic tape, any other physical storage media with a perforated pattern, RAM, ROM, PROM and EPROM, FLASH-EPROM, any other memory chips or cassette tapes, carrier waves for transmitting data or instructions, cables or links for transmitting such carrier waves, or any other media from which a computer may read programming code and / or data. Many of these forms of computer-readable media may involve transmitting one or more sequences of one or more instructions to a processor for execution.

[0161] Computer system 1001 may include or communicate with an electronic display 1035, which includes a user interface (UI) 1040. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs), mobile device applications, and web-based user interfaces.

[0162] Figure 11 A chipset 1300 according to some embodiments is described. The chipset 1300 may include, for example, processor and memory components incorporated in one or more physical packages. For example, a physical package includes an arrangement of one or more materials, components, and / or wires on a structural assembly (e.g., a substrate) to provide one or more characteristics, such as physical strength, dimensional retention, and / or limitation of electrical interactions.

[0163] In one embodiment, chipset 1300 includes a communication mechanism, such as bus 1302, for transferring information between components of chipset 1300. Processor 1304 is connected to bus 1302 to execute instructions and process information stored in memory 1306. Processor 1304 includes one or more processing cores, each configured to execute independently. Multi-core processors can implement multiprocessing within a single physical package. Examples of multi-core processors include two, four, eight, or more processing cores. Alternatively or additionally, processor 1304 includes one or more microprocessors configured in series via bus 1302 to enable independent execution of instructions, pipelines, and multiple threads. Processor 1304 may also be accompanied by one or more dedicated components to perform certain processing functions and tasks, such as one or more digital signal processors (DSPs) 1308 and / or one or more application-specific integrated circuits (ASICs) 1310. DSP 1308 may typically be configured to process real-world signals (e.g., sound) in real time independently of processor 1304. Similarly, the ASIC 1310 can be configured to perform special-purpose functions that are not easily performed by general-purpose processors. Other special-purpose components that help perform the functions of the invention described herein include one or more field-programmable gate arrays (FPGAs) (not shown), one or more controllers (not shown), or one or more other special-purpose computer chips.

[0164] Processor 1304 and accompanying components are connected to memory 1306 via bus 1302. Memory 1306 includes dynamic memory (e.g., RAM) and static memory (e.g., ROM) for storing executable instructions that, when executed by processor 1304, DSP 1308 and / or ASIC 1310 perform processes as described herein in the example embodiments. Memory 1306 also stores data associated with or generated by the execution of the process.

[0165] In this document, the terms “machine-readable medium,” “computer-readable medium,” and similar terms are generally used to refer to non-transient, volatile, or non-volatile media that store data and / or instructions that cause a machine to operate in a particular manner. Common forms of machine-readable media include, for example, hard disks, solid-state drives, magnetic tape or any other magnetic data storage media, optical discs or any other optical data storage media, any physical media with a pattern of holes, RAM, PROM, EPROM, FLASH-EPROM, NVRAM, any other memory chip or cassette memory, and their networking versions.

[0166] These and other various forms of computer-readable media can relate to delivering one or more sequences of one or more instructions to a processing device for execution. Such instructions embodied on the medium are generally referred to as “instructions” or “code.” Instructions may be grouped in the form of computer programs or other groups. When executed, such instructions enable the processing device to perform the features or functions of this application as discussed herein.

[0167] In this document, a "processing device" can be implemented as a single processor performing processing operations or a combination of dedicated and / or general-purpose processors performing processing operations. A processing device may include a CPU, GPU, APU, DSP, FPGA, ASIC, SOC, and / or other processing circuitry.

[0168] The various embodiments described herein are based on exemplary block diagrams, flowcharts, and other illustrations. As will become apparent to those skilled in the art upon reading this document, the illustrated embodiments and their various alternatives may be practiced without limitation from the illustrated examples. For example, the block diagrams and their accompanying descriptions should not be construed as imposing a particular architecture or configuration.

[0169] Each of the processes, methods, and algorithms described in the foregoing sections may be embodied in code components executed by one or more computer systems or computer processors including computer hardware, and may be fully or partially automated by them. Processes and algorithms may be implemented, partially or entirely, in dedicated circuitry. The various features and processes described above may be used independently of each other or may be combined in various ways. Different combinations and sub-combinations are intended to fall within the scope of this disclosure, and certain method or process blocks may be omitted in some embodiments. Furthermore, unless the context otherwise requires, the methods and processes described herein are not limited to any particular order, and the blocks or states associated with them may be executed in other suitable orders, or may be executed in parallel, or may be executed in other ways. Blocks or states may be added to or removed from the disclosed example embodiments. The performance of certain operations or processes may be distributed among computer systems or computer processors, residing not only within a single machine but also deployed across multiple machines.

[0170] The devices and methods described herein can be used in fields other than the aforementioned medical field. For example, these devices and methods can be used to provide information about the internal condition of mechanical systems, such as the engine or transmission of a vehicle. A stethoscope function can be used to detect abnormalities in the mechanical processes of an engine or transmission. An ultrasound function can be used to image an engine or transmission to determine if it has suffered internal damage. Non-stethoscope, non-ultrasound sensors can provide additional information about the condition of an engine or transmission, such as its temperature.

[0171] The equipment and methods can be used for non-destructive testing of infrastructure. For example, the equipment and methods can be used to inspect the internal structure of concrete (in streets or highways, bridges, buildings, or other structures) to determine if the concrete or metal reinforcing steel within the concrete is damaged. The equipment and methods can also be used to inspect the internal structure of pipes to determine if they are damaged and may pose a threat to life, property, or the environment.

[0172] The equipment and methods described herein can be used to inspect the internal structure of other building materials, such as stone, brick, wood, gypsum board, insulation materials, plastic pipes, polyvinyl chloride (PVC) pipes, fiberglass, or paint.

[0173] V. Currently Preferred Implementation Methods

[0174] 1. In a currently preferred embodiment, the present invention provides a blood pressure measuring device, comprising: a first transducer configured to emit a plurality of sound waves having a plurality of frequencies, the sound waves being configured to cause vibration of a blood vessel of a subject; a second transducer configured to capture one or more ultrasound images of the blood vessel; and a processing device configured to: determine a resonant frequency of the blood vessel based on the one or more captured ultrasound images; and calculate blood pressure of the blood vessel or the subject based on the wall thickness of the blood vessel, the radius or diameter of the blood vessel, and the determined resonant frequency.

[0175] 2. The blood pressure measuring device according to paragraph 1, wherein one or more captured ultrasound images are used to measure the wall thickness and radius or diameter of the blood vessel.

[0176] 3. The blood pressure measuring device according to paragraph 1 or 2, wherein one or more captured ultrasound images comprise a plurality of ultrasound images, wherein determining the resonant frequency of the blood vessels includes:

[0177] Determining the frequency that maximizes blood vessel vibration from multiple frequencies based on multiple ultrasound images; and

[0178] Choose the frequency as the resonant frequency.

[0179] 4. The blood pressure measuring device according to any of the preceding paragraphs further includes: an audio signal generator electrically coupled to the first transducer, the audio signal generator being configured to adjust the frequency of the sound waves emitted by the first transducer.

[0180] 5. The blood pressure measuring device according to any of the preceding paragraphs, wherein the audio signal generator includes at least one variable resistor that adjusts the frequency of the sound waves emitted by the first transducer.

[0181] 6. The blood pressure measuring device according to any of the preceding paragraphs, wherein each frequency is between 1 Hz and 3000 Hz.

[0182] 7. The blood pressure measuring device according to any of the preceding paragraphs, wherein each of the frequencies is between 670 Hz and 2300 Hz.

[0183] 8. The blood pressure measuring device according to any of the preceding paragraphs, wherein the blood vessel is the subject's carotid artery.

[0184] 9. The blood pressure measuring device according to any of the preceding paragraphs, wherein the first transducer is an audio speaker.

[0185] 10. The blood pressure measuring device according to any of the preceding paragraphs further includes: a substrate, wherein the substrate includes an adhesive surface for adhesion to the skin of a subject, wherein the first transducer and the second transducer are incorporated in the substrate.

[0186] 11. The blood pressure measuring device according to paragraph 10, wherein a substrate is adhered near a blood vessel.

[0187] 12. The blood pressure measuring device according to paragraph 11, wherein the blood vessel is the carotid artery.

[0188] 13. The blood pressure measuring device according to any one of paragraphs 10 to 12, wherein the substrate includes alignment lines.

[0189] 14. The blood pressure measuring device according to paragraph 13, wherein the substrate includes a transparent window.

[0190] 15. The blood pressure measuring device according to paragraph 10 further includes a third transducer configured to capture a second set of one or more ultrasound images of the blood vessels.

[0191] 16. The blood pressure measuring device according to paragraph 15, wherein the second transducer and the third transducer each have a corresponding resonant frequency, and wherein the second transducer includes a frequency response that partially overlaps with the frequency response of the third transducer; and the processing device processes the measurements performed by the first transducer and the second transducer.

[0192] 17. The blood pressure measuring device according to paragraph 16, wherein processing of measurements performed by the first transducer and the second transducer includes normalizing the first frequency response and the second frequency response.

[0193] 18. The blood pressure measuring device according to paragraph 15 further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessels.

[0194] 19. The blood pressure measuring device according to paragraph 15 further includes: a substrate, wherein the substrate includes an adhesive surface for adhesion to the skin of a subject, wherein the first transducer, the second transducer and the third transducer are incorporated in the substrate.

[0195] 20. The blood pressure measuring device according to paragraph 19, wherein a substrate is adhered near a blood vessel.

[0196] 21. The blood pressure measuring device according to paragraph 20, wherein the blood vessel is the carotid artery.

[0197] 22. The blood pressure measuring device according to paragraph 21, wherein the substrate includes alignment lines.

[0198] 23. The blood pressure measuring device according to paragraph 22, wherein the substrate further includes a transparent window.

[0199] 24. The blood pressure measuring device according to paragraph 16 further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessels.

[0200] 25. The blood pressure measuring device according to paragraph 24, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency response of the second transducer.

[0201] 26. The blood pressure measuring device according to paragraph 24, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency response of the third transducer.

[0202] 27. The blood pressure measuring device according to paragraph 24, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency responses of the second and third transducers.

[0203] 28. The blood pressure measuring device according to paragraph 24 further includes: a substrate, wherein the substrate includes an adhesive surface for adhesion to the skin of a subject, wherein the first transducer, the second transducer and the third transducer are incorporated in the substrate.

[0204] 29. The blood pressure measuring device according to paragraph 28, wherein a substrate is adhered near a blood vessel.

[0205] 30. The blood pressure measuring device according to paragraph 29, wherein the blood vessel is the carotid artery.

[0206] 31. The blood pressure measuring device according to paragraph 30, wherein the substrate includes alignment lines.

[0207] 32. The blood pressure measuring device according to paragraph 31, wherein the substrate further includes a transparent window.

[0208] 33. The blood pressure measuring device according to any of the preceding paragraphs further includes a third transducer configured to capture a second set of one or more ultrasound images of the blood vessels.

[0209] 34. The blood pressure measuring device according to paragraph 33, wherein the second transducer and the third transducer each have a corresponding resonant frequency, and wherein the second transducer includes a frequency response that partially overlaps with the frequency response of the third transducer; and the processing device processes the measurements performed by the first transducer and the second transducer.

[0210] 35. The blood pressure measuring device according to paragraph 34, wherein processing of measurements performed by the first transducer and the second transducer includes normalizing the first frequency response and the second frequency response.

[0211] 36. The blood pressure measuring device according to paragraph 33 further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessels.

[0212] 37. The blood pressure measuring device according to paragraph 34 further includes a fourth transducer configured to capture a third set of one or more ultrasound images of the blood vessels.

[0213] 38. The blood pressure measuring device according to paragraph 37, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency response of the second transducer.

[0214] 39. The blood pressure measuring device according to paragraph 37, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency response of the third transducer.

[0215] 40. The blood pressure measuring device according to paragraph 37, wherein the fourth transducer includes a frequency response that partially overlaps with the frequency responses of both the second and third transducers.

[0216] 41. In a currently preferred embodiment, the present invention provides a non-transitory computer-readable storage medium storing instructions executable by a processor, wherein execution of the instructions causes a blood pressure measuring device to perform operations including: emitting a plurality of sound waves having a plurality of frequencies using a first transducer near a blood vessel of a subject, the sound waves causing the blood vessel of the subject to vibrate; determining the resonant frequency of the blood vessel based on the vibration response of the blood vessel to the plurality of sound waves; determining the wall thickness and radius or diameter of the blood vessel using a second transducer emitting ultrasound; and calculating the blood pressure of the subject based on the resonant frequency, the wall thickness of the blood vessel, and the radius or diameter of the blood vessel.

[0217] 42. The non-transitory computer-readable storage medium according to paragraph 41, wherein the operation further comprises: capturing a plurality of ultrasound images of the blood vessel as the blood vessel vibrates in response to the sound wave using the second transducer, wherein determining the resonant frequency of the blood vessel comprises: determining the resonant frequency of the blood vessel based on the ultrasound images.

[0218] 43. The non-transitory computer-readable storage medium according to paragraph 41 or 42, wherein determining the wall thickness and radius of the blood vessel comprises: guiding ultrasound waves to the blood vessel using the second transducer; and receiving ultrasound waves reflected from the echo boundary of the blood vessel using the second transducer.

[0219] 44. The non-transitory computer-readable storage medium according to paragraph 41, wherein after calculating blood pressure, the operation further includes: using a first transducer and a second transducer to determine the renewal radius of the blood vessel and the renewal rate of blood flow through the blood vessel; and calculating the renewed blood pressure based on the renewal radius and the renewal rate.

[0220] 45. The non-transitory computer-readable storage medium according to any of the preceding paragraphs, wherein multiple frequencies of multiple sound waves are between 1 Hz and 3000 Hz.

[0221] 46. ​​The non-transitory computer-readable storage medium according to any of the preceding paragraphs, wherein multiple frequencies of multiple sound waves are between 670 Hz and 2300 Hz.

[0222] 47. The non-transitory computer-readable storage medium according to any of the preceding paragraphs, wherein the first transducer is an audio speaker.

[0223] 48. The non-transitory computer-readable storage medium according to any of the preceding paragraphs, wherein operation further includes capturing a first set of ultrasound images of the blood vessels using a third transducer.

[0224] 49. The non-transitory computer-readable storage medium according to paragraph 48, wherein operation further includes capturing a second set of ultrasound images of the blood vessel using a second transducer.

[0225] 50. The non-transitory computer-readable storage medium according to paragraph 49, wherein the operation further includes normalizing the second set of ultrasound images using the first set of ultrasound images.

[0226] 51. The non-transitory computer-readable storage medium according to paragraph 49, wherein operation further includes capturing a third set of ultrasound images of the blood vessels using a fourth transducer.

[0227] 52. The non-transitory computer-readable storage medium according to paragraph 51, wherein the operation further includes normalizing the second set of ultrasound images using the first set of ultrasound images.

[0228] 53. The non-transitory computer-readable storage medium according to paragraph 52, wherein the operation further includes normalizing the second set of ultrasound images using the third set of ultrasound images.

[0229] 54. In a currently preferred embodiment, the present invention provides a method comprising: emitting a plurality of sound waves having a plurality of frequencies using a first transducer located near a blood vessel of a subject, the sound waves causing vibration of the blood vessel of the subject; determining a resonant frequency of the blood vessel based on the vibrational response of the blood vessel to the sound waves; determining the wall thickness and radius or diameter of the blood vessel using a second transducer emitting ultrasound waves; and calculating the blood pressure of the subject based on the resonant frequency, the wall thickness of the blood vessel, and the radius or diameter of the blood vessel.

[0230] 55. The method according to paragraph 54 further includes: capturing multiple ultrasound images of the blood vessel as the blood vessel vibrates in response to sound waves using a second transducer, wherein determining the resonant frequency of the blood vessel includes: determining the resonant frequency of the blood vessel based on the ultrasound images.

[0231] 56. The method according to paragraph 54 or 55, wherein determining the wall thickness and radius of the blood vessel comprises: guiding ultrasound waves to the blood vessel using a second transducer; and receiving ultrasound waves reflected from the echo boundary of the blood vessel using the second transducer.

[0232] 57. The method according to any of the preceding paragraphs, wherein after calculating blood pressure, the method further comprises: using a first transducer and a second transducer to determine the renewal radius of the blood vessel and the renewal rate of blood flow through the blood vessel; and calculating the renewed blood pressure based on the renewal radius and the renewal rate.

[0233] 58. The method described in any of the preceding paragraphs, wherein each frequency is between 670 Hz and 2300 Hz.

[0234] 59. The method according to paragraph 55 further includes capturing a second set of multiple ultrasound images of the blood vessel using a third transducer when the blood vessel vibrates in response to sound waves.

[0235] 60. The method according to paragraph 59 further includes normalizing multiple ultrasound images of a blood vessel captured by a second transducer using a second set of multiple ultrasound images of the blood vessel captured by a third transducer.

[0236] 61. The method according to paragraph 59 further includes capturing a third set of multiple ultrasound images of the blood vessel using a fourth transducer when the blood vessel vibrates in response to sound waves.

[0237] 62. The method according to paragraph 61 further includes normalizing multiple ultrasound images of a blood vessel captured by a second transducer using a second set of multiple ultrasound images of the blood vessel captured by a third transducer.

[0238] 63. The method according to paragraph 62 further includes normalizing multiple ultrasound images of the blood vessel captured by the second transducer with a third set of multiple ultrasound images of the blood vessel captured by the fourth transducer.

[0239] 64. In a currently preferred embodiment, the present invention provides a blood pressure measuring device comprising: a first transducer configured to direct sound waves to a blood vessel; and a second transducer configured to direct ultrasound waves to the blood vessel, receive ultrasound waves reflected from the echo boundary of the blood vessel, measure the radius or diameter of a cross-section of the blood vessel, and measure the wall thickness of a cross-section of the blood vessel.

[0240] 65. The blood pressure measuring device according to paragraph 64, wherein the first transducer is an electroacoustic transducer and the second transducer is a piezoelectric ultrasonic transducer.

[0241] 66. The blood pressure measuring device according to paragraph 64 or 65, wherein the device further includes an audio signal generator coupled to the first transducer.

[0242] 67. The blood pressure measuring device according to paragraph 66, wherein the audio signal generator is configured to change the frequency of the sound waves.

[0243] 68. The blood pressure measuring device according to paragraph 67 further includes a display.

[0244] 69. The blood pressure measuring device according to paragraph 68, wherein the display shows the frequency of the sound waves.

[0245] 70. The blood pressure measuring device according to paragraph 69, wherein a second transducer monitors the vibration of the cross-section of the blood vessel.

[0246] 71. The blood pressure measuring device according to paragraph 67, wherein a second transducer monitors the vibration of the cross-section of a blood vessel, and wherein the second transducer records the frequency of the vibration of the cross-section and determines its resonant frequency.

[0247] 72. The blood pressure measuring device according to paragraph 71, wherein the resonant frequency is determined when the vibration of the cross-section of the blood vessel is at its maximum.

[0248] 73. The blood pressure measuring device according to any of the preceding paragraphs, wherein the frequency of the sound waves varies in the range of 1 Hz to 3000 Hz.

[0249] 74. The blood pressure measuring device according to any of the preceding paragraphs, wherein the frequency of the sound waves varies in the range of 670 Hz to 2300 Hz.

[0250] 75. The blood pressure measuring device according to any of the preceding paragraphs, wherein the electroacoustic transducer is an audio loudspeaker.

[0251] 76. The blood pressure measuring device according to paragraph 75, wherein the audio speaker is a tweeter.

[0252] 77. The blood pressure measuring device according to any one of paragraphs 64 to 76, wherein the blood vessel is an artery or a vein.

[0253] 78. The blood pressure measuring device according to any of the preceding paragraphs, wherein the first transducer and the second transducer are coupled to a substrate, and wherein the substrate includes an adhesive backing.

[0254] 79. The blood pressure measuring device according to paragraph 78, wherein a substrate is adhered near a blood vessel.

[0255] 80. The blood pressure measuring device according to paragraph 79, wherein the blood vessel is the carotid artery.

[0256] 81. The blood pressure measuring device according to any one of paragraphs 78 to 80, wherein the substrate includes alignment lines.

[0257] 82. The blood pressure measuring device according to any one of paragraphs 78 to 80, wherein the substrate includes alignment lines and a transparent window.

[0258] 83. In a currently preferred embodiment, the present invention provides a method for measuring blood pressure, the method comprising: determining the radius and wall thickness of a cross-section of a blood vessel; directing sound waves to the blood vessel; changing the frequency of the sound waves; detecting the maximum resonance of the cross-section of the blood vessel to determine the resonant frequency of the blood vessel; and calculating the blood pressure within the blood vessel based on the determined resonant frequency, the radius and wall thickness of the blood vessel.

[0259] 84. The method according to paragraph 83, wherein changing the frequency of the sound wave includes changing the frequency of the sound wave in the range of 1 Hz to 3000 Hz.

[0260] 85. The method according to paragraph 83, wherein changing the frequency of the sound wave includes changing the frequency of the sound wave in the range of 670 Hz to 2300 Hz.

[0261] 86. The method according to any of the preceding paragraphs, wherein the resonant frequency is determined by detecting the maximum resonance using a piezoelectric ultrasonic transducer.

[0262] 87. The method according to paragraph 86, wherein the piezoelectric ultrasonic transducer includes a sampling rate of at least 3 kHz.

[0263] 88. The method according to any of the preceding paragraphs, wherein the steps of determining the radius and wall thickness of the blood vessel include directing ultrasound waves to the blood vessel and receiving reflected ultrasound waves reflected from the echo boundary of the blood vessel.

[0264] 89. The method according to paragraph 88 further includes measuring the Doppler shift of the reflected ultrasound waves and calculating the wave velocity of the blood vessel.

[0265] 90. The method according to paragraph 89, wherein the Doppler frequency shift is measured by a piezoelectric ultrasonic transducer.

[0266] 91. The method described in any of the preceding paragraphs, wherein the blood vessel is an artery or a vein.

[0267] 92. The method according to any of the preceding paragraphs further includes directing the first set of transmitted ultrasound waves toward the blood vessel and capturing the first set of reflected ultrasound waves from the blood vessel.

[0268] 93. The method according to paragraph 92, wherein the steps of guiding the first set of transmitted ultrasound waves toward the blood vessel and capturing the first set of reflected ultrasound waves from the blood vessel are performed by a single ultrasound transducer.

[0269] 94. The method according to any of the preceding paragraphs further includes using a first ultrasound transducer to guide a first set of transmitted ultrasound waves toward a blood vessel and using a second ultrasound transducer to capture a first set of reflected ultrasound waves from the blood vessel.

[0270] 95. The method according to any of the preceding paragraphs further includes using a first ultrasound transducer to guide a first set of transmitted ultrasound waves toward a blood vessel and using the first ultrasound transducer and a second ultrasound transducer to capture a first set of reflected ultrasound waves from the blood vessel.

[0271] 96. The method according to any of the preceding paragraphs further includes using a first ultrasound transducer to guide a first set of transmitted ultrasound signals toward a blood vessel, and using the first ultrasound transducer to capture a first reflected ultrasound signal from the blood vessel.

[0272] 97. According to the method described in paragraph 96, the ultrasound signal from the second reflection from the blood vessel is further captured using a second ultrasound transducer.

[0273] 98. The method according to paragraph 97 further includes normalizing the first reflected ultrasonic signal with the second reflected ultrasonic signal.

[0274] 99. The method according to paragraph 97 further includes capturing ultrasound signals from a third reflection from the blood vessel using a third ultrasound transducer.

[0275] 100. The method according to paragraph 99 further includes normalizing the ultrasonic signal of the first reflection using the ultrasonic signal of the third reflection.

[0276] 101. The method described in any of the preceding paragraphs, wherein the blood vessel is the carotid artery.

[0277] 102. In a currently preferred embodiment, the present invention provides a system for transmitting and receiving ultrasonic signals, the system comprising: a software-defined radio including one or more outputs and one or more inputs; an ultrasonic signal processing circuit electrically coupled to the software-defined radio; and one or more ultrasonic transducers electrically coupled to the ultrasonic signal processing circuit, wherein the ultrasonic signal processing circuit processes one or more ultrasonic transmission signals from one or more outputs of the software-defined radio and transmits the processed ultrasonic transmission signals to the one or more ultrasonic transducers to generate ultrasonic waves, and wherein a signal processing unit processes one or more received ultrasonic signals from the one or more ultrasonic transducers and transmits the processed received ultrasonic signals to one or more inputs of the software-defined radio.

[0278] 103. The system according to paragraph 102, wherein the ultrasonic processing circuitry includes at least one high-voltage amplifier to amplify one or more ultrasonic transmission signals from one or more outputs of a software-defined radio.

[0279] 104. The system according to paragraph 103, wherein the ultrasonic processing circuitry includes at least one variable gain amplifier to amplify one or more ultrasonic signals received from one or more ultrasonic transducers.

[0280] 105. The system according to any of the preceding paragraphs, wherein the ultrasonic processing circuitry includes at least one variable gain amplifier to amplify one or more received ultrasonic signals from one or more ultrasonic transducers.

[0281] 106. The system according to any of the preceding paragraphs, wherein the output of the software-defined radio includes a gain ramp and a transmission pulse.

[0282] 107. The system according to paragraph 106, wherein the ultrasonic processing circuitry includes a high-voltage amplifier for amplifying the transmitted pulses.

[0283] 108. The system according to paragraph 107, wherein the ultrasonic processing circuitry includes a variable gain amplifier to amplify one or more received ultrasonic signals from one or more ultrasonic transducers based on a gain ramp defined by software-defined radio transmission.

[0284] 109. The system according to paragraph 108, wherein the amplification of the ramp signal corresponds to the time since the initial pulse of the software-defined radio transmitted ramp signal.

[0285] 110. According to the system described in paragraph 109, the ultrasonic transducer includes a first pixel group and a second pixel group.

[0286] 111. The system according to paragraph 110, wherein the first pixel group and the second pixel group each comprise 16 pixels.

[0287] 112. The system according to paragraph 111, wherein the first pixel group is configured to receive processed ultrasonic transmission signals.

[0288] 113. The system according to paragraph 111, wherein only the first pixel group receives the processed ultrasonic transmission signal.

[0289] 114. The system according to paragraph 113, wherein one or more received ultrasonic signals are received by a first pixel group and a second pixel group and transmitted to an ultrasonic processing circuit.

[0290] 115. The system according to paragraph 108, wherein the variable gain amplifier is a low-noise, single-ended, linear, general-purpose variable gain amplifier.

[0291] 116. The system according to any of the preceding paragraphs, wherein the ultrasonic transducer includes a first pixel group and a second pixel group.

[0292] 117. The system according to paragraph 116, wherein the first pixel group is configured to receive processed ultrasonic transmission signals.

[0293] 118. The system according to paragraph 117, wherein only the first pixel group receives the processed ultrasonic transmission signal.

[0294] 119. The system according to paragraph 118 further includes a computing device connected to the software-defined radio, such that the computing device controls one or more outputs of the software-defined radio.

[0295] 120. The system according to paragraph 119, wherein the computing device includes a display, wherein the display shows data received from one or more inputs of a software-defined radio.

[0296] 121. The system according to paragraph 120, wherein the display shows one or more ultrasonic images obtained by one or more ultrasonic transducers.

[0297] 122. The system according to any of the preceding paragraphs further includes a computing device connected to the software-defined radio, such that the computing device controls one or more outputs of the software-defined radio.

[0298] 123. The system according to paragraph 122, wherein the computing device includes a display, wherein the display shows data received from one or more inputs of a software-defined radio.

[0299] 124. The system according to paragraph 123, wherein the display shows one or more ultrasonic images obtained by one or more ultrasonic transducers.

[0300] 125. In a currently preferred embodiment, the present invention provides a method for modulating one or more ultrasonic signals, the method comprising: receiving a first transmitted signal from a software-defined radio; amplifying the first transmitted signal to form an amplified transmitted signal;

[0301] The amplified transmission signal is forwarded to one or more ultrasonic transducers using a first multiplexer; one or more received ultrasonic signals are received from one or more ultrasonic transducers using the first multiplexer; and the one or more received ultrasonic signals are amplified to form one or more amplified received ultrasonic signals.

[0302] 126. The method according to any of the preceding paragraphs, wherein the amplification of one or more received ultrasonic signals is based on a gain ramp of a software-defined radio transmission.

[0303] 127. The method described in paragraph 126, wherein the amplification is time-dependent.

[0304] 128. The method according to paragraph 127, wherein amplification of one or more received ultrasound signals is performed by one or more low-noise, single-ended, linear, universal variable gain amplifiers.

[0305] 129. The method according to any of the preceding paragraphs, wherein amplification of one or more received ultrasound signals is performed by one or more low-noise, single-ended, linear, general-purpose variable gain amplifiers.

[0306] 130. The method according to any of the preceding paragraphs further includes emitting one or more ultrasonic waves toward at least one object, wherein the at least one object reflects one or more ultrasonic waves, and wherein the reflected ultrasonic waves are detected by one or more ultrasonic transducers and form one or more received ultrasonic signals.

[0307] 131. The method according to paragraph 130, wherein the amplification of one or more received ultrasonic signals is based on a gain ramp of a software-defined radio transmission.

[0308] 132. The method described in paragraph 131, wherein the amplification is time-dependent.

[0309] 133. The method according to paragraph 132, wherein amplification of one or more received ultrasonic signals is performed by one or more low-noise, single-ended, linear, universal variable gain amplifiers.

[0310] 134. The method according to paragraph 130, wherein at least one object is a blood vessel of the subject.

[0311] 135. According to the method described in paragraph 134, the blood vessel is the carotid artery.

[0312] VI. Definition

[0313] Unless otherwise defined, all technical terms, symbols, and other technical and scientific terms or technical terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some instances, terms with generally understood meanings are defined herein for clarity and / or for ease of reference, and such definitions contained herein are not necessarily construed as indicating a material difference from what is commonly understood in the art.

[0314] Throughout this application, various embodiments may be presented in a range format. It should be understood that the range format is for convenience and brevity only and should not be construed as a rigid limitation on the scope of this disclosure. Therefore, the range description should be considered as having specifically disclosed all possible subranges and the individual values ​​within those ranges. For example, a description of a range such as 1 to 6 should be considered as having specifically disclosed subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., and individual numbers within that range, such as 1, 2, 3, 4, 5, and 6. This applies regardless of the width of the range.

[0315] As used in the specification and claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly specifies otherwise. For example, the term “sample” includes multiple samples, including mixtures thereof.

[0316] The terms “determine,” “measure,” “evaluate,” “assess,” “determine,” and “analyze” are used interchangeably in this document to refer to forms of measurement. These terms include determining the presence of an element (e.g., detection). These terms can include quantitative, qualitative, or a combination of quantitative and qualitative determinations. Evaluations can be relative or absolute. “Detecting presence” can include determining the quantity of something present, as well as determining its presence or absence depending on the context.

[0317] The terms “subject,” “individual,” or “patient” are used interchangeably throughout this document. A “subject” can be a biological entity containing expressed genetic material. A biological entity can be a plant, animal, or microorganism, including, for example, bacteria, viruses, fungi, and protozoa. A subject can be a tissue, cell, or progeny of a biological entity obtained in vivo or cultured in vitro. A subject can be a mammal. A mammal can be a human. A subject may be diagnosed or suspected of being at high risk for a disease. In some cases, a subject may not necessarily be diagnosed or suspected of being at high risk for the disease.

[0318] The term "in vivo" is used to describe events that occur inside a subject's body.

[0319] The term "ex vivo" is used to describe events that occur outside the subject's body. Measurements are not performed on the subject in vitro. Instead, they are performed on a sample separate from the subject. An example of an ex vivo measurement performed on a sample is an "in vitro" measurement.

[0320] The term "in vitro" is used to describe events that occur within a container holding a laboratory reagent to separate it from the biological source from which the material was obtained. In vitro assays can include cell-based assays using live or dead cells. In vitro assays can also include cell-free assays that do not use intact cells.

[0321] As used herein, the term "about" for a number means adding or subtracting 10% of that number. The term "about" for a range means subtracting 10% of its minimum value and adding 10% of its maximum value from that range.

[0322] As used herein, the term “or” can be interpreted as either inclusive or exclusive. Furthermore, descriptions of singular resources, operations, or structures should not be interpreted as excluding the plural. Conditional language (such as “can,” “may,” “may,” or “may”) is generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not, unless expressly stated otherwise or otherwise understood in the context in which it is used.

[0323] Unless otherwise expressly stated, the terms and phrases used in this document, and their variations thereof, should be interpreted as open-ended rather than restrictive. Adjectives such as “regular,” “traditional,” “normal,” “standard,” “known,” and terms with similar meanings should not be interpreted as limiting the described items to a given time period or up to a given time, but should be interpreted as encompassing regular, traditional, normal, or standard techniques that may be available or known at any time now or in the future. In some cases, the appearance of broadening words and phrases such as “one or more,” “at least,” “but not limited to,” or other similar phrases should not be construed as implying that a narrower scope is anticipated or necessary where such broadening phrases may not be present.

[0324] The chapter titles used in this article are for organizational purposes only and should not be construed as limiting the topics described.

[0325] VII. Example

[0326] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0327] Example 1: Using a cuff to measure blood pressure

[0328] In this example of measuring blood pressure using a previous method involving a blood pressure cuff, the patient's arm is placed on a comfortable surface. A trained nurse or doctor then places an appropriately sized cuff over the patient's upper arm. A stethoscope is placed on the patient's brachial artery, just below the cuff.

[0329] The trained person then inflates the cuff to 180 mmHg and begins releasing air from the cuff at the recommended rate of 3 mm / s. The trained person must observe the blood pressure monitor in the cuff while listening with a stethoscope.

[0330] The first "knock" indicates the point where the patient's systolic blood pressure will be measured using a blood pressure monitor. Once the "knock" stops, measure the patient's diastolic blood pressure using the blood pressure monitor. Record both the measured systolic and diastolic blood pressure.

[0331] Further recommendations include taking measurements in the other arm. Any discrepancies between the measurements from the arms should be recorded. Additionally, the subject's position and the cuff size used should be recorded.

[0332] If the subject's blood pressure appears elevated, it is recommended to measure the patient's blood pressure at least twice more. Allow a rest period between measurements.

[0333] Example 2: Using arterial resonance to measure blood pressure

[0334] An adhesive substrate comprising one or more ultrasonic transducers and an electroacoustic transducer is adhered to the vicinity of the patient's carotid artery. The electroacoustic transducer disposed on the adhesive substrate is activated.

[0335] The electroacoustic transducer varies within a range of audio frequencies. The ultrasound transducer detects when the resonance in the artery is at its maximum level. The resonant frequency is held for a moment and recorded. The ultrasound transducer determines the artery wall thickness and diameter. The patient's blood pressure is then calculated and recorded.

[0336] While preferred embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that these embodiments are provided by way of example only. Many variations, modifications, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of the invention, and the methods and structures within the scope of these claims, and their equivalents, are thereby covered.

Claims

1. A blood pressure measuring device, comprising: A first transducer is configured to emit multiple sound waves of multiple frequencies, the sound waves being configured to cause the blood vessels of the subject to vibrate. A second transducer is configured to capture one or more ultrasound images of the blood vessel; as well as The processing equipment is configured as follows: The resonant frequency of the blood vessel is determined based on the one or more captured ultrasound images; and The blood pressure of the blood vessel or the subject is calculated based on the wall thickness of the blood vessel, the radius or diameter of the blood vessel, and the determined resonant frequency.

2. The blood pressure measuring device of claim 1, wherein the one or more captured ultrasound images are used to measure the wall thickness of the blood vessel and the radius or diameter of the blood vessel.

3. The blood pressure measuring device of claim 1, wherein the one or more captured ultrasound images comprise a plurality of ultrasound images, wherein determining the resonant frequency of the blood vessel comprises: Based on the multiple ultrasound images, determine the multiple frequencies that maximize the vibration of the blood vessel; as well as The frequency is selected as the resonant frequency.

4. The blood pressure measuring device according to claim 1, further comprising: An audio signal generator electrically coupled to the first transducer, the audio signal generator being configured to adjust the frequency of sound waves emitted by the first transducer.

5. The blood pressure measuring device according to claim 1, wherein the audio signal generator includes at least one variable resistor that adjusts the frequency of the sound wave emitted by the first transducer.

6. The blood pressure measuring device according to claim 1, wherein each of the frequencies is between 1 Hz and 3000 Hz.

7. The blood pressure measuring device according to claim 6, wherein each of the frequencies is between 670 Hz and 2300 Hz.

8. The blood pressure measuring device according to claim 1, wherein the blood vessel is the carotid artery of the subject.

9. The blood pressure measuring device according to claim 1, wherein the first transducer is an audio speaker.

10. The blood pressure measuring device according to claim 1, further comprising: A substrate, wherein the substrate includes an adhesive surface for adhesion to the subject's skin, wherein the first transducer and the second transducer are incorporated in the substrate.

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