【摘要】：航空相機在空中飛行照相時，像移補償精度是影響航空相機成像質(zhì)量的關(guān)鍵因素，高精度像移補償?shù)那疤崾切枰獙λ俑弑冗M行高精度的測量。本文將速高比測量轉(zhuǎn)化為像移速度測量，從航空相機像移速度測量出發(fā)，，以空間濾波測速法（SFV）為基礎(chǔ)，對空間濾波器的濾波特性、濾波器的參數(shù)選擇、二維速度測量以及SFV信號處理等相關(guān)技術(shù)進行了深入研究。 通過對光學(xué)測速方法進行回顧，提出了利用空間濾波測速法對航空相機像移速度進行測量；介紹了空間濾波測速的原理和特性，并從數(shù)學(xué)角度對圖像光強分布的空間濾波效應(yīng)進行了介紹；討論了透射函數(shù)對于窄帶通濾波特性的影響，給出了不同形狀的濾波器窗口對于典型透射函數(shù)的功率譜表達式，并對其功率譜中的頻譜帶寬及中心頻率等特性進行了研究；通過研究空間濾波器的功率譜密度函數(shù)，對影響空間濾波特性的關(guān)鍵參數(shù)進行了分析；對比了透射光柵、棱鏡光柵、光電二極管陣列以及液晶元件陣列等各類空間濾波器件進行像移速度測量的適用性；討論了利用差分檢波對基頻成分的消除，提出了進行像移速度方向鑒別以及二維速度測量的方法；深入的討論了處理SFV信號所涉及的信號分析技術(shù)，介紹了頻譜分析，頻率跟蹤，計數(shù)方法以及相關(guān)技術(shù)等典型的信號分析技術(shù)。 提出了利用線陣CCD的空間濾波特性進行航空相機像移速度測量的新方法，利用線陣CCD的空間濾波特性，通過對線陣CCD推掃所產(chǎn)生的圖像進行隔行采樣，模擬了空間濾波器的窄帶通頻率特性，實現(xiàn)了對航空相機像移速度的光學(xué)非接觸測量，從而實現(xiàn)了速高比的測量。此方法可根據(jù)地面目標(biāo)的頻率分布靈活調(diào)整空間濾波器的頻率特性，能夠適用于航空相機速高比的精確測量。實驗對5mm/s~53.2mm/s范圍內(nèi)幾個典型像移速度進行了測量，結(jié)果表明，CCD像元尺寸為8μm，相機曝光時間為10ms時，測量誤差引起的像移量誤差最大為2μm，能夠滿足航空相機像移補償?shù)木纫�；實驗中采用了線陣CCD的像素binning功能，大幅度提高了數(shù)據(jù)的讀出速率，實現(xiàn)了動態(tài)累加的快速采樣，同時提高圖像的信噪比；提出了利用單個線陣CCD進行一維運動方向鑒別的方法，簡化了光學(xué)系統(tǒng)；介紹了基于模糊圖像的二維速度方向鑒別方法，并進行了試驗驗證。 本文成功的實現(xiàn)了航空相機像移速度的高精度測量，從而實現(xiàn)了速高比的高精度測量，試驗結(jié)果表明，文中提出的測量方法其精度完全滿足航空相機像移補償?shù)木纫蟆?br/>[Abstract]:When aerial camera is photographed in the air, the accuracy of image shift compensation is the key factor affecting the imaging quality of aerial camera, and the premise of high precision image shift compensation is the need to measure the ratio of speed to height with high precision. In this paper, the measurement of speed to height ratio is transformed into image shift velocity measurement. Based on the spatial filtering velocimeter method (SFV), the filtering characteristics of the spatial filter and the parameter selection of the filter are based on the image shift velocity measurement of the aerial camera. The related technologies such as two-dimensional velocity measurement and SFV signal processing are deeply studied. Based on the review of the optical velocimeter method, the spatial filtering velocimeter method is proposed to measure the image shift velocity of the aerial camera. The principle and characteristics of spatial filtering velocity measurement are introduced, and the spatial filtering effect of image light intensity distribution is introduced from the mathematical point of view. The influence of transmission function on narrow band pass filtering characteristics is discussed. The power spectrum expressions of filter windows with different shapes for typical transmission functions are given, and the characteristics of spectrum bandwidth and center frequency in the power spectrum are studied. By studying the power spectral density function of the spatial filter, the key parameters affecting the spatial filtering characteristics are analyzed. The applicability of various spatial filter devices, such as transmission grating, prism grating, photodiode array and liquid crystal element array, for image shift velocity measurement is compared. The elimination of fundamental frequency components by differential detection is discussed, and the methods of image shift velocity direction identification and two-dimensional velocity measurement are proposed. The signal analysis technology involved in processing SFV signal is discussed in detail, and the typical signal analysis techniques, such as spectrum analysis, frequency tracking, counting method and related technology, are introduced. A new method for measuring the image shift velocity of aerial camera by using the spatial filtering characteristics of linear CCD is proposed. By using the spatial filtering characteristics of linear CCD, the images generated by linear CCD push sweep are sampled interlaced. The narrowband frequency characteristics of the spatial filter are simulated, and the optical non-contact measurement of the image shift velocity of the aerial camera is realized, thus the measurement of the speed to height ratio is realized. This method can flexibly adjust the frequency characteristics of the spatial filter according to the frequency distribution of the ground target, and can be applied to the accurate measurement of the speed to height ratio of the aerial camera. Several typical image displacement speeds in the range of 5mm/s~53.2mm/s are measured experimentally. the results show that when the size of CCD pixel is 8 渭 m and the camera exposure time is 10ms, the maximum image shift error caused by the measurement error is 2 渭 m. It can meet the accuracy requirements of image shift compensation of aerial camera. The pixel binning function of linear CCD is used in the experiment, which greatly improves the readout rate of the data, realizes the fast sampling of dynamic accumulation, and improves the signal-to-noise ratio of the image at the same time. A method of one-dimensional motion direction identification based on single linear CCD is proposed, which simplifies the optical system, and the two-dimensional velocity direction identification method based on fuzzy image is introduced and verified by experiments. In this paper, the high precision measurement of image shift speed of aerial camera is successfully realized, and the high precision measurement of speed to height ratio is realized. The experimental results show that the accuracy of the measurement method proposed in this paper fully meets the accuracy requirements of image shift compensation of aerial camera.
【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】：博士
【學(xué)位授予年份】：2013
【分類號】：P231

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相關(guān)期刊論文 前10條

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本文編號：2492398