- 标题
- 摘要
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- 实验方案
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MedGA: A novel evolutionary method for image enhancement in medical imaging systems
摘要： Medical imaging systems often require the application of image enhancement techniques to help physicians in anomaly/abnormality detection and diagnosis, as well as to improve the quality of images that undergo automated image processing. In this work we introduce MedGA, a novel image enhancement method based on Genetic Algorithms that is able to improve the appearance and the visual quality of images characterized by a bimodal gray level intensity histogram, by strengthening their two underlying sub-distributions. MedGA can be exploited as a pre-processing step for the enhancement of images with a nearly bimodal histogram distribution, to improve the results achieved by downstream image processing techniques. As a case study, we use MedGA as a clinical expert system for contrast-enhanced Magnetic Resonance image analysis, considering Magnetic Resonance guided Focused Ultrasound Surgery for uterine fibroids. The performances of MedGA are quantitatively evaluated by means of various image enhancement metrics, and compared against the conventional state-of-the-art image enhancement techniques, namely, histogram equalization, bi-histogram equalization, encoding and decoding Gamma transformations, and sigmoid transformations. We show that MedGA considerably outperforms the other approaches in terms of signal and perceived image quality, while preserving the input mean brightness. MedGA may have a significant impact in real healthcare environments, representing an intelligent solution for Clinical Decision Support Systems in radiology practice for image enhancement, to visually assist physicians during their interactive decision-making tasks, as well as for the improvement of downstream automated processing pipelines in clinically useful measurements.
关键词： Medical imaging systems,Genetic Algorithms,Uterine fibroids,Magnetic resonance imaging,Bimodal image histogram,Image enhancement
更新于2025-09-23 15:21:01
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Composition and size controlled I-V-VI semiconductor nanocrystals
摘要： Non-isovalent ternary and quaternary semiconductors (i.e., having two or more cations with different valence) have unique structural and electronic properties that are leveraged in photovoltaic, thermoelectric, and phase-change memory devices. Making these complex semiconductors in the form of colloidal nanocrystals imparts size-dependent properties and solution processability. Here, we present results on I‐V‐VI group colloidal nanocrystals. We focus on achieving sub-10 nm sizes for a wide range of I-V-VI selenide nanocrystals, including AgSbSe2, AgSb2Se3, CuSbSe2, Cu3SbSe4, AgBiSe2, and CuBiSe2. To highlight one possible application for these I-V-VI colloidal nanomaterials, we analyze the optical absorption and show that through composition and size control, this class of materials offers bandgaps in the mid- to near-IR. Absorption coefficients of AgSbSe2, CuSbSe2, and Cu3SbSe4 nanocrystals are on par with or higher than the well-studied PbS nanocrystals highlighting their potential for devices such as solar cells, (mid-)infrared photodetectors, and near-infrared bio-imaging systems.
关键词： solar cells,optical absorption,bio-imaging systems,colloidal nanocrystals,infrared photodetectors,mid- to near-IR,I-V-VI semiconductor nanocrystals,bandgaps
更新于2025-09-23 15:19:57
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[IEEE 2018 New Generation of CAS (NGCAS) - Valletta, Malta (2018.11.20-2018.11.23)] 2018 New Generation of CAS (NGCAS) - High-Resolution ADCs for Biomedical Imaging Systems
摘要： With the rapid development of biomedical imaging systems, the requirement of the accuracy of an Analog-to-Digital Converter (ADC) becomes more and more critical. Traditional Nyquist-rate analog to digital data converters cannot meet the requirement any more. Sigma-Delta analog to digital data converter, which makes a trade-off between speed and accuracy, can achieve an ideal accuracy by employing the oversampling and noise-shaping technology. In this work, a Verilog-AMS model for sigma-delta modulator is built, including the topologic, the order of stage, oversampling rate, system parameters, etc. On the basic of theoretical analysis and scienti?c ?ow path, ?nally, a third-order 1-bit sigma-delta modulator is designed and optimized, whose performance agrees well with the theoretical module.
关键词： Analog-to-Digital Converter,Σ? ADC,Successive Approximation Register(SAR) ADC,Oversampling,Biomedical Imaging Systems
更新于2025-09-23 15:19:57
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Automated Optical Flow Based Registration For Adaptive Optics Scanning Laser Ophthalmoscope
摘要： This study presents an automated registration method based on optical flow for an adaptive optics scanning laser ophthalmoscope. The method was designed to align and average images to obtain a higher signal-to-noise ratio image. A correlation based optical flow image registration method, which has large registration degrees of freedom, is adopted as a local registration method. By comparing the images before and after image registration, we show the effectiveness of our method. Furthermore, the advantage of our method, which is the containment of large registration degrees of freedom, is confirmed.
关键词： Retinal images,Image processing,Imaging systems,Optical flow,Active or adaptive optics,Ophthalmology
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Computational Modelling of Metasurfaces for Strongly Divergent Beams
摘要： The content of the paper discusses the computational modelling of metasurfaces for strongly divergent beams, focusing on the design and application of metasurfaces with building blocks that can efficiently control light beams with high divergence. It highlights the potential of these metasurfaces in various applications, including optical tweezers, laser beam shaping, and imaging systems. The paper also explores the challenges and limitations in designing such metasurfaces, particularly in achieving high efficiency over a broad range of angles and wavelengths.
关键词： imaging systems,computational modelling,metasurfaces,optical tweezers,divergent beams,laser beam shaping
更新于2025-09-11 14:15:04
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Aberrated dark-field imaging systems
摘要： We study generalized dark-field imaging systems. These are a subset of linear shift-invariant optical imaging systems that exhibit arbitrary aberrations and for which normally incident plane-wave input yields zero output. We write down the theory for the forward problem of imaging coherent scalar optical fields using such arbitrarily aberrated dark-field systems and give numerical examples. The associated images may be viewed as a form of dark-field Gabor holography, utilizing arbitrary outgoing Green’s functions as generalized Huygens-type wavelets, with the Young-type boundary wave forming the holographic reference.
关键词： dark-field imaging,aberrations,linear shift-invariant optical imaging systems,Gabor holography,Huygens-type wavelets
更新于2025-09-09 09:28:46