航天返回与遥感
航天返迴與遙感
항천반회여요감
SPACECRAFT RECOVERY & REMOTE SENSING
2013年
3期
26-33
,共8页
交叉辐射%成像质量%点扩散函数%高分辨率%空间遥感
交扠輻射%成像質量%點擴散函數%高分辨率%空間遙感
교차복사%성상질량%점확산함수%고분변솔%공간요감
cross-radiance%imaging quality%point spread function%high ground sampling distance%space remote sensing
空间光学遥感成像卫星是利用接收来自地面目标反射的光辐射信息来实现对地目标的遥感观测。来自目标的光辐射信息在到达遥感卫星有效载荷前必须经过大气辐射传输环节，因此，作为成像链路中的一个环节，大气辐射传输对遥感卫星数据质量的影响不能避免。大气对遥感图像的影响主要包括大气程辐射和交叉辐射。文章利用蒙特卡洛算法计算分析了遥感卫星成像系统在不同大气条件、空间分辨率、观测天顶角等情况下的交叉辐射影响，通过5×5矩阵表示交叉辐射的点扩展函数(Point Spread Function，PSF)，通过变换将 PSF 得到不同情况下的调制传递函数(Modulation Transfer Function，MTF)值。随着大气能见度的降低、观测空间分辨率（Ground Sampling Distance，GSD）的逐渐减小以及观测天顶角的逐渐增大，根据计算结果及分析表明交叉辐射的影响逐渐严重，在大角度高分辨率观测时交叉辐射导致的临近像元辐射贡献增大尤其明显，交叉辐射导致成像质量的影响不能忽略。
空間光學遙感成像衛星是利用接收來自地麵目標反射的光輻射信息來實現對地目標的遙感觀測。來自目標的光輻射信息在到達遙感衛星有效載荷前必鬚經過大氣輻射傳輸環節，因此，作為成像鏈路中的一箇環節，大氣輻射傳輸對遙感衛星數據質量的影響不能避免。大氣對遙感圖像的影響主要包括大氣程輻射和交扠輻射。文章利用矇特卡洛算法計算分析瞭遙感衛星成像繫統在不同大氣條件、空間分辨率、觀測天頂角等情況下的交扠輻射影響，通過5×5矩陣錶示交扠輻射的點擴展函數(Point Spread Function，PSF)，通過變換將 PSF 得到不同情況下的調製傳遞函數(Modulation Transfer Function，MTF)值。隨著大氣能見度的降低、觀測空間分辨率（Ground Sampling Distance，GSD）的逐漸減小以及觀測天頂角的逐漸增大，根據計算結果及分析錶明交扠輻射的影響逐漸嚴重，在大角度高分辨率觀測時交扠輻射導緻的臨近像元輻射貢獻增大尤其明顯，交扠輻射導緻成像質量的影響不能忽略。
공간광학요감성상위성시이용접수래자지면목표반사적광복사신식래실현대지목표적요감관측。래자목표적광복사신식재도체요감위성유효재하전필수경과대기복사전수배절，인차，작위성상련로중적일개배절，대기복사전수대요감위성수거질량적영향불능피면。대기대요감도상적영향주요포괄대기정복사화교차복사。문장이용몽특잡락산법계산분석료요감위성성상계통재불동대기조건、공간분변솔、관측천정각등정황하적교차복사영향，통과5×5구진표시교차복사적점확전함수(Point Spread Function，PSF)，통과변환장 PSF 득도불동정황하적조제전체함수(Modulation Transfer Function，MTF)치。수착대기능견도적강저、관측공간분변솔（Ground Sampling Distance，GSD）적축점감소이급관측천정각적축점증대，근거계산결과급분석표명교차복사적영향축점엄중，재대각도고분변솔관측시교차복사도치적림근상원복사공헌증대우기명현，교차복사도치성상질량적영향불능홀략。
The optical imaging system of remote sensing satellite observes object on the earth by receiv-ing the radiance from it. Before arriving at the imaging system, the radiance from object should pass through the atmosphere. So as a part of the imaging chain, the atmospheric influence on the imaging quality of remote sensing satellite should be considered. The atmospheric influence can be divided into two parts: one part is the path radiance; the other part is cross-radiance. The point spread functions (PSFs) of cross-radiance influence on the remote sense imaging system at different conditions, such as atmospheric visibility, ground sampling dis-tance (GSD) and viewing zenith angle, are analyzed and calculated by using the Monte Carlo means. The PSF is expressed by 5×5 matrix, and the modulation transfer function (MTF) gotten by transforming the PSF. From the data of PSF and MTF in different conditions, it is shown that the cross-radiance influence gets more and more serious when the atmospheric visibility is from 25km to 5km, the GSD from 100m to 2m, and the view zenith angle from 0° to 60°. Form the result of such analysis the cross-radiance influence get most serious at big view zenith angle, so the cross-radiance influence cannot be neglected especially for high GSD remote sensing satellite at big view zenith angle.
