衛(wèi)星相機線擴散函數(shù)FWHM測量不確定度估計及其應(yīng)用
發(fā)布時間：2018-10-16 19:32
【摘要】：對衛(wèi)星相機在軌點擴散函數(shù)(Point Spread Function,PSF)及調(diào)制傳遞函數(shù)Modulation Transfer Function,MTF)進行測量具有十分重要的理論和實際工程應(yīng)用的意義。衛(wèi)星相機在軌狀態(tài)與地面靜態(tài)相比,工作環(huán)境等條件有較大的變化,因此在軌PSF/MTF不能使用靜態(tài)PSF/MTF來代替,必須通過實際獲得的遙感圖像進行提取。點光源法、周期靶標(biāo)法、脈沖法及傾斜刃邊法等是典型的從遙感圖像中提取成像時刻的PSF/MTF的方法。其中,傾斜刃邊法對高分辨率系統(tǒng)的空間響應(yīng)有較高的準(zhǔn)確性,同時對靶標(biāo)的要求不如點光源法嚴(yán)格,因而廣泛應(yīng)用于國內(nèi)外對高分辨率遙感系統(tǒng)的在軌PSF/MTF測量中。然而,衛(wèi)星相機只能根據(jù)刃邊靶標(biāo)布設(shè)的時間和位置進行檢測,不能滿足長期跟蹤衛(wèi)星相機性能與實時在軌PSF/MTF的獲取的要求,而這正是衛(wèi)星相機在軌PSF/MTF監(jiān)測希望達(dá)成的效果。設(shè)若傾斜刃邊法能夠突破靶標(biāo)的限制,通過合適的自然地物目標(biāo)影像就能夠得到較高精度的在軌MTF測量結(jié)果,就能夠?qū)πl(wèi)星相機在軌MTF進行連續(xù)的檢測和實時實地MTF的獲取,對衛(wèi)星相機長期在軌運行性能跟蹤和圖像實時復(fù)原有重要意義。在傾斜刃邊法的基礎(chǔ)上,對其關(guān)鍵步驟邊緣擴散函數(shù)(Edge Spread Function,ESF)提取方法進行研究。在MSG(Modified SG)方法的基礎(chǔ)上進行改進,提出一種自適應(yīng)SG(Self-Adaptive SG Method,SASG)方法。通過仿真實驗并結(jié)合在實際遙感圖像中的使用效果,驗證了SASG方法的有效性。對比典型的三次樣條方法(Spline Method),三次樣條-SG組合方法(SplineSG Method)實驗結(jié)果與Spline方法基本一致,而SASG方法有更強的抗條帶噪聲干擾能力。此外,SASG從算法復(fù)雜程度上相比Spline與SplineSG更為簡便。因此,SASG方法有一定的實用性。結(jié)合國內(nèi)外對傾斜刃邊法另一關(guān)鍵算法亞像素邊緣探測算法的研究,以Fermi函數(shù)探測方法為精度最高的探測方法,完成對傾斜刃邊法關(guān)鍵算法的優(yōu)化研究。在對傾斜刃邊法進行優(yōu)化的基礎(chǔ)上,通過仿真實驗研究適用傾斜刃邊法的地物影像需要滿足的條件,從而為傾斜刃邊法擺脫靶標(biāo)限制打下基礎(chǔ)。對于刃邊傾角、刃邊尺寸以及噪聲分布等圖像條件對算法準(zhǔn)確度影響的分析,以Nyquist頻率處的MTF值(NyquistMTF)、PSF的半高寬度(Full Width at Half Maximum,FWHM)等參數(shù)為統(tǒng)計量形成定量的分析結(jié)果。仿真實驗結(jié)果表明,地物影像傾角在6°~10°時,FWHM的計算精度在±1%以內(nèi),不確定度在2%以內(nèi);Nyquist MTF的計算精度在±5%以內(nèi),不確定度在2%以內(nèi),滿足對算法準(zhǔn)確度的要求。其中,結(jié)合精度與不確定度的考慮,8°可以作為準(zhǔn)確度最高的傾角。圖像有效尺寸隨傾角變化而變化,以8°傾角為基礎(chǔ),要求刃邊高度至少20pixel左右,刃邊寬度則需要盡量大的亮暗均勻區(qū)域。為保證算法精度,信噪比應(yīng)該不低于40dB。研究表明,NyquistMTF對于FWHM的變化非常敏感,因此,在不要求具體數(shù)值時,可以僅根據(jù)FWHM對成像系統(tǒng)性能做出定性分析。此外,由于衛(wèi)星側(cè)擺角范圍在0°~40°之內(nèi),大側(cè)擺對衛(wèi)星相機采樣分辨率的影響不能忽略,因此,刃邊邊緣灰度分布將發(fā)生變化,從而對傾斜刃邊法結(jié)果產(chǎn)生影響。通過仿真方法及實際遙感圖像的應(yīng)用,分析采樣分辨率變化對傾斜刃邊法算法準(zhǔn)確度的影響。實驗結(jié)果表明,對同一刃邊地物目標(biāo),當(dāng)?shù)孛娌蓸娱g隔(Ground Sampling Distance,GSD)增加時,地物影像尺寸減小,傾斜刃邊法FWHM估計結(jié)果下降,PSF與MTF提取值偏高,在圖像復(fù)原中引產(chǎn)生振鈴與模糊等。
[Abstract]:It is very important to measure the point Spread Function (PSF) and Modulation Transfer Function Modulation (MTF) in the orbit point spread function (MTF) of the satellite camera. When the orbit state of the satellite camera is compared with the static state of the ground, the working environment and other conditions have great changes. Therefore, the static PSF/ MTF cannot be used instead of the orbit PSF/ MTF, and the extracted remote sensing image must be extracted. The point light source method, the periodic target method, the pulse method and the inclined blade edge method are typical methods for extracting the PSF/ MTF of the imaging time from the remote sensing image. The inclined blade edge method has high accuracy for the spatial response of the high-resolution system, and the requirement of the target is not as strict as the point light source method, so it is widely applied to the measurement of the orbit PSF/ MTF of the high-resolution remote sensing system at home and abroad. However, the satellite camera can only detect the time and position of the target layout of the blade edge, and can not meet the requirement of long-term tracking satellite camera performance and real-time acquisition of the orbit PSF/ MTF, which is the effect of the satellite camera on the track PSF/ MTF monitoring. if the inclined blade edge method can break through the limitation of the target, the accurate orbit MTF measurement result can be obtained with a suitable natural figure target image, and continuous detection and real-time MTF acquisition of the satellite camera on the orbit MTF can be carried out on the satellite camera, It is of great significance to long-term track operation performance tracking and real-time image restoration of satellite camera. The Edge Spread Function (ESF) extraction method is studied on the basis of the oblique edge method. Based on the MSG (Modified SG) method, an adaptive SG (Self-Adaptive SG Method, SASG) method is proposed. The effectiveness of SASG method is verified by simulation experiment and combined use effect in real remote sensing image. Compared with the typical cubic spline method (Spline Method), the three-cubic spline-SG combination method (SplaneSG Method) experiment results are basically the same as the Spline method, while the SASG method has stronger anti-banding noise interference capability. In addition, SASG is simpler than Spline and SplineSG from the complexity of the algorithm. Therefore, SASG method has some practicability. Based on the research of the sub-pixel edge detection algorithm of another key algorithm of inclined blade edge method at home and abroad, the method of Fermi function detection is the highest precision detection method, and the optimization research on the key algorithm of inclined blade edge method is completed. On the basis of the optimization of the inclined blade edge method, the condition that the feature image needs to be satisfied is studied by the simulation experiment, thus laying the foundation for the inclined blade edge method to get rid of the target limit. For the analysis of the influence of image conditions such as edge inclination angle, blade edge size and noise distribution on the accuracy of the algorithm, quantitative analysis results are formed based on the parameters such as the MTF value at Nyquist frequency (Nyquist MTF), the half height of PSF (Full Width at Half Maximum, FWHM). The simulation results show that the accuracy of FWHM is within 1% and the uncertainty is within 2% at 6 擄 ~ 10 擄. The accuracy of the Nyquist MTF is within 5%, the uncertainty is within 2%, and the accuracy of the algorithm is satisfied. Among them, with the consideration of accuracy and uncertainty, 8 deg. can be used as the highest accuracy tilt angle. The effective size of the image changes with the change of the inclination angle. Based on the inclination angle of 8 擄, the height of the edge edge is required to be at least about 20Pixel, and the width of the edge shall be as large as possible. To ensure the accuracy of the algorithm, the signal-to-noise ratio should not be less than 40dB. The results show that the Nyquist MTF is very sensitive to FWHM's variation. Therefore, it is possible to make qualitative analysis of imaging system performance only according to FWHM when no specific values are required. In addition, since the satellite-side swing angle range is within 0 擄 ~ 40 擄, the influence of large-side pendulum on the sampling resolution of satellite camera can't be ignored. Therefore, the edge-edge gray-scale distribution will change, which will affect the results of edge-edge method. Through the simulation method and the application of the actual remote sensing image, the influence of the variation of the sampling resolution on the accuracy of the edge-edge method is analyzed. The experimental results show that when the ground sampling interval (GSD) increases, the image size decreases, the FWHM estimation result decreases, the PSF and MTF extraction value are high, and ringing and blurring are produced in image restoration.
【學(xué)位授予單位】：中國科學(xué)院研究生院(長春光學(xué)精密機械與物理研究所)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：V445.8
本文編號：2275407
[Abstract]:It is very important to measure the point Spread Function (PSF) and Modulation Transfer Function Modulation (MTF) in the orbit point spread function (MTF) of the satellite camera. When the orbit state of the satellite camera is compared with the static state of the ground, the working environment and other conditions have great changes. Therefore, the static PSF/ MTF cannot be used instead of the orbit PSF/ MTF, and the extracted remote sensing image must be extracted. The point light source method, the periodic target method, the pulse method and the inclined blade edge method are typical methods for extracting the PSF/ MTF of the imaging time from the remote sensing image. The inclined blade edge method has high accuracy for the spatial response of the high-resolution system, and the requirement of the target is not as strict as the point light source method, so it is widely applied to the measurement of the orbit PSF/ MTF of the high-resolution remote sensing system at home and abroad. However, the satellite camera can only detect the time and position of the target layout of the blade edge, and can not meet the requirement of long-term tracking satellite camera performance and real-time acquisition of the orbit PSF/ MTF, which is the effect of the satellite camera on the track PSF/ MTF monitoring. if the inclined blade edge method can break through the limitation of the target, the accurate orbit MTF measurement result can be obtained with a suitable natural figure target image, and continuous detection and real-time MTF acquisition of the satellite camera on the orbit MTF can be carried out on the satellite camera, It is of great significance to long-term track operation performance tracking and real-time image restoration of satellite camera. The Edge Spread Function (ESF) extraction method is studied on the basis of the oblique edge method. Based on the MSG (Modified SG) method, an adaptive SG (Self-Adaptive SG Method, SASG) method is proposed. The effectiveness of SASG method is verified by simulation experiment and combined use effect in real remote sensing image. Compared with the typical cubic spline method (Spline Method), the three-cubic spline-SG combination method (SplaneSG Method) experiment results are basically the same as the Spline method, while the SASG method has stronger anti-banding noise interference capability. In addition, SASG is simpler than Spline and SplineSG from the complexity of the algorithm. Therefore, SASG method has some practicability. Based on the research of the sub-pixel edge detection algorithm of another key algorithm of inclined blade edge method at home and abroad, the method of Fermi function detection is the highest precision detection method, and the optimization research on the key algorithm of inclined blade edge method is completed. On the basis of the optimization of the inclined blade edge method, the condition that the feature image needs to be satisfied is studied by the simulation experiment, thus laying the foundation for the inclined blade edge method to get rid of the target limit. For the analysis of the influence of image conditions such as edge inclination angle, blade edge size and noise distribution on the accuracy of the algorithm, quantitative analysis results are formed based on the parameters such as the MTF value at Nyquist frequency (Nyquist MTF), the half height of PSF (Full Width at Half Maximum, FWHM). The simulation results show that the accuracy of FWHM is within 1% and the uncertainty is within 2% at 6 擄 ~ 10 擄. The accuracy of the Nyquist MTF is within 5%, the uncertainty is within 2%, and the accuracy of the algorithm is satisfied. Among them, with the consideration of accuracy and uncertainty, 8 deg. can be used as the highest accuracy tilt angle. The effective size of the image changes with the change of the inclination angle. Based on the inclination angle of 8 擄, the height of the edge edge is required to be at least about 20Pixel, and the width of the edge shall be as large as possible. To ensure the accuracy of the algorithm, the signal-to-noise ratio should not be less than 40dB. The results show that the Nyquist MTF is very sensitive to FWHM's variation. Therefore, it is possible to make qualitative analysis of imaging system performance only according to FWHM when no specific values are required. In addition, since the satellite-side swing angle range is within 0 擄 ~ 40 擄, the influence of large-side pendulum on the sampling resolution of satellite camera can't be ignored. Therefore, the edge-edge gray-scale distribution will change, which will affect the results of edge-edge method. Through the simulation method and the application of the actual remote sensing image, the influence of the variation of the sampling resolution on the accuracy of the edge-edge method is analyzed. The experimental results show that when the ground sampling interval (GSD) increases, the image size decreases, the FWHM estimation result decreases, the PSF and MTF extraction value are high, and ringing and blurring are produced in image restoration.
【學(xué)位授予單位】：中國科學(xué)院研究生院(長春光學(xué)精密機械與物理研究所)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：V445.8
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