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- 2019
- Digital signal processing techniques for optical communications
- transmission impairments and their mitigations
- multiplexing and demultiplexing techniques including OTDM
- OFDM
- OCDM and SDM
- Optoelectronic Information Science and Engineering
- Beijing Electronic Science and Technology Institute
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Building Intermixed Donor-Acceptor Architectures for Water-Processable Organic Photovoltaics
摘要： A modified synthesis method for aqueous nanoparticle printing inks, based upon vacuum-assisted solvent removal, is reported. Poly(3-hexylthiophene) : phenyl C61 butyric acid methyl ester nanoparticle inks were prepared via this modified miniemulsion method; leading to both an improvement in photoactive layer morphology and a substantial reduction in the ink fabrication time. A combination of UV-visible spectroscopy, photoluminescence spectroscopy and scanning transmission X-ray microscopy measurements revealed a nanoparticle morphology comprised of highly intermixed donor-acceptor domains. Consistent with these measurements, dynamic mechanical thermal analysis of the nanoparticles showed a glass transition temperature (Tg) of 104 °C, rather than a pure polymer phase or pure fullerene phase Tg. Together the spectroscopy, microscopy and thermomechanical data indicate that rapid solvent removal generates a more blended nanoparticle morphology. As such, this study highlights a new experimental lever for optimising nanostructure in the photoactive layer of nanoparticulate organic photovoltaic devices by enabling highly intermixed donor-acceptor architectures to be built from customised nanoparticulate inks.
关键词： organic photovoltaic,scanning transmission X-ray microscopy,morphology,colloidal inks,exciton dissociation,Nanostructure,eco-friendly processing
更新于2025-11-19 16:46:39
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Plasma Texturing of Silicon Wafers and Finished Solar Cell for Mass Production
摘要： Standard plasma texturing of silicon wafers are not widely introduced within mass production due to several challenges which have to be overcome before implementation i.e. surface contamination, surface near damaging due to ion bombardment, and surface passivation. Within this contribution we will show our current status to overcome these challenges. We will present that the electrical and optical properties of ICP only plasma textured samples are sufficient for solar cell production. Since in ICP processes the ion bombardment is low we also will discuss our current understanding of the plasma process based on experimental results of the self-masking process. Furthermore, a new plasma texturing approach texturing the SiN layer of finished solar cells is introduced for the first time which overcome all problems introduced by the plasma texturing of bare solar wafers.
关键词： Plasma materials processing,silicon,SiN texturing,Plasma texturing,photovoltaic cells
更新于2025-10-22 19:40:53
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A Runtime-Scalable and Hardware-Accelerated Approach to On-Board Linear Unmixing of Hyperspectral Images
摘要： Space missions are facing disruptive innovation since the appearance of small, lightweight, and low-cost satellites (e.g., CubeSats). The use of commercial devices and their limitations in cost usually entail a decrease in available on-board computing power. To face this change, the on-board processing paradigm is advancing towards the clustering of satellites, and moving to distributed and collaborative schemes in order to maintain acceptable performance levels in complex applications such as hyperspectral image processing. In this scenario, hybrid hardware/software and reconfigurable computing have appeared as key enabling technologies, even though they increase complexity in both design and run time. In this paper, the ARTICo3 framework, which abstracts and eases the design and run-time management of hardware-accelerated systems, has been used to deploy a networked implementation of the Fast UNmixing (FUN) algorithm, which performs linear unmixing of hyperspectral images in a small cluster of reconfigurable computing devices that emulates a distributed on-board processing scenario. Algorithmic modifications have been proposed to enable data-level parallelism and foster scalability in two ways: on the one hand, in the number of accelerators per reconfigurable device; on the other hand, in the number of network nodes. Experimental results motivate the use of ARTICo3-enabled systems for on-board processing in applications traditionally addressed by high-performance on-Earth computation. Results also show that the proposed implementation may be better, for certain configurations, than an equivalent software-based solution in both performance and energy efficiency, achieving great scalability that is only limited by communication bandwidth.
关键词： FPGAs,hyperspectral imaging,on-board processing,ARTICo3,linear unmixing
更新于2025-09-23 15:23:52
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An image reconstruction method (IRBis) for optical/infrared interferometry
摘要： Aims.We present an image reconstruction method for optical/infrared long-baseline interferometry called IRBis (image reconstruction software using the bispectrum). We describe the theory and present applications to computer-simulated interferograms. Methods. The IRBis method can reconstruct an image from measured visibilities and closure phases. The applied optimization routine ASA_CG is based on conjugate gradients. The method allows the user to implement different regularizers, apply residual ratios as an additional metric for goodness-of-fit, and use previous iteration results as a prior to force convergence. Results. We present the theory of the IRBis method and several applications of the method to computer-simulated interferograms. The image reconstruction results show the dependence of the reconstructed image on the noise in the interferograms (e.g., for ten electron read-out noise and 139 to 1219 detected photons per interferogram), the regularization method, the angular resolution, and the reconstruction parameters applied. Furthermore, we present the IRBis reconstructions submitted to the interferometric imaging beauty contest 2012 initiated by the IAU Working Group on Optical/IR Interferometry and describe the performed data processing steps.
关键词： techniques: high angular resolution,methods: data analysis,instrumentation: interferometers,techniques: interferometric,methods: numerical,techniques: image processing
更新于2025-09-23 15:23:52
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Denoising, deconvolving, and decomposing multi-domain photon observations
摘要： Astronomical imaging based on photon count data is a non-trivial task. In this context we show how to denoise, deconvolve, and decompose multi-domain photon observations. The primary objective is to incorporate accurate and well motivated likelihood and prior models in order to give reliable estimates about morphologically different but superimposed photon flux components present in the data set. Thereby we denoise and deconvolve photon counts, while simultaneously decomposing them into diffuse, point-like and uninteresting background radiation fluxes. The decomposition is based on a probabilistic hierarchical Bayesian parameter model within the framework of information field theory (IFT). In contrast to its predecessor D3PO, D4PO reconstructs multi-domain components. Thereby each component is defined over its own direct product of multiple independent domains, for example location and energy. D4PO has the capability to reconstruct correlation structures over each of the sub-domains of a component separately. Thereby the inferred correlations implicitly define the morphologically different source components, except for the spatial correlations of the point-like flux. Point-like source fluxes are spatially uncorrelated by definition. The capabilities of the algorithm are demonstrated by means of a synthetic, but realistic, mock data set, providing spectral and spatial information about each detected photon. D4PO successfully denoised, deconvolved, and decomposed a photon count image into diffuse, point-like and background flux, each being functions of location as well as energy. Moreover, uncertainty estimates of the reconstructed fields as well as of their correlation structure are provided employing their posterior density function and accounting for the manifolds the domains reside on.
关键词： gamma rays: general,methods: data analysis,methods: statistical,X-rays: general,methods: numerical,techniques: image processing
更新于2025-09-23 15:23:52
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Versatile Processing of Metal-Organic Framework-Fluoropolymer Composite Inks with Chemical Resistance and Sensor Applications
摘要： We report a new class of MOF inks with a water-repellent, photocurable fluoropolymer (PFPE) having up to 90 wt% MOF loading. These MOF inks enable to process various MOFs through spray coating, pen writing, stencil printing, and moulding at room temperature. Upon UV-curing, the hydrophobic PFPE matrix efficiently blocks water permeation but allows accessibility of chemicals into MOF pores, thereby freeing the MOF to perform its unique function. Moreover, by introducing functional MOFs we successfully demonstrated a water-tolerant chemosensor for a class of aromatic pollutants in water and a chemical-resistant thermosensor for visualizing temperature image. This approach would open up innumerable opportunities for those MOFs that are otherwise dormant.
关键词： MOF-polymer composite,Chemosensor,MOF processing,Thermosensor,Metal-Organic Framework,Chemical resistance
更新于2025-09-23 15:23:52
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Methodology and implementation of a vision-oriented open CNC system for profile grinding
摘要： CNC systems with the vision function have become very valuable for intelligence machine tools because machine vision is a fast-growing intelligent feature for machines. A novel vision-oriented open CNC system was developed in this study and used in profile grinding machines for the precise machining of parts with contour surfaces, such as complex molds and cutting tools. The system is an innovation to the conventional profile grinding method and enabled the profile error to be visually detected and compensated during the machining process. In this study, a novel design methodology for a machine-vision-oriented CNC system was proposed. An Ethernet-based hardware architecture was constructed for the vision-oriented CNC system. The software characteristics of the developed CNC system were analyzed, including a new type of multi-thread software architecture, a seamless handover approach for multi-thread accessing of the memory space, the integration of the human-machine interface with image processing, and virtual-axis-based online error compensation. The running efficiency test of the software development platforms, time-consumption analysis of the measurement and control in the vision-oriented CNC system, and verification of the effectiveness of the developed vision-oriented CNC system were performed. The results indicate that the proposed vision-oriented open CNC system can effectively fuse image processing with motion control, meet the efficiency requirement, and improve the machining precision of profile grinding. The results are also valuable for developing other machine-vision-based intelligent machine tools.
关键词： Contour error,Profile grinding,Image processing,On-machine measurement,Open CNC,Machine vision
更新于2025-09-23 15:23:52
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An enhanced diabetic retinopathy detection and classification approach using deep convolutional neural network
摘要： The objective of this study is to propose an alternative, hybrid solution method for diagnosing diabetic retinopathy from retinal fundus images. In detail, the hybrid method is based on using both image processing and deep learning for improved results. In medical image processing, reliable diabetic retinopathy detection from digital fundus images is known as an open problem and needs alternative solutions to be developed. In this context, manual interpretation of retinal fundus images requires the magnitude of work, expertise, and over-processing time. So, doctors need support from imaging and computer vision systems and the next step is widely associated with use of intelligent diagnosis systems. The solution method proposed in this study includes employment of image processing with histogram equalization, and the contrast limited adaptive histogram equalization techniques. Next, the diagnosis is performed by the classification of a convolutional neural network. The method was validated using 400 retinal fundus images within the MESSIDOR database, and average values for different performance evaluation parameters were obtained as accuracy 97%, sensitivity (recall) 94%, specificity 98%, precision 94%, FScore 94%, and GMean 95%. In addition to those results, a general comparison of with some previously carried out studies has also shown that the introduced method is efficient and successful enough at diagnosing diabetic retinopathy from retinal fundus images. By employing the related image processing techniques and deep learning for diagnosing diabetic retinopathy, the proposed method and the research results are valuable contributions to the associated literature.
关键词： Image processing,Deep learning,Convolutional neural network,Diabetic retinopathy
更新于2025-09-23 15:23:52
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Formation of a keratin layer with silk fibroin-polyethylene glycol composite hydrogel fabricated by digital light processing 3D printing
摘要： Silk fibroin (SF)-incorporated 4-arm polyethylene glycol acrylate (PEG4A) was used as a bioink for digital light processing three-dimensional printing. A visible range of light was adopted for the process to assure the safety of the cells in the bioink. Fibroblast cells were embedded in the printed hydrogels, and the keratinocyte cells were cultured at the surfaces of the hydrogels. The proliferation of cells with the bioink materials, PEG4A and SF-PEG4A, and the toxicity of these materials, were verified by live/dead and alamarBlue assays. The primary human keratinocytes on the SF-PEG4A hydrogel scaffold generated a keratin layer by the tissue culture at the air-liquid interface, promoting maturation and stratification. SF-polyethylene glycol hydrogels showed higher cell proliferation and cell spreading, and the thicker keratin layer was formed with SF-PEG4A hydrogels compared with PEG4A hydrogels.
关键词： Digital light processing,Silk fibroin,3D printing,4-arm polyethylene glycol acrylate,Keratin
更新于2025-09-23 15:23:52
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Automated quantification of immunomagnetic beads and leukemia cells from optical microscope images
摘要： Quanti?cation of tumor cells is crucial for early detection and monitoring the progress of cancer. Several methods have been developed for detecting tumor cells. However, automated quanti?cation of cells in the presence of immunomagnetic beads has not been studied. In this study, we developed computer vision based algorithms to quantify the leukemia cells captured and separated by micron size immunomagnetic beads. Color, size based object identi?cation and machine learning based methods were implemented to quantify targets in the images recorded by a bright ?eld microscope. Images acquired by a 40× or a 20× objective were analyzed, the immunomagnetic beads were detected with an error rate of 0.0171 and 0.0384 respectively. Our results reveal that the proposed method attains 91.6% precision for the 40× objective and 79.7% for the 20× objective. This algorithm has the potential to be the signal readout mechanism of a biochip for cell detection.
关键词： Leukemia cells,Immunomagnetic beads,Support vector machines,Bright-?eld optical microscopy,Image-processing,Machine learning
更新于2025-09-23 15:23:52