Parametric Array Ultrasonic Imaging Through Opaque Fluids
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Solution Overview
Problem
Current methods for imaging objects in optically opaque and acoustically attenuating fluids, such as drilling mud and heavy crude oil, are inefficient and fail to provide clear, detailed images due to high attenuation and harsh environmental conditions, limiting depth of field information and spatial resolution.
Innovation Solution
The use of a low-frequency collimated ultrasonic sound source, generated by a parametric array combining high-frequency sound waves in a nonlinear fluid like Fluorinert 43, and a protected transducer system for scanning and receiving signals, allowing for imaging through metal plates in confined spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency ultrasound is used for imaging, then spatial resolution is improved, but acoustic attenuation increases making imaging impossible in highly attenuating fluids
Solution Approach 1:
A parametric array transducer acts as an intermediary device that generates difference frequency sound waves through nonlinear acoustic interactions in the fluid medium itself. The transducer emits two high-frequency primary waves (e.g., 1.5 MHz and 2.0 MHz) that interact in the fluid to produce a low-frequency difference wave (e.g., 500 kHz) that propagates with minimal attenuation, enabling imaging through highly attenuating fluids while maintaining spatial resolution through electronic beamforming
Solution Approach 2:
The system dynamically changes the frequency parameters of the ultrasound waves. Instead of using a single high-frequency wave that attenuates rapidly, the system generates difference frequency waves by combining two primary frequencies, effectively transforming the frequency characteristic to achieve both penetration depth and resolution. The frequency difference is controlled by adjusting the primary frequency components
2Adaptability or versatility
If a protected transducer system is used to image through metal plates, then imaging capability in confined spaces is improved, but device complexity increases
Solution Approach 1:
The transducer is nested within a protective metal tube assembly that allows the imaging system to operate through metal plates. The transducer is positioned inside the tube such that the sound beam passes through the metal plate at the tube end, providing both protection for the transducer and the necessary imaging capability through harsh environments and confined spaces
Solution Approach 2:
The system replaces complex mechanical scanning systems with electronic beamforming using phased array technology. Instead of mechanically moving the transducer or scanning components, electronic phase control directs the ultrasonic beam to different angles and positions, simplifying the mechanical structure while maintaining imaging capability through metal plates and confined spaces
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
Enables clear and identifiable imaging of objects in opaque fluids with improved depth of field and spatial resolution, overcoming the limitations of existing technologies by providing a compact, high-frequency bandwidth imaging system capable of penetrating highly attenuating media.
Implementation Method 1
at least one transducer for generating a directed, ultrasonic sound beam having a chosen frequency and also for receiving reflected or scattered sound from the target object
Implementation Method 2
receiving reflected or scattered sound from the target object
Implementation Method 3
The transducer is mechanically scanned to direct the sound beam in a two-dimensional pattern using a mechanical wobbler
Implementation Method 4
a low frequency collimated sound source, generated by a parametric array combining high-frequency sound waves in a nonlinear fluid like Fluorinert 43
Implementation Method 5
an array of transducers that can be electronically scanned in phased array manner to direct an ultrasonic beam and electronically scan the beam over of an area
Data Source
AI summary
The present invention is a method and an apparatus that can image objects immersed in optically opaque fluids using ultrasound in a confined space and in a harsh environment. If the fluid is not highly attenuating at frequencies above 1 MHz, where commercial ultrasound scanners are available, such scanners can be adapted for imaging in these fluids. In the case of highly attenuating fluids, such as drilling mud, then a low frequency collimated sound source is used.