Ultrasound beamforming system and method based on analog random access memory array
Inventors
Assignees
Ursus Medical Designs LLC • Ursus Medical LLC
Publication Number
US-10627510-B2
Publication Date
2020-04-21
Expiration Date
2035-11-16
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Abstract
An ultrasound beamformer architecture performs the task of signal beamforming using a matrix of analog random access memory cells to capture, store and process instantaneous samples of analog signals from ultrasound array elements and this architecture provides significant reduction in power consumption and the size of the diagnostic ultrasound imaging system such that the hardware build upon this ultrasound beamformer architecture can be placed in one or few application specific integrated chips (ASIC) positioned next to the ultrasound array and the whole diagnostic ultrasound imaging system could fit in the handle of the ultrasonic probe while preserving most of the functionality of a cart-based system. The ultrasound beamformer architecture manipulate analog samples in the memory in the same fashion as digital memory operates that can be described as an analog store—digital read (ASDR) beamformer. The ASDR architecture provides improved signal-to-noise ratio and is scalable.
Core Innovation
The invention presents an Analog Store Digital Read (ASDR) ultrasound beamforming architecture that utilizes a matrix of analog random access memory cells, specifically sample-hold cells, to capture, store, and process instantaneous analog signal samples from ultrasound array elements. This architecture performs beamforming by manipulating analog samples in memory similarly to how digital memory operates, but summing analog samples before digitization to improve signal-to-noise ratio (SNR). The ASDR architecture significantly reduces power consumption and size, enabling the diagnostic ultrasound hardware to be implemented on one or a few application-specific integrated circuits (ASICs) placed near the ultrasound array. This integration allows the whole diagnostic ultrasound imaging system to fit within the handle of an ultrasonic probe while preserving most functionality of larger cart-based systems.
The problem addressed arises from the high hardware complexity, size, and power consumption of traditional digital ultrasound beamformers. Prior analog beamforming methods suffered from low refresh rates, poor time discrimination, and irreversible beamforming processes limiting algorithm flexibility. Digital beamformers offer speed and precision but at the cost of higher power consumption, increased hardware size, and complexity. There is a continued need to reduce the size and power requirements of diagnostic ultrasound systems while maintaining or improving image quality and beamforming flexibility.
The ASDR system solves this by combining digital control with analog signal processing, enabling sequential or arbitrary access read/write operations in analog random access memory. By storing analog samples in sample-hold cells and summing selected analog samples from multiple channels per beamforming instance prior to digitization, the invention achieves dynamic, scalable, and multi-algorithm beamforming with improved SNR. Its design supports numerous array configurations, high channel counts, and various beamforming architectures including sub-aperture and multi-stage beamforming, with independent and variable sampling rates for writing, reading, and digitizing operations to optimize performance and power.
Claims Coverage
The patent includes multiple independent claims covering methods and systems of Analog Store Digital Read ultrasound beamforming.
Analog Store Digital Read ultrasound beamforming method with independent sampling speeds
Method comprising providing an ultrasonic array with channels, creating receiving input signals, sampling each channel's input at a sampling rate and storing the samples in banks of sample-hold cells forming analog random access memory, selecting sample-hold cell data per channel for each output time per beamforming instance according to a beamforming algorithm, summing these selected analog data from channels for beamforming, and digitizing the beamformed analog signal. The number of sample-hold cells per bank is at least the product of the sample rate and maximum desired path delay, and the sampling speed for storing is independent from the sampling speed for reading.
Analog Store Digital Read ultrasound beamforming method utilizing multiple beamforming instances and algorithms
Method similar to the above, further utilizing multiple beamforming instances associated with multiple algorithms, including storing each analog beamformed received signal from each beamforming instance in a bank of beamform sample-hold cells prior to digitizing.
Analog Store Digital Read ultrasound beamformer with multiple beamforming instances storage
System comprising an ultrasonic array with grouped channels each having at least one array element; receiving input signal control circuitry per channel; banks of sample-hold cells associated with each channel forming analog random access memory; a beamforming processor to select sample-hold cell data per beamforming instance according to a beamforming algorithm; an analog summation element summing selected sample-hold data per beamforming instance forming an analog beamformed received signal; an analog-to-digital converter digitizing the beamformed signal; and a bank of beamform sample-hold cells configured to store each analog beamformed received signal for each beamforming instance before digitization.
Channel power consumption limitation
Each channel comprises only one array element and consumes less than 40 milliwatts during operation.
Sample-hold cell capacitor-based construction and integrated circuit implementation
Each sample-hold cell is capacitor based and at least the beamforming processor is formed as an integrated circuit.
Memory depth relative to sampling rate and maximum delay
The number of sample-hold cells in each bank is equal to or greater than the sample rate times the maximum desired delay for the signal path.
Transmission beamformer using banks of transmission sample-hold cells
A transmission beamformer that stores at least portions of a transmission output pulse signal in a bank of transmission sample-hold cells associated with a channel.
Shared transmission sample-hold cell bank among multiple channels
A single bank of transmission sample-hold cells may be associated with multiple channels.
Same bank used for reception and transmission sample-hold cells
The same bank of sample-hold cells may form both the receiving bank and the bank of transmission sample-hold cells for at least one channel.
Separate banks for receiving and transmission sample-hold cells per channel
Each channel may be associated with one receiving bank of sample-hold cells and one distinct bank of transmission sample-hold cells.
The claims broadly cover both the method and system aspects of the ASDR ultrasound beamforming approach, focusing on the use of analog sample-hold cell banks as analog random access memory, independent sampling and read rates, multiple beamforming instances and algorithms, power-efficient single-element channels, capacitor-based cells, and configurable transmission sample-hold cell banks.
Stated Advantages
Provides significant reduction in system size allowing placement of beamforming hardware on one or few ASICs next to the ultrasound array enabling the entire system to fit within the handle of the ultrasonic probe.
Achieves improved signal-to-noise ratio by drastically reducing the signal path complexity from transducer elements to digitizer, eliminating components such as analog high voltage and channel multiplexers, cables, and connectors.
Enables full aperture beamforming with each array element having its own transmit and receive channel, improving image quality, diagnostic contrast, and spatial resolution.
Utilizes lower power consumption per channel, allowing extended operation on battery power suitable for portable system applications.
Supports scalable architecture allowing linear expansion for larger arrays and improving image quality while reducing production cost for arrays including 1.5D, 1.75D, and 2D arrays.
Facilitates wireless data and image transmission to any equipped display device, enabling compact and flexible diagnostic system designs.
Documented Applications
Medical diagnostic ultrasound imaging for human and animal applications.
Non-destructive testing and evaluation including pipeline testing, airframe testing, turbine blade inspection, bridge and structural testing, and manufacturing testing of metals.
Geophysical exploration and sonar applications.
Other ultrasound imaging or image-like applications requiring beamforming for transmission and/or reception such as radar, terahertz, infrared, optical imaging systems, and seismic exploration.
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