共查询到18条相似文献,搜索用时 78 毫秒
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首先分析了引起CCD 非均匀性的原因,将其归纳为两个方面,一为因制作工艺、材料、偏置等因素引起的空间噪声,二为CCD 响应特性随时间的漂移而引起的时间噪声,两者的共同作用将严重影响CCD 的测量性能。为了能够定量描述空间噪声和时间噪声对CCD 产生非均匀性的影响,文中基于CCD 光电响应曲线呈线性状态这一假设建立了CCD 光电响应的数学模型,然后在该模型的基础上提出了利用最小二乘法来估计校正系数,从而消除CCD 的非均匀性,实验证明该算法是有效的。 相似文献
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凝视红外焦平面CCD非均匀性校正 总被引:5,自引:0,他引:5
对CCD器件的非均匀性校正的理论方法进行了讨论、分析和比较,并对32×64元硅化铂肖特基势垒红外焦平面器件进行了响应率非均匀性的校正,针对该器件响应率非线性度大、传输率低、疵点数目多和噪声大等问题,选取先进的多点定标分段校正算法,实现了实时校正及显示。校正后,不均匀度为2%,图像质量明显得到改善。 相似文献
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宽幅CCD相机的输出非均匀性校正对获取高质量的遥感图像具有重要意义。通过分析造成CCD输出非均匀的原因,提出了基于辐射亮度反演的非均匀性线性校正概念。在已知的多种辐亮度照明下,采集相机每个像素的灰度值,利用最小二乘法建立像元灰度值与辐亮度的函数,求出像元的两项非均匀性校正系数——暗信号与响应度。实验结果表明:利用这两项校正系数进行相机非均匀性校正,改善效果明显。校正前图像的灰度值均方根偏差为1.3%,校正后为0.2%;从图像上看,校正前图像上的明暗条纹很明显,校正后得到消除。不仅如此,采用该校正方法还能够有效去除通道间输出非均匀性造成的整幅拼接图像的明暗不一致,得到均匀清晰的图像,结果令人满意。 相似文献
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可见光面阵CCD响应非均匀性的检测与校正 总被引:1,自引:2,他引:1
通过分析可见光面阵CCD的响应非均匀性,提出了一种适用于所有面阵CCD的响应非均匀性检测系统。利用该检测系统对全帧型面阵CCD485进行了辐射定标,建立了面阵CCD485数字图像的灰度值和积分球出口处辐照度之间的响应关系,并描绘了响应度曲线。从定标采集得到的数字图像可以看出灰度值有明显的跳跃,响应非均匀性已经超过了5%,在微光拍照时将严重影响成像的质量,所以必须进行校正。根据面阵CCD响应度曲线来选择非均匀性校正算法,考虑到面阵CCD485的响应度为线性,这里采用了两点校正算法,求出面阵CCD各个像元的校正因子(增益和偏置),并存储到校正矩阵中,通过乘积加法运算把各个像元的信号校正成面阵CCD的平均信号值。实验结果表明,两点校正算法使面阵CCD485的响应非均匀性降低到原来的1/10左右,是一种实用有效的校正方法。 相似文献
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根据科学级CMOS(sCMOS)图像传感器开发的工程实际需求,设计了基于FPGA的二阶多项式拟合的非均匀性校正算法.该非均匀性校正算法首先通过定标得出每个像素的响应曲线,然后采用最小二乘法将sCMOS像素响应曲线参考平均响应曲线进行拟合,得出校正系数并通过FPAG对像素值进行实时校正.通过处理后的图像非均匀性从17.1%降低到7.6%.该算法有效提高了sCMOS器件对高动态、非线性响应特性的适应能力,并具备实时计算校正优点,通过模块化设计可以方便移植和集成. 相似文献
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为了获取高质量高帧频紫外图像数据,设计了一套基于科学级紫外CCD的成像电路系统。整个系统以E2V公司CCD57-10图像探测器为核心,以Microsemi公司低功耗FPGA—A3PE3000L为逻辑控制单元进行展开。首先,给出了系统的总体设计方案,分析了CCD57-10 的工作特性,并设计了一套性能可靠的硬件电路系统;分析了CCD探测器的时序关系并确定了详细的时序参数,在不影响探测能力前提下,为了提高系统帧频,设计上采用了CCD开窗工作模式;通过优化时序设计,在FPGA内完成了不同曝光时间工作模式的自适应。实验结果表明,系统在200KHz读出频率,256*256开窗条件下,帧频可达3f/s,读出噪声低至10个电子,具有较好的性能。成像系统性能稳定、可靠性高,设计理念具有较好的可扩展性。 相似文献
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为解决多通道TDI CCD成像系统响应非均匀的问题,根据成像系统视频信号的处理流程,详细分析了影响成像系统响应非均匀性的各个因素,对比了当前主要的非均匀性校正处理方法,提出了改进单点校正法,其集成了单点校正法与两点校正法的优点,具有算法简单,效率高,实用性强,测试工作量小等特点,利用该方法对系统所采集的图像进行非均匀校正,试验结果表明,系统响应的非均匀性由3.5%降低至1.5%,在系统响应全部灰度范围内,最大的非均匀性小于2.5%,满足成像系统的使用要求。 相似文献
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A new, simple and rapid method for determining threshold voltage (VT) non-uniformity in two-dimensional CCD multiplexers (MUXs) for hybrid focal plane arrays is presented. The method is based on simple oscilloscopic measurement of non-uniformity in the output signal of CCD MUX. The non-uniformity in VT, measured by this method, is compared with conventional current forcing method. The results of the proposed new method agree within 7.8% with the conventional method. Additionally, intrinsic non-uniformity due to processing and material variations is also measured by this method. 相似文献
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目前采用高分辨率全帧面阵CCD FTF5066M 作图像传感器的航拍相机帧频一般不超过1 fps,为了满足高帧频应用,文中首先介绍了全帧型面阵CCDFTF5066M 的基本驱动电路,并对其进行了改进,利用CCD 4个输出放大器进行同时输出,使最高帧频达到了3.4 fps,介绍了4 路输出时CCD驱动时序、前端处理电路、直流偏置电路、接口电路等的设计,改进后的驱动电路能满足多种航拍相机的应用要求。然后对全帧型面阵CCDFTF5066M 的非均匀性进行了分析,并建立了一种响应非均匀性检测系统。利用该系统分别对面阵CCD5066M 的4 个象限之间的非均匀性和每个像元之间的非均匀性进行了检测。在CCD 响应度为线性的基础上,提出了两点校正算法并对非均匀性进行校正。通过校正4 个象限响应灵敏度的标准偏差降低到原来的1/13。通过对鉴别率板的重新拍摄,可以看出面阵CCD 的非均匀性得到了明显的改善。 相似文献
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Kuriyama T. Kodama H. Kozono T. Kitahama Y. Morita Y. Hiroshima Y. 《Electron Devices, IEEE Transactions on》1991,38(5):949-953
A 1/3-in interline transfer charge-coupled-device (CCD) image sensor with 270000 pixels has been developed. The effective sensing area of (4.8(H)×3.6(V)) mm2 is adopted for the 1/3-in format. This sensor realizes 330 TV lines of color horizontal resolution. In addition, a new on-chip color filter is used, and a minimum object illuminance of 3 1x has been achieved. The electronic shutter was realized by developing the vertical-extraction method, with a wide range of shutter speed from 1/60 to 1/10000 s. Moreover, the use of an embedded photodiode makes it possible to achieve a low dark current. This feature, together with the 5-V drive, gives the sensor additional high performance, including low smear (0.01%) 相似文献
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The variance versus average signal has been measured for a pixel in an electronically shuttered and back-illuminated CCD imaging array. The measurements demonstrate that, over a certain operating range, the electronic shutter modifies the input Poisson distributed photoelectrons during the collection process such that the charge signal accumulated in the CCD well has a sub-Poisson distribution (variance less than the mean). A simple one-dimensional model has been developed that explains the experimental results 相似文献
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《Electron Devices, IEEE Transactions on》1976,23(2):152-155
Some experimental and practical considerations of performing convolution or transversal filtering with charge-coupled devices (CCD's) using optical inputs are described. The basic principle involves shining light from a signal-modulated light-emitting diode (LED) onto an optical mask which controls the amount of light reaching the various CCD electrodes. The experimental results for a 91-tap Hamming window are presented. The relative advantages of using this approach as a means of obtaining fixed tap-weight transversal filters are discussed in comparison with the split electrode CCD filter. It is shown that a compact lens free optical signal processor is possible, using standard imaging structures. Although there is a disadvantage in terms of the need for an LED and current driver, this may be outweighed in certain contexts by improvements in linearity, intermodulation, dynamic range, and the scale of processing which is possible. 相似文献
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《Solid-State Circuits, IEEE Journal of》1976,11(1):84-87
Some experimental and practical considerations of performing convolution or transversal filtering with charge-coupled devices (CCD's) using optical inputs are described. The basic principle involves shining light from a signal-modulated light-emitting diode (LED) onto an optical mask which controls the amount of light reaching the various CCD electrodes. The experimental results for a 91-tap Hamming window are presented. The relative advantages of using this approach as a means of obtaining fixed tap-weight transversal filters are discussed in comparison with the split electrode CCD filter. It is shown that a compact lens free optical signal processor is possible, using standard imaging structures. Although there is a disadvantage in terms of the need for an LED and current driver, this may be outweighed in certain contexts by improvements in linearity, intermodulation, dynamic range, and the scale of processing which is possible. 相似文献