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Pixel image lag in a 4-T CMOS image sensor is analyzed and simulated in a two-dimensional model.Strategies of reducing image lag are discussed from transfer gate channel threshold voltage doping adjustment,PPD N-type doping dose/implant tilt adjustment and transfer gate operation voltage adjustment for signal electron transfer.With the computer analysis tool ISE-TCAD,simulation results show that minimum image lag can be obtained at a pinned photodiode n-type doping dose of 7.0×10~(12) cm~(-2),an implant ... 相似文献
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《Electron Devices, IEEE Transactions on》1976,23(6):534-537
The use of polycrystalline Se as the photosensitive target of a vidicon image tube has been demonstrated for the first time. The mode of operation of this target layer is fundamentally different from that of the amorphous-Se vidicon target, which is commonly described as a photosensitive insulator layer. In contrast, the explanation for the crystalline-Se vidicon operation, as proposed here, is based on the utilization of a reverse-biased heterojunction contact between n-type SNO2 and p-type crystalline Se. A fabrication process has been developed which yields target layers with an attractive combination of operating characteristics. This new type of vidicon has the following nominal operating parameters: dark current ≃ 5-10 nA, peak sensitivity ≃ 0.270 A/W, peak quantum efficiency ≃ 60 percent, and 50-ms lag ≃ 10 percent. Compared to the standard Sb2 S3 vidicon, this experimental crystalline-Se vidicon has more than twice the sensitivity and less than half as much lag and dark current. 相似文献
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We report advances in the power conversion (wall-plug) efficiency of vertical-cavity top-surface-emitting lasers. The devices were fabricated from molecular beam epitaxial layers using deep proton implants to define gain-guided lasers. The epitaxial structure included low resistance, piecewise linearly graded n-type and p-type mirrors, a triple In0.2Ga0.8As quantum-well active region, and a delta-doped contact layer. Power conversion efficiencies as high as 12.7% for continuous-wave single-mode operation were measured after several hours of device operation 相似文献
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为改善小尺寸背照式CMOS图像传感器像素单元满阱容量不足缺点,本文基于提高光电二极管电容的角度,提出了一种通过改变光电二极管结构来提升满阱容量的新方法。该结构优化由两步实现。第一步,通过在传统光电二极管N型区域下额外注入高能量、低剂量N型掺杂,形成一个浓度渐变,深度扩展的新光电二极管N型区。这种光电二极管的满阱容量将因侧壁结电容的扩展而显著提高;第二步,为了帮助扩展的阱容量实现全耗尽,一个由两步不同能量的P型杂质形成的P型插入区被嵌入到深度得以扩展的光电二极管N型区域内。这个纵向插入的P型插入区保证了该光电二极管结构可以在复位完成后实现电子的全耗尽。仿真结果显示,像素单元满阱容量可以由初始的1289e- 提升到6390e-,且该阱容量扩展技术不会以恶化图像拖尾为代价。除此之外,量子效率在全波段下均得以提升,尤其在520nm处提升6.3%。这项改进不仅可以用于背照式像素结构,而且可以被用于任何PD型正面照射式像素结构中。 相似文献
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针对长波线列5k×6探测器组件的图像采集处理要求,设计并实现了一种多路、高速、大数据量的实时图像采集显示处理系统。图像采集接口为5路并行标准CameraLink协议,采集卡选用3块DALSA公司的Xcelera-CL_PX4。实验中,采集5路每路1024×8889×16 bit大小的图像数据,进行图像的拼接、非均匀性校正、直方图均衡等处理。实验表明,对于这种多路、大分辨率图像的实时处理,该系统是稳定可靠的,并且已成功应用于某成像NETD和MTF测试系统中。 相似文献
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为利用数字图像处理技术实现导弹武器自动化瞄准,图像采集装置采用直接调焦方式
实现自动调焦;综合考虑曝光时间、光圈大小、景深等对采集图像的影响,通过计算整体清晰度,选择最佳曝光值组合;在图像采集中进行预处理,提高图像质量,减小自动瞄准中图像处理的负担。 相似文献
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A design of an inverse U-shape buried doping in a pinned photodiode(PPD) of CMOS image sensors is proposed for electrical crosstalk suppression between adjacent pixels.The architecture achieves no extra fill factor consumption,and proper built-in electric fields can be established according to the doping gradient created by the injections of the extremely low P-type doping buried regions in the epitaxial layer,causing the excess electrons to easily drift back to the photosensitive area rarely with a diffusion probability; the overall junction capacitance and photosensitive area extensions for a full well capacity(FWC) and internal quantum efficiency(IQE) improving are achieved by the injection of a buried N-type doping.By considering the image lag issue,the process parameters of all the injections have been precisely optimized.Optical simulation results based on the finite difference time domain method show that compared to the conventional PPD,the electrical crosstalk rate of the proposed architecture can be decreased by 60%–80% at an incident wavelength beyond 450 nm,IQE can be clearly improved at an incident wavelength between 400 and 600 nm,and the FWC can be enhanced by 107.5%.Furthermore,the image lag performance is sustained to a perfect low level.The present study provides important guidance on the design of ultra high resolution image sensors. 相似文献
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光电成像中的一种编码解码方法 总被引:5,自引:2,他引:3
本文提出了光电成像中的环形编码孔径编码成像及图像恢复处理方法。实验表明,利用该方法成像可以在保证高分辨率的情况下,具有较高的集光效率和信噪比,成像效果很好。 相似文献
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针对在高动态范围图像合成的过程中有噪声影响图像的质量这一问题,采取一种基于多曝光图像的高动态范围图像合成降噪算法。通过对各曝光图像的灰度数据进行提取、整理、分析,能合成代表原始场景光线分布的亮度图像。通过分析噪声对高动态范围图像合成质量的影响,提出在图像合成前将图像中含有的噪声进行处理。根据光子散粒噪声变化的特点,将图像混有的噪声问题转化为求解一个多曝光图像序列组的平均值问题,合成的图像视觉效果与真实图像极为接近。 相似文献
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小波变换在特征级多重图像融合与目标分类中的应用 总被引:2,自引:1,他引:1
针对特征级图像融合的一般规律,用小波变换算法实现了图像的多分辨分割,提取目标的多分辨特征矢量,在特征级完成CCD图像和热成像图像的信息融合,并基于融合特征实现目标分类,最后,对实验结果进行了分析,提出了在特征级图像融合及目标分类中应考虑的问题。 相似文献
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针对目前基于内容的图像检索技术中低级特征无法准确全面地描述高级语义的问题,本文提出了一种基于多级图像描述模型的渐进式图像内容理解.该图像描述模型在不同层次上对图像内容进行分析和提取,实现了图像内容的全方位描述,从底层向高层的过渡是渐进式的图像理解过程.特别是从视觉感知层到目标层,体现了图像低级特征与高级语义之间的过渡.本文给出了一种基于先验知识的上下文驱动的目标理解算法,实现了图像语义的提取.作为一个应用实例,本文给出了以上方法在基于内容的图像检索技术中的具体应用. 相似文献
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微光图像特征分析及图像融合技术研究 总被引:6,自引:1,他引:5
从微光图像的成像过程、灰度分布和像素空间与时间相关性等几个方面对微光图像特征作较系统的分析,用信息容量这一示性参数来表征高相关图像灰度层次的丰富程度,这与视觉效果达到了很好的一致,通过分析这些特性,对微光多光谱图像融合技术研究具有重要的指导意义。 相似文献