The article proposes a segmentation method based on the construction of a binary mask that hides the glare of reflectors.
The use of TOFD technology in the development of the ECHOPLUS. Overview of the capabilities of the equipment and software developed by the ECHOPLUS in order to implement the TOFD technology.
In this article you will learn what a nuclear power plant is and how it is used. Advantages and features of nuclear power plants. Areas of application.
Ultrasonic inspection of welds and joints. The service of the Research and Production Center ECHOPLUS in Moscow. Advantages and equipment for narrow control. Scheme and results of the work.
In this article you will learn what ultrasonic thickness measurement is, when and where it is used. Devices for conducting ultrasound. Types of thickness measurement. Principles and algorithms of work.
In this article you will learn what non-destructive ultrasonic testing is and what advantages it has. Types of non-destructive testing. Methods and algorithms of work.
In this article you will learn what mechanized ultrasound control is and when it is applied. Equipment for mechanized ultrasonic inspection. Areas of application and algorithms of work.
Many grades of bronze are a poor material for ultrasonic testing, since bronze has a high level of structural noise and noticeable anisotropy. This note describes technologies for reducing the level of structural noise using the example of using ultrasonic antenna arrays with high frequency.
Conducting ultrasonic inspection (ultrasound) of two samples of thick-walled pipes made of high-pressure polyethylene using Plane Wave Imaging (PWI) technology and combining partial images using coherent factor (CF) technology in order to increase the signal-to-noise ratio.
In welded joints made by contact butt welding by reflow (CSF), the most dangerous and difficult to detect defects are vertical non-melts that do not have access to any of the pipeline surfaces.
To increase the speed of recording echo signals and increase the speed of image recovery of reflectors, it is proposed to use a thinned switching matrix (SMC). To obtain a switching matrix that allows to obtain images minimally different from the image obtained by the full switching matrix (FMC), it is proposed to use a genetic algorithm. Two variants of optimization of the switching matrix are considered: element-wise thinning and column thinning. Numerical and model experiments have shown that a thinned switching matrix determined using a genetic algorithm, filled by 25%, allows the formation of images that differ from the image obtained by FMC, with an error of about 3%. Working with the switching matrix by columns allows you to increase the speed of recording echo signals by 4 times. The speed of image recovery increases by the same number of times.
An effective method of replacing zonal focusing with an antenna array is proposed, which is traditionally used in automated ultrasonic inspection of welded joints with narrow cutting to detect defects at the fusion boundary. This method, based on the use of multi-circuit digital focusing antenna technology (CFA), allows you to obtain and analyze high-quality images of reflectors. The proposed method, compared with zonal focusing made using phased array technology (HEADLIGHTS), is less sensitive to the accuracy of positioning the antenna array relative to the seam axis and to changes in the thickness of the control object, makes it possible to estimate the height of defects not by amplitude, but by the size of the glare reflectors.
Currently, in order to increase the speed of preparation of the ultrasound control protocol and reduce the influence of the human factor, reflector recognition (classification) systems based on artificial neural networks are being actively developed. For their more efficient operation, the images of the reflectors must be processed in order to increase the signal-to-noise ratio of the image and its segmentation (clustering). One of the segmentation methods consists in image processing with an adaptive anisotropic diffuse filter, which is used for processing optical images. In model experiments, the effectiveness of using this texture filter for segmentation of images of reflectors reconstructed from echo signals measured using antenna arrays has been demonstrated.
Ultrasonic flaw detection has developed methods for recording and analyzing echo signals to determine the type of reflector and its dimensions. The method of digital focusing with an antenna (CFA) allows you to restore the image of the entire discontinuity boundary using echo signals reflected from the bottom of the control object, taking into account the transformation of the wave type. However, this approach is not always applicable in practice, since the shape of the bottom of the object of control may be unknown. Using the features of the behavior of the reflection coefficient for different types of waves, it is possible to draw a conclusion about the type of reflector from images only on a direct beam. Numerical and model experiments have confirmed the operability of the proposed approach.
Image restoration of reflectors by digital focusing antenna (CFA), along with such advantages as high resolution over the entire area of image restoration of reflectors, the ability to obtain images taking into account the reflection and transformation of the wave type from the boundaries of the object of control, has several disadvantages: a large volume of measured echo signals, a long image recovery time and insufficiently high energy of ultrasonic waves, entered into the object of control. The Plane Wave Imaging (PWI) method allows you to combine the advantages of phased array antenna technology (FAR) and CFA technology. In PWI mode, when a plane wave is emitted, all elements of the antenna array (AR) work (as in the HEADLIGHT mode), which allows you to increase the energy entered into the control object, and echo signals are recorded by all elements of the AR (as in the CFA mode). The images of the reflectors are restored by the combination SAFT method. To obtain an image, the number of emitted plane waves can be used less than the number of antenna array elements, which reduces the volume of measured echo signals. The transfer of calculations to the area of spatial sectors makes it possible to increase the speed of restoration of the presentation of reflectors. Model experiments have shown the positive and negative sides of obtaining images of reflectors by the PWI method in comparison with the CFA method both for the case of using a prism and without a prism.
The TOFD method, widely used in ultrasonic flaw detection, allows to distinguish a crack from a volumetric reflector by the phase of the echo signals and to determine its height with high accuracy. However, the TOFD method without scanning with piezoelectric converters across the welded joint does not allow to determine the displacement of the reflector from the center of the seam, which is very important when evaluating the control results. The scanning devices used for this purpose have a complex design, their price is higher than that of one—dimensional sanitizing devices, and, most importantly, the control time increases significantly. If we use echo signals reflected from the bottom of the object of control, taking into account the change in the type of wave, then a combined image of the reflector can be obtained from a set of partial images recovered by the digital focusing antenna (CFA) method. If the echo signals measured in the combined mode for each piezoelectric transducer are used, it is possible to estimate the displacement of the reflector across the welded joint with an accuracy of ± 1.5 mm. Numerical and model experiments have confirmed the operability of the proposed approach.
There is a concept of technology maturity levels (technology readiness level — TRL), which describes the technology transition from the TRL 1 level. “The fundamental concept of technology has been formulated” to the TRL 9 level. “The product meets all requirements: engineering, production, operational, quality and reliability.” So the Total Focusing Method technology, aka digital antenna focusing (CFA), aka combinational SAFT, aka IWEX, aka Sampled Phased Arrays (SPA) has turned from an exotic and contested algorithm into a standardized one.