Method and system for speckle reduction

Abstract

Systems and methods for reducing speckle while maintaining frame rate are disclosed. Multiple sub-images associated with different receive angles are acquired at an observation angle for a single transmit / receive event. The sub-images are composited to generate a final image with reduced speckle. In some examples, multiple sub-images from multiple transmit / receive events are composited to generate the final image. In some examples, the observation angle and / or the receive angle can vary between transmit / receive events.

Description

TECHNICAL FIELD

[0001] This application relates to speckle reduction. More specifically, this application relates to speckle reduction in ultrasound without reducing frame rate. BACKGROUND

[0002] During an ultrasound examination, when scanning soft tissue, speckle is often observed even in areas that appear homogeneous to the naked eye due to the random distribution of sub-resolution scatterers. Speckle is often treated as noise, and techniques have been developed to reduce speckle variance, such as spatial compounding and frequency compounding. In addition to speckle reduction, spatial compounding often also provides better border delineation. However, spatial compounding often requires multiple transmit / receive events to acquire a frame. This reduces the frame rate of the ultrasound scan, which can not be desirable when observing tissue in motion, such as due to hand motion or heart beat. SUMMARY

[0003] Methods and systems for reducing speckle without reducing frame rate are described. A transducer array can transmit ultrasound beams at observation angles for a transmit / receive event, and receive echo signals resulting from the transmit / receive event. A beamformer can receive signals from the transducer elements via channels. The beamformer can selectively delay and sum appropriate signals from the channels to simultaneously generate sub-images from different receive angles. The sub-images can be combined to form an image with reduced speckle.

[0004] According to at least one example described herein, a medical imaging system can include a transducer array, wherein, wherein the transducer array is configured to transmit ultrasound beams, receive echoes in response to the ultrasound beams, and generate electrical signals corresponding to the echoes; a controller circuit, wherein the controller circuit is configured to cause the transducer array to transmit the ultrasound beams at observation angles for a transmit / receive event; and a beamformer, wherein the beamformer is configured to receive the electrical signals from the transmit / receive event, and generate a first plurality of beamformed signals, wherein each beamformed signal of the first plurality of beamformed signals is associated with a corresponding one of a first plurality of receive angles, wherein the medical imaging system is configured to compound the first plurality of beamformed signals to generate a final image.

[0005] According to at least one example described herein, a method can include transmitting a first ultrasound beam at a first observation angle during a first transmit / receive event; receiving a first plurality of echoes generated in response to the first transmit / receive event; converting the first plurality of echoes to a corresponding first plurality of electrical signals; generating a first plurality of beamformed signals from the first plurality of electrical signals, wherein individual ones of the first plurality of beamformed signals are associated with corresponding ones of a first plurality of receive angles; compounding the first plurality of beamformed signals to generate a first combined signal; and generating a final image from the first combined signal. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is an illustration of an example of spatial compounding.

[0007] Figure 2 is a block diagram of an ultrasound imaging system arranged in accordance with some embodiments of the present disclosure.

[0008] Figure 3 is a block diagram illustrating an example processor in accordance with some embodiments of the present disclosure.

[0009] Figure 4 is an illustration of an example of spatial compounding in accordance with some embodiments of the present disclosure.

[0010] Figure 5A and Figure 5B is an illustration of translating the active aperture of a transducer array with depth in accordance with some embodiments of the present disclosure.

[0011] Figure 6 is a flowchart of a method in accordance with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0012] The following description of certain examples is merely exemplary in nature and is in no way intended to limit the application or its applications or uses. In the following detailed description of embodiments of the present system and method, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the described system and method can be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the presently disclosed system and method, and it is to be understood that other embodiments can be utilized and that structural and logical changes can be made without departing from the spirit and scope of the present system. Furthermore, to the extent that certain features of the present system are described as being implemented in specific combinations and / or sequences, other combinations and / or sequences can likewise be implemented that are not specifically described below, but that still fall within the spirit and scope of the present system. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present system is defined only by the appended claims.

[0013] Figure 1 is an illustration of an example of spatial compounding. The ultrasound probe 100 is at different points in time (i.e., transmit / receive events 114A-N). The ultrasound probe 100 can include a transducer array 102 that includes a plurality of transducer elements 104. The transducer elements 104 can transmit ultrasound beams 108A-N steered along an observation angle and receive a corresponding echo for each transmit / receive event 114A-N along a receive angle 110A-N. The observation angle 110A-N and the receive angle 110A-N are shown with respect to a plane 105. The plane 105 is normal to a plane 103; the plane 103 is parallel to a face of the transducer array 102. The observation angle can sometimes be referred to as a transmit steering angle or a transmit angle. The received echoes can be used to generate a sub-image 112A-N for each transmit / receive event 114A-N. To perform spatial compounding, a single ultrasound probe 100 can perform a plurality of transmit / receive events 114A-N (each transmit / receive event 114A-N at a different observation angle 108A-N) and acquire a corresponding echo along a different receive angle 110A-N. Spatial compounding sums N T non-coherent the number of sub-images 112A-N (e.g., three, five, six, nine) to form a final image (not shown) with reduced speckle, where N T equals the number of transmit / receive events. In other words, the number of sub-images combined to form the final image equals the number of transmit / receive events. Spatial compounding can also include averaging the summed images to arrive at the final image. As Figure 1 shown, in each sub-image 112A-N, the steering angle 110 at reception is linked to the steering angle 108 at transmission. By acquiring images of the same region in N T directions and then averaging them, the effective frame rate is reduced by a factor of N T at the cost of reducing the speckle variance in the final compounded image. In certain applications (e.g., applications where motion is present), this frame rate reduction can not be desirable.

[0014] Example systems and methods that can reduce speckle without reducing frame rate are disclosed herein. As described herein, in some examples, a medical imaging system can include a transducer array configured to transmit an ultrasound beam and receive echoes in response to the ultrasound beam and generate electrical signals corresponding to the echoes, a controller circuit configured to cause the transducer array to transmit the ultrasound beam at an observation angle, a beamformer configured to receive the electrical signals and generate a plurality of beamformed signals, each of the plurality of beamformed signals being associated with a corresponding plurality of receive angles, and a signal processor configured to complex the plurality of beamformed signals to generate a final image. This is in contrast to the systems and methods shown in Figure 1 which generate beamformed signals associated with only a single receive angle. Figure 1

[0015] As described further herein, in some examples, a medical imaging system can include a transducer array configured to transmit an ultrasound beam and receive echoes in response to the ultrasound beam and generate electrical signals corresponding to the echoes, a controller circuit configured to cause the transducer array to transmit the ultrasound beam at a first observation angle, and a beamformer configured to receive the electrical signals associated with the first observation angle and generate a plurality of beamformed signals, the plurality of beamformed signals being associated with a corresponding plurality of receive angles, wherein the beamformer is further configured to combine the plurality of beamformed signals into a combined signal.

[0016] The medical imaging systems described herein can allow for speckle reduction without reducing the frame rate of the medical imaging system.

[0017] Figure 2 ​A block diagram of an ultrasound imaging system 200 constructed according to the principles of the present disclosure is shown. The ultrasound imaging system 200 according to the present disclosure can include a transducer array 214, which can be included in an ultrasound probe 212 (e.g., an external probe or an internal probe (e.g., an intravascular ultrasound (IVUS) catheter probe)). In other embodiments, the transducer array 214 can be in the form of a flexible array configured to be conformally applied to the surface of a subject (e.g., a human patient or an animal) to be imaged. The transducer array 214 is configured to transmit ultrasound signals (e.g., beams, waves) and receive echoes in response to the ultrasound signals. The transducer elements of the transducer array 214 can convert the echoes from a transmit / receive event into corresponding electrical signals. Various transducer arrays can be used, such as a linear array, a curved array, or a phased array. For example, the transducer array 214 can include a two-dimensional array of transducer elements (as shown), which is capable of scanning in both the elevation dimension and the azimuth dimension for 2D imaging and / or 3D imaging. It is generally known that the axial direction is the direction normal to the array face (in the case of a curved array, the axial direction is the fan-out direction), the azimuth direction is generally defined by the longitudinal dimension of the array, and the elevation direction is transverse to the azimuth direction.

[0018] In some embodiments, the array 214 can be coupled to a transmit / receive (T / R) switch 218, which switches between transmission and reception and protects a main beamformer 222 from high-energy transmit signals. In some embodiments, such as in a portable ultrasound system, the T / R switch 218 and other elements in the system can be included in the ultrasound probe 212, rather than in an ultrasound system base, which can house image processing electronics. The ultrasound system base typically includes software components and hardware components, including circuitry for signal processing and image data generation, and executable instructions for providing a user interface. In some examples, the ultrasound probe 212 can be coupled to the ultrasound system base via a probe cable. In other examples, the ultrasound probe 212 can be wirelessly coupled to the ultrasound system base.

[0019] The process of transmitting ultrasound signals from the transducer array 214 (e.g., a transmit / receive event) is directed by a transmit controller 220, which can be coupled to the T / R switch 218 and a main beamformer 222. In some embodiments, the transmit controller 220 can control the process of transmitting signals by the transducer elements in the array 214. The transmit controller 220 can control the direction in which the beam is steered (e.g., the angle of view). The beam can be steered straight ahead from the front of the transducer array 214 (normal to the transducer array 214), or at different angles to obtain a wider field of view. The transmit controller 220 can also be coupled to a user interface 224 and receive input from user operation of user controls. In some embodiments, the transmit controller 220 can include controller circuitry (e.g., an application specific integrated circuit).

[0020] The user interface 224 can include one or more input devices (e.g., a control panel 252), which can include one or more mechanical controls (e.g., buttons, encoders, etc.), touch sensitive controls (e.g., a trackpad, a touchscreen, etc.), and / or other known input devices. The user interface 224 can also include the display 238.

[0021] In some embodiments, via the switch 218, electrical signals generated by the transducer elements of the array 214 can be provided to the main beamformer 222 via the channels 216, where the electrical signals from the individual channels can be combined into a beamformed signal. The beamformer 222 can apply delays to the electrical signals provided on the channels 216 and sum the delayed electrical signals to form the beamformed signal. As described in more detail below, the beamformed signal can be used to generate an image, e.g., a B-mode image. The beamformer 222 can be a multi-line beamformer. However, the multi-line is not used to increase the line density of the plane or volume being scanned, but can be used to simultaneously acquire multiple sub-images. Examples of multi-line beamformers can be found in U.S. Patent No. 6,695,783 and U.S. Patent No. 8,137,272, which are incorporated by reference herein, however, other multi-line beamformers can also be used.

[0022] According to some of the principles of the present disclosure, the beamformer 222 can apply appropriate delays and / or weights to the electrical signals of the channels 216 and / or subsets of the electrical signals and sum the delayed electrical signals to generate beamformed signals, in turn, for generating sub-images associated with reception angles. By using a multi-line beamforming function, the beamformer 222 can apply appropriate delays and weights to the electrical signals of the channels 216 from a single transmit / receive event to generate a plurality of beamformed signals for a corresponding sub-image, where each individual sub-image is associated with a different reception angle. In some applications, the number of beamformed signals can be limited to the number of multi-lines of the beamformer 222.

[0023] In some embodiments, a micro-beamformer (not shown) can be included in the probe 212, which can receive the electrical signals from the transducer elements and combine the signals from groups (tiles) of transducer elements and provide partially beamformed signals to the beamformer 222. Including a micro-beamformer can reduce the number of required channels to be provided between the ultrasound probe 212 and the beamformer 222.

[0024] In embodiments with and without a micro-beamformer, the beamformed signals of the beamformer 222 are coupled to the processing circuitry 250, which can include one or more processors (e.g., signal processor 226, B-mode processor 228, Doppler processor 260, and one or more image generation and processing components 268) configured to produce ultrasound images from the beamformed signals (i.e., beamformed RF data).

[0025] The processing components 268 can include a scan converter 230, a local memory 242, a graphics processor 240, an image processor 236, a volume renderer 234, and a multiplanar reformatter 232.

[0026] The signal processor 226 can be configured to process the received beamformed RF data in various ways, such as bandpass filtering, decimation, I and Q component separation, and harmonic signal separation. The signal processor 226 can also perform additional signal enhancements, such as speckle suppression, signal compounding, and noise elimination. The processed signals, also referred to as I and Q components or IQ signals, can be coupled to additional downstream signal processing circuitry for image generation. The IQ signals can be coupled to multiple signal paths within the system, each of which can be associated with a particular arrangement of signal processing components suitable for generating different types of image data (e.g., B-mode image data, Doppler image data). For example, the system 200 can include a B-mode signal path 258 that couples signals from the signal processor 226 to a B-mode processor 228 for producing B-mode image data.

[0027] The B-mode processor can employ amplitude detection for imaging structures in the body. Signals produced by the B-mode processor 228 can be coupled to a scan converter 230, a multiplanar reformatter 232, and / or a compounding processor 244. The scan converter 230 can be configured to arrange the echo signals into a desired image format according to the spatial relationships at which the echo signals were received. For example, the scan converter 230 can arrange the echo signals into a two-dimensional (2D) sector format or a three-dimensional (3D) format in the shape of a pyramid or other shape. The multiplanar reformatter 232 can convert echoes received from points in a common plane in a volumetric region of the body into an ultrasound image (e.g., a B-mode image) of that plane, for example, as described in U.S. Patent 6,443,896 (Detmer), incorporated herein by reference. In some embodiments, the scan converter 230 and the multiplanar reformatter 232 can be implemented as one or more processors.

[0028] In some embodiments, the compounding processor 244 can compound signals associated with different sub-images to generate a final image and / or a combined signal that can be used to generate a final image. In some examples, compounding the signals can include summing the signals processed by the B-mode processor 228 and then averaging the summed signals. In some examples, the sum can be used to generate the final image. Other compounding techniques can also be used, such as taking the maximum value from the sub-images for each pixel. The compounding can be performed on envelope data or log-compressed envelope data. The combined signal or the final image can be provided to the B-mode processor 228, the scan converter 230, and / or the multiplanar reformatter 232.

[0029] The volume renderer 234 can generate an image of the 3D data set as viewed from a given reference point (also referred to as a projection, a rendered map, a rendering), e.g., as described in U.S. Patent No. 6,530,885 (Entrekin et al.), which is incorporated herein by reference. In some embodiments, the volume renderer 234 can be implemented as one or more processors. The volume renderer 234 can generate a rendered map (e.g., a positive rendered map or a negative rendered map) by any known technique or future known technique (e.g., surface rendering and maximum intensity rendering).

[0030] In some embodiments, the system can include a Doppler signal path 262 that couples the output from the signal processor 226 to a Doppler processor 260. The Doppler processor 260 can be configured to estimate Doppler shifts and generate Doppler image data. The Doppler image data can include color data that is then overlaid with B-mode (i.e., grayscale) images for display. The Doppler processor 260 can be configured to filter out unwanted signals (i.e., noise or clutter associated with non-moving tissue), e.g., using a wall filter. The Doppler processor 260 can also be configured to estimate velocity and power according to known techniques. For example, the Doppler processor can include a Doppler estimator (e.g., a self-correlator), where velocity (Doppler frequency) estimates are based on the argument of the lag-one autocorrelation function and Doppler power estimates are based on the magnitude of the lag-zero autocorrelation function. Motion can also be estimated by known phase domain (e.g., parametric frequency estimators such as MUSIC, ESPRIT, etc.) or time domain (e.g., cross-correlation) signal processing techniques. Other estimators related to the temporal or spatial distribution of velocity (e.g., estimators of acceleration or temporal and / or spatial velocity derivatives) can be used in place of or in addition to velocity estimators. In some examples, the velocity and power estimates can be subjected to further thresholding to further reduce noise, and to segmentation and post-processing (e.g., padding and smoothing). The velocity and power estimates can then be mapped to a desired display color range according to a color map. The color data (also referred to as Doppler image data) can then be coupled to the scan converter 330, where it can be converted to a desired image format and overlaid on the B-mode image of the tissue structure to form a color Doppler or power Doppler image.

[0031] Output from the scan converter 230, the multiplanar reformatter 232, and / or the volume renderer 234 (e.g., B-mode images, Doppler images) can be coupled to an image processor 236 for further enhancement, buffering, and temporary storage prior to being displayed on an image display 238. A graphics processor 240 can generate graphical overlays for display with the images. These graphical overlays can include, for example, standard identifying information (e.g., patient name), date and time of the images, imaging parameters, and the like. The graphics processor can be configured to receive input from the user interface 224 (e.g., typed patient name or other annotations) for these purposes. The user interface 224 can also be coupled to the multiplanar reformatter 232 for selecting and controlling the display of multiplanar reformatted (MPR) images.

[0032] The system 200 can include a local storage 242. The local storage 242 can be implemented as any suitable non-transitory computer readable medium (e.g., a flash drive, a disk drive). The local storage 242 can store data generated by the system 200 (including B-mode images), executable instructions, input provided by a user via the user interface 224, or any other information required for operation of the system 200.

[0033] As previously mentioned, the system 200 includes a user interface 224. The user interface 224 can include a display 238 and a control panel 252. The display 238 can include a display device implemented using various known display technologies (e.g., LCD, LED, OLED, or plasma display technologies). In some embodiments, the display 238 can include multiple displays and / or a touch-sensitive display. The control panel 252 can be configured to receive user input. Examples of user input can include a number of emission / reception events, an observation angle for each emission / reception event, a number of sub-images to be acquired from each emission / reception event, and / or a reception angle for the sub-images. The control panel 252 can include one or more hard controls (e.g., buttons, knobs, dials, encoders, mice, trackballs, etc.). In some embodiments, the control panel 252 can additionally or alternatively include soft controls (e.g., GUI control elements or simply GUI controls) provided on a touch-sensitive display. In some embodiments, the display 238 can be a touch-sensitive display that includes one or more soft controls of the control panel 252.

[0034] In some embodiments, Figure 2 The various components shown in FIG. 1 can be combined. For example, the image processor 236 and the graphics processor 240 can be implemented as a single processor. In another example, the B-mode processor 228 and the complex processor 244 can be implemented as a single processor. In some embodiments,Figure 2 The various components shown can be implemented as separate components. For example, the signal processor 226 can be implemented as a separate signal processor for each imaging mode (e.g., B-mode, Doppler). In some embodiments, Figure 2 One or more of the various processors shown can be implemented by a general purpose processor and / or a microprocessor configured to perform specific tasks. In some embodiments, one or more of the various processors can be implemented as an application specific integrated circuit. In some embodiments, one or more of the various processors (e.g., the image processor 236) can be implemented with one or more graphics processing units (GPUs).

[0035] Figure 3 is a block diagram illustrating an example processor 300 according to the principles of the present disclosure. The processor 300 can be used to implement one or more processors described herein, for example, Figure 2 The image processor 236 shown or any controller described herein. The processor 300 can be any suitable processor type, including but not limited to a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable array (FPGA) (where the FPGA has been programmed to form a processor), a graphics processing unit (GPU), an application specific integrated circuit (ASIC) (where the ASIC has been designed to form a processor), or a combination thereof.

[0036] The processor 300 can include one or more cores 302. The core 302 can include one or more arithmetic logic units (ALUs) 304. In some embodiments, the core 302 can include a floating point logic unit (FPLU) 306 and / or a digital signal processing unit (DSPU) 308 in addition to or instead of the ALU 304.

[0037] The processor 300 can include one or more registers 312 communicatively coupled to the core 302. The registers 312 can be implemented using dedicated logic gate circuitry (e.g., a bistable flip-flop) and / or any memory technology. In some embodiments, the registers 312 can be implemented using static memory. The registers can provide data, instructions, and addresses to the core 302.

[0038] In some embodiments, the processor 300 can include one or more levels of cache memory 310 communicatively coupled to the core 302. The cache memory 310 can provide computer-readable instructions for execution by the core 302. The cache memory 310 can provide data for processing by the core 302. In some embodiments, the computer-readable instructions can have been provided to the cache memory 310 through a local memory (e.g., a local memory attached to the external bus 316). The cache memory 310 can be implemented with any suitable cache memory type, such as a metal-oxide semiconductor (MOS) memory, for example, a static random access memory (SRAM), a dynamic random access memory (DRAM), and / or any other suitable memory technology.

[0039] The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology. Figure 2 The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology. Figure 2 The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology. The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology.

[0040] The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology. The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology.

[0041] The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology. The processor 300 can include a controller 314 that can provide input to the processor 300 from other processors and / or components included in the system (e.g., the control panel 252 and scan converter 230) and / or output from the controller 300 to other processors and / or components included in the system (e.g., the display 238 and volume renderer 234) shown. The controller 314 can control the data paths in the ALU 304, FPLU 306, and / or DSPU 308. The controller 314 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of the controller 314 can be implemented as standalone gates, FPGAs, ASICs, or any other suitable technology.

[0042] Bus 316 may be coupled to one or more external memories. The external memory may include read-only memory (ROM) 332. ROM 332 may be a mask ROM, electronically programmable read-only memory (EPROM), or any other suitable technology. The external memory may include random access memory (RAM) 333. RAM 333 may be static RAM, battery-backed static RAM, dynamic RAM (DRAM), or any other suitable technology. The external memory may include electrically erasable programmable read-only memory (EEPROM) 335. The external memory may include flash memory 334. The external memory may include a magnetic storage device such as a disk 336. In some embodiments, the external memory may be included in the system (e.g., Figure 2 In the ultrasound imaging system 200 shown, for example, local memory 242.

[0043] Figure 4 This is an illustration of an example of spatial composition according to the present disclosure. An ultrasonic probe 400 may include a transducer array 402, which includes a plurality of transducer elements 404. In some examples, the ultrasonic probe 400 may be composed of… Figure 2 This is implemented using transducer probe 212. Transducer element 404 can emit an ultrasonic beam directed along the observation angle 408 and receive corresponding echoes along the reception angles 410A-N. Similar to... Figure 1 The observation angles 408A-N and the receiving angles 410A-M are shown relative to plane 405. Plane 405 is normal to plane 403. Plane 403 is parallel to the surface of transducer array 402. The number of observation angles can be referred to as N. T And the number of receiving angles can be called N. R The same ultrasound probe can be used iteratively up to N times (400 iterations). T Each iteration can use a different transmission angle 408A-N. For each transmission / reception event 416A-N, an ultrasound signal is transmitted at a single observation angle 408A-N. For each observation angle 408A-N, multiple sub-images 412A-M, 418A-M, and 420A-M corresponding to the reception angles 410A-M, 411A-M, and 413A-M are simultaneously acquired, thus allowing the signal to be transmitted only from N at the time of transmission. T From any angle, we can obtain the total N. T N R A format image.

[0044] For reference Figure 2As mentioned, sub-images 412A-M, 418A-M, and / or 420A-M may not be generated for display, and signals associated with sub-images 412A-M, 418A-M, and / or 420A-M may be composited to form the final image 414. When the ultrasound system has sufficient multi-line capability, the number of receiving angles 410M, 411M, and / or 413M (e.g., N) R The value of ( ) has no effect on the frame rate. For example, from Figure 4 Understandably, generation with N R The signal formed by the beam corresponding to each receiving angle can be used with a multiline with a total number equal to the following: N R Multiply by the number of lines required for a single sub-image. In other words, a sub-image for each receiving angle has its own set of receiving lines.

[0045] Line 401 acts as a picture separator between transmit / receive event 416A and transmit / receive event 416B. As shown on the left-hand side of dashed line 401, N T =1. That is, for a single transmit / receive event 416A, N is generated. R Sub-images, each sub-image for a different receiving angle of 410 Å-M, these N R Sub-images can be composited into a single image for speckle reduction without decreasing the frame rate. However, N can be utilized T =2 or greater N T To achieve greater speckle reduction. As shown on the right-hand side of line 401, multiple transmit / receive events 416A-N can be performed at different viewing angles 408A-N, and multiple sub-images from all transmit / receive events 416A-N can be composited into a final image 414. However, when a higher frame rate is desired, N T They should be kept relatively small. In some examples, both the viewing angle and the receiving angle can vary between transmit / receive events.

[0046] In examples where multiple sub-images are acquired for multiple transmit / receive events, in some embodiments, a beamformer (e.g., beamformer 222) can generate a beamformed signal associated with a sub-image for each transmit / receive event. The beamformed signals for all sub-images for all transmit / receive events can be provided to a signal processor (e.g., signal processor 226) and / or a mode-B processor (e.g., mode-B processor 228), and then to a composite processor (e.g., composite processor 244) for composite processing. In some examples, the beamformer, signal processor, mode-B processor, and / or composite processor may include buffers or other memories to store signals from multiple transmit / receive events.

[0047] Examples are provided herein that improve frame rate without loss of performance. Consider using standard spatial compounding, where N T，1 = θ R，1 = -20°, θ T，2 = θ R，2 = -10°, θ T , 3 = θ R，3 = 0°, θ T，4 = θ R，4 = 10°, and θ T，5 = θ R，5 = 20°. By the principles of the present disclosure, similar speckle reduction performance can be achieved with the following settings: N T = 2, N R = 3, and transmit / receive steering angles {θ T，1 = -12°, θ R，11 = -28°, θ R，12 = -12°, θ R，13 = 4°} and {θ T，2 = 12°, θ R，21 = 4°, θ R，22 = 12°, θ R，23 = 28°}, resulting in an average steering angle of -20°, -12°, -4°, 4°, 12°, and 20°. The examples provided are for illustrative purposes only, and the principles of the present disclosure are not limited to the examples provided. In some examples, the number of transmit / receive events, the number of sub-images to be acquired, the observation angle, and / or the receive angle can be determined by a user. In some examples, some or all of these parameters can be pre-set in the system.

[0048] The observation angle (i.e., the transmit steering angle or transmit angle) can be decoupled from the receive angle. That is, they need not rely on one another. To decouple the observation angle from the receive angle, the center of the active aperture of the transducer array can be translated with changes in depth of the ultrasound signal (e.g., from the depth at which the echo is received). The active aperture is a set of transducer elements in the transducer array that receive the ultrasound signal and transmit an electrical signal responsive to the ultrasound signal to the beamformer.

[0049] In some examples, the translation of the active aperture can be close. That is, all of the transducer elements can receive the ultrasound signal and provide the signal to the beamformer. The beamformer can receive the signals from all of the transducer elements simultaneously. However, for individual sub-images, the beamformer can select only the signals from certain ones of the transducer elements. The certain ones of the transducer elements can constitute the active aperture for the individual sub-image. The beamformer can delay and sum the signals from the active aperture for the individual sub-image to generate a beamformed signal, generating the sub-image.

[0050] The beamformer can select the signals from certain ones of the transducer elements received from the channels for all of the desired sub-images (e.g., from all of the desired receive angles) simultaneously. That is, the beamformer can delay and sum the signals from multiple active apertures simultaneously, each active aperture corresponding to a sub-image. In some cases, the active apertures can overlap. Thus, in some cases, all of the transducer elements of the transducer array can be active during reception, but the effective aperture for each sub-image can be a certain subset of the transducer elements of the array defined by the beamformer.

[0051] Figure 5A and Figure 5B is a diagram of the translation of the active aperture of a transducer array with depth according to examples described herein.

[0052] Figure 5A A transducer array 502A is shown that includes a plurality of transducer elements 504A. The transducer elements 504A that are active for a depth 518A are covered by a bar 506A. The transducer elements 504A for a depth 520A are covered by a bar 508A. The bars 506A and 508A can be referred to as the active aperture for the depths 518A and 520A, respectively. As shown, an observation angle 510A and a receive angle 512A are equal. The observation angle 510A and the receive angle 512A are shown with respect to a plane 513A. The plane 513 is orthogonal to a plane (not shown) parallel to the face of the transducer array 502. Figure 5A

[0053] Figure 5B A transducer array 502B is shown that includes a plurality of transducer elements 504B. The transducer elements 504B that are active for a depth 518B are covered by a bar 506B. The transducer elements 504B that are active for a depth 520B are covered by a bar 508B. The bars 506B and 508B can be referred to as the active aperture for the depths 518B and 520B, respectively. As shown, an observation angle 510B and a receive angle 512B are equal. The observation angle 510B and the receive angle 512B are shown with respect to a plane 513B. The plane 513 is orthogonal to a plane (not shown) parallel to the face of the transducer array 502. Figure 5B ​As shown, the observation angle 510B and the receive angle 512B are different. The observation angle 510B and the receive angle 512B are shown with respect to a plane 513B. The plane 513B is orthogonal to a plane (not shown) parallel to the face of the transducer array 502B. The receive angle 512B is shown twice, once for depth 518B and once for depth 520B.

[0054] In contrast to the active apertures 506A and 508A shown, the active apertures 506B and 508B are translated (i.e., moved laterally) across the transducer elements 504B of the transducer array 502B as a function of depth to keep the receive angle 512B constant. However, in other embodiments, different receive angles can be used for different depths (e.g., the receive angles for depths 520B and 518B can be different, as can be the case in Figure 5A For focused transmission, the observation angle 510B is determined by two points: the center of the transmit aperture (not shown) and the transmit focal point (not shown). The pixels that are imaged for a given transmit / receive event are along the line segment 514B connecting the center of the transmit aperture and the transmit focal point. However, to focus during reception, receive beamforming is performed by processing so that the pixels to be imaged can be arbitrarily chosen. The receive angle 512B can be determined by the center of the receive aperture and the desired pixel of interest. Thus, as shown by the active apertures 506B and 508B, during the transmit / receive event, aperture shifting occurs only at reception. However, the active aperture must include transducer elements 504B of the transducer array 502B. Beyond a certain depth (e.g., below depth 518B), it can no longer be effective to translate the center of the active aperture. Thus, the receive angle 512B can not remain constant as a function of depth below a certain depth. Figure 5A As shown, the active apertures 506A and 506B include a greater number of transducer elements 504A, 504B than the active apertures 508A and 508B. This is because the width of the active aperture decreases as the depth decreases and increases as the depth increases. Thus, the effective receive angle can deviate from the desired angle beyond the depth at which the active aperture has reached one or more edges of the array. This can be seen in

[0055] Figure 5A As shown, the active apertures 506A and 506B include a greater number of transducer elements 504A, 504B than the active apertures 508A and 508B. This is because the width of the active aperture decreases as the depth decreases and increases as the depth increases. Thus, the effective receive angle can deviate from the desired angle beyond the depth at which the active aperture has reached one or more edges of the array. This can be seen in Figure 5B Figure 5A As shown, the active apertures 506A and 506B include a greater number of transducer elements 504A, 504B than the active apertures 508A and 508B. This is because the width of the active aperture decreases as the depth decreases and increases as the depth increases. Thus, the effective receive angle can deviate from the desired angle beyond the depth at which the active aperture has reached one or more edges of the array. This can be seen in Figure 5B

[0056] ​​​Figure 6 This is flowchart 600, based on the example method described herein. At block 602, the step of "emitting a first ultrasonic beam at a first viewing angle" can be performed. This emission can be performed during a first emission / reception event. In some examples, this emission can be performed via a transducer array of an ultrasonic probe (e.g., Figure 2 This is performed by the transducer array 214 of the ultrasonic probe 212 shown. In some examples, the user can select the viewing angle. At block 604, the step of "receiving the first plurality of echoes" can be performed. The first plurality of echoes may have been generated in response to the first transmit / receive event. In some examples, this reception can be performed by the transducer array. At block 606, the step of "converting the first plurality of echoes into corresponding first plurality of electrical signals" can be performed. In some examples, this conversion can be performed by the transducer elements of the transducer array (e.g., Figure 2 This can be performed using the transducer array 214 shown. At block 608, the step of "generating a first plurality of beamforming signals based on a first plurality of electrical signals" can be performed. In some examples, this generation can be performed using a beamformer (e.g., Figure 2 The beamformer 222 shown is used to perform this. In some examples, the signal formed by an individual beamformed in the first plurality of beamformed signals can be associated with a corresponding receiving angle in the first plurality of receiving angles.

[0057] At box 610, the step of "combining the signals of the first plurality of beamformed signals to generate a first combined signal" can be performed. In some examples, this combination can be performed by a combination processor (e.g., Figure 2 The composite processor 244 in the middle is used to execute this. In some examples, it can be executed by a signal processor and / or a B-mode processor (e.g., Figure 2 The signal processor 226 and the B-mode processor 228 shown execute this composite signal processing. At block 612, the step of "generating the final image based on the first combined signal" can be performed. In some examples, the generation of the final image can be performed by a composite processor, a scan converter, and / or an image processor (e.g., Figure 2 The scan converter 230 and image processor 236 shown are used to perform this. In some examples, boxes 602-610 can be repeated for different viewing angles and / or different receiving angles for different transmit / receive events.

[0058] In various embodiments implementing components, systems, and / or methods using programmable devices (e.g., computer-based systems or programmable logic units), it should be understood that the above-described systems and methods can be implemented using a variety of known or later-developed programming languages (e.g., "C," "C++," "FORTRAN," "Pascal," etc.). Accordingly, a variety of storage media (e.g., computer disks, optical disks, electronic memory, etc.) can be prepared that contain information which can direct a device such as a computer to perform the functions of the above-described systems and / or methods. Once the appropriate device has accessed the information and programs contained on the storage media, the storage media can provide the device with the information and programs, thereby enabling the device to perform the functions of the systems and / or methods described herein. For example, if a computer disk containing the appropriate material (e.g., source files, object files, executable files, etc.) is provided to a computer, the computer can receive the information, configure itself appropriately, and perform the functions of the various systems and methods outlined in the above figures and flowcharts, thereby implementing the various functions. That is, the computer can receive portions of various information relating to different elements of the above-described systems and / or methods from the disk, implement the various systems and / or methods, and coordinate the functions of the various systems and / or methods described above.

[0059] In view of the present disclosure, it should be noted that the various methods and devices described herein can be implemented in hardware, software, and / or firmware. In addition, the various methods and parameters are included by way of example only, and any limitation they can have is not to be taken as limiting. In view of the present disclosure, those of ordinary skill in the art can implement the present teachings in determining their own techniques and needed apparatuses to affect these techniques, while remaining within the scope of the present invention. The functions of one or more of the processors described herein can be incorporated into a fewer number or single processing unit (e.g., CPU), and can be implemented using application specific integrated circuits (ASICs) or general purpose processing circuits programmed with executable instructions to carry out the functions described herein and illustrated in the figures. Figure 3 The functions illustrated can be carried out using a general purpose processing circuit programmed with executable instructions to carry out the functions described herein and illustrated in the figures.

[0060] While the present system has been described with specific reference to an ultrasound imaging system, it is also contemplated that the present system can be extended to other medical imaging systems in which one or more images are obtained in a systematic manner. Thus, the present system can be used to obtain and / or record image information relating to, but not limited to, kidneys, testicles, breasts, ovaries, uterus, thyroid, liver, lungs, musculoskeletal, spleen, heart, arteries and vasculature, and other imaging applications related to ultrasound-guided interventions. Additionally, the present system can also include one or more programs that can be used with conventional imaging systems such that the one or more programs can provide the features and advantages of the present system. Certain additional advantages and features of this disclosure can be learned by those skilled in the art upon study of the disclosure, or can be learned by one of ordinary skill in the art after adoption of the novel systems and methods of this disclosure. Another advantage of the present system and method can be that conventional medical image systems can be easily upgraded to incorporate the features and advantages of the present system, devices, and methods.

[0061] It should be understood, of course, that any of the examples, embodiments, or processes described herein can be combined with one or more of the other examples, embodiments, and / or processes, or can be separated into additional examples, embodiments, and / or processes, and / or incorporated into devices or device portions according to the present system, devices, and methods.

[0062] Finally, the above discussion is meant to be illustrative only of the present system and method and should not be construed as limiting the claims to any particular embodiment or group of embodiments. Thus, while the present system has been described in detail with reference to exemplary embodiments, it should be apparent that those skilled in the art can devise many modifications and alternative embodiments without departing from the broader spirit and scope of the present system and method as set forth in the claims. Accordingly, the specification and drawings are to be regarded as illustrative in nature and not as restrictive.

Claims

1. A medical imaging system, comprising: A transducer array, wherein the transducer array is configured to: emit an ultrasonic beam, receive an echo in response to the ultrasonic beam, and generate an electrical signal corresponding to the echo; A controller circuit, wherein the controller circuit is configured to cause the transducer array to emit the ultrasonic beam at an observation angle in response to a transmit / receive event; and Beamformer The beamformer is configured to receive the electrical signal from the transmit / receive event and simultaneously generate a first plurality of beamforming signals. In this configuration, each of the first plurality of beamforming signals is associated with a corresponding reception angle among the first plurality of reception angles, and each of the first plurality of beamforming signals corresponds to multiple lines in a single sub-image for the corresponding reception angle. The medical imaging system is configured to combine the signals formed by the first plurality of beams to generate a final image.

2. The medical imaging system according to claim 1 further includes a composite processor, wherein, The composite processor is configured to combine the signals formed by the first plurality of beamforming to generate the final image.

3. The medical imaging system according to claim 1 further includes a signal processor, wherein, The signal processor is configured to receive the signals formed by the first plurality of beamforms and to perform noise reduction on the signals formed by the first plurality of beamforms.

4. The medical imaging system according to claim 1 further includes a mode-B processor, wherein, The B-mode processor is configured to receive the signals formed by the first plurality of beamforms and to perform amplitude detection on the signals formed by the first plurality of beamforms.

5. The medical imaging system according to claim 1, in, The controller circuit is configured to cause the transducer array to emit the ultrasonic beam at a second viewing angle in response to the second transmit / receive event. and The beamformer is configured to receive the electrical signal from the second transmit / receive event and generate a second plurality of beamformed signals, each of the second plurality of beamformed signals being associated with a corresponding reception angle from a second plurality of reception angles. The medical imaging system is further configured to combine the signals formed by the first plurality of beams with the signals formed by the second plurality of beams into a combined signal.

6. The medical imaging system according to claim 5, wherein, The first plurality of receiving angles are different from the second plurality of receiving angles.

7. The medical imaging system according to claim 5, wherein, The second observation angle is different from the first observation angle.

8. The medical imaging system according to claim 5, wherein, The beamformer includes a buffer for storing the signals formed by the first plurality of beamformations.

9. The medical imaging system according to claim 1, wherein, The beamformer is a multi-line beamformer.

10. The medical imaging system of claim 1 further includes a user interface, the user interface including a first control for receiving user input indicating a value of the observation angle.

11. The medical imaging system according to claim 10, wherein, The user interface includes a second control for receiving user input indicating a value for at least one of the first plurality of receiving angles.

12. The medical imaging system according to claim 10, wherein, The user interface includes another control for receiving user input indicating the number of the first plurality of receiving angles.

13. The medical imaging system according to claim 1, wherein, The beamformer is configured to provide a first activation aperture associated with a first receiving angle among the first plurality of receiving angles and a second activation aperture associated with a second receiving angle among the first plurality of receiving angles, wherein the first activation aperture and the second activation aperture overlap.

14. The medical imaging system according to claim 1, wherein, The position of the active aperture of the transducer array varies with the value of the receiving angle of the first plurality of receiving angles.

15. The medical imaging system according to claim 14, wherein, The width of the activation aperture of the transducer array varies with the depth of the echo.

16. A method comprising: During the first transmit / receive event, a first ultrasonic beam is emitted at a first observation angle; Receive the first plurality of echoes generated in response to the first transmit / receive event; Convert the first plurality of echoes into corresponding first plurality of electrical signals; Based on the first plurality of electrical signals, a plurality of beamforming signals are simultaneously generated, wherein an individual beamforming signal in the plurality of beamforming signals is associated with a corresponding receiving angle in the plurality of receiving angles, and each beamforming signal in the plurality of beamforming signals corresponds to multiple lines of a single sub-image for a corresponding receiving angle. The signals formed by the first plurality of beams are combined to generate a first combined signal; and The final image is generated based on the first combined signal.

17. The method of claim 16, further comprising: During the second transmit / receive event, a second ultrasonic beam is emitted at a second observation angle; Receive a second plurality of echoes generated in response to the second transmit / receive event; Convert the second plurality of echoes into corresponding second plurality of electrical signals; The second plurality of beamforming signals are generated based on the second plurality of electrical signals, wherein the individual beamforming signal in the second plurality of beamforming signals is associated with the corresponding receiving angle in the second plurality of receiving angles; The signals formed by the second plurality of beamforms are combined with the signals formed by the first plurality of beamforms to generate a second combined signal; and The final image is generated based on the second combined signal.

18. The method according to claim 17, wherein, The receiving angle in the first plurality of receiving angles is different from the receiving angle in the second plurality of receiving angles.

19. The method of claim 16, wherein, Combining the signals formed by the first plurality of beams includes summing the signals formed by the first plurality of beams and taking the average value.

20. The method of claim 16, wherein, The compositing is performed by the compositing processor.

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