Retrospective Dynamic Transmit Focusing for Ultrasound Spatial Compounding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasound imaging systems face challenges in achieving efficient transmit focusing over a significant depth of field without the need for extensive data storage and processing, and in reducing speckle artifacts, particularly in retrospective dynamic transmit focusing methods.
Innovation Solution
The use of multiline acquisition to acquire image data by transmitting beams normal to the transducer array, applying delays to echo data from different sub-apertures to steer echo signals to the same point from different look directions, and combining these signals to reduce speckle, allowing for spatial compounding without multiple look directions, thereby increasing frame rate and reducing data storage needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synthetic focusing is used to focus ultrasound signals at every point in the image field, then lateral resolution is improved, but a significant amount of data storage and processing is required
Solution Approach 1:
The patent divides the transducer array into multiple sub-apertures, each responsible for transmitting or receiving ultrasound beams in specific directions. This segmentation allows the system to process data from smaller, manageable subsets of elements rather than requiring storage and processing of data from all elements simultaneously, thereby reducing the overall data storage requirement while maintaining focusing capability.
Solution Approach 2:
The patent uses multiple sub-apertures to transmit beams in different look directions, acquiring partial views of the image field from each sub-aperture. By combining these partial views through spatial compounding, the system achieves improved lateral resolution and reduced speckle without requiring complete data from all possible transmit-receive combinations, thus reducing data storage needs.
2Use of energy by moving object
If multiple transmissions are used to scan the entire image field with traditional beamforming, then penetration depth is improved, but frame rate decreases
Solution Approach 1:
The patent combines multiple functions into a single transmission event: multiple sub-apertures transmit simultaneously in different look directions, and multiple receive beams are formed from each transmission. This merging allows the system to achieve both improved penetration (through coherent combination of multiple sub-aperture signals) and maintained frame rate (through parallel processing of multiple beams from single transmissions).
Solution Approach 2:
The patent implements continuous scanning by having multiple sub-apertures transmit and receive simultaneously in overlapping regions. This continuous overlapping acquisition ensures that every point in the image field is insonified from multiple look directions without requiring separate transmissions, maintaining high frame rates while achieving the penetration depth benefits of multiple transmissions through spatial compounding.
3Reliability
If spatial compounding is performed by transmitting beams in multiple look directions, then speckle reduction is improved, but data storage and processing requirements increase
Solution Approach 1:
The patent segments the transducer array into multiple sub-apertures that independently transmit and receive ultrasound signals. Each sub-aperture acquires data from a specific look direction, and the system processes these segmented data sets separately before combining them. This segmentation reduces the complexity of processing full-aperture data from multiple look directions while still achieving speckle reduction through the combination of independent sub-aperture views.
4Measurement precision
If retrospective dynamic transmit focusing is used to extend depth of field, then lateral resolution outside focal region is improved, but processing complexity increases
Solution Approach 1:
The patent applies delays to echo data from different sub-apertures to steer echo signals to the same point from different look directions before combining them. This preliminary delay application performs the focusing operation in advance during the data acquisition phase, rather than requiring complex post-processing of all received signals. The delayed steering of signals from multiple sub-apertures pre-aligns the data for coherent combination, achieving extended depth of field with reduced processing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient retrospective dynamic transmit focusing over a greater depth of field with reduced speckle artifacts, improving image quality and frame rate by combining echo signals from multiple look directions without the need for extensive data storage or processing.
Implementation Method 1
an ultrasound pulse is sequentially transmitted from each element of an ultrasonic transducer array. The echo signals received from each transmission
Implementation Method 2
the time of flight of an ultrasound signal to and from each point. The appropriate received signals are combined to form a coherent echo signal for each point in the image
Data Source
Figure 1A~1C
Figure 2A~2D
Figure 3A~3B
AI summary
An ultrasonic diagnostic imaging system transmits a plurality of focused beams normal to the plane of a transducer aperture and receives multiple receive lines in response to each transmitted beam. Sub-apertures of the transducer aperture are defined by apodization and signals of the sub-apertures are aligned and combined to produce signals exhibiting the effect of transmit steering at different angles with respect to the sub-apertures. The steered signals are detected and the detected signals relating to common points in an image field are combined. The combined detected signals are used to produce an ultrasound image with reduced speckle.