基于一种图像恢复技术的光谱CCD图像宇宙线剔除算法(英文)

提出一种单幅光谱CCD图像宇宙线剔除方法.即先采用一种改进的中值滤波器找到可能被宇宙线污染的像素点作为噪声候选点;然后采用一种边缘保持算法——TV inpainting恢复被噪声污染的像素点值.模拟实验结果表明,该方法能够很好地剔除宇宙线,同时恢复被宇宙线污染像素点的流量值.

玉米冠层叶片氮素营养估测研究——基于近地多光谱图像

运用图像处理技术对不同氮营养成分下玉米冠层叶片的近地CCD多光谱图像进行分析,建立玉米叶片氮素营养含量的快速、非破坏性估测模型。实验基于红通道和近红外通道的CCD图像,通过图像切割提取两个通道的主叶片区域的平均灰度值和叶片周围的土壤平均灰度值,根据土壤平均灰度值比值来调整叶片的近红外平均灰度值,计算玉米叶片的基于灰度的植被指数,建立了氮素营养含量和两个通道的图像灰度以及灰度植被指数间的经验线性模型。经过多元线性回归分析后,两者间的相关系数R可以达到0.704。由此实现了对玉米冠层氮营养含量的快速估测。

图像光谱技术实现精确测温

建立了一种以灰体辐射为基础测量温度的新方法,它不仅可以测定辐射体的实时温度,而且可以实现无接触和高精度测量。首先,利用多通道CCD图像光谱仪精确测量辐射体在较宽波段内的辐射光谱,作为该辐射体的指纹光谱,将其定义为一个等效的灰体;其次,通过对所测光谱的拟合确定该辐射体的灰体辐射模型的系数,从而确定待测辐射体的灰体辐射模型;最后,通过光谱技术与灰体辐射模型的结合确定给定辐射体的任意温度。通过对无火焰和有火焰这两类热辐射体的实验检验,表明该测温方法具有实时、准确和无接触等优点。

Auto-registration and Orthorecification Algorithm for the Time Series HJ-1A/B CCD Images

How to deal with geometric distortion is an open problem when using the massive amount of satellite images at a national or global scale, especially for multi-temporal image analysis. In this paper, an algorithm is proposed to automatically rectify the geometric distortion of time-series CCD multi- spectral data of small constellation for environmental and disaster mitigation （HJ-1A/B） which was launched by China in 2008. In this algorithm, the area-based matching method was used to automatically search tie points firstly, and then the polynomial function was introduced to correct the systematic errors caused by the satellite motion along the roll, pitch and yaw direction. The improved orthorectification method was finally used to correct pixel displacement caused by off-nadir viewing of topography, which are random errors in the images and cannot be corrected by the polynomial equation. Nine scenes of level 2 HJ CCD images from one path/row were taken as the warp images to test the algorithm. The test result showed that the overall accuracy of the proposed algorithm was within 2 pixels （the average residuals were 37.8 m, and standard deviations were 19.8 m）. The accuracies of 45.96% validation points （VPs） were within 1 pixel and 90.33% VPs were within 2 pixels. The discussion showed that three main factors including the distortion patterns of HJ CCD images, pereent of cloud cover and the varying altitude of the satellite orbit may affect the search of tie points and the accuracy of results. Although the influence of varying altitude of the satellite orbits is less than the other factors, it is noted that detailed satellite altitude information should be given in the future to get a more precise result. The proposed algorithm should be an efficient tool for the geo-correction of HJ CCD multi-spectral images.

环境和介质对测温结果的影响

建立了一种理论模型和实验方法,可以有效地修正来自于环境和介质对测温结果的影响。这种修正方法通过计入测温环境对辐射体的衰减系数,可以显著改善以灰体辐射为基础的测温技术的精度和普适性。首先,利用多通道CCD图像光谱仪快速准确地获得给定辐射体在空气中的指纹光谱,并将其等效为一个标准的灰体模型;其次,将该辐射体放入未知的环境和介质中,重复测量该辐射体的辐射光谱,并建立包含待测介质对辐射体的衰减特征的灰体模型。最后,通过对比上述两种情况下的灰体模型,便可精确确定该辐射体在该环境和介质下的温度。通过对处于不同环境和介质下的相同辐射体的系统实验,检验了该测温技术和修正方法的普适性和准确性。