Ultrasound imaging system, method and computer readable medium

Abstract

An ultrasound imaging system, method, and computer readable medium, wherein the method performs enhanced B-mode imaging by a pulse reversal (PI) process. The controller sends a PI sequence including positive and negative ultrasound pulses into the biological tissue. The signal processing circuit receives an echo signal generated by the PI sequence, and extracts three different signals: a DC harmonic DCH signal, a fundamental wave signal of a sending frequency, and a second harmonic signal. Weights are assigned to the signals to create weighted signals across different non-linear frequency bands. Compared with a standard method, the method has the advantages that the image penetrating power and the resolution are improved, and clutters are reduced.

Description

Technical Field

[0001] The present invention relates to ultrasound imaging, and more particularly to a method and apparatus for improving and enhancing B-mode imaging, or brightness mode imaging, through the use of nonlinear frequency compounding. Background Art

[0002] B-mode imaging, also known as brightness-mode imaging, is a foundational technology in medical ultrasound imaging. It generates two-dimensional cross-sectional images by analyzing the intensity of ultrasound waves reflected (echoes) from various tissues within the body. The brightness levels in the resulting images correspond to the echo intensity, providing crucial information about the body's internal structures. This technology is indispensable in applications such as diagnosing various diseases, guiding surgery, and monitoring fetal development.

[0003] Despite its widespread utility, B-mode imaging faces challenges, particularly in terms of image clarity and depth penetration. As sound waves pass through nonlinear tissue, they generate a range of signals, including extremely low-frequency signals centered around DC (0 Hz) and nonlinear second harmonic signals. Traditionally, nonlinear second harmonic signals have been used to improve the quality of ultrasound images, resulting in less clutter and artifacts than using only the fundamental frequency signal. On the other hand, the DC component is considered "noise" due to its very low frequency and is typically removed from the imaging process. This standard approach ignores the potential utility of the DC signal, which, given its presence in the low-frequency band, may carry valuable information that can enhance image penetration. Furthermore, preliminary evaluations have shown that the DC signal offers advantages in reducing clutter and enhancing boundaries compared to conventional fundamental and second harmonic signals. Summary of the Invention

[0004] In one embodiment, an ultrasound imaging system is provided. The ultrasound imaging system may include:

[0005] a controller for transmitting a pulse inversion (PI) sequence including positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe;

[0006] Signal processing circuitry for:

[0007] receiving the echo signal generated by the PI sequence;

[0008] Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the echo signal;

[0009] Assigning weights to the DCH signal, the fundamental signal, and the second harmonic signal to obtain a nonlinear frequency weighted signal;

[0010] A final image is generated based on this nonlinear frequency weighted signal.

[0011] In one embodiment, the DCH signal corresponds to a low frequency component centered at 0 Hz.

[0012] In one embodiment, weights are assigned to the DCH signal, the fundamental signal, and the second harmonic signal based on at least one of imaging depth or clinical application mode.

[0013] In one embodiment, the DCH signal is given a higher weight to improve image penetration, reduce clutter levels, and enhance edge visibility in the final image.

[0014] In one embodiment, the second harmonic signal is given a higher weight to improve the image clarity and resolution of the final image.

[0015] In one embodiment, weights are assigned to the DCH signal, the fundamental signal, and the second harmonic signal based on a predefined clinical imaging scenario, wherein the predefined clinical imaging scenario is selected from a group consisting of fetal skull imaging, transcranial imaging, visual acupuncture, and deep tissue imaging.

[0016] In one embodiment, the signal processing circuit is configured to extract the DCH signal and the second harmonic signal by summing the received echo signals, and to extract the fundamental signal by subtracting the received echo signals.

[0017] In one embodiment, the received echo signal includes a first echo signal of the positive ultrasonic pulse and a second echo signal of the negative ultrasonic pulse.

[0018] In one embodiment, the DCH signal, the fundamental signal, and the second harmonic signal are derived from a nonlinear frequency band in the echo signal.

[0019] In one embodiment, an ultrasound imaging system is provided, which may include:

[0020] a controller for transmitting a pulse inversion (PI) sequence including positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe;

[0021] Signal processing circuitry for:

[0022] receiving the echo signal generated by the PI sequence;

[0023] Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the echo signal;

[0024] generating an image based on the DCH signal, the fundamental signal, and the second harmonic signal respectively;

[0025] Assign weights to these images to obtain weighted images;

[0026] A final image is generated based on the weighted image.

[0027] In one embodiment, an ultrasound imaging method is provided, which may include:

[0028] sending a pulse inversion (PI) sequence comprising positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe;

[0029] receiving the echo signal generated by the PI sequence;

[0030] Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the received echo signal;

[0031] assigning weights to the DCH signal, the fundamental signal, and the second harmonic signal to obtain a nonlinear frequency weighted signal;

[0032] A final image is generated based on this nonlinear frequency weighted signal.

[0033] In one embodiment, the DCH signal corresponds to a low frequency component centered at 0 Hz.

[0034] In one embodiment, the weight is assigned based on at least one of imaging depth or clinical application mode.

[0035] In one embodiment, the DCH signal is given a higher weight to improve image penetration, reduce clutter levels, and enhance edge visibility in the final image.

[0036] In one embodiment, the second harmonic signal is given a higher weight to improve the image clarity and resolution of the final image.

[0037] In one embodiment, the weights assigned to the DCH signal, the fundamental signal, and the second harmonic signal are performed based on a predefined clinical imaging scenario, wherein the predefined clinical imaging scenario is selected from a set including fetal skull imaging, transcranial imaging, visual acupuncture, and deep tissue imaging.

[0038] In one embodiment, extracting the DCH signal and the second harmonic signal includes summing the received echo signals, and extracting the fundamental signal includes subtracting the received echo signals.

[0039] In one embodiment, an ultrasound imaging method is provided, which may include:

[0040] sending a pulse inversion (PI) sequence comprising positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe;

[0041] receiving the echo signal generated by the PI sequence;

[0042] Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the received echo signal;

[0043] generating an image based on the DCH signal, the fundamental signal, and the second harmonic signal respectively;

[0044] Assign weights to these images to obtain weighted images;

[0045] A final image is generated based on the weighted image.

[0046] In one embodiment, a non-transitory computer-readable medium storing instructions is provided. When the instructions are executed by one or more processors, the one or more processors are caused to perform the method of any of the aforementioned embodiments.

[0047] In the aforementioned embodiments, novel systems and methods are provided that utilize regular pulse inversion transmission technology to generate not only a DC signal and a second harmonic signal, but also a fundamental signal (and possibly other odd harmonic signals). By extracting these signals, the method is able to generate an ultrasound image based on these signals, or to generate three or more different ultrasound images based on these signals, and to composite the images derived from the DC component, the second harmonic, and the fundamental signal. This composite provides flexibility and can optimize image quality at different tissue depths (in different patient groups, different parts of a patient's body, and different locations on a body part), thereby overcoming traditional limitations associated with signal extraction and image clarity. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic block diagram of an exemplary embodiment of an ultrasound imaging system according to the present invention is shown;

[0049] Figure 2 A mathematical model indicating the source of a DC component signal according to an exemplary embodiment is shown;

[0050] Figure 3 A mathematical model according to an exemplary embodiment is shown that indicates how different signals can be derived by combining received signals, which come from transmitted positive and negative pulses;

[0051] Figure 4 shows a signal spectrum according to an exemplary embodiment, which shows that a DC component signal, a fundamental signal, and a second harmonic signal can be generated simultaneously with a conventional PI transmit signal;

[0052] Figure 5An example image is shown according to an exemplary embodiment, which is generated based on a DC component signal, a second harmonic signal, a fundamental signal, and a composite signal;

[0053] Figure 6 An example method of ultrasound imaging using nonlinear frequency compounding according to an exemplary embodiment is shown;

[0054] Figure 7 An exemplary computing device is shown in which any of the embodiments described herein may be implemented. DETAILED DESCRIPTION

[0055] The embodiments disclosed herein introduce an advanced ultrasound imaging method that primarily enhances B-mode imaging by utilizing nonlinear frequency recombination and signal extraction. The core of this technology is the simultaneous generation and utilization of multiple signal types: nonlinear harmonic signals, fundamental signals, and unique direct current harmonic signals (Direct Current Harmonic, DCH). Unlike conventional approaches, this method not only identifies the value of the DCH signal, which is traditionally considered noise, but also allows for flexible weighted recombination of images generated based on these different nonlinear signals. The synthesized composite image significantly improves the penetration and clarity of the image. In addition, the method can be implemented using standard ultrasound imaging hardware, thereby facilitating seamless integration with existing diagnostic frameworks.

[0056] Specifically, the method is able to simultaneously generate the DCH signal, the fundamental signal, and the second harmonic signal using a standard pulse inversion (PI) transmit sequence. This means that all three signal types can be extracted from the same transmit-receive event without requiring any additional transmit cycles or hardware modifications. This capability represents a core innovation: it not only exploits the full spectrum of nonlinearly propagating signals, including signals that were previously discarded, but also maintains system efficiency and compatibility with existing ultrasound platforms.

[0057] The potential applications of this technology are numerous and include, but are not limited to: B-mode imaging for patients who are difficult to image due to depth or tissue composition; acupuncture imaging for enhanced visualization of medical procedures; transcranial imaging (TCI), where penetrating the skull with sufficient clarity has been problematic in the past; and reducing clutter levels beneath the fetal skull in obstetric imaging.

[0058] Depending on the implementation, enhanced B-mode imaging may include one or more of the following features:

[0059] DC component harmonic signal (DCH)

[0060] Since the late 1990s, tissue harmonic imaging (THI), particularly second harmonic imaging, has been widely used clinically due to its advantages such as reduced sidelobes. During the nonlinear propagation of acoustic waves, the generation of second harmonic signals is always accompanied by a very low-frequency signal centered around DC, which exhibits the same nonlinear characteristics as the second harmonic. Figure 2 A mathematical model indicating the source of the DC component signal is shown. In the following description, the DC component signal is used as a special harmonic signal, denoted as a DC harmonic (DCH) signal.

[0061] Historically, this DC harmonic (DCH) signal has been largely dismissed as “noise” and has not received the attention it deserves. However, with the advent of broadband transducers capable of covering the low-frequency range of DCH, and sophisticated signal processing techniques that can individually extract the signals in different spectral bands, DCH signals can now be “extracted” and used to improve image quality, particularly in terms of penetration depth, clutter reduction, and edge enhancement.

[0062] Band extraction

[0063] This section describes how to extract DCH, fundamental signal, and higher harmonic signals by leveraging existing pulse inversion (PI) technology without using new hardware. As used in this article, the term "DCH signal" refers to the very low frequency component centered at 0 Hz that appears during the nonlinear propagation of ultrasound through tissue. The DCH signal has nonlinear characteristics with even harmonic signals and has historically been regarded as noise. The term "fundamental signal" refers to the component in the received echo that corresponds to the original transmission frequency of the ultrasound (such as the PI sequence), also known as the fundamental frequency. The term "higher harmonic signal" refers to the nonlinear components of the echo signal that appear at integer multiples of the fundamental frequency, such as the second harmonic (2f), third harmonic (3f), and above.

[0064] PI technology is a widely used method in tissue harmonic imaging (THI), primarily because it enhances the suppression of unwanted fundamental frequency leakage in the harmonic signal. In THI, the goal is to create images using the harmonics generated by ultrasound as it passes through the body rather than the fundamental frequency (the original frequency of the ultrasound), because the harmonic signal provides clearer images with less noise.

[0065] PI technology works by sending a pair of ultrasound pulses into tissue: one pulse is the positive (original) version of the waveform, and the second pulse is its negative (inverted) counterpart.

[0066] Figure 3The mathematical model in indicates how different signals are derived by combining the received signals from the transmitted positive and negative pulses in the PI. According to the model, once the positive and negative pulses pass through the tissue, the signal from the positive pulse remains positive, while the signal from the negative pulse exhibits negative values ​​(the first term represents the fundamental frequency component) at odd positions and positive values ​​at even positions. As a result, by adding the received signals from the transmitted positive and negative pulses, the system effectively cancels out the fundamental frequency component (i.e., a i f(t)-a i f(t)), and isolates the DC harmonic (DCH) signal ( Figure 3 (not shown in the model) and even harmonics (e.g., the second harmonic signal a2[f(t)] 2 This summing process, traditionally used in imaging systems, is designed to isolate and subsequently eliminate the DCH, thereby focusing on extracting the second harmonic signal to improve image clarity and resolution.

[0067] In this paper, the novel system uses PI transmission to isolate the fundamental frequency component by subtracting the signals generated by positive and negative pulse transmission. Figure 3 As shown, this subtraction process generates odd harmonics, including the fundamental (1st harmonic) and 3rd harmonic signals. Therefore, by using the subtraction step as part of the standard PI transmission strategy, at least the DCH, the fundamental signal, and the second harmonic signal can be extracted simultaneously (assuming the transducer bandwidth does not accommodate the higher harmonics). In certain configurations where the transducer frequency range is wide enough, it is still feasible to capture the higher harmonic signals and incorporate them into the weighted composite process to further improve image quality. The simultaneous extraction of various signals from a single PI transmission cycle is an advantage of this system, enabling it to capture richer spectral content without increasing acquisition time or hardware complexity.

[0068] Figure 4 Figure 1 shows an example signal spectrum illustrating the transmission of a DCH component signal, a fundamental signal, and a second harmonic signal generated simultaneously with conventional PI. As shown, the DCH signal exhibits higher decibels (dB) at low frequencies, the fundamental signal exhibits higher dB at mid-frequency bands, and the second harmonic signal exhibits higher dB at high frequencies. Essentially, the DCH signal is stronger at lower frequencies, the fundamental signal is stronger at mid-frequency bands, and the second harmonic signal exhibits greater strength at higher frequencies.

[0069] Those skilled in the art will appreciate that a stronger signal can improve image clarity by providing clearer differentiation between tissues or between tissues and fluid-filled spaces. This is particularly important for detecting fine details and structures within the body. Furthermore, low-frequency signals, such as those from the DCH, can penetrate deeper into the body because they attenuate less than high-frequency signals. Therefore, a stronger signal (higher dB) at these lower frequencies may improve the visibility of deeper structures. Furthermore, preliminary clinical evaluations indicate that the DCH signal helps clear the "haze" clutter that often appears in the near field of an image better than fundamental or second harmonic signals, thereby revealing more structures previously hidden by the "haze." Furthermore, the DCH signal has stronger reflections at boundaries. Therefore, it has great potential for specialized applications such as visualizing acupuncture.

[0070] On the other hand, higher frequency signals, such as second harmonics, although they may not penetrate as deeply, can produce higher resolution images because they can distinguish smaller structures. Higher dB in these signals can further improve resolution, making images more detailed and easier to interpret.

[0071] Given that the unique properties of these signals make them more suitable for different applications in ultrasound imaging, the new system described in this paper further introduces a post-detection weighted composite method that allows users or researchers to assign different weights to these signals to generate optimized images based on specific needs.

[0072] Post-detection compounding with appropriate weighting settings (weighted compounding or nonlinear frequency compounding)

[0073] After extracting the direct current harmonics (DCH), fundamental signal, and second harmonic signal from the pulse inversion (PI) transmission, a weighted composite method can be used. This method involves assigning specific depth-dependent weights to the signals themselves or the images derived from them, effectively controlling their respective contributions to the final image synthesis. In this context, "weight" refers to the relative importance or influence assigned to each signal during the composite process. By adjusting these weights, the imaging system can emphasize or deemphasize certain aspects of the signal at different imaging depths based on specific diagnostic needs or imaging objectives.

[0074] For example, increasing the weight of the second harmonic signal, which is valued for higher resolution and clearer image quality, can improve the overall clarity and detail of the composite image. This is particularly useful for identifying fine structures or tiny pathological features.

[0075] If deeper tissue penetration is required, the system may assign a higher weight to the DCH signal, or fundamental signal, because its lower frequency allows it to better penetrate deeper into the body and capture features from deeper tissues. Because the weighting is depth-dependent, for shallower locations, the system can still give a greater weight to the second harmonic signal to maintain high resolution. This adjustment allows the composite image to achieve an optimized image throughout the entire image.

[0076] The fundamental signal, with its intermediate frequency, provides a balanced view, with good penetration and reasonable resolution. Adjusting its weight helps achieve an ideal balance between contrast and specificity in the image, making it easier to distinguish between various tissue types. Furthermore, because the fundamental signal occupies a separate spectral band and exhibits different characteristics from the harmonic signals, mixing it in can further reduce clutter levels.

[0077] By carefully choosing the weights assigned to each signal, the nonlinear compounding process also helps minimize artifacts and noise in the final image. For example, if certain signals are prone to artifacts under specific conditions, their weights can be reduced to reduce their impact on overall image quality.

[0078] Different diagnostic scenarios may require attention to different tissue features. For example, imaging vascular structures may benefit from different weighting strategies than solid organ imaging or tumor detection. Nonlinear weighted composite methods allow for this customization, allowing the imaging process to be tailored to the precise needs of each examination.

[0079] In addition to depth-based weighting, the system can also employ case-specific or application-specific weighting curves, enabling it to optimize image quality for specific clinical scenarios. For example, for applications requiring better deep tissue penetration or clutter reduction, such as fetal skull imaging or transcranial Doppler, a preset weighting curve can be used to emphasize the DCH signal. Conversely, scenarios such as visualizing acupuncture may benefit from a higher weighting of the high-frequency second harmonic signal to improve edge definition and resolution.

[0080] Figure 5 The example images generated based on DCH signal, second harmonic signal, fundamental signal and composite signal are shown. As shown in the figure, through the properly designed weighting setting, Figure 5 The composite image in the image is optimized for various parameters. These include penetration depth, spatial resolution, contrast resolution, and clutter reduction.

[0081] This process is also known as nonlinear frequency compounding because the weighted signals come from different frequency components—for example, the DCH signal occupies a low-frequency band centered at 0 Hz, the fundamental signal corresponds to the original transmitted frequency of the ultrasound pulse, and the second harmonic signal is located in a higher frequency band—each signal contributes different imaging properties to the final composite image.

[0082] refer to Figure 1 The device 100 shown is an embodiment of the above-mentioned ultrasound imaging system, which implements mixed signal extraction (e.g., extracting DCH, fundamental signal and second harmonic signal) and then generates a weighted composite image. It should be noted that Figure 1 The components shown in FIG. 1 are for example purposes only. The actual composition of device 100 may vary, including additional, fewer, or different components, depending on its implementation.

[0083] In some embodiments, the structure of the ultrasound device 100 includes an ultrasound probe 101, a transmission and reception controller 102, a data processor 105, a display device 106, and a memory 107. In a specific embodiment, the device 100 also includes a transmission and reception circuit 103 and a signal processing circuit 104. The transmission and reception controller 102 is connected to the ultrasound probe 101 through the transmission and reception circuit 103, and the ultrasound probe 101 is connected to the signal processing circuit 104 through the transmission and reception circuit 103. The memory 107 is connected to the data processor 105.

[0084] The ultrasonic probe 101 includes a plurality of transducers, also referred to as array elements, and the plurality of transducers are used to realize the mutual conversion between electrical pulse signals and ultrasonic waves, so as to transmit ultrasonic waves to the biological tissue to be detected (for example, biological tissue in the human body or animal body) 108 and receive ultrasonic echoes reflected by the biological tissue. The plurality of transducers can be arranged in rows to form a linear array, or arranged in a two-dimensional matrix to form a surface array, and the plurality of transducers can also form a convex array. The transducer can transmit ultrasonic waves excited by an electrical signal, or convert received ultrasonic echoes into electrical signals. Therefore, each transducer can be used to transmit ultrasonic waves to a region of interest of the biological tissue, and can also be used to receive ultrasonic echoes reflected from a region of interest of the biological tissue.

[0085] When performing ultrasonic testing, the transmit and receive sequences can control which transducers are used to transmit and which are used to receive ultrasound, or they can control the transducers to transmit ultrasound waves or receive ultrasound echoes in a time-slotted manner. All transducers participating in ultrasonic transmission can be excited by electrical signals simultaneously, thereby transmitting ultrasound waves simultaneously; or the transducers participating in ultrasonic transmission can be excited by several electrical signals with a certain time interval, thereby continuously transmitting ultrasound waves at a certain time interval.

[0086] The transmit and receive controller 102 is used to generate a transmit / receive sequence and output the transmit / receive sequence to the ultrasound probe. The transmit sequence is used to control some or all of the multiple array elements to transmit ultrasound waves to the region of interest of biological tissue. The transmit sequence also provides transmit parameters (e.g., the amplitude, frequency, number of transmissions, transmission angle, mode, and / or focal position of the ultrasound waves). Depending on the purpose, the transmit parameters can be adjusted to control the mode, transmission direction, and focal position of the ultrasound waves. The type of ultrasound waves can be pulsed ultrasound waves, planar ultrasound waves, etc. The receive sequence is used to control some or all of the multiple array elements to receive ultrasound echoes reflected from the region of interest of biological tissue.

[0087] The transmitting and receiving circuit 103 is connected between the ultrasonic probe and the transmitting and receiving controller 102 and the signal processing circuit 104, and is used to transmit the transmitting / receiving sequence controlled by the transmitting and receiving controller 102 to the ultrasonic probe 101, and transmit the ultrasonic echo signal received by the ultrasonic probe 101 to the signal processing circuit 103.

[0088] In some embodiments, Figures 3 to 5 The PI transmission described in is implemented by the transmission and reception controller 102 and executed by the transmission and reception circuit 103, wherein the positive signal transmission / reception sequence and the negative signal transmission / reception sequence are executed in sequence (for example, the positive signal sequence is executed first and then the negative signal sequence).

[0089] The signal processing circuit 104 is used to process the ultrasonic echo signals, for example, by filtering, amplifying, and beamforming the ultrasonic echo signals to obtain ultrasonic echo data. In a specific embodiment, the signal processing circuit 104 can be used to output the ultrasonic echo data to the data processor 105 and can also first store the ultrasonic echo data in the memory 107 so that the data processor 105 can read the ultrasonic echo data from the memory 107 when an operation based on the ultrasonic echo data is required. The memory 107 is used to store data and programs. Programs include system programs for the ultrasound device, various application programs, or algorithms for implementing various specific functions. The data processor 105 is used to obtain ultrasonic echo data after processing the ultrasonic echoes and generate an ultrasonic image based on the processed ultrasonic echo data.

[0090] In some embodiments, Figures 3 to 5 The mixed signal extraction process described in is implemented by the signal processing circuit 104, which performs even harmonic signal extraction (eg, extracting DCH and second harmonic signals) and odd harmonic signal extraction (eg, extracting the fundamental signal).

[0091] In some embodiments, Figures 4 and 5The weighted composite process described in can also be implemented in the signal processing circuit 104. For example, the weights assigned to different signals can be adjusted and sent to the signal processing circuit 104 to generate a weighted composite image based on the signals and the weights.

[0092] The display device 106 may also be used to display detection results, such as ultrasound images, calculation results, graphical charts, or text descriptions.

[0093] Figure 6 An example method of ultrasound imaging using nonlinear frequency compounding according to an example embodiment is shown. In some embodiments, Figure 6 One or more processing stages may be performed by a device.

[0094] like Figure 6 As shown, process 600 may include transmitting a pulse inversion (PI) sequence having positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe (step 602). For example, the device may transmit the PI sequence as described above. Figure 6 As shown, process 600 may include receiving an echo signal generated by a PI sequence (step 604). For example, the device may receive an echo signal generated by a PI sequence as described above. Figure 6 As shown, process 600 may include extracting a direct current harmonic (DCH) signal, a fundamental signal representing positive and negative ultrasound pulse frequencies, and a second harmonic signal from the received echo signal (step 606). For example, the device may perform the extraction as described above. Figure 6 As shown, process 600 may include assigning weights to the DCH signal, the fundamental signal, and the second harmonic signal to obtain a nonlinear frequency weighted signal (step 608). For example, the device may assign weights as described above. Finally, as Figure 6 As shown, process 600 may include generating a final image based on the nonlinear frequency weighted signal (step 610). For example, the apparatus may generate the final image based on the weighted signal as described above.

[0095] Process 600 may include additional embodiments, such as any single embodiment or any combination of embodiments described below and / or in connection with one or more other processes described elsewhere herein. In a first embodiment, the DCH signal corresponds to a low-frequency component centered at 0 Hz. In a second embodiment, alone or in combination with the first embodiment, a weight is assigned based on at least one of imaging depth or clinical application mode. In a third embodiment, alone or in combination with the first and second embodiments, a higher weight is assigned to the DCH signal to improve image penetration, reduce clutter levels, and enhance boundary visibility in the final image. In a fourth embodiment, alone or in combination with one or more of the first to third embodiments, a higher weight is assigned to the second harmonic signal to improve image clarity and resolution in the final image. In a fifth embodiment, alone or in combination with one or more of the first to fourth embodiments, a corresponding weight is assigned based on a predefined clinical imaging scenario, which can be selected from the group consisting of fetal skull imaging, transcranial imaging, visual acupuncture, and deep tissue imaging. In a sixth embodiment, employed alone or in combination with one or more of the first to fifth embodiments, extracting the DCH signal and the second harmonic signal may include summing the received echo signals, and extracting the fundamental signal may include subtracting the received echo signals. In a seventh embodiment, employed alone or in combination with one or more of the first to sixth embodiments, the DCH signal corresponds to a low-frequency component centered at 0 Hz. In an eighth embodiment, employed alone or in combination with one or more of the first to seventh embodiments, extracting the DCH signal and the second harmonic signal may include summing the received echo signals, and extracting the fundamental signal may include subtracting the received echo signals.

[0096] although Figure 6 Example steps of process 600 are shown, but in some implementations, process 600 may include Figure 6 6. In some embodiments, the process 600 may include additional steps, fewer steps, different steps, or a different arrangement of steps than those shown in FIG. Additionally or alternatively, two or more steps of process 600 may be performed in parallel.

[0097] Figure 7 1 shows an example computing device in which any of the embodiments described herein may be implemented. Computing device 700 may be used to implement Figures 1 to 6 The computing device 700 may include a bus 702 or other communication mechanism for communicating information, and one or more hardware processors 704 coupled to the bus 702 for processing information. The hardware processor 704 may be, for example, one or more general-purpose microprocessors.

[0098] The computing device 700 may also include a main memory 708, such as random access memory (RAM), a cache, and / or other dynamic storage device, coupled to the bus 702 for storing information and instructions to be executed by the processor 704. The main memory 708 may also be used to store temporary variables or other intermediate information during the execution of instructions by the processor 704. When stored in a storage medium accessible to the processor 704, such instructions can render the computing device 700 as a special-purpose machine customized to perform the operations specified in the instructions. The main memory 708 may include non-volatile and / or volatile media. Non-volatile media may include, for example, optical or magnetic disks. Volatile media may include dynamic memory. Common forms of media may include, for example, floppy disks, diskettes, hard disks, solid-state drives, magnetic tape or any other magnetic data storage medium, CD-ROMs, any other optical data storage medium, any physical medium with a pattern of holes, RAM, DRAM, PROM and EPROM, FLASH-EPROM, NVRAM, any other memory chip or cartridge, or a network thereof.

[0099] The computing device 700 may implement the techniques described herein using custom hardwired logic, one or more ASICs or FPGAs, firmware, and / or program logic, which, in combination with the computing device, may enable the computing device 700 to become a special-purpose machine or be programmed. According to one embodiment, the techniques herein are performed by the computing device 700 in response to the processor 704 executing one or more sequences of one or more instructions contained in the main memory 708. Such instructions may be read into the main memory 708 from another storage medium, such as the storage device 709. Execution of the sequences of instructions contained in the main memory 708 may cause the processor 704 to perform the processing steps described herein. For example, the processes / methods disclosed herein may be implemented using computer program instructions stored in the main memory 708. When these instructions are executed by the processor 704, they may perform the steps shown in the corresponding figures and described above. In alternative embodiments, hardwired circuitry may be used in place of or in combination with software instructions.

[0100] The computing device 700 also includes a communication interface 710 coupled to the bus 702. The communication interface 710 can provide a bidirectional data communication coupling with one or more network links connected to one or more networks. As another example, the communication interface 710 can be a local area network (LAN) card to provide a data communication connection to a compatible LAN (or a WAN component that communicates with a WAN). Wireless links can also be employed.

[0101] The performance of certain operations may be distributed among processors, not only residing within a single machine, but also deployed on multiple machines. In some example embodiments, the processor or processor-implemented engine may be located in a single geographic location (e.g., in a home environment, an office environment, or a server farm). In other example embodiments, the processor or processor-implemented engine may be distributed across multiple geographic locations.

[0102] In the aforementioned embodiments, a novel system and method are described that utilizes a regular pulse inversion transmission technique to simultaneously generate not only a DC signal and a second harmonic signal, but also a fundamental signal (and possibly other odd harmonic signals). By extracting these signals, the method is able to generate an ultrasound image based on these signals, or to generate three or more different ultrasound images based on each signal type. In addition, the proposed method and system can also employ selective compounding of images derived from the DC component, the second harmonic, and the fundamental signal. This selective compounding provides flexibility to optimize image quality at different tissue depths (between different patient groups, different body parts of a patient, and different locations on a body part), thereby overcoming traditional limitations associated with signal extraction and image clarity.

[0103] Furthermore, a feature of the method and system is its ability to maintain a frame rate comparable to that achieved in conventional harmonic imaging using regular pulse inversion (PI). This ensures that enhanced image quality and depth penetration are achieved without sacrificing the speed and efficiency of the imaging process, marking a significant advancement in B-mode imaging technology.

[0104] Each process, method, and algorithm described in the preceding sections may be embodied in a code module executed by one or more computer systems or computer processors comprising computer hardware, and fully or partially automated by them. These processes and algorithms may be implemented in part or in whole in dedicated circuits.

[0105] When the functions disclosed herein are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium executable by a processor. The specific technical solutions (in whole or in part) disclosed herein or aspects that contribute to current technology can be embodied in the form of a software product. The software product can be stored in a storage medium that includes multiple instructions for causing a computing device (which can be a personal computer, server, network device, etc.) to execute all or some steps of the method of an embodiment of the application. The storage medium can include a flash drive, a portable hard drive, a ROM, a RAM, a magnetic disk, an optical disk, another medium operable to store program code, or any combination thereof.

[0106] Certain embodiments further provide a system including a processor and a non-transitory computer-readable storage medium storing instructions executable by the processor, so that the system performs operations corresponding to the steps in any of the methods of the above embodiments. Certain embodiments further provide a non-transitory computer-readable storage medium configured with instructions executable by one or more processors, so that the one or more processors perform operations corresponding to the steps in any of the methods of the above embodiments.

[0107] The embodiments disclosed herein may be implemented through a cloud platform, server, or server group (hereinafter collectively referred to as the "service system") that interacts with a client. A client may be a terminal device or a client registered by a user on the platform. The terminal device may be a mobile terminal, a personal computer (PC), or any device that can be installed with a platform application.

[0108] The various features and processes described above can be used independently of each other or combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of the present invention. In addition, certain method or process steps may be omitted in certain implementations. The methods and processes described herein are not limited to any particular order, and the steps or states associated therewith may be performed in other appropriate orders. For example, the steps or states described may be performed in an order different from that specifically disclosed, or multiple steps or states may be combined in a single step or state. The example steps or states may be performed serially, in parallel, or in some other manner. Steps or states may be added to or deleted from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, their constituent elements may be added, deleted, or rearranged compared to the disclosed example embodiments.

[0109] The various operations of the exemplary methods described herein may be performed, at least in part, by an algorithm. The algorithm may be implemented in program code or instructions stored in a memory (e.g., the aforementioned non-transitory computer-readable storage medium). Such an algorithm may include a machine learning algorithm. In some embodiments, the machine learning algorithm may not explicitly program a computer to perform a function, but may learn from training data to build a predictive model that performs the function.

[0110] The various operations of the exemplary methods described herein may be performed, at least in part, by one or more processors that are temporarily configured (e.g., by software) or permanently configured to perform the relevant operations. Whether temporarily configured or permanently configured, these processors may constitute a processor-implemented engine for performing one or more operations or functions described herein.

[0111] Similarly, the methods described herein can be implemented at least in part by a processor, with the specific one or more processors being examples of hardware. For example, at least some of the operations of a method can be performed by one or more processors or processor-implemented engines. In addition, one or more processors can also support the performance of related operations in a "cloud computing" environment or as "software as a service" (SaaS). For example, at least some operations can be performed by a group of computers (as an example of a machine including a processor), which can be accessed via a network (e.g., the Internet) and via one or more appropriate interfaces (e.g., application program interfaces (APIs)).

[0112] The performance of certain operations may be distributed among processors, not only residing within a single machine, but also deployed on multiple machines. In some example embodiments, the processor or processor-implemented engine may be located in a single geographic location (e.g., in a home environment, an office environment, or a server farm). In other example embodiments, the processor or processor-implemented engine may be distributed across multiple geographic locations.

[0113] In this specification, multiple instances can implement the components, operations or structures described as single instances. Although the individual operations of one or more methods are shown and described as separate operations, one or more separate operations can be performed simultaneously, and it is not required to perform these operations in the order shown. The structure and function presented as separate components in the example configuration can be implemented as a combined structure or component. Similarly, the structure and function presented as a single component can be implemented as a separate component. These and other variations, modifications, additions and improvements belong to the scope of this paper theme.

[0114] Although the overview of the invention has been described with reference to specific example embodiments, various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments of the invention. The term "invention" may be used herein to refer to these embodiments of the subject matter, either individually or generally, for convenience only and without any intention to voluntarily limit the scope of this application to any single aspect or concept, if multiple aspects are in fact disclosed.

[0115] The embodiments shown herein are described in sufficient detail to enable those skilled in the art to practice the disclosed teachings. Other embodiments may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of the present invention. Therefore, the detailed description should not be taken in a limiting sense, and the scope of the various embodiments is defined solely by the appended claims and all equivalents to which such claims are entitled.

[0116] Any process description, element or step in the flowcharts described herein and / or shown in the accompanying drawings should be understood to potentially represent a module, segment or portion of code, which includes one or more executable instructions for implementing a specific logical function or step in the process. Those skilled in the art will understand that alternatives are included within the scope of the embodiments described herein, in which elements or functions may be deleted, executed in the order shown or discussed, including substantially simultaneously or in reverse order, depending on the functionality involved.

[0117] Unless expressly stated otherwise or the context indicates otherwise, “or” as used herein is inclusive, not exclusive. Thus, unless expressly stated otherwise or the context indicates otherwise, herein, “A, B, or C” means “A, B, A and B, A and C, B and C, or A, B, and C”. Furthermore, unless expressly stated otherwise or the context indicates otherwise, “and” is both collectively and individually. Thus, unless expressly stated otherwise or the context indicates otherwise, herein, “A and B” means “A and B, collectively or individually”. Furthermore, multiple instances may be provided for a resource, operation, or structure described herein as a single instance. Furthermore, the boundaries between various resources, operations, engines, and data stores are somewhat arbitrary, and particular operations are described in the context of particular illustrative configurations. Other allocations of functionality are contemplated and may fall within the scope of various embodiments of the invention. In general, structures and functionality presented as separate resources in the example configurations may be implemented as combined structures or resources. Similarly, structures and functionality presented as single resources may be implemented as separate resources. These and other changes, modifications, additions and improvements fall within the scope of the embodiments of the present invention as expressed by the appended claims.Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0118] The words "include" or "comprising" are used to indicate the presence of subsequently stated features, but do not preclude the addition of other features. Unless specifically stated otherwise, or understood otherwise in the context of use, conditional language, such as "can," "have," or "may," is generally intended to convey that some embodiments include, while other embodiments do not, certain features, elements, and / or steps. Thus, such conditional language generally does not imply that one or more embodiments require features, elements, and / or steps in any way, or that one or more embodiments must include logic for deciding, with or without user input or prompting, whether to include or perform such features, elements, or steps in any particular embodiment.

Claims

1. An ultrasonic imaging system, characterized in that: include: a controller for transmitting a pulse inversion (PI) sequence including positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe; Signal processing circuitry for: receiving the echo signal generated by the PI sequence; Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the echo signal; Assigning weights to the DCH signal, the fundamental signal, and the second harmonic signal to obtain a weighted signal of a nonlinear frequency; A final image is generated based on the nonlinear frequency weighted signals.

2. The ultrasonic imaging system according to claim 1, wherein: The DCH signal corresponds to a low-frequency component centered at 0 Hz.

3. The ultrasonic imaging system according to claim 1, wherein: Weights are assigned to the DCH signal, the fundamental signal, and the second harmonic signal based on at least one of imaging depth or clinical application mode.

4. The ultrasonic imaging system according to claim 1, wherein: The DCH signal is given a higher weight to improve image penetration, reduce clutter levels, and enhance edge visibility in the final image.

5. The ultrasonic imaging system according to claim 1, wherein: The second harmonic signal is given a higher weight to improve the image clarity and resolution of the final image.

6. The ultrasonic imaging system according to claim 1, wherein: Weights are assigned to the DCH signal, the fundamental signal, and the second harmonic signal based on a predefined clinical imaging scenario, wherein the predefined clinical imaging scenario is selected from the group consisting of fetal skull imaging, transcranial imaging, visual acupuncture, and deep tissue imaging.

7. The ultrasonic imaging system according to claim 1, wherein: The signal processing circuit is configured to extract the DCH signal and the second harmonic signal by summing the received echo signals, and extract the fundamental signal by subtracting the received echo signals.

8. The ultrasonic imaging system according to claim 7, wherein: The received echo signals include a first echo signal of the positive ultrasonic pulse and a second echo signal of the negative ultrasonic pulse.

9. The ultrasonic imaging system according to claim 1, wherein: The DCH signal, the fundamental signal, and the second harmonic signal are derived from a nonlinear frequency band in the echo signal.

10. An ultrasonic imaging system, characterized in that: include: a controller for transmitting a pulse inversion (PI) sequence including positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe; Signal processing circuitry for: receiving the echo signal generated by the PI sequence; Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the echo signal; generating an image based on the DCH signal, the fundamental signal, and the second harmonic signal respectively; Assign weights to these images to obtain weighted images; A final image is generated based on the weighted images.

11. An ultrasonic imaging method, characterized in that: include: sending a pulse inversion (PI) sequence comprising positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe; receiving the echo signal generated by the PI sequence; Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the received echo signal; assigning weights to the DCH signal, the fundamental signal, and the second harmonic signal to obtain a weighted signal of a nonlinear frequency; A final image is generated based on the nonlinear frequency weighted signals.

12. The method according to claim 11, characterized in that The DCH signal corresponds to a low-frequency component centered at 0 Hz.

13. The method according to claim 11, characterized in that The weights are assigned based on at least one of imaging depth or clinical application mode.

14. The method according to claim 11, characterized in that The DCH signal is given a higher weight to improve image penetration, reduce clutter levels, and enhance edge visibility in the final image.

15. The method according to claim 11, characterized in that The second harmonic signal is given a higher weight to improve the image clarity and resolution of the final image.

16. The method according to claim 11, characterized in that The weighting of the DCH signal, the fundamental signal and the second harmonic signal is performed based on a predefined clinical imaging scenario, wherein the predefined clinical imaging scenario is selected from a set including fetal skull imaging, transcranial imaging, visual acupuncture and deep tissue imaging.

17. The method according to claim 11, characterized in that Extracting the DCH signal and the second harmonic signal includes summing the received echo signals, and extracting the fundamental signal includes subtracting the received echo signals.

18. An ultrasonic imaging method, characterized in that: include: sending a pulse inversion (PI) sequence comprising positive ultrasound pulses and negative ultrasound pulses into biological tissue via an ultrasound probe; receiving the echo signal generated by the PI sequence; Extracting a direct current harmonic DCH signal, a fundamental wave signal representing the frequency of a positive ultrasonic pulse and a negative ultrasonic pulse, and a second harmonic signal from the received echo signal; generating an image based on the DCH signal, the fundamental signal, and the second harmonic signal respectively; Assign weights to these images to obtain weighted images; A final image is generated based on the weighted images.

19. A non-transitory computer-readable medium storing instructions, characterized in that When the instructions are executed by one or more processors, the one or more processors are caused to perform the method according to any one of claims 11 to 18.

Images