摘要
大气传递函数（ＭＴＦ），Ｈ，所引起的图象畸变可看作两个成分的贡献之和：一个确定成分＜Ｈ＞和一个随机成分△Ｈ而＜Ｈ＞又是大气扰动的平均ＭＴＦ和尘埃雾气微粒ＭＴＦ的和实际大气的Ｈ是完全未知的，要通过实验测量确定Ｄ．Ｓａｄｏｔ等人提出了一种改进的滤波器，其中以确定成分＜Ｈ＞作为滤波器的传函，而把△Ｈ作为噪音成分对待，但传函＜Ｈ＞的获取要依赖于实时实验测量显然，伴随ＰＳＦ实验测量的方法将难以履行某些应用场合（如卫星摄影测绘）的图象复原此外，经由该方法的复原结果已被表面噪音过重由于＜Ｈ＞的精确解析式已被Ｆｒｉｅｄ等人在总结前人研究的基础上给出，并被实验所证实，但解析式中的Ｆｒｉｅｄ参数ｒ０（表征能见度）仍然是未知的，依然要通过实验测量给出如果能从模糊图象本身中识别出参数ｒ０，则可解析求得平均扰动传函＜Ｈ＞所以关键是如何从识别ｒ０本文提出一种大气畸变图象复原的新方法该技术的先进性在于避开昂贵且费时的实验测量，而直接从模糊图象中识别＜Ｈ＞我们开发的这种识别是基于以下物理事实：１）＜Ｈ＞包含尘雾微粒ＭＴＦ和扰动ＭＴＦ的平均效果，它在秒级照相曝光时间内是确定不变的；２）模糊图象可由具有Ｇａｕｓ传函Ｈｇ的?
A new blind method of restoration of images distorted by atmosphere is presented in this paper.In imaging through the atmosphere,the system MTF can be decomposed into the sum of its mean <H>,and random component ΔH.The <H> have been studied by Fried 6 who derived analytical expressions.This technique deals with identification of Fried parameter r 0 in expression of <H>.The identification of r 0 is based on the facts:1)<H>,including average turbulence MTF and aerosol MTF,is determinate in a few second exposure times,and located at low frequency areas;2)A approximate restoration can be obtained by Wiener filter with Caussian H g;3)<H> has the same zero cross point as the H g and the image degraded by this <H>.It will be seen that a corrected r 0 can result in a good restoration result.This is due to the main contribution on blur is <H>,while the random MTF,ΔH,can be removed by Wiener filter.
出处
《光子学报》
EI
CAS
CSCD
1998年第12期1091-1097,共7页
Acta Photonica Sinica
关键词
图象复原
传递函数
大气扰动
功率谱
MTF
Image restoration
Atmospheric modulation transfer function
Turbulence
Point spread function (PSF)
Wiener filter
Power spectral
