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αionizing particle radiation detection and damage compensation methods for CMOS active pixel sensors
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作者 Shou-Long Xu Cui-Yue Wei +4 位作者 Zhi-Wei Qin Shu-Liang Zou Yong-Chao Han Qing-Yang Wei You-Jun Huang 《Nuclear Science and Techniques》 2026年第4期115-126,共12页
In this study,the mechanism and characteristics of the responseαparticles and the damage caused by them in CMOS active pixel(APS)sensors were investigated.A detection and compensation algorithm for dead pixels caused... In this study,the mechanism and characteristics of the responseαparticles and the damage caused by them in CMOS active pixel(APS)sensors were investigated.A detection and compensation algorithm for dead pixels caused byαparticle ionizing radiation was proposed,and the effects of dead-pixel compensation algorithms were compared and analyzed under different parameter conditions.The experimental results show thatαparticle response signal has highest accuracy at 9 dB gain,with an obvious“target-ring”distribution.With increasing cumulative dose,the CMOS APS pedestal tends to saturation while dead pixels continue increasing.Though some pixel damage recovers through natural annealing,the dead-to-noise ratio increases with irradiation time,reaching 32.54%after 72 h.A hierarchical clustering dead-pixel detection method is proposed,categorizing pixels into two types:those within and outside the response event.A classification compensation strategy combining mean and majority filtering is proposed.This compensation algorithm can address dead-pixel interference without affectingαparticle radiation response data.When iterated multiple times and with integration time exceeding 6.31 ms,the number of dead pixels can be effectively reduced. 展开更多
关键词 CMOS active pixel sensor αparticles Response event Radiation damage Dead-pixel compensation
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低能量Pixel调Q像束激光联合米诺环素治疗玫瑰痤疮的临床效果评价
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作者 付明婧 赵思成 +2 位作者 张哲 赵玥 吴亭妍 《中国美容医学》 2025年第2期110-114,共5页
目的:探讨玫瑰痤疮患者采用低能量Pixel调Q像束激光与米诺环素联合治疗后红斑情况及面部功能改善情况。方法:研究对象选自于2020年3月-2023年7月在上海交通大学医学院苏州九龙医院接受治疗的玫瑰痤疮患者110例,并分为对照组和观察组,每... 目的:探讨玫瑰痤疮患者采用低能量Pixel调Q像束激光与米诺环素联合治疗后红斑情况及面部功能改善情况。方法:研究对象选自于2020年3月-2023年7月在上海交通大学医学院苏州九龙医院接受治疗的玫瑰痤疮患者110例,并分为对照组和观察组,每组例数均为55例,分组方法为随机数字表法。对照组给予盐酸米诺环素片,在对照组患者治疗的基础上,采用低能量Pixel调Q像束激光对观察组患者进行治疗。两组治疗时间均为6周。比较两组临床疗效(治疗6周后),玫瑰痤疮情况、整体病情、p38丝裂原活化蛋白激酶(p38 mitogen activated protein kinase,p38MAPK)通路蛋白、生活质量、红斑情况、面部功能、炎性因子(治疗前、治疗6周后),不良反应(治疗期间)。结果:治疗6周后,观察组总有效率高于对照组(76.36%vs.54.55%,P<0.05)。与治疗前比较,两组治疗6周后的玫瑰痤疮医师全球评分(Patient's global assessment,PGA)、整体病情评估(Investigator global assessment,IGA)、皮肤病生活质量量表(Dermatology life quality index,DLQI)评分、红斑评估量表(Clinician′s erythema assessment,CEA)评分、皮损区红斑指数(Erythema index,EI)、经皮水分丢失(Trans epidermal water loss,TEWL)、皮肤酸碱度(Pondus Hydrogenii,pH)值、炎性因子及p38MAPK通路蛋白相关因子水平均降低,且相比于对照组,观察组更低;两组角质层含水量均升高,且相比于对照组,观察组更高(P<0.05)。观察组和对照组治疗期间的不良反应发生率比较差异无统计学意义(P>0.05)。结论:玫瑰痤疮患者经低能量Pixel调Q像束激光联合米诺环素治疗后,其相关临床症状可得到有效缓解,炎症反应得以减轻,并可调节p38MAPK信号通路蛋白的表达,进一步可促进患者红斑情况及面部功能的改善,进而促使患者生活质量及临床疗效得以提高,且具有良好的安全性。 展开更多
关键词 玫瑰痤疮 米诺环素 低能量pixel调Q像束激光 红斑
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SiM:Satellite Image Mixed Pixel Deforestation Analysis in Optical Satellite for Land Use Land Cover Application 被引量:1
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作者 Priyanka Darbari Ankush Agarwal Manoj Kumar 《Journal of Environmental & Earth Sciences》 2025年第2期228-247,共20页
Brazil’s deforestation monitoring integrates accuracy and current monitoring for land use and land cover applications.Regular monitoring of deforestation and non-deforestation requires Sentinel-2 multispectral satell... Brazil’s deforestation monitoring integrates accuracy and current monitoring for land use and land cover applications.Regular monitoring of deforestation and non-deforestation requires Sentinel-2 multispectral satellite images of several bands at various frequencies,the mix of high-and low-resolution images that make object classification difficult because of the mixed pixel problem.Accuracy is impacted by the mixed pixel problem,which occurs when pixels belong to different classes and makes detection challenging.To identify mixed pixels,Band Math is used to merge numerous bands to generate a new band NDVI.Thresholding is used to analyze the edges of deforested and non-deforested areas.Segmentation is then used to analyze the pixels which helps to identify the number of mixed pixels to compute the deforested and non-deforested areas.Segmented image pixels are used to categorize the deforestation of the Brazilian Amazon Forest between 2019 and 2023.Verify how many pixels are mixed to improve accuracy and identify mixed pixel issues;compare the mixed and pure pixels of fuzzy clustering with the subtracted morphological image pixels.With the help of segmentation and clustering researchers effectively validate mixed pixels in a specific area.The proposed methodology is easy to analyze and helpful for an appropriate calculation of deforested and non-deforested areas. 展开更多
关键词 Amazon Forest Mixed pixel Problem Band Math SEGMENTATION CLUSTERING
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Sea-Surface Target Enhanced Detection Based on Attentional Multi-Pixel Fusion
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作者 SHI Bo WANG Zi-tao +2 位作者 CHEN Lin CAO Tian-yu GE Qi-qi 《China Ocean Engineering》 2025年第3期548-561,共14页
Maritime target recognition and image perception enhancement are gradually being promoted and applied in ocean engineering. This paper proposes the attentional multi-pixel fusion(AMF) algorithm for the intelligent nav... Maritime target recognition and image perception enhancement are gradually being promoted and applied in ocean engineering. This paper proposes the attentional multi-pixel fusion(AMF) algorithm for the intelligent navigation of unmanned surface vessels(USVs). The algorithm preprocesses the image pixel matrix in blocks, computes the mapping between regional and full-pixel matrices, and adaptively equalizes the mapping weights via a Gaussian-fuzzy matrix.This approach guarantees the preservation of the target contour and texture information. Compared with five classic enhancement algorithms, the AMF algorithm improves the peak signal-to-noise ratio(PSNR) and structural similarity index(SSIM). Experimental validation via YOLOv8 for maritime target detection demonstrates 2.1% and 2.4%improvements in the evaluation indices over training on 4000 original images, with shorter training times and lower confusion rates. In maritime target ranging, the AMF algorithm, coupled with the ISR method, exhibits the lowest improved stereo ranging mean absolute error and standard deviation values and higher similarity between the regional and full-pixel matrices. In summary, the AMF algorithm excels in target detection and ranging, offering promising applications in ocean engineering, such as marine resource exploitation, path planning, and intelligent collaboration among unmanned vessels. 展开更多
关键词 regional pixel AMF fusion enhancement USV perception
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Central-Pixel Guiding Sub-Pixel and Sub-Channel Convolution Network for Hyperspectral Image Classification
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作者 Xin Guan Shan Wang Qiang Li 《Journal of Beijing Institute of Technology》 2025年第5期510-525,共16页
In hyperspectral image classification(HSIC),accurately extracting spatial and spectral information from hyperspectral images(HSI)is crucial for achieving precise classification.However,due to low spatial resolution an... In hyperspectral image classification(HSIC),accurately extracting spatial and spectral information from hyperspectral images(HSI)is crucial for achieving precise classification.However,due to low spatial resolution and complex category boundary,mixed pixels containing features from multiple classes are inevitable in HSIs.Additionally,the spectral similarity among different classes challenge for extracting distinctive spectral features essential for HSIC.To address the impact of mixed pixels and spectral similarity for HSIC,we propose a central-pixel guiding sub-pixel and sub-channel convolution network(CP-SPSC)to extract more precise spatial and spectral features.Firstly,we designed spatial attention(CP-SPA)and spectral attention(CP-SPE)informed by the central pixel to effectively reduce spectral interference of irrelevant categories in the same patch.Furthermore,we use CP-SPA to guide 2D sub-pixel convolution(SPConv2d)to capture spatial features finer than the pixel level.Meanwhile,CP-SPE is also utilized to guide 1D sub-channel con-volution(SCConv1d)in selecting more precise spectral channels.For fusing spatial and spectral information at the feature-level,the spectral feature extension transformation module(SFET)adopts mirror-padding and snake permutation to transform 1D spectral information of the center pixel into 2D spectral features.Experiments on three popular datasets demonstrate that ours out-performs several state-of-the-art methods in accuracy. 展开更多
关键词 hyperspectral image classification similar spectra mixed pixel ATTENTION
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Quantitative identification method for pores in shale inorganic components based on pixel information
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作者 Shitan Ning Xianglu Tang +5 位作者 Liang Xu Wei Wu Xuewen Shi Zhenxue Jiang Xinyue Zhang Xinlei Wang 《Natural Gas Industry B》 2025年第4期447-461,共15页
The types and structures of inorganic pores are key factors in evaluations of the reservoir space and distribution characteristics of shale oil and gas.However,quantitative identification methods for pores of differen... The types and structures of inorganic pores are key factors in evaluations of the reservoir space and distribution characteristics of shale oil and gas.However,quantitative identification methods for pores of different inorganic components have not yet been fully developed.For this reason,a quantitative characterization method of inorganic pores using pixel information was proposed in this study.A machine learning algorithm was used to assist the field emission scanning electron microscopy(FE-SEM)image processing of shale to realize the accurate identification and quantitative characterization of inorganic pores on the surface of high-precision images of shale with a small view.Moreover,large-view image splicing technology,combined with quantitative evaluation of minerals by scanning electron microscopy(QEMSCAN)image joint characterization technology,was used to accurately analyze the distribution characteristics of inorganic pores under different mineral components.The quantitative methods of pore characteristics of different inorganic components under the pixel information of shale were studied.The results showed that(1)the Waikato Environment for Knowledge Analysis(WEKA)machine learning model can effectively identify and extract shale mineral components and inorganic pore distribution,and the large-view FE-SEM images are representative of samples at the 200μm×200μm view scale,meeting statistical requirements and eliminating the influence of heterogeneity;(2)the pores developed by different mineral components of shale had obvious differences,indicating that the development of inorganic pores is highly correlated with the properties of shale minerals themselves;and(3)the pore-forming ability of different mineral components is calculated by the quantitative method of single component pore-forming coefficient.Chlorite showed the highest pore-forming ability,followed by(in descending order)illite,pyrite,calcite,dolomite,albite,orthoclase,quartz,and apatite.This study contributes to advancing our understanding of inorganic pore characteristics in shale. 展开更多
关键词 pixel information Large-view image splicing technology QEMSCAN Inorganic pore Quantitative identification method
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Infrared Single Pixel Imaging Based on Generative Adversarial Network
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作者 JIANG Yilin ZHANG Yilong ZHANG Fangyuan 《Journal of Shanghai Jiaotong university(Science)》 2025年第6期1114-1124,共11页
In the field of imaging,the image resolution is required to be higher.There is always a contradiction between the sensitivity and resolution of the seeker in the infrared guidance system.This work uses the rosette sca... In the field of imaging,the image resolution is required to be higher.There is always a contradiction between the sensitivity and resolution of the seeker in the infrared guidance system.This work uses the rosette scanning mode for physical compression imaging in order to improve the resolution of the image as much as possible under the high-sensitivity infrared rosette point scanning mode and complete the missing information that is not scanned.It is effective to use optical lens instead of traditional optical reflection system,which can reduce the loss in optical path transmission.At the same time,deep learning neural network is used for control.An infrared single pixel imaging system that integrates sparse algorithm and recovery algorithm through the improved generative adversarial networks is trained.The experiment on the infrared aerial target dataset shows that when the input is sparse image after rose sampling,the system finally can realize the single pixel recovery imaging of the infrared image,which improves the resolution of the image while ensuring high sensitivity. 展开更多
关键词 image resolution rose sampling generative adversarial networks single pixel imaging
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Multifunctional and reprogrammable 4D pixel mechanical metamaterials
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作者 Xiaozhou Xin Cheng Lin +5 位作者 Bingxun Li Ruikang Zhang Chengjun Zeng Liwu Liu Yanju Liu Jinsong Leng 《International Journal of Extreme Manufacturing》 2025年第1期595-608,共14页
Metamaterials have exotic physical properties that rely on the construction of their underlying architecture.However,the physical properties of conventional mechanical metamaterials are permanently programmed into the... Metamaterials have exotic physical properties that rely on the construction of their underlying architecture.However,the physical properties of conventional mechanical metamaterials are permanently programmed into their periodic interconnect configurations,resulting in their lack of modularity,scalable fabrication,and programmability.Mechanical metamaterials typically exhibit a single extraordinary mechanical property or multiple extraordinary properties coupled together,making it difficult to realize multiple independent extraordinary mechanical properties.Here,the pixel mechanics metamaterials(PMMs)with multifunctional and reprogrammable properties are developed by arraying uncoupled constrained individual modular mechanics pixels(MPs).The MPs enable controlled conversion between two extraordinary mechanical properties(multistability and compression-torsion coupling deformation).Each MP exhibits 32 independent and reversible room temperature programming configurations.In addition,the programmability of metamaterials is further enhanced by shape memory polymer(SMP)and 4D printing,greatly enriching the design freedom.For the PMM consisting of m×n MPs,it has 32(m×n)independent room temperature programming configurations.The application prospects of metamaterials in the vibration isolation device and energy absorption device with programmable performance have been demonstrated.The vibration isolation frequencies of the MP before and after programming were[0 Hz-5.86 Hz],[0 Hz-13.67 Hz and 306.64 Hz-365.23 Hz].The total energy absorption of the developed PMM can be adjusted controllably in the range of 1.01 J-3.91 J.Six standard digital logic gates that do not require sustained external force are designed by controlling the closure between the modules.This design paradigm will facilitate the further development of multifunctional and reprogrammable metamaterials. 展开更多
关键词 4D printing shape memory polymer pixel mechanical metamaterials multistable compression-twist coupling metamaterials digital logic gates
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Optimizing 2D Image Quality in CartoonGAN:A Novel Approach Using Enhanced Pixel Integration
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作者 Stellar Choi HeeAe Ko +3 位作者 KyungRok Bae HyunSook Lee HaeJong Joo Woong Choi 《Computers, Materials & Continua》 2025年第4期335-355,共21页
Previous research utilizing Cartoon Generative Adversarial Network(CartoonGAN)has encountered limitations in managing intricate outlines and accurately representing lighting effects,particularly in complex scenes requ... Previous research utilizing Cartoon Generative Adversarial Network(CartoonGAN)has encountered limitations in managing intricate outlines and accurately representing lighting effects,particularly in complex scenes requiring detailed shading and contrast.This paper presents a novel Enhanced Pixel Integration(EPI)technique designed to improve the visual quality of images generated by CartoonGAN.Rather than modifying the core model,the EPI approach employs post-processing adjustments that enhance images without significant computational overhead.In this method,images produced by CartoonGAN are converted from Red-Green-Blue(RGB)to Hue-Saturation-Value(HSV)format,allowing for precise adjustments in hue,saturation,and brightness,thereby improving color fidelity.Specific correction values are applied to fine-tune colors,ensuring they closely match the original input while maintaining the characteristic,stylized effect of CartoonGAN.The corrected images are blended with the originals to retain aesthetic appeal and visual distinctiveness,resulting in improved color accuracy and overall coherence.Experimental results demonstrate that EPI significantly increases similarity to original input images compared to the standard CartoonGAN model,achieving a 40.14%enhancement in visual similarity in Learned Perceptual Image Patch Similarity(LPIPS),a 30.21%improvement in structural consistency in Structural Similarity Index Measure(SSIM),and an 11.81%reduction in pixel-level error in Mean Squared Error(MSE).By addressing limitations present in the traditional CartoonGAN pipeline,EPI offers practical enhancements for creative applications,particularly within media and design fields where visual fidelity and artistic style preservation are critical.These improvements align with the goals of Fog and Edge Computing,which also seek to enhance processing efficiency and application performance in sensitive industries such as healthcare,logistics,and education.This research not only resolves key deficiencies in existing CartoonGAN models but also expands its potential applications in image-based content creation,bridging gaps between technical constraints and creative demands.Future studies may explore the adaptability of EPI across various datasets and artistic styles,potentially broadening its impact on visual transformation tasks. 展开更多
关键词 CartoonGAN enhanced pixel integration(EPI) image quality enhancement POST-PROCESSING HSV color adjustment visual fidelity fog computing edge computing creative applications technical advancements
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High-Quality Single-Pixel Imaging Based on Large-Kernel Convolution under Low-Sampling Conditions
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作者 Chenyu Yuan Yuanhao Su Chunfang Wang 《Chinese Physics Letters》 2025年第4期55-61,共7页
In recent years,deep learning has been introduced into the field of Single-pixel imaging(SPI),garnering significant attention.However,conventional networks still exhibit limitations in preserving image details.To addr... In recent years,deep learning has been introduced into the field of Single-pixel imaging(SPI),garnering significant attention.However,conventional networks still exhibit limitations in preserving image details.To address this issue,we integrate Large Kernel Convolution(LKconv)into the U-Net framework,proposing an enhanced network structure named U-LKconv network,which significantly enhances the capability to recover image details even under low sampling conditions. 展开更多
关键词 large kernel convolution lkconv recover image details U lkconv network high quality single pixel imaging U Net low sampling conditions enhanced network structure large kernel convolution
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面向机场跑道的探地雷达杂波抑制算法
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作者 李海丰 刘文强 +1 位作者 李南莎 桂仲成 《计算机应用》 北大核心 2026年第2期659-665,共7页
针对机场跑道探地雷达(GPR)数据中的复杂背景杂波和层间强反射干扰信号的问题,提出一种基于改进U-Net的深度学习杂波抑制算法。该算法在U-Net的跳跃连接处引入细节增强模块DE-Conv,从而增强网络对多尺度浅层特征中目标信号细节的捕捉能... 针对机场跑道探地雷达(GPR)数据中的复杂背景杂波和层间强反射干扰信号的问题,提出一种基于改进U-Net的深度学习杂波抑制算法。该算法在U-Net的跳跃连接处引入细节增强模块DE-Conv,从而增强网络对多尺度浅层特征中目标信号细节的捕捉能力;同时,采用含杂波-无杂波图像对计算特征-像素双级融合损失函数优化训练过程。具体地,通过共享权重编码器提取的含杂波与无杂波数据的高维特征,计算特征级别损失来指导编码器的训练,并使用解码器输出图像与对应的无杂波仿真图像计算像素级别损失以优化解码器性能。实验结果表明,在合成数据集上,所提算法的峰值信噪比(PSNR)和结构相似度(SSIM)分别达到37.114 7 dB和0.999 8;而在真实机场跑道数据集上,所提算法的平均信杂比(SCR)和改善系数(IF)分别为8.28 dB和5.90 dB,以上4种指标相较于基准模型的数据分别提升了0.952 8 dB、0.000 4、6.58 dB和5.32 dB。与鲁棒非负矩阵分解(RNMF)、鲁棒主成分分析(RPCA)及同样基于深度学习的基于U-Net改进的杂波去除神经网络(CR-Net)相比,所提算法在杂波抑制效果和计算效率上均表现出优势。同时,大量的消融实验结果验证了细节增强模块和特征-像素双级损失函数对杂波去除和目标信号恢复的有效性。 展开更多
关键词 探地雷达 杂波抑制 细节增强网络 特征-像素双级融合损失 机场跑道
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面向耕地地块的水稻种植信息精细提取
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作者 刘善磊 李梦梦 +1 位作者 范雪婷 张亮 《测绘与空间地理信息》 2026年第1期53-56,共4页
针对江南水乡河网密布、耕地破碎的特点,结合多源影像数据在时间和空间分辨率的优势,探讨了面向耕地地块的水稻种植信息精细提取。首先以国土变更调查数据和优于1 m的卫星遥感影像数据为基础,构建多源、多时相、多尺寸耕地地块影像样本... 针对江南水乡河网密布、耕地破碎的特点,结合多源影像数据在时间和空间分辨率的优势,探讨了面向耕地地块的水稻种植信息精细提取。首先以国土变更调查数据和优于1 m的卫星遥感影像数据为基础,构建多源、多时相、多尺寸耕地地块影像样本库,接着通过深度学习框架获取耕地地块。在此基础上基于多时序Sentinel-2数据,利用时序数据重构和缺失信息插补等技术结合水稻物候期,从地块级别获得水稻种植信息,与董浜镇农业统计年鉴数据相比,精度达到94%,基于地理方格网的目标随机抽样精度达96%。研究表明,所采用的方法适用于小区域水稻的精细提取,能为小型灌区内水稻遥感监测和种植结构调整提供有效可行的参考和借鉴。 展开更多
关键词 耕地地块 混合像元 时序重构 种植结构
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一种改进的三次样条插值划痕宽度检测方法
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作者 张丽玲 刘洋 +1 位作者 饶繁星 齐贤敏 《机械设计与制造》 北大核心 2026年第1期89-93,98,共6页
由于对光学镜片划痕的像素级检测算法检测精度低,对相机分辨率要求高,且亚像素边缘检测方法无法直接完成宽度计算。因此,提出一种基于改进的三次样条插值亚像素宽度自动测量方法。首先,对经典Sobel算子模板进行拓展用于划痕的粗定位并... 由于对光学镜片划痕的像素级检测算法检测精度低,对相机分辨率要求高,且亚像素边缘检测方法无法直接完成宽度计算。因此,提出一种基于改进的三次样条插值亚像素宽度自动测量方法。首先,对经典Sobel算子模板进行拓展用于划痕的粗定位并确定边缘梯度,再由三次样条插值对边缘梯度进行精确定位,确定图像中的亚像素边缘点,根据边缘梯度方向对划痕宽度计算方法改进,最终完成对划痕宽度的检测。实验分析表明,该方法可以满足生产实际需要,能够实时精确地检测出划痕宽度。 展开更多
关键词 亚像素 三次样条插值 光学镜片 边缘检测
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Pixel激光治疗面部痤疮瘢痕 被引量:12
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作者 向淑英 赵小忠 +3 位作者 宋燕哲 纪彦林 马冰冰 张京姬 《中国美容医学》 CAS 2009年第3期348-350,共3页
目的:观察Pixel激光治疗面部痤疮瘢痕的临床效果。方法:采用以色列飞顿2940nm像素激光对54例痤疮瘢痕的患者进行治疗,共治疗3~5次,每次间隔时间2~3周。除少数对疼痛敏感的患者治疗前外涂表面麻醉,其余不用任何处理。对比治疗前后的照... 目的:观察Pixel激光治疗面部痤疮瘢痕的临床效果。方法:采用以色列飞顿2940nm像素激光对54例痤疮瘢痕的患者进行治疗,共治疗3~5次,每次间隔时间2~3周。除少数对疼痛敏感的患者治疗前外涂表面麻醉,其余不用任何处理。对比治疗前后的照片并进行疗效评价。结果:共治疗54例痤疮瘢痕患者,有效率75%~100%。Pixel同时可以有效改善4种不同类型痤疮,无一例色沉和瘢痕。结论:Pixel激光治疗痤疮凹陷性瘢痕疗效满意,对增生瘢痕疗效有限。是一种适合东方人痤疮瘢痕的安全,有效的治疗方法。 展开更多
关键词 pixel激光 痤疮瘢痕
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Design,Analysis,and Optimization of a CMOS Active Pixel Sensor 被引量:2
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作者 徐江涛 姚素英 +2 位作者 李斌桥 史再峰 高静 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第9期1548-1551,共4页
A three-transistor active pixel sensor and its double sampling readout circuit implemented by a switch capacitor amplifier are designed. The circuit is embedded in a 64 × 64 pixel array CMOS image sensor and succ... A three-transistor active pixel sensor and its double sampling readout circuit implemented by a switch capacitor amplifier are designed. The circuit is embedded in a 64 × 64 pixel array CMOS image sensor and success-fully taped out with a Chartered 0.35μm process. The pixel pitch is 8μm × 8μm with a fill factor of 57%, the photo-sensitivity is 0.8V/(lux · s) ,and the dynamic range is 50dB. Theoretical analysis and test results indicate that as the process is scaled down, a smaller pixel pitch reduces the sensitivity. A deep junction n-well/p-substrate photodiode with a reasonable fill factor and high sensitivity are more appropriate for submicron processes. 展开更多
关键词 CMOS image sensor active pixel sensor fill factor photo-response sensitivity
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基于联合邻域像素结构化低秩的层析SAR三维成像方法
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作者 周弘昊 刘艳阳 +3 位作者 李涛 崔硕 徐刚 邢孟道 《雷达学报(中英文)》 北大核心 2026年第1期80-94,共15页
层析合成孔径雷达(TomoSAR)三维成像能够克服场景叠掩、投影几何失真等问题,具有重要的科学研究和应用价值。由于TomoSAR高程分辨率受到高程向孔径限制,通常利用压缩感知等超分辨算法提升三维成像性能。然而,传统压缩感知方法需预先划... 层析合成孔径雷达(TomoSAR)三维成像能够克服场景叠掩、投影几何失真等问题,具有重要的科学研究和应用价值。由于TomoSAR高程分辨率受到高程向孔径限制,通常利用压缩感知等超分辨算法提升三维成像性能。然而,传统压缩感知方法需预先划分离散网格导致存在网格失配等问题,同时在通道数少、信噪比低等限制条件下,成像分辨精度受限。针对以上问题,该文提出了一种基于联合邻域像素结构化低秩的层析SAR超分辨三维成像方法,通过增强信号内部结构性表征以增加有效样本数量,提高三维重建性能。具体而言,基于邻域像素高程一致性假设,可联合邻域像素稀疏特性构建无网格结构化低秩非凸优化模型,以增强信号内部结构表征并克服传统稀疏网格化的缺陷。此外采用投影梯度下降算法进行高效求解,引入非相干可行域约束,有效降低重构性能对采样位置的依赖性。最后,利用仿真数据、实测SARMV3D-1.0机载阵列数据和陆地探测一号卫星数据进行了验证。实验结果表明,所提方法在三维重建精度和稳定性方面均显著优于现有大多数主流方法。 展开更多
关键词 三维SAR 联合邻域 超分辨 结构化低秩 陆地探测一号
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基于外部增设交错排列分布屏蔽体的全方向伽马成像技术研究
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作者 席禹 张译文 +2 位作者 梁秀佐 帅磊 魏龙 《原子能科学技术》 北大核心 2026年第1期110-118,共9页
放射源的监测、检测与精准定位技术对保障核安全、公众健康和国土安全具有重要意义。为提高伽马成像系统的全方向角分辨能力,本研究创新性地设计了一种采用外部交错排列屏蔽体结构的4π全方向伽马成像系统。基于Geant4平台的模拟数据,... 放射源的监测、检测与精准定位技术对保障核安全、公众健康和国土安全具有重要意义。为提高伽马成像系统的全方向角分辨能力,本研究创新性地设计了一种采用外部交错排列屏蔽体结构的4π全方向伽马成像系统。基于Geant4平台的模拟数据,通过系统评估空间像素响应对比度、单/双点源成像角分辨率、定位精度及成像灵敏度,全面分析了增设外部屏蔽体对系统综合性能的影响。利用^(137)Cs开展的测试结果表明,外部交错排列屏蔽体结构可有效提升伽马成像系统的角分辨能力。在单点源条件下,伽马成像系统定位精度均小于6°,角分辨率小于10°。在双点源条件下,伽马成像系统定位精度均小于9°,对双源间距实际方位角ϕ约为25°及极角θ为20°具备稳定分辨能力。此外,成像灵敏度测试结果表明,在增设外部交错排列屏蔽体后,系统需约5 min即可清晰分辨双源位置。 展开更多
关键词 全方向伽马成像 屏蔽体 空间像素响应对比度 角分辨 成像灵敏度
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Steganography in binary image by checking data-carrying eligibility of boundary pixels 被引量:6
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作者 梁光岚 王朔中 张新鹏 《Journal of Shanghai University(English Edition)》 CAS 2007年第3期272-277,共6页
We present a novel scheme for embedding secret data into a binary image without introducing noticeable artifacts. Unlike some block-based methods, the proposed scheme encodes the secret bits directly into boundary pix... We present a novel scheme for embedding secret data into a binary image without introducing noticeable artifacts. Unlike some block-based methods, the proposed scheme encodes the secret bits directly into boundary pixels by checking each pixel of the cover image in a pseudo-random order for embedding eligibility. A set of rules ensures correct identification of data-carrying pixels in blind extraction. The proposed scheme does not generate isolated dots, and can incorporate various coding methods such as matrix encoding to further improve the embedding performance. It is shown that up to one fourth of the boundary pixels may be used to carry secret data. Experimental results indicate that the method can achieve good visual quality with fairly large data capacity. 展开更多
关键词 binary image STEGANOGRAPHY embedding eligibility boundary pixel.
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Pixel激光治疗黄褐斑的疗效和安全性分析 被引量:1
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作者 徐阳 王丹丹 杨蓉娅 《中国美容医学》 CAS 2010年第8期1186-1188,共3页
目的:评估Pixel激光治疗黄褐斑的疗效及安全性。方法:采用Pixel激光治疗黄褐斑患者72例,3~4周治疗1次,3~5次为一个疗程,每次复诊由医生和患者共同评定疗效和安全性。结果:72例患者中,痊愈17例(23.61%),显效18例(25.0%),有效率48.61%... 目的:评估Pixel激光治疗黄褐斑的疗效及安全性。方法:采用Pixel激光治疗黄褐斑患者72例,3~4周治疗1次,3~5次为一个疗程,每次复诊由医生和患者共同评定疗效和安全性。结果:72例患者中,痊愈17例(23.61%),显效18例(25.0%),有效率48.61%。轻度组:痊愈率45.45%(15例),显效率36.36%(12例),有效率81.81%;重度组:痊愈率5.13%(2例),显效率15.38%(6例),有效率20.51%;两组比较有显著性差异。病程小于2年者,有效率68.42%,疗效高于病程大于2年者。21例患者术后出现轻度色素沉着,均于术后3个月消退。结论:Pixel激光治疗黄褐斑安全有效,病程短、颜色浅者疗效更佳。 展开更多
关键词 pixel激光 黄褐斑 疗效 安全性
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Pixel^(TM)2940 Er:YAG像束激光治疗浅表性瘢痕 被引量:2
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作者 马丽 文辉才 +3 位作者 简雪平 眭云鹏 徐桂珍 刘艳平 《中国美容整形外科杂志》 CAS 2016年第7期410-412,共3页
目的探讨Pixel^(TM)2940 Er:YAG像束激光分别采用剥脱性及非剥脱性参数治疗浅表性瘢痕的临床效果。方法采用Pixel^(TM)2940 Er:YAG像束激光对75例浅表性瘢痕患者进行治疗,每次治疗时先划定治疗区域,根据患者瘢痕的深度和密度选择适宜的... 目的探讨Pixel^(TM)2940 Er:YAG像束激光分别采用剥脱性及非剥脱性参数治疗浅表性瘢痕的临床效果。方法采用Pixel^(TM)2940 Er:YAG像束激光对75例浅表性瘢痕患者进行治疗,每次治疗时先划定治疗区域,根据患者瘢痕的深度和密度选择适宜的治疗参数。结果对所有患者随访6~12个月,全部好转,无一例色素沉着及增生性瘢痕发生。多数患者短时间内出现灼热感、皮肤轻微红肿等,可自行消退;少数患者出现色素沉着,未予特殊处理,3~6个月自行消退。结论采用Pixel^(TM)2940ET:YAG像束激光治疗浅表性瘢痕,创伤小,恢复时间短,同时使得瘢痕变得更加平整、细腻,萎缩的瘢痕处皮肤纹路及质感恢复,色素沉着减退等并发症发生率较低。 展开更多
关键词 pixel^TM2940 Er:YAG像束激光 浅表性瘢痕 激光治疗 剥脱性治疗 非剥脱性治疗
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