2D SAFT technique to reduce grating lobes in volumetric imaging

Martín, Carlos Javier Blanco; Martínez-Graullera, Óscar; Octavio, A.; Montero, F.; Ullate, L.G.

doi:10.1016/j.phpro.2010.01.050

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…In the case of a

-side aperture, we have simulated how the data

is mapped in three different configurations: the full array, a flat coarray with one signal per element, and an example of sparse bin array with 100 elements. When the resultant coarray is composed of only one element per location, this is named Minimum Redundancy Coarray (MRC) [ 23 , 25 , 30 ]. When a reflector is at the focus point, in this case

(see Figure 1 for coordinate system), the reflectivity is present in all signals, producing an increasing intensity in all coarray elements, as can be observed in Figure 2 a–c.…”

Section: Beampattern Analysismentioning

confidence: 99%

“…Based on these observations, it seems reasonable to propose solutions for sparse arrays based on the completeness of the coarray, and several works have addressed this objective in two different ways: searching two complementary apertures, one in emission and the other in reception, that generate this completeness [ 16 , 28 ]; alternatively, based on synthetic aperture, using different configurations in emission/reception to complete the coarray [ 30 ].…”

Section: Beampattern Analysismentioning

confidence: 99%

See 1 more Smart Citation

Design of 2D Planar Sparse Binned Arrays Based on the Coarray Analysis

Martínez-Graullera

Souza

Parrilla

et al. 2021

Sensors

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The analysis of the beampattern is the base of sparse arrays design process. However, in the case of bidimensional arrays, this analysis has a high computational cost, turning the design process into a long and complex task. If the imaging system development is considered a holistic process, the aperture is a sampling grid that must be considered in the spatial domain through the coarray structure. Here, we propose to guide the aperture design process using statistical parameters of the distribution of the weights in the coarray. We have studied three designs of sparse matrix binned arrays with different sparseness degrees. Our results prove that there is a relationship between these parameters and the beampattern, which is valuable and improves the array design process. The proposed methodology reduces the computational cost up to 58 times with respect to the conventional fitness function based on the beampattern analysis.

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“…In the case of a

-side aperture, we have simulated how the data

(see Figure 1 for coordinate system), the reflectivity is present in all signals, producing an increasing intensity in all coarray elements, as can be observed in Figure 2 a–c.…”

Section: Beampattern Analysismentioning

confidence: 99%

Section: Beampattern Analysismentioning

confidence: 99%

Design of 2D Planar Sparse Binned Arrays Based on the Coarray Analysis

Martínez-Graullera

Souza

Parrilla

et al. 2021

Sensors

View full text Add to dashboard Cite

show abstract

“…The 1024 (32×32) and 361 (19×19) ultrasonic waveforms obtained for the model with probes A and B were reconstructed to generate images of flaw shapes using the Synthetic Aperture Focusing Technique (SAFT) (14), (15) . Figure 8 shows the visualization result for the SCC and slit model with probe A.…”

Section: Numerical Simulation and Flaw Visualizationmentioning

confidence: 99%

Development of Flaw Visualization Technique at Near Field of Phased Array Probe

Kurokawa

Inoue

2010

JMMP

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Ultrasonic flaw detection and sizing is an important issue for ensuring structural reliability of industrial plants. The ultrasonic phased array technique is one of the most effective tools for visualizing the flaws in structural components. It is important to enhance the spatial resolution of phased array images to clearly visualize flaws; however, the spatial resolution of phased array images needs more research. A high spatial resolution phased array probe was designed as the first stage of this study. To investigate the spatial resolution of the phased array probe, acoustic analysis was conducted utilizing the Rayleigh-Sommerfeld Integral. The spatial resolution was investigated by changing the total aperture of the probe. As a result, the large-aperture phased array probe achieved high spatial resolution. Next, ultrasonic testing was simulated by the finite differential method using conventional and specially designed phased array probes. For the conventional probe, the flaw could be visualized but the shape was not clear enough. On the other hand, for the specially designed large-aperture probe, extensive noise appeared in the image and the flaws could not be visualized. Because of mode conversion, Rayleigh waves are generated at the contact surface between the transducer and testing material. The amplitude of Rayleigh waves are much higher than the diffraction echoes, hence the Rayleigh waves disturb the visualized image at the near field of the probe. Consequently a new technique for flaw visualization at the near field of the phased array probe was developed by eliminating detrimental waves. As a result the flaws could be clearly visualized using this technique.

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“…Such a solution, using the minimum number of signals, provides the maximum degrees-of-freedom, better lateral resolution and avoids grating lobes. Furthermore, depending on the available hardware/electronic resources, it can be achieved with different acquisition strategies [ 12 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Design of Ultrasonic Synthetic Aperture Imaging Systems Based on a Non-Grid 2D Sparse Array

Souza

Parrilla

Higuti

et al. 2021

Sensors

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This work provides a guide to design ultrasonic synthetic aperture systems for non-grid two-dimensional sparse arrays such as spirals or annular segmented arrays. It presents an algorithm that identifies which elements have a more significant impact on the beampattern characteristics and uses this information to reduce the number of signals, the number of emitters and the number of parallel receiver channels involved in the beamforming process. Consequently, we can optimise the 3D synthetic aperture ultrasonic imaging system for a specific sparse array, reducing the computational cost, the hardware requirements and the system complexity. Simulations using a Fermat spiral array and experimental data based on an annular segmented array with 64 elements are used to assess this algorithm.

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2D SAFT technique to reduce grating lobes in volumetric imaging

Cited by 3 publications

References 12 publications

Design of 2D Planar Sparse Binned Arrays Based on the Coarray Analysis

Design of 2D Planar Sparse Binned Arrays Based on the Coarray Analysis

Development of Flaw Visualization Technique at Near Field of Phased Array Probe

Design of Ultrasonic Synthetic Aperture Imaging Systems Based on a Non-Grid 2D Sparse Array

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