In general, synthetic aperture radar (SAR) imaging and image processing are two sequential steps in SAR image processing. Due to the large size of SAR images, most image processing algorithms require image segmentation before processing. However, the existence of speckle noise in SAR images, as well as poor contrast and the uneven distribution of gray values in the same target, make SAR images difficult to segment. In order to facilitate the subsequent processing of SAR images, this paper proposes a new method that combines the back-projection algorithm (BPA) and a first-order gradient operator to enhance the edges of SAR images to overcome image segmentation problems. For complex-valued signals, the gradient operator was applied directly to the imaging process. The experimental results of simulated images and real images validate our proposed method. For the simulated scene, the supervised image segmentation evaluation indexes of our method have more than 1.18%, 11.2% and 11.72% improvement on probabilistic Rand index (PRI), variability index (VI), and global consistency error (GCE). The proposed imaging method will make SAR image segmentation and related applications easier.
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http://dx.doi.org/10.3390/s18124133 | DOI Listing |
Biomaterials
January 2025
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen, 361102, China. Electronic address:
Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment due to its precise spatiotemporal selectivity and non-invasive nature. However, several challenges, including the inability of photosensitizers to discriminate between tumor and healthy tissues, as well as the limited tissue penetration depth of light sources, impede its broader application. To surmount these impediments, our research introduces a two-photon photosensitizer (TPSS) that specifically targets tumor overexpressing carbonic anhydrase IX (CA IX), thereby exhibiting exceptional specificity for tumor cells.
View Article and Find Full Text PDFBackground: Intracranial atherosclerotic stenosis is a leading cause of ischemic stroke and recurrent events due to plaque instability. High-resolution magnetic resonance imaging identifies plaque enhancement as a key marker of instability. This study evaluated the efficacy of combined high-intensity statins and proprotein convertase subtilisin/kexin type 9 inhibitors in plaque stabilization.
View Article and Find Full Text PDFAn Acad Bras Cienc
January 2025
Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brazil.
The region of the Maritime Antarctic suffers significantly from climate change, resulting in regional warming and consequently affecting coverage. This study characterized three surface zones of Collins Glacier and three other zones in ice-free areas on the Fildes Peninsula, which has an area of 29.6 km².
View Article and Find Full Text PDFBioelectromagnetics
January 2025
Bioelectromagnetics Laboratory, University of Wollongong, Wollongong, Australia.
In this paper, we present the design, RF-EMF performance, and a comprehensive uncertainty analysis of the reverberation chamber (RC) exposure systems that have been developed for the use of researchers at the University of Wollongong Bioelectromagnetics Laboratory, Australia, for the purpose of investigating the biological effects of RF-EMF in rodents. Initial studies, at 1950 MHz, have focused on investigating thermophysiological effects of RF exposure, and replication studies related to RF-EMF exposure and progression of Alzheimer's disease (AD) in mice predisposed to AD. The RC exposure system was chosen as it allows relatively unconstrained movement of animals during exposures which can have the beneficial effect of minimizing stress-related, non-RF-induced biological and behavioral changes in the animals.
View Article and Find Full Text PDFJ Med Chem
January 2025
Guangdong Medicine-Engineering Interdisciplinary Technology Research Center, School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China.
Positron emission tomography (PET) is a common imaging technique and can provide accurate information about the size, shape, and location of tumors. Recent evidence has shown that G-quadruplex structures (G4s) are identified in human oncogenes, and these special structures are recognized as diagnostic cancer markers and drug targets for anticancer therapies. Although a number of techniques for in vivo imaging of G4s have been developed, achieving sufficient sensitivity and selectivity in vivo remains challenging.
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