Brillouin spectroscopy can suffer from low signal-to-noise ratios (SNRs). Such low SNRs can render common data analysis protocols unreliable, especially for SNRs below ∼10. In this work we exploit two denoising algorithms, namely maximum entropy reconstruction (MER) and wavelet analysis (WA), to improve the accuracy and precision in determination of Brillouin shifts and linewidth. Algorithm performance is quantified using Monte-Carlo simulations and benchmarked against the Cramér-Rao lower bound. Superior estimation results are demonstrated even at low SNRs (≥ 1). Denoising is furthermore applied to experimental Brillouin spectra of distilled water at room temperature, allowing the speed of sound in water to be extracted. Experimental and theoretical values were found to be consistent to within ±1% at unity SNR.
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http://dx.doi.org/10.1364/BOE.380798 | DOI Listing |
J Belg Soc Radiol
December 2024
Faculty of Medicine, Departments of Internal Medicine, İnönü University, Turkey.
This study aims to assess the performances of T1‑weighted (T1W) and T2‑weighted (T2W) Dixon sequences as replacements for the standard magnetic resonance imaging (MRI) protocol for diagnosing active and chronic sacroiliitis. This single‑centre, prospective study included 107 patients who underwent 3 Tesla MRIs. The patients with inflammatory low‑back pain (aged 18-50 years) were included.
View Article and Find Full Text PDFAcad Radiol
December 2024
Department of Radiology, Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (H.Z., Q.C., W.M., J.Y., S.W., G.T., J.X., H.J., H.Y., L.Z.). Electronic address:
Rationale And Objectives: To comprehensively assess the feasibility of low-dose computed tomography (LDCT) using deep learning image reconstruction (DLIR) for evaluating pulmonary subsolid nodules, which are challenging due to their susceptibility to noise.
Materials And Methods: Patients undergoing both standard-dose CT (SDCT) and LDCT between March and June 2023 were prospectively enrolled. LDCT images were reconstructed with high-strength DLIR (DLIR-H), medium-strength DLIR (DLIR-M), adaptive statistical iterative reconstruction-V level 50% (ASIR-V-50%), and filtered back projection (FBP); SDCT with FBP as the reference standard.
ACS Cent Sci
November 2024
Center of Excellence for Renewable Energy and Storage Technologies, Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
X-ray detection technology is essential in various fields, including medical imaging and security checks. However, exposure to large doses of X-rays poses considerable health risks. Therefore, it is crucial to reduce the radiation dosage without compromising detection efficiency.
View Article and Find Full Text PDFEar Hear
November 2024
Department of Communication Sciences & Disorders, Northwestern University, Evanston, Illinois, USA.
Objectives: Previous research has shown that speech recognition with different wide dynamic range compression (WDRC) time-constants (fast-acting or Fast and slow-acting or Slow) is associated with individual working memory ability, especially in adverse listening conditions. Until recently, much of this research has been limited to omnidirectional hearing aid settings and colocated speech and noise, whereas most hearing aids are fit with directional processing that may improve the listening environment in spatially separated conditions and interact with WDRC processing. The primary objective of this study was to determine whether there is an association between individual working memory ability and speech recognition in noise with different WDRC time-constants, with and without microphone directionality (binaural beamformer or Beam versus omnidirectional or Omni) in a spatial condition ideal for the beamformer (speech at 0 , noise at 180 ).
View Article and Find Full Text PDFJ Acoust Soc Am
November 2024
Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education, Southeast University, Nanjing, 210096, China.
In this paper, a frequency line detection network (FLDNet) is proposed to effectively detect multiple weak frequency lines and time-varying frequency lines in underwater acoustic signals under low signal-to-noise ratios (SNRs). FLDNet adopts an encoder-decoder architecture as the basic framework, where the encoder is designed to obtain multilevel features of the frequency lines, and the decoder is responsible for reconstructing the frequency lines. FLDNet includes attention-based feature fusion modules that combine deep semantic features with shallow features learned by the encoder to reduce noise in the decoder's deep feature representation and improve reconstruction accuracy.
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