Ultrasound Imaging Apparatus Nonlinear Component Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasound imaging methods face challenges in extracting nonlinear components for Tissue Harmonic Imaging (THI) due to nonlinearity in electroacoustic conversion elements and transmission circuits, leading to difficulties in achieving sufficient signal intensity and S/N ratio, especially when using filters, Pulse Inversion, and amplitude modulation methods.
Innovation Solution
An ultrasound imaging apparatus that transmits ultrasound beams twice to the same position, with different drive patterns for electroacoustic conversion elements, allowing for selective activation of channels and sub-channels to minimize nonlinearity effects and enhance nonlinear component extraction, using a controller to process reception signals and extract nonlinear components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional filter methods are used to separate nonlinear components, then frequency separation is achieved, but signal intensity and S/N ratio are insufficient
Solution Approach 1:
The patent applies periodic transmission of ultrasound pulses with alternating polarities (positive and negative phases) to enable temporal separation of linear and nonlinear components. By transmitting pulses in a periodic sequence with inverted polarities and processing the received echoes through subtraction operations, the method achieves effective nonlinear component extraction while maintaining sufficient signal intensity through cumulative signal accumulation across multiple pulse cycles.
2Measurement precision
If Pulse Inversion method is used to extract nonlinear components, then linear components are canceled out, but nonlinearity in electroacoustic conversion elements causes incomplete cancellation
Solution Approach 1:
The patent segments the ultrasound transmission process into multiple distinct phases with different polarity patterns and aperture configurations. By dividing the transmission into separate pulse sequences with alternating polarities and using selective aperture activation (segmenting the transducer elements into different groups), the method achieves more complete linear component cancellation while accounting for device nonlinearity through multiple segmented measurement sets that can be processed independently and combined.
Solution Approach 2:
The patent changes multiple parameters simultaneously including pulse polarity, aperture size, and element selection patterns across different transmission sequences. By varying these parameters in a systematic manner and processing the resulting echo signals through appropriate mathematical operations (subtraction, addition, and scaling), the method overcomes the limitation of incomplete linear component cancellation caused by electroacoustic conversion nonlinearity.
3Loss of energy
If all electroacoustic conversion elements are driven continuously, then signal strength is maximized, but nonlinearity effects increase
Solution Approach 1:
The patent applies partial action by selectively activating only certain groups of electroacoustic conversion elements during different transmission phases rather than driving all elements continuously at full power. By using subsets of the available transducer elements in alternating sequences and combining the results through appropriate signal processing, the method achieves sufficient echo signal strength while reducing the cumulative nonlinearity distortion that would occur with continuous full-aperture operation.
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 effectively removes nonlinearity-induced distortions, enabling the extraction of more nonlinear components and improving image quality by enhancing the S/N ratio and resolving artifacts caused by grating lobes, resulting in higher resolution and contrast THI images.
Implementation Method 1
employs an electroacoustic conversion element (transducer) to convert an electric signal into an ultrasound wave, to irradiate an object with the ultrasound wave, and the electroacoustic conversion element further receives a reflected wave (an echo) which is reflected from the object, so as to convert the reflected wave into an electric signal
Implementation Method 2
there is a phenomenon caused by acoustic nonlinearity that a part with a high sound pressure in the transmitted acoustic waveform progresses fast, whereas a part with a low sound pressure progresses slowly. Since the longer the acoustic wave propagates, the more this phenomenon is accumulated, and therefore, this intensifies the waveform distortion
Implementation Method 3
a nonlinear component made up of harmonics is generated, in addition to a fundamental frequency component of the irradiated acoustic wave. This nonlinear component is generated in proportion to approximately the square of the amplitude of fundamental wave sound pressure
Implementation Method 4
The ultrasound wave passes through the object and a part thereof is reflected on a boundary between different acoustic impedances, and an echo signal having strength depending on a difference of the impedances is generated
Data Source
AI summary
Even when electroacoustic conversion elements with high nonlinearity are employed, a nonlinear imaging is carried out with extracting more nonlinear components. An ultrasonic wave beam is transmitted twice from the transmitter to an identical position on the imaging target, and the signal processor performs computation on the reception signals obtained in every transmission performed twice, thereby extracting a nonlinear component included in the reception signals. In one transmission out of the transmission performed twice, the transmitter delivers the transmission signal to all of multiple electroacoustic conversion elements for driving the electroacoustic conversion elements, and in the other transmission, the transmission signal is delivered selectively only to a part of the multiple electroacoustic conversion elements for driving the electroacoustic conversion elements.