A lightweight imaging ultrasound system with unfixed scanning probe and an ultrasound detection method

Abstract

The present invention proposes a lightweight imaging ultrasound system without a fixed scanning probe, the imaging ultrasound system includes a wireless scanning probe, a terminal device, and a three-dimensional imaging computing device; wherein the wireless scanning probe transmits ultrasound image data and the acceleration and angular velocity data of the probe to the terminal device and the three-dimensional imaging computing device in a wireless manner respectively; the terminal device provides the required two-dimensional ultrasound image to the three-dimensional imaging computing device; the three-dimensional imaging computing device transmits the reconstructed three-dimensional ultrasound data to the terminal device. The present invention solves the problem that doctors find it difficult to understand two-dimensional ultrasound images, enables doctors to understand tissue and organ structures more intuitively through real-time three-dimensional views, trains doctors to perform ultrasound scanning and understand two-dimensional ultrasound images in a more efficient way, and solves the problem of time-consuming ultrasound doctor training.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic technology and relates to a lightweight imaging ultrasonic system with an unfixed scanning probe and an ultrasonic detection method. Background Art

[0002] In the medical field, ultrasound scanning is widely used in clinical diagnosis due to its unique advantages. Compared with computed tomography (CT) and magnetic resonance imaging (MRI), ultrasound imaging technology has the advantages of being non-invasive, radiation-free and inexpensive. In traditional ultrasound examinations, doctors place ultrasound scanning probes on the patient's body to scan and obtain two-dimensional images of cross-sections of human tissues and organs. However, in this traditional method, doctors must reconstruct two-dimensional ultrasound images into three-dimensional anatomical structures of the human body in their brains. In order to achieve this effect, doctors must undergo professional training, and the training process takes a lot of time and money. Compared with two-dimensional ultrasound images, three-dimensional ultrasound images can provide the entire volume of the area of ​​interest, providing doctors with a more intuitive spatial structure.

[0003] Early three-dimensional reconstruction of ultrasound images can be completed in three stages, namely acquisition, reconstruction and visualization. The specific process is to collect a series of ultrasound images obtained by ultrasound scanning of the target position, and visualize them through the corresponding three-dimensional reconstruction algorithm. This three-dimensional reconstruction technology separates the ultrasound scanning, volume reconstruction and visualization stages, and belongs to non-real-time three-dimensional image reconstruction. In this reconstruction method, a micro-motor generally drives a mechanical device to translate, tilt and rotate the probe to achieve cross-sectional scanning, slowly acquire a series of two-dimensional ultrasound images of the detection area, and then record them in the computer. Since the scanning is performed by a mechanical device that controls the fixed probe according to a pre-set scheme, the relative position and angle of each image can be known, but there are problems such as bulky scanning devices and inflexible scanning methods, and three-dimensional reconstruction can only be performed after scanning, so it is not practical in clinical practice.

[0004] At present, the main technology for achieving real-time three-dimensional reconstruction of two-dimensional ultrasound images is to add sensors to the ultrasound probe, and then hold the ultrasound probe for free arm scanning. The sensor transmits the recorded real-time spatial position of the ultrasound probe and the scanning direction and other spatial information back to the computer in real time. The computer combines the real-time two-dimensional ultrasound image and the spatial information of the probe, and then performs real-time three-dimensional reconstruction and visualization of the ultrasound image. Among them, the sensor positioning technology is mainly optical positioning and electromagnetic positioning. For example, an optical locator is used to measure the three-dimensional spatial position coordinates of the ultrasound probe, such as "Three-dimensional ultrasound imaging method, storage medium and equipment based on spatial positioning device" (patent publication number: CN113081033A). There are also electromagnetic tracking systems, that is, using an ultrasound probe equipped with an electromagnetic sensor and an electromagnetic transmitter that can track the position and direction of the electromagnetic sensor for positioning, such as "Handheld unconstrained scanning wireless three-dimensional ultrasound real-time voxel imaging system" (patent publication number: CN111184535A). In addition, there is also the use of acoustic positioning technology. The specific method is to fix three acoustic emission devices on the ultrasound probe, fix a microphone array on the patient, and obtain positioning information by measuring the sound propagation time. Recently, the Kinect sensor with a depth camera is used in combination with an angle sensor to realize the positioning of the ultrasound probe, such as "A three-dimensional ultrasound imaging method for reconstructing a set of two-dimensional ultrasound images" (patent publication number: CN107582098A).

[0005] Different sensors have different requirements for applicable scenarios, so they all have certain shortcomings. The problem found in the optical tracking and positioning system is that the marker installed on the ultrasound probe is too large, which makes the ultrasound scanning process inconvenient, and the camera's line of sight cannot be blocked. The problem with electromagnetic positioning is that the surrounding environment contains ferrous metals that affect the magnetic field, resulting in deviations in position measurement. The problem with acoustic positioning is that the microphone must be placed above the patient so that the sound line can reach unimpeded, and the distance between the transmitter and the microphone must be close enough to ensure a high signal-to-noise ratio, and the speed of sound will change with the change of air humidity, resulting in certain errors. The problem with the Kinect somatosensory detection device with a depth of field camera is that the requirements for the environment and light intensity are relatively high when used outdoors, because it is easily affected by strong natural light outdoors, resulting in the projected coded light being submerged, the effect is not satisfactory, and it is easily affected by the reflection of smooth planes. Therefore, these methods not only have the problems mentioned above, but also have problems such as large size of ultrasound equipment, being bound by wires, and being unable to move and operate freely.

[0006] In addition, "A Three-Dimensional Ultrasonic Reconstruction System Based on Inertial Navigation System" (Publication No.: CN114533111A) proposes a method for ultrasonic three-dimensional reconstruction using inertial navigation. Among them, the position solution algorithm mentioned is too simple, the accuracy error of the position solution is too large, and because the data of the two-dimensional ultrasound image and the IMU sensor are discretely collected in time, after mapping these data to the real three-dimensional space, there will be some vacancies in the three-dimensional space. Even if the sampling frequency is increased, the vacancies still exist, so the reconstruction result is inaccurate. At the same time, this method also has the disadvantage that the device is bound by wires and cannot be truly freely moved and operated. Summary of the invention

[0007] In order to solve the deficiencies in the prior art, the present invention provides a lightweight imaging ultrasound system and an ultrasound detection method without a fixed scanning probe.

[0008] The present invention can guide doctors to scan and read two-dimensional images without difficulty through three-dimensional image reconstruction, that is, it is not limited by the scanning probe fixed by a mechanical arm, and is not limited by the abstract and difficult-to-read two-dimensional images. The expected optimal two-dimensional image can be obtained by using free-arm scanning.

[0009] Specifically, the present invention installs a wireless inertial measurement unit on a wireless ultrasound probe, uses the inertial measurement unit and the wireless ultrasound probe to obtain ultrasound image data and spatial information, thereby achieving real-time three-dimensional reconstruction of a two-dimensional ultrasound image, and finally simultaneously displays the two-dimensional ultrasound image and the reconstructed three-dimensional ultrasound image on the screen of a mobile device in real time. Since the two-dimensional ultrasound image and the corresponding three-dimensional ultrasound image can be displayed on the mobile device at the same time, the three-dimensional ultrasound image can help doctors understand the two-dimensional ultrasound image more intuitively, solving the problem that doctors have difficulty understanding the two-dimensional ultrasound image, enabling doctors to understand the structure of tissues and organs more intuitively through real-time three-dimensional views, and training doctors to perform ultrasound scanning and understand two-dimensional ultrasound images in a more efficient way, solving the problem of time-consuming ultrasound doctor training.

[0010] Secondly, the present invention uses a wireless ultrasound probe to scan the part of interest in a free scanning manner. Therefore, the scanning method of the imaging system is flexible, lightweight and compact, solving the problems of the previous three-dimensional ultrasound imaging system probe with cables, fixed / semi-fixed scanning method, and bulky scanning device.

[0011] The present invention provides a lightweight imaging ultrasound system with an unfixed scanning probe, the imaging ultrasound system comprising a wireless scanning probe, a terminal device, and a three-dimensional imaging computing device; the wireless scanning probe wirelessly transmits ultrasound image data and data such as acceleration and angular velocity of the probe to the terminal device and the three-dimensional imaging computing device respectively; the terminal device provides the required two-dimensional ultrasound image to the three-dimensional imaging computing device, and the three-dimensional imaging computing device transmits the reconstructed three-dimensional ultrasound data to the terminal device.

[0012] The wireless scanning probe of the present invention includes two modules, namely a wireless ultrasonic probe module and a wireless inertial measurement unit module; specifically, the present invention obtains the real-time spatial position information of the probe during ultrasonic scanning by installing a wireless inertial measurement unit on the wireless ultrasonic probe. The scanning probe is a wireless ultrasonic probe, which has the advantages of convenient wireless transmission and is not bound by cables. Secondly, it has low power and therefore has a longer battery life. The wireless ultrasonic probe module is used to encode and decode ultrasonic echo signals into JPEG image data, and transmit the image data to the terminal device through a USB module or a WIFI module.

[0013] The wireless inertial measurement unit installed on the wireless ultrasound probe consists of a gyroscope and an accelerometer. The accelerometer is used to detect the three-axis acceleration signal of the ultrasound probe, and the gyroscope detects the angular velocity signal. The function of the wireless inertial measurement unit module is to transmit the three-dimensional posture data of the probe to the three-dimensional imaging computing device through the wireless module. The advantage of using an inertial measurement unit for positioning is that the measurement data can be obtained using only internal sensors without any external help. In addition, the inertial measurement unit has low requirements for the external environment, is not affected by light and electromagnetic interference, and can even work underwater.

[0014] The terminal device is a mobile display device installed with ultrasound imaging software, which is used to simultaneously and in real time visualize the two-dimensional ultrasound image obtained by the ultrasound probe and the three-dimensional ultrasound image obtained by the three-dimensional imaging computing device. The terminal device establishes a connection between the two-dimensional ultrasound image and the three-dimensional imaging computing device through a socket and uses a mobile network for communication, and transmits the two-dimensional ultrasound image to the three-dimensional imaging computing device in real time. The three-dimensional imaging computing device then transmits the reconstructed three-dimensional ultrasound image data back to the terminal device, and the terminal device synchronously displays the two-dimensional ultrasound image and the three-dimensional ultrasound image in real time. Since the terminal device is a mobile device such as a mobile phone or a tablet device, it has the advantages of being small, lightweight and easy to operate.

[0015] The three-dimensional imaging computing device is a high-performance computer. The real-time angular velocity and acceleration data of the ultrasonic probe in three-dimensional space obtained by the wireless inertial measurement unit are transmitted to the three-dimensional imaging computing device through the 433 wireless transparent transmission module. The three-dimensional imaging computing device then solves the data to obtain the posture of the ultrasonic probe and combines it with the two-dimensional ultrasonic image obtained in real time by the terminal device for three-dimensional reconstruction. At the same time, the reconstructed three-dimensional ultrasonic image data is transmitted to the terminal device.

[0016] In order to solve the problems of poor position solution accuracy and gaps in pixel-to-voxel mapping after solution in existing methods, the present invention proposes a complete position solution algorithm and a three-dimensional reconstruction interpolation algorithm.

[0017] The principle of calculating the attitude and position of the 3D imaging computing device based on the data of the inertial measurement unit is as follows:

[0018] In the process of attitude and position solution, two coordinate systems are involved, one is the coordinate system b of the IMU (Inertial Measurement Unit) itself, and the other is the final reconstructed reference coordinate system R. Therefore, the information output by the IMU needs to be converted into the reference system through solution.

[0019] IMU contains a three-axis accelerometer and a three-axis gyroscope. The accelerometer is used to measure the changes in three-axis acceleration during movement, and the gyroscope is used to measure the changes in three-axis angular velocity.

[0020] (1) Calculation of three-axis attitude

[0021] The IMU outputs orientation information in the form of quaternions. The general form of a quaternion is a scalar q0 (the angle of rotation) followed by a vector q (the axis of rotation), q = (q1, q2, q3)

[0022]

[0023] Quaternions are similar to complex numbers. Quaternions are composed of real numbers plus three imaginary units. And they have the following relationship: Every quaternion is 1. A linear combination of . The geometric meaning of itself can be understood as a rotation, in which The rotation represents the rotation from the positive direction of the Z axis to the positive direction of the Y axis in the plane where the Z axis and the Y axis intersect. The rotation represents the rotation from the positive direction of the X axis to the positive direction of the Z axis in the plane where the X axis and the Z axis intersect. The rotation represents the rotation from the positive direction of the Y axis to the positive direction of the X axis in the plane where the Y axis and the X axis intersect.

[0024] like Figure 1 As shown, given the rotation axis defined by the vector A quaternion can represent a rotation around this axis u with an angle θ:

[0025]

[0026] Therefore, an operation that transforms vector v into a square rotation around the u axis with a rotation angle of θ can be represented by the multiplication of quaternions, and the formula is:

[0027]

[0028] Among them, q * =q0-q, which is the conjugate quaternion of q.

[0029] Therefore, the attitude of the motion system b (the coordinate system of the ultrasonic probe with IMU) relative to the reference system R (the coordinate system of the final 3D reconstruction) can be completely determined by the two parameters of the rotation axis u and the rotation angle θ. Using the two parameters u and θ, an attitude quaternion can be constructed:

[0030]

[0031] The above formula indicates that the reference coordinate system R rotates around u by an angle θ and coincides with the moving coordinate system b, so the posture of the moving coordinate system b can be obtained through the posture quaternion Transformed into the posture in the reference system R, the coordinate transformation formula is:

[0032]

[0033] After the initial attitude information is given, the attitude quaternion can be recursively deduced in real time to convert the rotation attitude information of the IMU's own coordinate system b into the rotation attitude information of the reference coordinate system R. The recursive formula of the attitude quaternion is as follows:

[0034]

[0035] Among them, t represents the time, and t starts from 0, so the attitude quaternion of the current moment can be recursively derived from the attitude information of the previous moment, so as to further calculate the attitude information of the IMU at every moment.

[0036] (2) Calculation of displacement

[0037] The three-axis accelerometer in the IMU can obtain the acceleration value of the three axes at the current moment, but it is necessary to compensate for the Earth's gravity acceleration and the Coriolis acceleration caused by the Earth's rotation. By integrating the acceleration, the velocity can be obtained, that is, the velocity v at time k k It can be obtained from the integration of velocity and acceleration at time k-1 and the error compensation term:

[0038]

[0039] Where Δv g / cor(k) It represents the influence of local gravity acceleration and Coriolis acceleration at time k, which can be calculated using the local latitude, the angular velocity of the earth's rotation, and the output of the IMU gyroscope. α(τ) is the output of the IMU accelerometer. The attitude transformation matrix can be obtained by transforming the attitude quaternion calculated in the first step. It means transforming the acceleration output of IMU from its own coordinate system b to the reference coordinate system R, and the subscript k represents time.

[0040] (3) Positioning

[0041] By integrating and accumulating the velocity, we can get the position P at time k: k :

[0042]

[0043] (4) Complete process

[0044] First, the initial attitude, position and velocity information of the IMU is given, and then the ultrasonic probe with the IMU is moved. As time goes by, the above attitude solution and displacement solution are combined for real-time recursion, and the current real-time position of the ultrasonic probe can be obtained to complete the final positioning. The present invention is different from the simple integration of IMU data in the existing method. Since the attitude and position of the current ultrasonic probe are solved by real-time dynamic recursion of attitude quaternion, and the influence of the earth's gravity and rotation on the IMU output is taken into account, the attitude and position solved are more accurate.

[0045] The present invention also provides an ultrasonic detection method using the above-mentioned imaging ultrasonic system, the ultrasonic detection method comprising the following steps:

[0046] Step 1: Collect data by moving and rotating the wireless scanning probe; the data includes ultrasonic data of the area to be detected and information such as acceleration and angular velocity measured by an inertial measurement unit;

[0047] Step 2: Transmitting the ultrasonic data collected by the wireless scanning probe to the terminal device;

[0048] Step 3: The terminal device visualizes the two-dimensional ultrasound image according to the ultrasound data, and transmits the two-dimensional ultrasound image to the three-dimensional imaging computing platform;

[0049] Step 4: The inertial measurement unit transmits the measured acceleration, angular velocity and other information to the three-dimensional imaging computing platform;

[0050] Step 5: The three-dimensional imaging computing platform performs three-dimensional reconstruction based on the two-dimensional ultrasound image obtained in step 3 and the acceleration, angular velocity and other information obtained in step 4 in combination with the interpolation algorithm; if the reconstruction is complete, the three-dimensional imaging computing platform transmits the three-dimensional ultrasound image data to the terminal device for visualization, and the ultrasound detection is completed; if the reconstruction is not complete, return to step 1 and perform the subsequent steps again.

[0051] The interpolation algorithm and visualization during 3D reconstruction are described as follows:

[0052] (1) Interpolation algorithm

[0053] In step five, the three-dimensional computing device will first synchronize the two-dimensional ultrasound image and the information output by the IMU according to the timestamp information, and then calculate the position of each frame of the two-dimensional ultrasound image in the three-dimensional space according to the previously described solution process, and then use the interpolation algorithm to complete the final three-dimensional reconstruction for the vacant voxels that are not mapped in the three-dimensional space.

[0054] This method finally uses voxels to represent the reconstructed 3D ultrasound data. Voxels are cubic blocks of fixed size in 3D space. They are the smallest unit used to represent 3D data. Voxels correspond to pixels in 2D images. 2D ultrasound images are grayscale images, and each pixel has a certain grayscale value. The interpolation algorithm is to assign the grayscale value of the pixel in the 2D ultrasound image to the corresponding voxel through a certain strategy based on the positioning information.

[0055] The interpolation algorithm of this 3D reconstruction method uses a square distance weighted algorithm to complete the interpolation. The specific algorithm is described as follows:

[0056]

[0057]

[0058] Among them, I(V T ) is the grayscale value of the target voxel, and n refers to the grayscale value of the target voxel within the predefined range V T is the number of pixels in the spherical area at the center of the sphere, I(P i ) represents the gray value of the i-th pixel in the area, W i is the weight of the i-th pixel, and is related to the voxel V at the center of the sphere T The square of the distance d is inversely proportional to the distance d, which can be obtained by the previous position solution. By traversing each voxel, all voxels can be assigned values. The schematic diagram of the algorithm is as follows Figure 2 As shown, Figure 2 The three-dimensional space is mapped onto a two-dimensional plane, where the small squares represent voxels in the three-dimensional space, the gray circular area represents the pre-defined spherical area, the straight line passing through the voxels represents the two-dimensional ultrasound image, and the black dots on the straight line represent pixels.

[0059] (2) Visualization

[0060] The 3D computing device communicates with the terminal device through Socket and mobile network, and transmits the reconstructed 3D voxel data to the terminal device in real time. The terminal device uses a cache queue to store this data and performs volume rendering through a ray casting algorithm. Finally, the 3D voxel data is rendered in real time and displayed on the screen simultaneously with the 2D ultrasound image in the form of picture-in-picture.

[0061] The beneficial effects of the present invention include: the present invention proposes a non-fixed, highly flexible wireless scanning probe, which is composed of a wireless ultrasonic probe and a wireless inertial measurement unit. The advantages of using a wireless ultrasonic probe are that the host and the probe are an integrated lightweight design, the probe is small and easy to hold, it is not bound by wires, and the image is transmitted in real time. The advantage of using a wireless inertial measurement unit for positioning is that the measurement data can be obtained using only internal sensors without any external help. In addition, the inertial measurement unit has low requirements for the external environment, is not affected by light and electromagnetic interference, and can even work underwater. The two-dimensional ultrasonic image and the reconstructed three-dimensional ultrasonic image will be displayed in real time on a portable mobile device (such as a smart phone or tablet computer). The advantage of using a mobile device to display the ultrasonic image is that the mobile device is small and easy to carry and carry. The present invention can perform three-dimensional reconstruction of ultrasonic images in real time during ultrasonic scanning, which solves the problem of low efficiency and long time consumption in the three-dimensional reconstruction process of the existing technology. The wireless ultrasound probe used in the present invention integrates a host, and the ultrasound probe can directly encode and decode ultrasound echo signals into JPEG image data. Compared with traditional ultrasound equipment, this greatly reduces the size of the equipment, and the built-in WIFI module of the probe can transmit the image data to the terminal device wirelessly. The sensor used to obtain the three-dimensional posture of the probe is an inertial measurement unit, which can transmit the real-time acceleration and angular velocity of the wireless probe to the three-dimensional computing platform wirelessly. The present invention will greatly improve the efficiency of three-dimensional reconstruction of ultrasound images, and can use three-dimensional views in real time to help doctors understand two-dimensional images, which can solve the problem that doctors find it difficult to correctly scan and understand two-dimensional ultrasound images when training ultrasound doctors. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of the transformation of the rotation axis in the process of solving the posture of the present invention.

[0063] Figure 2 It is a schematic diagram of the interpolation algorithm used in the present invention.

[0064] Figure 3 It is a system structure diagram of an imaging ultrasound system without a fixed scanning probe according to the present invention.

[0065] Figure 4It is a structural diagram of the ultrasonic probe and inertial measurement unit used in the present invention.

[0066] Figure 5 It is an internal structure diagram of the wireless scanning probe with an inertial measurement unit of the present invention.

[0067] Figure 6 It is a flow chart of the ultrasonic detection method of the present invention. DETAILED DESCRIPTION

[0068] The present invention is further described in detail with reference to the following specific examples and drawings. The process, conditions, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art and are not particularly limited by the present invention.

[0069] The present invention provides a lightweight imaging ultrasound system and ultrasound detection method without a fixed scanning probe. The wireless ultrasound probe is used to process the original ultrasound data into image coding data, which is then transmitted to a terminal device for display. The terminal device then transmits the obtained image data to a three-dimensional computing platform. The wireless inertial measurement unit in the probe transmits the probe posture data obtained in real time to the three-dimensional computing platform. The three-dimensional computing platform uses all the received data to perform three-dimensional reconstruction of the ultrasound image, and finally transmits the reconstructed three-dimensional data to the terminal device. The terminal device will display the two-dimensional ultrasound image and the three-dimensional ultrasound image simultaneously.

[0070] The system structure diagram of the present invention is as follows Figure 3 As shown in FIG. 1 , the wireless scanning probe is composed of the following parts: a wireless scanning probe, a terminal device, and a three-dimensional imaging computing device. The external and internal structures of the wireless scanning probe are shown in FIG. Figure 4 , Figure 5 As shown, it consists of the following two parts: a wireless ultrasonic probe and a wireless inertial measurement unit, wherein the wireless inertial measurement unit integrates a wireless 433 transparent transmission module, and the wireless inertial measurement unit and the wireless ultrasonic probe work together with the battery in the wireless ultrasonic probe.

[0071] The specific process of the ultrasonic detection method of the present invention is shown in Figure 6 The specific description is as follows:

[0072] Step 1: Use a wireless ultrasound probe equipped with a sensor to scan the human organ tissue of interest to collect ultrasound signals. The scanning method is to hold the ultrasound probe in hand and repeatedly scan the part of interest by freely rotating and translating the probe.

[0073] Step 2, obtain spatial information through the sensor installed on the outside of the wireless ultrasound probe. The selected sensor is an inertial measurement unit. The inertial measurement unit will transmit the acceleration and angular velocity information of the wireless ultrasound probe during movement and rotation to the three-dimensional imaging calculation device. The data is transmitted through the 433 wireless transparent transmission module.

[0074] Step 3: The wireless ultrasound probe transmits the ultrasound signals collected during the scanning process to the terminal device in real time. The ultrasound data is transmitted via WIFI.

[0075] Step 4: The terminal device (mobile phone or tablet) reconstructs the ultrasound signal obtained from the ultrasound probe into a two-dimensional ultrasound image in real time and visualizes it on the terminal device.

[0076] Step 5: The terminal device transmits the two-dimensional ultrasound image to the three-dimensional imaging computing device via the mobile network in real time.

[0077] In step 6, the three-dimensional imaging computing device calculates the acceleration and angular velocity information obtained by the inertial measurement unit to obtain the coordinate position of the ultrasound probe in three-dimensional space, and then reconstructs the three-dimensional ultrasound image in real time by combining the two-dimensional ultrasound image obtained in real time from the terminal device with the spatial information obtained by the calculation.

[0078] In step 7, the three-dimensional imaging computing device transmits the reconstructed three-dimensional ultrasound image data to the terminal device through the network in real time, and the terminal device visualizes the real-time two-dimensional ultrasound image and the three-dimensional ultrasound image at the same time for comparison.

[0079] In this example, a wireless ultrasound probe is used in step 1. Figure 5 As shown, one large-scale integrated circuit B controls two large-scale integrated circuits A to complete the function of transmitting high-voltage pulses to the ultrasonic probe (ultrasonic probe has a minimum of 128 array elements) and receiving echoes from the ultrasonic probe. The two large-scale integrated circuits A are used to transmit high-voltage driving pulses to the ultrasonic probe and receive the sound wave signals reflected by the probe at the same time. Each large-scale integrated circuit A transmits high-voltage driving pulses to half of the array elements and receives the sound wave signals reflected by the probe. The two functions of transmitting and receiving are controlled and switched by the large-scale integrated circuit B. The large-scale integrated circuit B has at least 64 physical channels to complete analog front-end amplification and analog-to-digital conversion. The digital signal is converted into a brightness signal, converted into JPEG through its internal codec, and then the JPEG is transmitted to the WIFI module through the synchronous serial bus, and finally the WIFI module is wirelessly transmitted to the terminal device, realizing and ensuring the real-time nature of wireless transmission. At the same time, it also has the function of wired transmission. If WIFI is not used to transmit data, the large-scale integrated circuit B can also transmit JPEG data to the terminal device in real time in a wired manner via USB.

[0080] In this example, the scanning method of the wireless ultrasound probe in step 1 is a non-fixed free scanning method, including translation and rotation of the ultrasound probe. The translation of the wireless ultrasound probe can detect longitudinal sections at different positions in the target three-dimensional space. Translation alone cannot further increase the detected information. The rotation ultrasound sensor can detect the target three-dimensional space from different angles. Combining the two movement methods of translation and rotation can detect the three-dimensional imaging area.

[0081] In this example, the sensor used to detect the spatial position of the wireless ultrasonic probe in step 2 is an inertial measurement unit, whose main components include a gyroscope and an accelerometer. The accelerometer is used to detect the three-axis acceleration signal of the wireless ultrasonic probe, while the gyroscope detects the angular velocity signal. The advantage of using an inertial measurement unit for positioning is that measurement data can be obtained using only internal sensors without any external help. In addition, the inertial measurement unit has low requirements for the external environment, is not affected by light and electromagnetic interference, and can even work underwater, making it suitable for more application scenarios. Figure 5 As shown, the inertial measurement unit is connected to the 433 wireless transparent transmission module using an asynchronous serial bus. The inertial measurement unit transmits the measured data to the 433 wireless transparent transmission module in real time through the asynchronous serial bus, and then the 433 wireless module transmits the data to the three-dimensional imaging calculation device through the 433MHz wireless frequency band.

[0082] In this example, the three-dimensional imaging computing device in step 2 is a high-performance computer that can receive two-dimensional ultrasound image data from the terminal device and data from the inertial measurement unit, and reconstruct the obtained data in three dimensions through a three-dimensional reconstruction algorithm, and finally transmit it to the terminal device through a mobile network.

[0083] In this example, the terminal device in step 3 is a mobile device such as a mobile phone or a tablet computer. The wireless ultrasound probe transmits the collected ultrasound to the terminal device through a wireless transmission protocol, and the terminal device visualizes the ultrasound two-dimensional image and the three-dimensional ultrasound image.

[0084] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. A lightweight imaging ultrasound system without a fixed scanning probe, characterized in that: The imaging ultrasound system includes a wireless scanning probe, a terminal device, and a three-dimensional imaging computing device; wherein, The wireless scanning probe transmits the ultrasonic image data and the acceleration and angular velocity data of the probe to the terminal device and the three-dimensional imaging computing device in a wireless manner respectively; The terminal device provides the required two-dimensional ultrasound image to the three-dimensional imaging calculation device; The three-dimensional imaging computing device transmits the reconstructed three-dimensional ultrasound data to the terminal device; the three-dimensional imaging computing device performs posture and position calculation method as follows: There are two coordinate systems involved in the attitude and position calculation process. One is the IMU's own coordinate system b, and the other is the final reconstructed reference system R. The information output by the IMU is converted to the reference system through calculation: IMU contains a three-axis accelerometer and a three-axis gyroscope. The accelerometer is used to measure the changes in three-axis acceleration during movement, and the gyroscope is used to measure the changes in three-axis angular velocity; (1) Calculation of three-axis attitude The IMU outputs orientation information in the form of quaternions; the general form of a quaternion is a rotation angle scalar q0 followed by a rotation axis vector q, q = (q1, q2, q3): in, Every quaternion is 1. A linear combination of The geometric meaning of itself is understood as a rotation, in which The rotation represents the rotation from the positive direction of the Z axis to the positive direction of the Y axis in the plane where the Z axis and the Y axis intersect. The rotation represents the rotation from the positive direction of the X axis to the positive direction of the Z axis in the plane where the X axis and the Z axis intersect. The rotation represents the rotation from the positive direction of the Y axis to the positive direction of the X axis in the plane where the Y axis and the X axis intersect; Given an axis of rotation defined by a vector The quaternion represents a rotation around the axis u with an angle θ: An operation that transforms vector v into a square rotation around the u axis with a rotation angle of θ is represented by the multiplication of quaternions, and the formula is: Among them, q * =q0-q, which is the conjugate quaternion of q; The attitude of coordinate system b relative to reference system R is determined by two parameters: rotation axis u and rotation angle θ. Use u and θ to construct an attitude quaternion: The above formula indicates that the reference coordinate system R rotates around u by an angle θ and coincides with the moving coordinate system b. The attitude of the coordinate system b is expressed by the attitude quaternion Transformed into the posture in the reference system R, the coordinate transformation formula is: After the initial attitude information is given, the attitude quaternion is recursively deduced in real time to convert the rotation attitude information of the IMU's own coordinate system b into the rotation attitude information of the reference system R. The recursive formula of the attitude quaternion is as follows: Among them, t represents the time, t starts from 0, the attitude quaternion of the current moment is recursively derived from the attitude information of the previous moment, and the attitude information of the IMU at each moment is further calculated; (2) Calculation of displacement The three-axis acceleration value at the current moment is compensated by the three-axis accelerometer in the IMU for the Earth's gravity acceleration and the Coriolis acceleration caused by the Earth's rotation. The velocity is obtained by integrating the acceleration, that is, the velocity v at time k. k The integral of the velocity and acceleration at time k-1 and the error compensation term yields: Where Δv g / cor(k) It represents the influence of local gravity acceleration and Coriolis acceleration at time k, which is calculated using the local latitude, the angular velocity of the earth's rotation, and the output of the IMU gyroscope. α(τ) is the output of the IMU accelerometer. The attitude transformation matrix is ​​obtained by transforming the attitude quaternion calculated in the first step. It means transforming the acceleration output of IMU from coordinate system b to reference system R, and the subscript k represents time; (3) Positioning By integrating and accumulating the velocity, we can get the position P at time k. k :

2. The lightweight imaging ultrasound system with a non-fixed scanning probe as claimed in claim 1, characterized in that: The wireless scanning probe includes a wireless ultrasonic probe module and a wireless inertial measurement unit module; wherein, The real-time spatial position information of the probe during the ultrasonic scanning process is obtained by installing a wireless inertial measurement unit module on the wireless ultrasonic probe module; The probe used for scanning by the wireless ultrasonic probe module is a wireless ultrasonic probe, and the wireless ultrasonic probe module encodes and decodes the ultrasonic echo signal into image data, and transmits the image data to the terminal device; The wireless inertial measurement unit module is composed of a gyroscope and an accelerometer, the accelerometer is used to detect the three-axis acceleration signal of the wireless ultrasonic probe, and the gyroscope detects the angular velocity signal; The wireless inertial measurement unit module transmits the three-dimensional posture data of the wireless ultrasonic probe to the three-dimensional imaging calculation device through the wireless module.

3. The lightweight imaging ultrasound system with a non-fixed scanning probe as claimed in claim 1, characterized in that: The terminal device is a mobile display device installed with ultrasound imaging software, which is used to simultaneously and in real time visualize the two-dimensional ultrasound image obtained by the ultrasound probe and the three-dimensional ultrasound image obtained by the three-dimensional imaging computing device; The terminal device establishes a connection between the two-dimensional ultrasound image and the three-dimensional imaging computing device through the Socket and uses the mobile network to communicate, and transmits the two-dimensional ultrasound image to the three-dimensional imaging computing device in real time. The three-dimensional imaging computing device then transmits the reconstructed three-dimensional ultrasound image data back to the terminal device, and the terminal device synchronously displays the two-dimensional ultrasound image and the three-dimensional ultrasound image in real time.

4. The lightweight imaging ultrasound system with a non-fixed scanning probe as claimed in claim 1, characterized in that: The data of the ultrasound probe in three-dimensional space obtained by the wireless scanning probe is transmitted to the three-dimensional imaging calculation device through the wireless transparent transmission module. The three-dimensional imaging calculation device then solves the data to obtain the posture of the wireless scanning probe and performs three-dimensional reconstruction in combination with the two-dimensional ultrasound image obtained in real time by the terminal device, and at the same time transmits the reconstructed three-dimensional ultrasound image data to the terminal device.

5. An ultrasonic detection method using a lightweight imaging ultrasonic system with a non-fixed scanning probe as claimed in any one of claims 1 to 4, characterized in that: The steps include: Step 1: Collect data by moving and rotating the wireless scanning probe; the data includes ultrasonic data of the area to be detected and acceleration and angular velocity information measured by the inertial measurement unit; Step 2: Transmitting the ultrasonic data collected by the wireless scanning probe to the terminal device; Step 3: The terminal device visualizes the two-dimensional ultrasound image according to the ultrasound data, and transmits the two-dimensional ultrasound image to the three-dimensional imaging computing platform; Step 4: The inertial measurement unit transmits the measured acceleration and angular velocity information to the three-dimensional imaging computing platform; Step 5: The three-dimensional imaging computing platform performs three-dimensional reconstruction based on the two-dimensional ultrasound image obtained in step 3 and the acceleration and angular velocity information obtained in step 4 in combination with the interpolation algorithm; if the reconstruction is complete, the three-dimensional imaging computing platform transmits the three-dimensional ultrasound image data to the terminal device for visualization, and the ultrasound detection is completed; if the reconstruction is not complete, return to step 1 and perform the subsequent steps again.

6. The ultrasonic detection method according to claim 5, characterized in that: The interpolation algorithms in the 3D reconstruction process include: In step 5, the 3D computing device first synchronizes the 2D ultrasound image and the information output by the IMU according to the timestamp information, and then calculates the position of each frame of the 2D ultrasound image in the 3D space according to the solution process, and uses the interpolation algorithm to complete the final 3D reconstruction for the vacant voxels that are not mapped in the 3D space; The reconstructed 3D ultrasound data is represented by voxels; the 2D ultrasound image is a grayscale image, and the interpolation algorithm assigns the grayscale value of the pixel in the 2D ultrasound image to the corresponding voxel through a strategy based on the positioning information; The interpolation algorithm uses a square distance weighted algorithm to complete the interpolation. The specific algorithm is described as follows: Among them, I(V T ) is the grayscale value of the target voxel, and n refers to the grayscale value of the target voxel within the predefined range V T is the number of pixels in the spherical area at the center of the sphere, I(P i ) represents the gray value of the i-th pixel in the area, W i is the weight of the i-th pixel, and is related to the voxel V at the center of the sphere T It is inversely proportional to the square of the distance d, where d is obtained through the previous position solution; by traversing each voxel, all voxels are finally assigned values; the three-dimensional space is mapped to a two-dimensional plane, in which the small squares represent the voxels in the three-dimensional space, the gray circular area represents the pre-defined spherical area, the straight line passing through the voxels represents the two-dimensional ultrasound image, and the black dots on the straight line represent pixels.

7. The ultrasonic detection method according to claim 5, characterized in that: Visualization during 3D reconstruction includes: The 3D computing device communicates with the terminal device through Socket and mobile network, and transmits the reconstructed 3D voxel data to the terminal device in real time. The terminal device uses a cache queue to store this data and performs volume rendering through a ray casting algorithm. Finally, the 3D voxel data is rendered in real time and displayed on the screen simultaneously with the 2D ultrasound image in the form of picture-in-picture.

Images