On the signal-to-noise ratio of a synthetic aperture ultrasound imaging method

<div>Frequency compounding is an ultrasound imaging technique used to reduce artifacts and improve signal-to-noise-ratio (SNR). In this work a new nonlinear frequency compounding (NLFC) method was introduced, and its application in B-mode imaging and noninvasive thermometry was investigated. NLFC input frequencies were optimized to maximize speckle-signal-to-noise-ratio (SSNR) in a tissue mimicking phantom, and the method was then used to produce maps of the temperature sensitive change in backscattered energy of acoustic harmonics (<i>h</i>CBE) during heating of ex vivo porcine tissue with a focused ultrasound transducer. A <i>h</i>CBE-to-temperature calibration was also performed and temperature maps produced. Lastly, a comparative study of the NLFC and previously used nonlinear single frequency (NLSF) method was completed. By using the NLFC method it was concluded that SSNR of B-mode and backscattered energy images, SNR of <i>h</i>CBE maps, and temperature map agreement with a theoretical COMSOL based model were improved over the previously used NLSF method.</div>

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Low-latency time-of-flight non-line-of-sight imaging at 5 frames per second

Nature Communications ◽

10.1038/s41467-021-26721-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ji Hyun Nam ◽

Eric Brandt ◽

Sebastian Bauer ◽

Xiaochun Liu ◽

Marco Renna ◽

...

Keyword(s):

Signal To Noise Ratio ◽

Time Of Flight ◽

Motion Blur ◽

Line Of Sight ◽

Low Latency ◽

Imaging Method ◽

Signal To Noise ◽

Array Detectors ◽

Noise Ratio ◽

Non Line Of Sight

AbstractNon-Line-Of-Sight (NLOS) imaging aims at recovering the 3D geometry of objects that are hidden from the direct line of sight. One major challenge with this technique is the weak available multibounce signal limiting scene size, capture speed, and reconstruction quality. To overcome this obstacle, we introduce a multipixel time-of-flight non-line-of-sight imaging method combining specifically designed Single Photon Avalanche Diode (SPAD) array detectors with a fast reconstruction algorithm that captures and reconstructs live low-latency videos of non-line-of-sight scenes with natural non-retroreflective objects. We develop a model of the signal-to-noise-ratio of non-line-of-sight imaging and use it to devise a method that reconstructs the scene such that signal-to-noise-ratio, motion blur, angular resolution, and depth resolution are all independent of scene depth suggesting that reconstruction of very large scenes may be possible.

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Intrapulse polarimetric inverse synthetic aperture radar imaging under low signal-to-noise ratio based on range profile fusion and improved motion compensation

Journal of Applied Remote Sensing ◽

10.1117/1.jrs.12.035005 ◽

2018 ◽

Vol 12 (03) ◽

pp. 1

Author(s):

Jing Jingyu Li ◽

Qianqiang Lin ◽

Xiangyu Peng

Keyword(s):

Synthetic Aperture Radar ◽

Motion Compensation ◽

Signal To Noise Ratio ◽

Radar Imaging ◽

Synthetic Aperture ◽

Inverse Synthetic Aperture Radar ◽

Signal To Noise ◽

Range Profile ◽

Noise Ratio ◽

Aperture Radar

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Development Of A Nonlinear Frequency Compounding Method With Applications In Ultrasound Imaging And Thermometry

10.32920/16821232 ◽

2021 ◽

Author(s):

Tyler Hornsby

Keyword(s):

Ultrasound Imaging ◽

Focused Ultrasound ◽

Ex Vivo ◽

Signal To Noise Ratio ◽

Single Frequency ◽

Temperature Sensitive ◽

Nonlinear Frequency ◽

Signal To Noise ◽

Noise Ratio ◽

Temperature Maps

<div>Frequency compounding is an ultrasound imaging technique used to reduce artifacts and improve signal-to-noise-ratio (SNR). In this work a new nonlinear frequency compounding (NLFC) method was introduced, and its application in B-mode imaging and noninvasive thermometry was investigated. NLFC input frequencies were optimized to maximize speckle-signal-to-noise-ratio (SSNR) in a tissue mimicking phantom, and the method was then used to produce maps of the temperature sensitive change in backscattered energy of acoustic harmonics (<i>h</i>CBE) during heating of ex vivo porcine tissue with a focused ultrasound transducer. A <i>h</i>CBE-to-temperature calibration was also performed and temperature maps produced. Lastly, a comparative study of the NLFC and previously used nonlinear single frequency (NLSF) method was completed. By using the NLFC method it was concluded that SSNR of B-mode and backscattered energy images, SNR of <i>h</i>CBE maps, and temperature map agreement with a theoretical COMSOL based model were improved over the previously used NLSF method.</div>

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Increasing reliability of forensic analysis while research on destroyed relief marking with magneto-optical devices

Theory and Practice of Forensic Science and Criminalistics ◽

10.32353/khrife.1.2021.11 ◽

2021 ◽

Vol 23 (1) ◽

pp. 148-166

Author(s):

Yu. Agalidi ◽

O. Koshel

Keyword(s):

Optical Imaging ◽

Signal To Noise Ratio ◽

Forensic Analysis ◽

Imaging Method ◽

Signal Recognition ◽

Visualization Method ◽

Signal To Noise ◽

Instrumental Data ◽

Noise Ratio ◽

Correct Signal

While research on destroyed relief marking of metal objects using the magneto-optical method, visualization of (invisible) fields of internal stress in the VIN plate area is performed and then a forensic analysis of obtained instrumental data is carried out (indirect organoleptic observation of the visualization results); thus, forensic analysis reliability of results directly depends on sensitivity of instruments and informativeness of instrumental data. The main quantitative characteristic in this case is probability of correct signal recognition (contours of marking signs) against the background of noise (structural noise of investigated surface and the noise of the visualization method itself) determined by the signal-to-noise ratio. This article presents results of a comparative experimental assessment of signal-to-noise ratio and probability of correct signal recognition while restoringthe destroyed relief markings for two complexes of magneto-optical imaging – models of 2006 and 2018. This article purpose is a quantitative and qualitative comparative assessment of results of visualization of internal stresses in areas of completely removed relief marking of metal objects. The results of successful practical research obtained by forensic experts from different countries make it possible to assess effectiveness and prospects of using the magneto-optical imaging method. In a new modification of the magneto-optical complex: signal level is 4.35 dB higher (contrast of reconstructed marking signs); 2.71 dB lower noise level (surface relief/texture and magnetic copying noise);• probability of correct character recognition is P> 0.995 (increased by 14.9%). Technical improvements in implementation of magneto-optical visualization method made it possible to expand the range of materials for research objects(magnetic and electrically conductive materials were investigated). The high efficiency of method for restoring marking is illustrated by results of forensic examinations for materials with a low level of residual stresses (aluminum alloy, low-carbon steel) which chemical etching method did not give results for. The use of new modification allows examining the rust layer, up to cases of corrosion to the entire depth of marks. Considering non-destructive nature of magneto-optical researches, possibility of their repeated repetition without losing object properties, this method (in accordance with the order of application of types of studies) deserves more attention for application.

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An Investigation of Binary Coded Excitation Methods Using Golay Code Pairs for High Frequency Ultrasound Imaging

10.32920/ryerson.14661585.v1 ◽

2021 ◽

Author(s):

Xuegang Su

Keyword(s):

Ultrasound Imaging ◽

High Frequency ◽

Signal To Noise Ratio ◽

High Frequency Ultrasound ◽

Golay Code ◽

Signal To Noise ◽

Coded Excitation ◽

High Frequency Ultrasound Imaging ◽

Noise Ratio ◽

Frequency Ultrasound

We are investigating the feasibility of binary coded excitation methods using Golay code pairs for high frequency ultrasound imaging as a way to increase the signal to noise ratio. I present some theoretical models used to simulate the coded excitation method and results generated from the models. A new coded excitation high frequency ultrasound prototype system was built to verify the simulation results. Both the simulation and the experimental results show that binary coded excitation can improve the signal to noise ratio in high frequency ultrasound backscatter signals. These results are confirmed in phantoms and excised bovine liver. If just white noise is considered, the encoding gain is 15dB for a Golay pair of length 4. We find the system to be very sensitive to motion (i.e. phase shift) and frequency dependent (FD) attenuation, creating sidelobes and degrading axial resolution and encoding gain. Methods to address these issues are discussed.

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