Ultrasonic Visualization System Research Articles

Defect monitoring system of the internal structures of a sodium fast reactor using an artificial intelligence model

This study developed a defect-monitoring system with an artificial intelligence model, YOLOv7, which is tailored for processing image data from an ultrasonic visualization system within sodium fast reactor (SFR) internal structures. For the safety of SFR internal structures, although it is a crucial inspection for defect monitoring, it is difficult to identify structural defects because of the invisible environment. Therefore, we applied the YOLOv7 model in this study; however, we encountered challenges including decreased accuracy with complex defect shapes and complications from data augmentation during pre-training. To solve these problems, we additionally applied the enhanced super-resolution generative adversarial network for higher resolution and a Sobel noise-filtering algorithm to enhance the defect detection accuracy. And we evaluated our system by comparing it with a confidence score. This underscores the effectiveness of the approach in enhancing the defect detection capabilities. Therefore, this defect-monitoring system should be designed to preemptively identify internal structure deformations and enhance SFR safety and maintenance practices.

An ultrasonic visualization system using a fiber-optic Bragg grating sensor and its application to damage detection at a temperature of 1000 °C

Structural health monitoring (SHM) techniques are required to evaluate the reliability of aging heat-resistant structures. To build a method of high-temperature in situ damage diagnosis, the authors developed a laser ultrasonic visualization system with a heat-resistant fiber-optic Bragg grating (FBG) sensing configuration. In this system, an ultrasonic wave is excited by laser irradiation on the surface of a material and then received by a remotely installed FBG sensor. Because both the wave excitation and wave sensing parts have excellent heat resistance, the proposed sensing system enables a stable ultrasonic measurement at a temperature of 1000 °C. In this research, a wavenumber-frequency analysis shows that the proposed sensing system was able to visualize the correct laser ultrasonic wavefield in a planar structure. The ultrasonic visualization performance was then verified for a plate of heat-resistant material at temperatures of 200 and 1000 °C. A wavenumber-frequency analysis based on a three-dimensional Fourier transform was also conducted to extract the wave components corresponding to the reflection caused by an artificial defect in the plate. As a result, the developed method enabled clear damage identification at temperatures as high as 1000 °C.

Investigation of the Sound Field of Phased Array Using the Photoelastic Visualization Technique and the Accurate FEM

In this study, we tried to obtain an accurate ultrasonic sound field of the commercial phased array system. For this purpose, the experimental photoelastic ultrasonic visualization system was improved to evaluate a phased array system and the analytical special large-scale finite element method (FEM) code for ultrasonic transmission was applied. As the results, an actual sound field of phased array system was much more complicate than that of the conventional industrial assumption based on a simple superposition. One of the causes of the difference might be the accuracy of the directivity for each element in the array transducer. Thus, the combination of photoelastic visualization method and FEM analysis was useful for the accurate sound field investigation of the phased array measurement. [doi:10.2320/matertrans.I-M2012806]

1P2-20 Development of photoelastic ultrasonic visualization system using pulse laser for the evaluation of high frequency phased array system(Poster Session)

1P2-20 Development of photoelastic ultrasonic visualization system using pulse laser for the evaluation of high frequency phased array system(Poster Session)

Three-Dimensional Sound Pressure Field Measurement Using Photoelastic Computer Tomography Method

A photoelastic computer tomography method is developed to determine the three-dimensional sound pressure distribution of a longitudinal wave. An acoustic wave emitted from a probe gives a three-dimensional sound pressure distribution that depends on the ultrasonic transducer used. Since the sound pressure distribution affects the results of the ultrasonic measurements, the authors have experimentally studied the sound pressure distribution using a photoelastic ultrasonic visualization system. Hence we have developed a highly sensitive visualization system for the quantitative measurement of a weak emitted wave. However, since this method utilizes photoelasticity, the estimated sound field is limited to a two-dimensional one. In this study, the basic measurement system and the analysis algorithm for ultrasonic visualization have been improved to measure the three-dimensional propagation in solids using the computer tomography technique based on the two-dimensional photoelastic ultrasonic visualization technique. Using this system, three-dimensional sound pressure distribution of a commercial probe in the near field and/or far field are measured and compared with the results of the theoretical estimations.

Coaxial circular spherical array for ultrasonic imaging

A new type of receiving array has been designed and constructed for the purpose of visualizing an object by using the ultrasonic wave at low frequency. The array consists of 24 receiving elements around three coaxial circles on a spherical surface. The multiplication of three additive outputs, each of which is the sum of the eight element outputs on a circle, is performed for the signal processing of the array. After theoretical and experimental studies, it has been proven that the array proposed is appropriate for the high-directional receiver in the ultrasonic visualization system. A preliminary experiment on imaging the object in the air has been carried out.

Ultrasonic visualization system employing new scanning and presentation methods (Employing an on-line digital computer): Fry, W.J. et al, Journal of the Acoustical Society of America, Vol 44, No 5 (November 1968) pp 1324–1338 (1326)

Ultrasonic visualization system employing new scanning and presentation methods (Employing an on-line digital computer): Fry, W.J. et al, Journal of the Acoustical Society of America, Vol 44, No 5 (November 1968) pp 1324–1338 (1326)

Ultrasonic two-dimensional visualization for medical diagnosis.

The spot size of the display unit may be used as the design criterion of the ultrasonic visualization system. Methods to design the transducer to comply with the criterion are presented, and the performance of the scanner and the receiver are discussed. The technique is prone to artifacts caused by axial and nonaxial multiple reflections, velocity changes in tissue, and signal processing. Echograms of the pregnant uterus are used to illustrate the application of the technique.

Ultrasonic visualization system employing new scanning and presentation methods.

New methods for the ultrasonic visualization of tissue, achieved by employing a newly developed versatile instrumentation system, are outlined and their application to the examination of brain is illustrated. The complete system, whose operating characteristics are described in detail, incorporates an on-line medium-sized digital computer, implementing omnidirectional scanning, utilizing three translational and two rotational degrees of freedom; relief display, which combines intensity modulation and deflection of the oscillograph beam by the echo signals; and segmental construction of echograms, which incorporates wide dynamic range combined with high resolution via program control of receiver gain as a function of range and echo strength. Omnidirectional scanning permits the more complete viewing of tissue interfaces than is possible with the usual compound-scanning methods. Relief display provides an additional parameter as compared to the common flat format for the presentation of echo information in a two-dimensional picture, and the type of echo signal composition at individual positions on an echogram thus can be represented The relief format also facilitates detection of significant echo signals against the background. Comprehensive presentation eliminates the need for, and problems associated with, time-variable gain in receiver amplification and also provides for much greater flexibility in the choice of an amplifier gain characteristic as a function of signal amplitude. The illustrative results presented demonstrate that new ultrasonic visualization methods can be used to detect and localize (1) internal structural features of the cranial vault, (2) external features of the brain (ventricular, cisternal, and fissural surfaces); and (3) major blood vessels (midsagittal sinuses) in considerable detail, under the condition that acoustic energy does not traverse bone.

Ultrasonic B-Scanning of the Brain

U LTRASOUND restricted to one-dimensional echo-ranging can provide little information other than the location of a plane reflecting surface. I ts value in neurological diagnosis, therefore, is limited virtually to detect ion of a shift of midline structures of the brain. ',6,s,15 The purpose of the present paper is to report early experiences with a two-dimensional ultrasonic visualization system, and to discuss the possible uses of this method for more precise demonst ra t ion of various norreal and abnormal intracranial structures. The physical principles underlying the use of ultrasound as a diagnostic technique have been presented in numerous reports} ,~,7,u,n Likewise, descriptions of the instrumentation of ultrasonic methods, including those used in this study, are readily available. Therefore, only certain fundamenta l details essential to unders tanding the clinical applications of this me thod will be repeated here. Sound consists of mechanical vibrations propagated in a medium. Sinee sound travels in a wave form, it is subject to many phenomena well known in optics, including reflection, refraction, absorpt ion and diffraction. When used for the purpose of delineating an object, the resolving power of sound, as in the ease of light, is limited to about 1 wave length. Because the velocity of sound in most soft tissues, including brain, is approximately 1500 m./sec. , frequencies well above audibility, i.e., ul t rasound, must be used to achieve useful resolution in these media. For example, wi th a f requency of 1.5 !VIc./sec., the wave length in soft tissue is about 1 ram. and under opt imal conditions the depth resolution,' i.e., the resolution in