共查询到18条相似文献,搜索用时 390 毫秒
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为解决反射式拼接CCD相机成像渐晕问题,依据辐射定标理论采用多亮度点渐晕图像校正算法处理渐晕图像。首先,针对典型的反射镜拼接方式,分析了成像时产生渐晕的原因;然后,根据实验室多亮度等级下成像结果,得出拼接CCD渐晕区各像元数码输出值与入瞳处辐射亮度成线性关系的结论;最后,应用多亮度点校正算法,计算出渐晕区各像元的渐晕校正因子,校正渐晕图像。实验结果表明:对非均匀性大于10%的多幅原始渐晕拼接图像,校正后,图像的非均匀性下降到0.5%以内,可满足反射镜拼接CCD相机非均匀性指标要求。 相似文献
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TDI CCD相机实验室辐射定标的研究 总被引:2,自引:0,他引:2
TDI CCD相机辐射定标的目的是建立输入辐亮度和探测器数字化输出之间的关系,为相机提供调光参数.本文推导了辐射定标的原理,并针对特定的TDI CCD相机在应用光学国家重点实验室里使用积分球对其进行了基于光谱辐照度灯的辐射定标,标定了TID CCD相机响应的线性度、TDI CCD相机响应分别与增益和级数的关系,根据实验结果我们得到了在不同的辐亮度值下的增益和级数参考值,从而确定了TDI CCD相机的调光参数,并给出了标定的误差和各项误差源的影响. 相似文献
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详述了安装在JEM_2100高分辨透射电镜上的OlympusCCD图像采集系统的使用技巧和参数设置,包括电子束强度的调整、图像亮度以及对比度的调整、图片标尺的显示和标定、电子衍射分析图片采集、特殊情况下样品观察和图片采集、电子束过曝保护设置、荧光屏抬起和落下控制、CCD与TEM的通讯恢复等。 相似文献
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在数码相机测光原理和数字图像处理的基础上利用均匀亮度源对数码相机进行光学标定,获取数码相机采集到的图像灰度值与曝光量之间的确切关系,并以此来获得亮度回归公式.在均匀亮度源标定下数码相机的亮度回归曲线的相关系数R2达到了0.984 5.利用标定完的数码相机进行亮度测试时取得了很好的实验效果,并且在进行点目标物亮度测试时相对误差可以控制到5%左右,在进行面目标物亮度分布测试时整体误差基本上可以控制到10%左右. 相似文献
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讨论了积分球均匀光源在CCD、TDI焦平面阵列器件、数码相机和遥感、天文观测探测系统标定中的应用,对积分球出口的辐射场分布及其在传播过程中辐射场能量和均匀性变化的情况给出了理论分析和数值解。 相似文献
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为检测纸浆模塑产品厚度,采用CCD的光学方法进行非接触式测量。通过标定,结果以待测物壁厚的灰度图形式给出,通过像素与实际厚度之间的转换,测出纸浆模塑产品厚度。实验表明,该方法能够准确测量1mm以下包装产品厚度,且具有精度高、非接触测量、白光照明和适合现场测试的特点。 相似文献
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激光打在漫反射屏上形成直径几厘米的近场光斑,人工使用照度计能直接测量光斑照度,但容易造成误差.本文通过数字摄像法得到相机拍摄的光斑图像的灰度,在Tsai模型基础上考虑漫反射率和相机离轴角的影响,建立了光斑照度映射与图像灰度的数学模型,由图像中的灰度能计算得到漫反射屏上光斑的照度.该方法简单、准确.通过实验和数据分析结果表明:光斑上不同位置目标点的照度映射后和图像对应像元灰度的关系符合CCD响应度的线性关系,从而为研究漫反射屏上照度测量方法提供了新的参考. 相似文献
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Brown SW Johnson BC Biggar SF Zalewski EF Cooper J Hajek P Hildum E Grant P Barnes RA Butler JJ 《Applied optics》2005,44(30):6426-6443
The National Aeronautics and Space Administration's (NASA's) Ames Research Center's Airborne Sensor Facility (ASF) is responsible for the calibration of several airborne Earth-viewing sensor systems in support of NASA Earth Observing System (EOS) investigations. The primary artifact used to calibrate these sensors in the reflective solar region from 400 to 2500 nm is a lamp-illuminated integrating sphere source. In September 1999, a measurement comparison was made at the Ames ASF Sensor Calibration Facility to validate the radiometric scale, establish the uncertainties assigned to the radiance of this source, and examine its day-to-day repeatability. The comparison was one of a series of validation activities overseen by the EOS Calibration Program to ensure the radiometric calibration accuracy of sensors used in long-term, global, remote-sensing studies. Results of the comparison, including an evaluation of the Ames Sensor Calibration Laboratory (SCL) measurement procedures and assigned radiometric uncertainties, provide a validation of their radiometric scale at the time of the comparison. Additionally, the maintenance of the radiance scale was evaluated by use of independent, long-term, multiyear radiance validation measurements of the Ames sphere source. This series of measurements provided an independent assessment of the radiance values assigned to integrating sphere sources by the Ames SCF. Together, the measurements validate the SCF radiometric scale and assigned uncertainties over the time period from September 1999 through July 2003. 相似文献
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Ohno Y 《Applied optics》1994,33(13):2637-2647
A method is proposed for realizing the total flux scale of light sources by use of an integrating sphere with an opening to introduce a known amount of flux from a luminous intensity standard or a spectral irradiance standard lamp placed outside the sphere. Computer simulations were made on several models of an integrating sphere, designed to compare the total flux of a test lamp inside the sphere with the flux introduced from an external source. I describe the theory and algorithm of the simulation, present the results of the simulation for varying conditions of sphere geometry such as size and location of the baffles, internal source, and wall reflectance, and predict that one of the models has sufficient accuracy to calibrate lamps for total flux. 相似文献