本文選題：數(shù)字圖像 + 掃描鏡　； 參考：《中國科學(xué)院研究生院(上海技術(shù)物理研究所)》2016年博士論文

【摘要】：新一代靜止氣象衛(wèi)星“風(fēng)云四號”是三軸穩(wěn)定平臺衛(wèi)星,其載荷之一掃描成像輻射計采用二維掃描成像技術(shù)實現(xiàn)對地成像。在18°×18°地球視場范圍內(nèi),掃描鏡的動態(tài)運動精度指標高達1″(1σ)。如何評價掃描鏡在工作模式下的動態(tài)運動精度成為一個技術(shù)難題。針對這個技術(shù)難題,本課題進行了基于數(shù)字圖像的掃描鏡動態(tài)精度(掃描精度)測量方法的研究,分別從方法原理提出、系統(tǒng)構(gòu)建、成像信息處理、方法精度論證、方法實施這幾個層次進行了研究和探討。首先,本文提出了基于數(shù)字圖像的掃描鏡動態(tài)精度測量方法,即在掃描鏡動態(tài)掃描模式下,給定一個精密標準圖案進行掃描成像,通過檢測所成圖像上像點與理想像點位置之間的偏差反演掃描鏡的動態(tài)精度。本文選用帶有13*13陣列菱形圖案的目標板作為精密標準圖案場景,采用積分球作為照明系統(tǒng)對目標板進行照明,目標板發(fā)出的光線經(jīng)過平行光管(投影系統(tǒng))輸出平行光到達掃描輻射計進行成像。文中關(guān)于目標板的標準圖案選取、尺寸參數(shù)設(shè)計、材質(zhì)選型,以及照明系統(tǒng)的選取、投影系統(tǒng)的指標分別進行了詳細論證。其次,對于成像的信息處理是該方法基于數(shù)字圖像的含義所在。本文采用角點和質(zhì)心點作為掃描圖像的特征點進行位置檢測,進而反演掃描精度。選取Harris Affine角點檢測算法進行角點檢測,選取了傳統(tǒng)質(zhì)心檢測算法進行質(zhì)心點檢測。針對每一個檢測算法,文中進行了詳細的精度仿真論證。再次,本文對該方法分別從仿真和試驗這兩個方面進行了方法本身精度的分析和標定。本課題通過可控亞像素偏移成像序列進行測角方法精度的試驗標定,得出基于角點的測角方法精度為0.56~0.91urad(1σ),基于質(zhì)心點的測角方法精度為0.56~0.84urad(1σ),可以滿足FY-4掃描鏡動態(tài)精度檢測需求。最后,基于搭建的測試平臺,在掃描鏡10°/s的運動模式下,采用該測角方法對掃描鏡進行動態(tài)精度測試。測得在局部小視場范圍(0.33°×0.33°)內(nèi),掃描鏡的動態(tài)指向角位置精度為2.64urad(1σ,0.54″)。通過以上四個層次的研究工作,本文提出并論證了基于數(shù)字圖像的掃描鏡動態(tài)精度測量方法,并取得了良好的測試結(jié)果和精度,為掃描鏡在大視場掃描工作模式下的動態(tài)精度測量提供了有效參考。本方法研究的創(chuàng)新之處在于基于輻射計掃描成像工作原理,對掃描數(shù)字圖像進行處理和像點信息獲取,實現(xiàn)了掃描鏡在動態(tài)運動過程中的動態(tài)精度測量,并通過數(shù)字圖像處理技術(shù)提高了測角精度。
[Abstract]:The new generation geostationary meteorological satellite "Fengyun 4" is a triaxial stabilized platform satellite. One of its payloads, scanning imaging radiometer, uses two-dimensional scanning imaging technology to realize earth imaging. In the range of 18 擄脳 18 擄Earth field of view, the dynamic motion accuracy index of scanning mirror is as high as 1 "/ 1 蟽". How to evaluate the dynamic motion accuracy of scanning mirror in working mode has become a technical problem. In view of this technical problem, this subject has carried on the research based on the digital image scanning mirror dynamic precision (scanning precision) measurement method, respectively from the method principle, the system construction, the imaging information processing, the method precision demonstration, Methods the implementation of these levels was studied and discussed. Firstly, the dynamic precision measurement method of scanning mirror based on digital image is proposed, that is, in the dynamic scanning mode of scanning mirror, a precise standard pattern is given for scanning imaging. The dynamic accuracy of the scanning mirror is inversed by detecting the deviation between the image points and the ideal image points. In this paper, the target board with 1313 array diamond pattern is selected as the precision standard pattern scene, and the integrated sphere is used as the lighting system to illuminate the target board. The light emitted from the target plate passes through a parallel tube (projection system) and reaches the scanning radiometer for imaging. In this paper, the standard pattern selection, dimension parameter design, material selection, lighting system selection and projection system index of the target board are discussed in detail. Secondly, the information processing of imaging is the meaning of the method based on digital image. In this paper, the corner and centroid are used as the feature points of the scanning image to detect the position, and then the scanning accuracy is retrieved. Harris Affine corner detection algorithm is selected for corner detection, and traditional centroid detection algorithm is selected for centroid detection. For each detection algorithm, a detailed accuracy simulation is presented in this paper. Thirdly, this paper analyzes and calibrates the accuracy of the method from two aspects: simulation and experiment. In this paper, the precision of angle measurement method is calibrated by using controllable sub-pixel migration imaging sequence. It is concluded that the precision of angle measurement method based on corner point is 0.56~0.91urad(1 蟽, and the precision of angle measurement method based on centroid point is 0.56~0.84urad(1 蟽, which can meet the need of dynamic precision detection of FY-4 scanning mirror. Finally, based on the test platform, the dynamic precision of the scanning mirror is tested by the angle measuring method under the motion mode of 10 擄/ s. In the range of local small field of view (0. 33 擄脳 0. 33 擄), the position accuracy of the dynamic pointing angle of the scanning mirror is 2.64urad(1 蟽 0. 54 ". Through the above four levels of research work, this paper puts forward and demonstrates the dynamic precision measurement method of scanning mirror based on digital image, and obtains good test results and accuracy. It provides an effective reference for dynamic precision measurement of scanning mirror in large field scanning mode. The innovation of this method is that, based on the principle of radiometer scanning imaging, the scanning digital image is processed and the image point information is obtained, and the dynamic precision measurement of scanning mirror in the dynamic motion process is realized. The precision of angle measurement is improved by digital image processing technology.
【學(xué)位授予單位】：中國科學(xué)院研究生院(上海技術(shù)物理研究所)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TP391.41
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本文編號：1944709