Implementation issues of 3D SAFT in time and frequency domain for the fast inspection of heavy plates

Krieg, Fabian; Kirchhof, Jan N.; Römer, Florian; Ihlow, Alexander; Galdo, Giovanni Del; Osman, Ahmad

doi:10.1109/ultsym.2017.8092833

Cited by 3 publications

(3 citation statements)

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“…Figs. 3(a) and 3(b) show the outputs of the algorithm [12], [13] as isosurfaces of the normalized image when using the spline interpolation [32] and an interpolation method with a simpler implementation based on the minimum distance criterion (given below), respectively:…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

et al. 2022

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In this paper, rapid reconstruction of a three-dimensional (3D) image of a scene for nearfield microwave imaging using a dynamic metasurface antenna (DMA) is addressed. The imaging system consists of a fixed transmitting DMA and a single moving antenna as the receiver. In the proposed approach, after pre-processing the raw data and converting it into an applicable form for Fourier computations, the converted data are processed by the presented algorithm (all with fast Fourier computations, without the need for the heavy Stolt interpolation step). Furthermore, after extracting a closed-form expression for image reconstruction, a minimization problem is defined using the compressive-sensing (CS) theory, which allows a sparse pattern to be sampled instead of collecting full data, thereby significantly improving the data acquisition rate (according to the CS rate). The performance of the proposed approach is examined by computer simulations and analytical discussions.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

et al. 2022

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“…Synthetic transmit aperture (STA) is a widely adopted technology in the field of pulse-echo imaging, such as radar and sonar systems (Brown andPorcello 1969, Hayes andGough 2009), nondestructive testing (Chang et al 2013, Krieg et al 2017 and medical ultrasound imaging (Ylitalo and Ermert 1994, O'Donnell et al 1997, Vray et al 2001, because it is capable of achieving high spatial resolution over the entire imaging area. The complete STA dataset consists of backscattered echoes corresponding to all transmit element and receive element pairs.…”

Section: Introductionmentioning

confidence: 99%

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method

Zhang¹,

Liu²,

Fan³

et al. 2022

Phys. Med. Biol.

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Objective: Synthetic transmit aperture (STA) ultrasound imaging is well known for ideal focusing in the full field of view. However, it suffers from low signal-to-noise ratio (SNR) and low frame rate, because each transducer element must be activated individually. In our previous study, we encoded all the transducer elements with partial Hadamard matrix and reconstructed the complete STA dataset with compressed sensing (CS) algorithm (CS-STA). As all the elements are activated in each transmission and the number of transmissions is smaller than that of STA, this method can achieve higher SNR and higher frame rate. Its main drawback is the time-consuming CS reconstruction (~ hours). In this study, we propose to accelerate the complete STA dataset reconstruction with minimal l2-norm least squares method. Approach: Partial Hadamard apodized PW transmissions were performed to acquire the PW dataset. Thereafter, the complete STA dataset can be reconstructed from the PW dataset with minimal l2-norm least squares method. Due to the orthogonality of partial Hadamard matrix, the minimal l2-norm least squares solution can be easily calculated. Main results: The proposed method is tested with simulation data and experimental phantom and in-vivo data. The results demonstrate that the proposed method achieves ~5×103 times faster reconstruction speed than CS algorithm. The simulation results demonstrate that the proposed method is capable of achieving the same accuracy as the conventional CS-STA method for the STA dataset reconstruction. The simulations, phantom and in-vivo experiments show that the proposed method is capable of improving the generalized contrast-to-noise ratio (gCNR) and SNR with maintained spatial resolution and fewer transmissions, compared with STA. Significance: In conclusion, the improved image quality and reduced computational time of LS-STA pave the way for its real-time applications in the clinics.

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“…The SAFT-C algorithm is a time-domain SAFT algorithm based on the delay-and-sum method that focuses reflections in accordance with delayed times [ 12 ]. Although a frequency-domain SAFT algorithm, such as the wavenumber [ 13 ] and migration algorithm [ 14 ], which manipulate the Fast Fourier Transform to calculate resulting images, show a faster calculation speed and better resolution [ 15 ], the time-domain SAFT algorithm seemed to be adapted in the MIRA device due to its simplicity and low-performance requirement on a microprocessor [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

3D Internal Visualization of Concrete Structure Using Multifaceted Data for Ultrasonic Array Pulse-Echo Tomography

Kwon

Joh

Chin

2021

Sensors

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This research proposes a 3D internal visualization using ultrasonic pulse-echo tomography technique to evaluate accurately the state of concrete structures for their efficient maintenance within a limited budget. Synthetic aperture focusing technique (SAFT) is used as a post-processing algorithm to manipulate the data measured by the ultrasonic pulse-echo technique. Multifaceted measurements improve the weakness of the existing ultrasonic pulse-echo tomography technique that cannot identify the area beyond a reflector as well as the area located far away from measuring surfaces. The application of apodization factor, pulse peak delay calibration and elimination of trivial response not only complements the weaknesses of the SAFT algorithm but also improves the accuracy of the SAFT algorithm. The results show that the proposed method reduces the unnecessary surface noise and improves the expressiveness of the reflector’s boundaries on the resulting images. It is expected that the proposed 3D internal visualization technique will provide a useful non-destructive evaluation tool in combination with another structure evaluation method.

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Implementation issues of 3D SAFT in time and frequency domain for the fast inspection of heavy plates

Cited by 3 publications

References 0 publications

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method

3D Internal Visualization of Concrete Structure Using Multifaceted Data for Ultrasonic Array Pulse-Echo Tomography

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Implementation issues of 3D SAFT in time and frequency domain for the fast inspection of heavy plates

Cited by 3 publications

References 0 publications

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

Efficient 3D Image Reconstruction for Near-Field Microwave Imaging Using Dynamic Metasurface Antenna

Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l 2-norm least squares method

3D Internal Visualization of Concrete Structure Using Multifaceted Data for Ultrasonic Array Pulse-Echo Tomography

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Partial Hadamard encoded synthetic transmit aperture for high frame rate imaging with minimal l ₂-norm least squares method