scholarly journals Architecture Exploration of a Backprojection Algorithm for Real-Time Video SAR

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8258
Author(s):  
Seokwon Lee ◽  
Inmo Ban ◽  
Myeongjin Lee ◽  
Yunho Jung ◽  
Wookyung Lee
Keyword(s):  
Frame Rate ◽  
Synthetic Aperture ◽  
Profile Data ◽  
Pixel Resolution ◽  
Multiple Gpus ◽  
Range Resolution ◽  
Full Resolution ◽  
Range Profile ◽  
Processing Data ◽  
Target Data

This paper explores novel architectures for fast backprojection based video synthetic aperture radar (BP-VISAR) with multiple GPUs. The video SAR frame rate is analyzed for non-overlapped and overlapped aperture modes. For the parallelization of the backprojection process, a processing data unit is defined as the phase history data or range profile data from partial synthetic-apertures divided from the full resolution target data. Considering whether full-aperture processing is performed and range compression or backprojection are parallelized on a GPU basis, we propose six distinct architectures, each having a single-stream pipeline with a single GPU. The performance of these architectures is evaluated in both non-overlapped and overlapped modes. The efficiency of the BP-VISAR architecture with sub-aperture processing in the overlapped mode is accelerated further by filling the processing gap from the idling GPU resources with multi-stream based backprojection on multiple GPUs. The frame rate of the proposed BP-VISAR architecture with sub-aperture processing is scalable with the number of GPU devices for large pixel resolution. It can generate 4096 × 4096 video SAR frames of 0.5 m cross-range resolution in 23.0 Hz on a single GPU and 73.5 Hz on quad GPUs.

scholarly journals Improvement of Performance Degradation in Synthetic Aperture Extension of Enhanced Axial Resolution Ultrasound Imaging Based on Frequency Sweep

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2414
Author(s):  
Jing Zhu ◽  
Norio Tagawa
Keyword(s):  
Finite Element Method ◽  
Performance Degradation ◽  
Original Method ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
Axial Resolution ◽  
Frequency Sweep ◽  
Type Method ◽  
Range Resolution ◽  
Pulse Transmission

We are studying a method based on the carrier frequency sweep for axial high resolution ultrasonic imaging to provide the range resolution that corresponds to the carrier wavelength. The first proposal for this type of method was based on the focused pulse transmission. Then, to improve the frame rate, the method was extended to a synthetic aperture-type method that transmits divergent pulses. While the method is effective in terms of the frame rate, degradation of the enhanced axial resolution performance is a concern. Therefore, using finite element method simulations and simple experiments, the performance of the synthetic aperture method with high axial resolution is evaluated via comparison with the original method using focused pulses. The evaluation confirmed that the performance degradation of the synthetic aperture method is caused by weakness in the transmitted wave intensity and deterioration of the phase coherence in the reception beamforming. Based on this result, we propose a method that is less affected by the latter cause and show its effectiveness.

scholarly journals Bionic Birdlike Imaging Using a Multi-Hyperuniform LED Array

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4084
Author(s):  
Xin-Yu Zhao ◽  
Li-Jing Li ◽  
Lei Cao ◽  
Ming-Jie Sun
Keyword(s):  
Imaging System ◽  
Color Image ◽  
Digital Camera ◽  
Frame Rate ◽  
Digital Cameras ◽  
Structured Illumination ◽  
Pixel Resolution ◽  
Led Array ◽  
Frequency Aliasing ◽  
Imaging Sensors

Digital cameras obtain color information of the scene using a chromatic filter, usually a Bayer filter, overlaid on a pixelated detector. However, the periodic arrangement of both the filter array and the detector array introduces frequency aliasing in sampling and color misregistration during demosaicking process which causes degradation of image quality. Inspired by the biological structure of the avian retinas, we developed a chromatic LED array which has a geometric arrangement of multi-hyperuniformity, which exhibits an irregularity on small-length scales but a quasi-uniformity on large scales, to suppress frequency aliasing and color misregistration in full color image retrieval. Experiments were performed with a single-pixel imaging system using the multi-hyperuniform chromatic LED array to provide structured illumination, and 208 fps frame rate was achieved at 32 × 32 pixel resolution. By comparing the experimental results with the images captured with a conventional digital camera, it has been demonstrated that the proposed imaging system forms images with less chromatic moiré patterns and color misregistration artifacts. The concept proposed verified here could provide insights for the design and the manufacturing of future bionic imaging sensors.

scholarly journals Broadband Generalized Sidelobe Canceler Beamforming Applied to Ultrasonic Imaging

2020 ◽  
Vol 10 (4) ◽  
pp. 1207
Author(s):  
Jiake Li ◽  
Zhe Ma ◽  
Lei Mao ◽  
Zhengjun Wang ◽  
Yi Wang ◽  
...  
Keyword(s):  
Near Field ◽  
Simulated Data ◽  
Noise Signal ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
Lateral Resolution ◽  
Wavelet Domain ◽  
Sidelobe Level ◽  
Wave Emission ◽  
Single Emission

A broadband generalized sidelobe canceler (Broadband-GSC) application for near-field beamforming is proposed. This approach is implemented in the wavelet domain. Broadband-GSC provides a set of complex, adapted apodization weights for each wavelet subband. The proposed method constrains interference and noise signal to improve the lateral resolution with only one single emission. Performance of the proposed beamforming is tested on simulated data obtained with Field II. Experiments have proved that the new beamforming can significantly increase the image quality compared with delay-and-sum (DAS) and synthetic aperture (SA). Imaging of scattering points show that Broadband-GSC improves the lateral resolution by 43.2% and 58.0% compared with SA and DAS, respectively. Meanwhile，Broadband-GSC reduces the peak sidelobe level by 11.6 dB and 26.4 dB compared with SA and DAS, respectively. Plane wave emission experiment indicates that Broadband-GSC can improve the lateral resolution by 44.2% compared with DAS. Furthermore, the new beamforming introduces the possibility for higher frame-rate and higher investigation depth with increased lateral resolution.

scholarly journals High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

2016 ◽  
Author(s):  
Carlos A. Villagómez-Hoyos ◽  
Matthias B. Stuart ◽  
Thor Bechsgaard ◽  
Michael Bachmann Nielsen ◽  
Jørgen Arendt Jensen
Keyword(s):  
Transthoracic Echocardiography ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
Flow Imaging ◽  
High Frame Rate

SIMS Determination of MG+ and AS+ Range Profiles in Photoresist and Polyimide Implant Masks.

1989 ◽  
Vol 147 ◽  
Author(s):  
D. L. Dugger ◽  
M. B. Stern ◽  
T. M. Rubico
Keyword(s):  
Standard Deviation ◽  
Mass Spectroscopy ◽  
Range Data ◽  
Profile Data ◽  
Projected Range ◽  
Range Profile ◽  
P Type ◽  
Secondary Ion ◽  
Good Agreement

AbstractThe distribution of Mg+ (a p-type dopant for GaAs) and As+ (an p-type dopant for Si) implanted into both photoresist (PR) and polyimide (PI) have been determined experimentally. Range data of Mg ions at 200 keV and 300 keV and As ions at 150 keV have been measured by Secondary Ion Mass Spectroscopy (SIMS). SIMS values for the projected range Rp and the standard deviation ARp were compared to range profile data calculated using the Projected Range Algorithm (PRAL) of Biersack [1] as well as the standard LSS theory [2]. While the values for Rp calculated from the PRAL model generally agreed within 10% of the SIMS values, the calculations underestimated Rp for PR but were in good agreement for PI. The LSS calculations underestimated Rp in both materials.

scholarly journals High frame rate synthetic aperture duplex imaging

2013 ◽  
Author(s):  
Matthias Bo Stuart ◽  
Borislav Gueorguiev Tomov ◽  
Michael Johannes Pihl ◽  
Jorgen Arendt Jensen
Keyword(s):  
Frame Rate ◽  
Synthetic Aperture ◽  
High Frame Rate ◽  
Duplex Imaging

scholarly journals An Inter-Comparison of Techniques for Determining Velocities of Maritime Arctic Glaciers, Svalbard, Using Radarsat-2 Wide Fine Mode Data

2016 ◽  
Author(s):  
Thomas Schellenberger ◽  
Wesley Van Wychen ◽  
Luke Copland ◽  
Andreas Kääb ◽  
Laurence Gray
Keyword(s):  
Speckle Tracking ◽  
Ice Sheets ◽  
Synthetic Aperture ◽  
Pixel Resolution ◽  
Tidewater Glaciers ◽  
Ice Caps ◽  
Spatial Coverage ◽  
Fine Mode ◽  
Comparison Of Techniques ◽  
Glacier Velocity

Glacier dynamics play an important role in the mass balance of many glaciers, ice caps and ice sheets. In this study we exploit Radarsat-2 (RS-2) Wide Fine (WF) data to determine the surface speed of Svalbard glaciers in the winters of 2012/2013 and 2013/2014 using Synthetic Aperture RADAR (SAR) offset and speckle tracking. The RS-2 WF mode combines the advantages of the large spatial coverage of the Wide mode (150 x 150 km) and the high pixel resolution (9m) of the Fine mode and thus has a major potential for glacier velocity monitoring from space through offset and speckle tracking. Faster flowing glaciers (1.95 m d-1 - 2.55 m d-1) which are studied in detail are Nathorstbreen, Kronebreen, Kongsbreen and Monacobreen. Using our Radarsat-2 WF dataset, we compare the performance of two SAR tracking algorithms, namely the GAMMA Remote Sensing Software and a custom written MATLAB script (GRAY method) that has primarily been used in the Canadian Arctic. Both algorithms provide comparable results, especially for the faster flowing glaciers and the termini of slower tidewater glaciers. A comparison of the WF data to RS-2 Ultrafine and Wide mode data reveals the superiority of RS-2 WF data over the Wide mode data.

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