Terahertz (THz) computed tomography is an emerging nondestructive and non-ionizing imaging method. Most THz reconstruction methods rely on the Radon transform, originating from x-ray imaging, in which x rays propagate in straight lines. However, a THz beam has a finite width, and ignoring its shape results in blurred reconstructed images. Moreover, accounting for the THz beam model in a straightforward way in an iterative reconstruction method results in extreme demands in memory and in slow convergence. In this paper, we propose an efficient iterative reconstruction that incorporates the THz beam shape, while avoiding the above disadvantages. Both simulation and real experiments show that our approach results in improved resolution recovery in the reconstructed image. Furthermore, we propose a suitable preconditioner to improve the convergence speed of our reconstruction.
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IEEE Access
November 2024
University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
The achievable spatial resolution of C metabolic images acquired with hyperpolarized C-pyruvate is worse than H images typically by an order of magnitude due to the rapidly decaying hyperpolarized signals and the low gyromagnetic ratio of C. This study is to develop and characterize a volumetric patch-based super-resolution reconstruction algorithm that enhances spatial resolution C cardiac MRI by utilizing structural information from H MRI. The reconstruction procedure comprises anatomical segmentation from high-resolution H MRI, calculation of a patch-based weight matrix, and iterative reconstruction of high-resolution multi-slice C MRI.
View Article and Find Full Text PDFInt J Biomed Res Pract
June 2024
University of Utah, Salt Lake City, UT, United States.
Motivation: In cine MRI, the measurements within each timeframe alone are too noisy for image reconstruction. Some information must be 'borrowed' from other time frames and the reconstruction algorithm is a slow iterative procedure.
Goals: We set up a constrained objective function, which uses the measurements at other time frames to regularize the image reconstruction.
Sci Rep
December 2024
School of Petroleum Engineering, Xi'an Shiyou University, Xi'an, 710065, China.
Horizontal well hydraulic fracturing technology has significantly enhanced the productivity of shale reservoirs. However, our understanding of the expansion patterns within the complex fracture network and fluid seepage mechanisms under field conditions remains inadequate. Here, this work develops a dynamic geomechanical (DG) model to simulate the complete sequence of operations in hydraulic fracturing.
View Article and Find Full Text PDFUrogynecology (Phila)
December 2024
From the Division of Urogynecology and Reconstructive Pelvic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Importance: Pelvic organ prolapse recurrence following native tissue repair occurs with composite failure rates of 9-19% within 12 months, predominantly involving apical/anterior compartments. Objective The objective of this study was to develop a novel vaginal orthosis (NVO) device prototype through an iterative design process based on investigator and user feedback.
Study Design: The NVO was designed based on pelvic floor biomechanical principles to mitigate unopposed intra-abdominal pressure of the anterior vagina by absorbing and redirecting intra-abdominal forces to the levator ani and tailored to accommodate postoperative vaginal caliber and axis.
J Vis Exp
December 2024
School of Biological Science and Medical Engineering, Southeast University; Mathematical Sciences Department, Worcester Polytechnic Institute.
Quantifying the mechanical properties of coronary arterial walls could provide meaningful information for the diagnosis, management, and treatment of coronary artery diseases. Since patient-specific coronary samples are not available for patients requiring continuous monitoring, direct experimental testing of vessel material properties becomes impossible. Current coronary models typically use material parameters from available literature, leading to significant mechanical stress/strain calculation errors.
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