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[IEEE 2018 IEEE 3rd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - Chongqing, China (2018.10.12-2018.10.14)] 2018 IEEE 3rd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - Medical image segmentation based on improved watershed algorithm
摘要： The watershed segmentation algorithm has the problem of over-segmentation. The paper proposed an improved watershed algorithm for medical image segmentation. Combined with improved gray morphological reconstruction and watershed algorithm, the segmentation of medical cells and brain CT images is improved, which improves the accuracy of image segmentation of medical tissues and organs and assists doctors to diagnose the diseases. The simulation results show that the improved algorithm can effectively suppress the over-segmentation for two different medical tissue images.
关键词： watershed algorithm,medical image,segmentation,grayscale morphology
更新于2025-09-23 15:23:52
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A monolithic on-chip magneto-optical isolator with 3 dB insertion loss and 40 dB isolation ratio
摘要： On-chip optical isolators constitute an essential building block for photonic integrated circuits (PICs). Here we experimentally demonstrated a magneto-optical isolator monolithically integrated on silicon featuring 3 dB insertion loss and 40 dB isolation ratio, both of which represent significant improvements over state-of-the-art. The isolator is also fully passive and operates under a simple unidirectional magnetization scheme. Such superior performance is enabled through a three-way combination of a strip-loaded waveguide design, a compositionally optimized chalcogenide glass as the light guiding medium, and low-loss taper structures created via gray-scale lithographic processing. The device represents an important step towards a practical solution for on-chip isolation in PICs.
关键词： Integrated optics devices,Magneto-optical materials,Chalcogenide glass,Resonators,Grayscale-lithography,Isolators
更新于2025-09-23 15:21:21
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Performance Improvement of Gate-Tunable Organic Light-Emitting Diodes with Electron-Transport and Hole-Blocking Layers
摘要： The current density and luminance of gate-tunable organic light-emitting diodes (OLEDs) can be modulated by application of an external gate potential. However, existing gate-tunable OLEDs require further optimization to make them suitable for practical use. In this work, the rapid electron conduction of 4,4’-bis(N-carbazolyl)-1,1’biphenyl (CBP) molecules under low operating potential is demonstrated in polymer electrolyte-coated super yellow (SY) polymer light-emitting diodes (PLEDs). This behavior is attributed to the facile electrochemical n-doping of CBP by the polymer electrolyte infiltrated into the SY PLED through the porous aluminum cathode. The field-modulated conductivity of CBP upon applying an external gate potential to electrolyte-gated (EG) PLEDs is demonstrated. These phenomena lead to the improved performance of EG SY PLEDs with a CBP electron-transport layer and 1,3,5-tris[(3-pyridyl)-phen-3-yl]benzene) (TmpypB) hole-blocking layer between the porous aluminum cathode and SY emissive layer, including low turn-on voltage (1.5 V), low current density leakage (0.01 mA/cm2), low off luminance (<0.01 cd/m2), saturated on-current density (2 mA/cm2) and on-luminance (100 cd/m2), and largely suppressed hysteresis. These results pave the path for practical application of EG OLEDs in displays, especially near-to-eye displays.
关键词： facile electrochemical doping,saturated on-current density and on-luminance,low off-current density leakage and off-luminance,suppressed hysteresis,near-to-eye displays,gate-tunable organic light-emitting diodes,grayscale displaying,porous electrodes
更新于2025-09-23 15:21:01
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[ASME ASME 2018 13th International Manufacturing Science and Engineering Conference - College Station, Texas, USA (Monday 18 June 2018)] Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing - High-Throughput 3D Printing of Customized Imaging Lenses
摘要： The emerging 3D printing technology has the potential to transform manufacturing customized optical elements, which currently heavily relies on the time-consuming and costly polishing and grinding processes. However, the inherent speed-accuracy trade-off seriously constraints the practical applications of 3D printing technology in optical realm. In addressing this issue, here, we report a new method featuring a significantly faster fabrication speed, at 24.54 mm3/h, without compromising the fabrication accuracy or surface finish required to 3D-print customized optical components. We demonstrated a high-speed 3D printing process with deep subwavelength (sub-10 nm) surface roughness by employing the projection micro-stereolithography process and the synergistic effects from the grayscale photopolymerization and the meniscus equilibrium post-curing methods. Fabricating a customized aspheric lens with 5 mm in height and 3 mm in diameter could be accomplished in less than four hours. The 3D-printed singlet aspheric lens demonstrated a maximal imaging resolution of 2.19 μm with low field distortion less than 0.13% across a 2-mm field of view. This work demonstrates the potential of 3D printing for rapid manufacturing of optical components.
关键词： optical lenses,meniscus equilibrium post-curing,projection micro-stereolithography,3D printing,grayscale photopolymerization
更新于2025-09-23 15:21:01
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Colour Image Represention of Multispectral Image Fusion
摘要： The availability of imaging sensors operating in multiple spectral bands has led to the requirement of image fusion algorithms that would combine the image from these sensors in an efficient way to give an image that is more perceptible to human eye. Multispectral Image fusion is the process of combining images optically acquired in more than one spectral band. In this paper, we present a pixel-level image fusion that combines four images from four different spectral bands namely near infrared(0.76-0.90um), mid infrared(1.55-1.75um),thermal- infrared(10.4-12.5um) and mid infrared(2.08-2.35um) to give a composite colour image. The work coalesces a fusion technique that involves linear transformation based on Cholesky decomposition of the covariance matrix of source data that converts multispectral source images which are in grayscale into colour image. This work is composed of different segments that includes estimation of covariance matrix of images, cholesky decomposition and transformation ones. Finally, the fused colour image is compared with the fused image obtained by PCA transformation.
关键词： Grayscale image,cholesky decomposition,Multispectral image fusion,principal component analysis
更新于2025-09-23 15:21:01
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Grayscale e-beam lithography: Effects of a delayed development for well-controlled 3D patterning
摘要： Grayscale electron beam lithography (g-EBL) is a fabrication technique that allows for tunable control of resist topography. In most cases, the height of the structures is in the submicron regime. Here, we present an extensive experimental characterization of the post electron beam exposure behavior of poly(methyl methacrylate) (PMMA) 950K for grayscale structuring with several micrometers in height. The obtained results show that the development depth for the same electron dose is dependent on the time between exposure and development. This dependence becomes more prominent at higher exposure doses. Additionally, it was found that a post-exposure bake influences the dose-response behavior of the resist material and, therefore, also the obtained three-dimensional (3D) structure. This work paves the way for well-controlled 3D micrometer structuring via g-EBL.
关键词： delayed development,PMMA 950K,3D microstructuring,post-exposure bake,grayscale e-beam lithography
更新于2025-09-23 15:19:57
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Grayscale Nanopatterning of Phase-Change Materials for Subwavelength-Scaled, Inherently Planar, Nonvolatile, and Reconfigurable Optical Devices
摘要： The integration of phase-change materials into the design of optical metasurfaces already enables dynamically switchable, tunable, and reconfigurable optical devices. Their functionality is based on fast and repeatable switching between two stable states - amorphous and crystalline - which is typically accompanied by drastic changes of the electrical and optical properties and can be accomplished by external stimuli. In this study, we demonstrate that focused ion beam irradiation can be used to locally tailor the amount of disorder in phase-change materials in highly confined regions, which was examined both in the visible and mid infrared by using optical nano-imaging techniques such as photo-induced force microscopy and scattering type scanning near-field optical microscopy. Our approach enables grayscale patterning at the nanoscale circumventing the diffraction limit of common laser light sources and thus literally adds a further degree of freedom for the design of optical devices that are subwavelength-scaled, inherently planar, nonvolatile, and reconfigurable.
关键词： focused ion irradiation,grayscale,tailoring disorder,nanopatterning,phase-change materials,nano-imaging
更新于2025-09-19 17:13:59
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Higher Resolution in Cone Beam Computed Tomography Is Accompanied by Improved Bone Detection in Peri-implant Bone Despite Metal Artifact Presence
摘要： The aim of this study was to determine the possibility and extent of artifact reduction by an optimized use of cone beam computed tomography (CBCT) parameter configuration (geometric resolution, implant geometric parameters, and image analyses). It furthermore sought to determine the distance from correctly reproduced bone tissue to an implant, where the grayscale values are equal to the pre-implantation values. Materials and Methods: Titanium implants were inserted into pig tibia under standardized conditions. CBCT investigations in the form of bone density mapping were performed under various CBCT settings and implantation situations. The circumference of the implants was measured in order to determine the extent of metal artifacts. This was done by determining grayscale and comparing it to the bone area prior to implantation. Results: Using CBCT to determine bone density postimplantation showed a correlation in dependence of CBCT parameter configuration. Higher resolution led to a better detection of correct bone density values in the peri-implant region. Normal bone density values can be recognized at a distance of 370 μm from the implant surface, when the spatial resolution is 125 μm. Therefore, higher resolution in CBCT is accompanied by an improved bone detection in peri-implant bone, despite the presence of metal artifacts. Peri-implant bone defects that extend 400 μm around implants were reliably detected by using a spatial resolution of 125 μm. In specimens, where multiple implants are present in one line, pronounced artifact formations were present. The artifacts were visible as a combination of streak-like hardening and extinction effects. Conclusion: Bone geometric data and density values may be determined correctly in close proximity to the implant surface, and can detect peri-implant bone defects. When multiple implants are placed, the implant radiation direction geometry must be considered.
关键词： peri-implant defects,metal artifact,implant,CBCT,spatial resolution,grayscale
更新于2025-09-10 09:29:36
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Positive and negative correlations in computational ghost imaging for a grayscale object
摘要： Our previous work has studied the positive-negative correlations in computational ghost imaging for a binary object. In this work, we focus on the computational ghost imaging system for a grayscale object. We studied the second-order correlation function of this system, and gave the criterion of the positive and negative correlations. Furthermore, this criterion was verified by using numerical simulations.
关键词： computational ghost imaging,grayscale object,second-order correlation function,positive-negative correlations
更新于2025-09-10 09:29:36
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A Spatially Constrained Shifted Asymmetric Laplace Mixture Model for the Grayscale Image Segmentation
摘要： In this paper, the grayscale image segmentation problem is investigated and a new mixture model with shifted asymmetric Laplace distribution component is proposed. Instead of the conventional Gaussian model, the shifted asymmetric Laplace distribution model is adopted to model the pixels. The spatial constraint on neighboring pixels is introduced into the proposed shifted asymmetric Laplace mixture model, which makes the model be robust to noise and outliers of the images. The unknown model parameters are estimated via the expectation-maximization (EM) algorithm, which can guarantee convergence to a local minimum. The experimental verification is performed on both synthesized images and images of real chip to prove the effectiveness of our image segmentation method.
关键词： Shifted asymmetric Laplace mixture model,Expecation-maximization algorithm,Grayscale image segmentation,Experimental verification
更新于2025-09-10 09:29:36