本文選題：復(fù)雜流場　切入點：光學層析重建　出處：《深圳大學》2016年博士論文　論文類型：學位論文

【摘要】：復(fù)雜流場的測量主要應(yīng)用于空氣動力學以及爆轟等軍事場合,具有重要意義。至少有兩大特點使得測量困難,(1)內(nèi)部環(huán)境苛刻,高溫、高壓、腐蝕等環(huán)境限制了接觸式傳感器的使用;(2)高速場,過程幾近瞬態(tài),在極短的時間內(nèi)發(fā)生變化。而光學層析是計算機層析的一個分支領(lǐng)域,是非接觸的不干擾待測物理場分布的測量技術(shù),在復(fù)雜流場的眾多應(yīng)用領(lǐng)域展現(xiàn)了極大的優(yōu)越性。其中干涉層析以干涉條紋為觀測,具有靈敏度高、反應(yīng)快等優(yōu)點,在復(fù)雜流場測量具有較高的研究和實用價值。本文針對現(xiàn)有技術(shù)的缺陷,提出一個框架性的解決方案,即結(jié)合統(tǒng)計學、圖論等現(xiàn)代工具,重點應(yīng)用馬爾科夫隨機場理論對干涉層析中的幾個關(guān)鍵問題進行建模并尋優(yōu),具有以下幾點重要創(chuàng)新:(1)為光學層析重建領(lǐng)域提出一個全新的解決方案,即應(yīng)用馬爾科夫隨機場理論,將光學層析重建問題涉及的多個關(guān)鍵技術(shù)統(tǒng)一于同一個理論框架之內(nèi);(2)提出一種基于反余弦及其區(qū)間反轉(zhuǎn)相位恢復(fù)新方法,該方法實現(xiàn)簡便,計算簡單,在不同的相對載頻下都擁有小而穩(wěn)定的恢復(fù)誤差及較好的恢復(fù)效果;(3)提出一種基于馬爾科夫隨機場的相位提取方法,此方法不依賴于空間載波,有效地從單幅干涉圖中恢復(fù)相位差,應(yīng)用場合更廣泛;(4)提出一種基于馬爾科夫隨機場的圖像重建方法,這一方法可在極少投影量下得到大大優(yōu)于傳統(tǒng)技術(shù)的結(jié)果,不僅可應(yīng)用于二值層析問題,也可以應(yīng)用于多像素值的情況。論文在上述的創(chuàng)新點上開展了大量研究工作,主要研究內(nèi)容簡述如下。(1)基于反余弦區(qū)間反轉(zhuǎn)的相位恢復(fù)方法相位重建是干涉層析的首要解決的問題。論文分析了余弦函數(shù)正負號歧義問題,導(dǎo)出了反余弦相位和相位2π模之間的關(guān)系。由于在反余弦的(π,2π)區(qū)間需要對相位反轉(zhuǎn),將反轉(zhuǎn)區(qū)間的確定問題轉(zhuǎn)換為一個三段式折線擬合問題。利用遺傳算法等優(yōu)化方法求解了折線的最小均方擬合,且使用最小二乘法估計了干涉圖的載頻,進而獲得最佳相位估計。仿真過程及結(jié)果表明,提出方法實現(xiàn)簡便,計算簡單,在各種相對載頻下都擁有小而穩(wěn)定的恢復(fù)誤差及較好的恢復(fù)效果,相對于傳統(tǒng)的傅里葉變換和條紋分析等方法,更適用于具有各種不同梯度大小的相位圖。(2)基于馬爾科夫隨機場的相位提取方法符號不確定性是從單幅干涉圖中恢復(fù)相位差的一個關(guān)鍵問題,本研究提出了一種基于馬爾科夫隨機場能量最小化的符號不確定性消除新方法。提出的方法使用馬爾科夫隨機場構(gòu)建符號圖中像素點之間的點對關(guān)系,這是“全局”與“局部”之間的折中。方法注意到相鄰位置的符號反轉(zhuǎn)時,干涉圖反余弦的梯度方向圖將有一個π大小的跳躍。利用這一信息建立了馬爾科夫隨機場的點對能量函數(shù)。為了進一步減少噪聲影響,使用鄰域直接平均和自適應(yīng)濾波來取代光流,結(jié)果表明該法能正確地平滑梯度方向圖用作隨機場的輸入。仿真結(jié)果表明方法有效地從單幅干涉圖中恢復(fù)相位差,且不依賴于空間載波,應(yīng)用場合更廣泛。相位恢復(fù)的好壞直接影響層析重建的效果,因此前兩部分研究內(nèi)容為干涉層析重建提供了重要的技術(shù)支持。(3)基于馬爾科夫隨機場的切片圖像重建方法從少量的投影數(shù)據(jù)中重建切片圖像一直是一個具有挑戰(zhàn)性的任務(wù)。本文將該問題數(shù)學表達為一個統(tǒng)計圖模型推理問題。馬爾科夫隨機場可以簡便整合各種先驗信息,例如光滑先驗,即離得近的像素之間具有較一致的灰度值。應(yīng)用信任傳播推理時遭遇高階簇引起的指數(shù)級增長計算難題,本文提出了一個變量變換的技巧,可以將指數(shù)級計算量降為多項式計算量,即從Ο(MN-1)降至Ο((N-2)M2),從而獲得一個快速和積推理算法。實踐證實其有效性,即可在極少投影量下得到大大優(yōu)于傳統(tǒng)技術(shù)的結(jié)果,且不僅可應(yīng)用于二值層析問題,也可以應(yīng)用于多像素值的情況。(4)基于馬爾科夫隨機場的切片插值方法層析切片圖像需要插值重建才能做到完整的體視化。本文針對傳統(tǒng)數(shù)學插值的缺陷,提出了一種基于馬爾科夫隨機場的統(tǒng)計重建技術(shù),對層析切片數(shù)據(jù)在垂線方向上建模,并使用全局優(yōu)化算法模擬退火來實現(xiàn)尋優(yōu)。這成為后續(xù)的層析物理場的智能理解的技術(shù)基礎(chǔ)。上述關(guān)鍵技術(shù)統(tǒng)一于馬爾科夫隨機場理論框架,借助于統(tǒng)計學、模式識別等先進數(shù)學工具更高效更有效地尋找最優(yōu)解,極大地豐富了復(fù)雜流場測量與光學層析重建技術(shù)。
[Abstract]:The measurement of complex flow field is mainly used in aerodynamics, detonation and other military applications, which is of great significance. There are at least two major characteristics of the measurement difficulties, (1) the internal environment of high temperature, high pressure, harsh, corrosive environment limits the use of non-contact sensor; (2) high speed field, almost instantaneous change in the process. Within a very short period of time. While the optical tomography is a subfield of computer tomography, is not interference measurement technology to measure the physical distribution of non contact, show great superiority in many application fields. The complex flow of interference fringes were observed by chromatography, with high sensitivity, fast response and other advantages that is high in complex flow field measurement research and practical value. This paper aims at the defects of the existing technology, puts forward a framework solution, which combines statistics, graph theory and other modern tools, focusing on the application of Markoff The random field theory of interference of several key problems in chromatography was applied to modeling and optimization, has the following innovation: (1) put forward a new solution for optical tomography reconstruction, namely the application of Markov random field theory, will involve the optical tomography reconstruction problem of multiple key technologies within the same unified the theoretical framework; (2) put forward a new method to restore the arccosine and interval based on phase inversion, this method is easy to realize, simple calculation, in the relative frequency under different have small and stable error and better recovery recovery effect; (3) proposed an extraction method based on Markov random phase. This method does not depend on the spatial carrier, effectively from the single interferogram in recovery phase difference applications more widely; (4) we propose an image reconstruction method based on Markov random field method, this method can be used in very little investment The results are much better than the traditional shadow volume, can be used not only in the value of two chromatography, can also be applied to multi pixel values. This paper carried out a lot of research work in the innovation, the main research contents are summarized as follows. (1) recovery method based on phase reconstruction phase anticosine interval inversion is to solve the problem of interferometric tomography. This paper analyzes the cosine function of sign ambiguity, the relationship between the arccosine phase and derived 2 pi mode. Because the arccosine of (PI 2, PI) interval needs to convert the problem to determine the phase inversion, inversion interval for a three segment line fitting the problem. By using the genetic algorithm optimization method to solve the linear least square fitting and least square method is used to estimate the carrier frequency of the interferogram, and then obtain the optimal phase estimation. The simulation process and results show that the proposed method. This simple, simple calculation, various relative carrier has a small and stable error recovery and recovery effect is better, compared with Fourier transform and fringe analysis of traditional methods, more suitable for the phase diagram with different gradient size. (2) Markoff random phase extraction method of uncertainty is from a single symbol interference is a key problem in the recovery phase difference based on this study, a method based on the Markoff energy minimization random symbol uncertainty elimination method. The proposed method uses pixels random field to construct symbolic figure Markoff point to the relationship, this is the "global" and "local" compromise between note that the sign reversal method. Adjacent position when the interference graph gradient direction cosine will jump a PI size. The establishment of Marco's with the use of this information The airport of the energy function. In order to further reduce the influence of noise, instead of using the neighborhood average optical flow directly and adaptive filtering, the results show that this method can correct horizontal slide direction diagram is used as the random input. The simulation results show that the method of interference effectively from a single figure in the recovery phase, and does not depend on the spatial carrier, application the occasion is more extensive. Phase recovery directly influences the tomographic reconstruction effect, so the research work of two parts for interferometric tomography reconstruction provides an important technical support. (3) based on Markov random slices like airport reconstruction method of the reconstructed slice image from the projection of a small amount of data has been a challenging task. The expression of the mathematical problem as a statistical inference problem. The graph model of Markov random field can easily integrate various prior information, such as that from a smooth prior. Between near pixels with gray values. The index is consistent with the application of trust propagation reasoning encountered high order cluster caused by the growth of computing problem, this paper proposes a variable transformation technique, exponential computation can be reduced to polynomial computation, namely from April (MN-1) to April ((N-2) M2) thus, to obtain a fast and integrated reasoning algorithm. Practice proves its effectiveness can be much better than the traditional technology results in little projection, and can be used not only in the value of two chromatography, can also be applied to multi pixel value. (4) with Markov chromatography slice interpolation method of airport section image interpolation reconstruction can achieve visualization based on the complete. Aiming at the defects of traditional interpolation, is proposed based on the Markov random field of statistical reconstruction technology, tomographic slice data modeling in the vertical direction, and the use of all Optimization algorithm simulated annealing to achieve the optimization. This technology as the basis for intelligent chromatography subsequent understanding of the physical field. The key technologies in unified Markov random field theory, using advanced mathematical tools in statistics, pattern recognition more efficiently and effectively find the optimal solution, greatly enriched the complex flow field and optical measurement the tomographic reconstruction technique.

【學位授予單位】：深圳大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：O211.62

【參考文獻】

相關(guān)期刊論文 前6條

1 閆海濤;孟偉東;趙曉艷;甄志強;;基于干涉條紋圖像對比法測量微位移[J];應(yīng)用光學;2012年06期

2 李博;陳磊;邊疆;王軍;;相位拼接閉合條紋干涉圖處理技術(shù)[J];紅外與激光工程;2011年04期

3 陳永權(quán);趙建科;袁湘蘭;鄭中林;;絕對相位展開方法研究[J];紅外與激光工程;2008年S1期

4 王寧宇,張?zhí)煨?洪漢玉,余國亮;湍流退化圖像相位恢復(fù)算法研究[J];紅外與激光工程;2005年05期

5 姚衛(wèi),李振華,賀安之;用伽柏小波作干涉波前重建[J];光學學報;1999年06期

6 是度芳,鐘志有,王榮,陳韶華;相移全息CT技術(shù)測量雙燭火焰溫度場[J];光學學報;1996年06期

，

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