Extracting Projections from Laser Moire Interference Spectra
SONG Yi-zhong1,2,ZHAO Zhi-min1,HE An-zhi3
1. Department of Physics, Science Institute, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China 2. Department of Physics, Dezhou University, Dezhou 253000, China 3. Department of Information Physics and Engineering, Science Institute, Nanjing University of Science and Technology, Nanjing 210094, China
Abstract:Laser Moire Interference spectra of rocket exhausted plumes were analyzed. Projections for reconstruction were figured out, and air density distribution was reconstructed. Moire deflectograms of the plumes were produced and captured with a home-made, wide-range, high-sensitivity Moire deflectometer. Moire interference spectra were processed by phase unwrapping technique with Fourier transform, so the space phase distribution of Moire deflectograms was extracted. The background was worked out based on the margin of the Moire deflectograms, and so was the space phase distribution of the background. The phase shift distribution of distorted Moire interference spectra could easily be obtained by calculating the difference between the two space phase distributions. The relative projections could be extracted from the phase shift distribution. The air density distribution of the plumes was calculated by simple self-correlative algebraic reconstruction technique (SSART) based on deflected angles for projections. Eight projections with equal direction interval of 20 degree were used for reconstructing the air density distribution of a plume section. As a result, with phase unwrapping technique based on Fourier transform, any cross section projection could conveniently be worked out from the Moiré deflectogram of rocket exhausted plumes. The air density distribution of the cross section could be reconstructed by SSART. So, SSART with deflected angle for projection is a kind of super nonlinear deflection tomography.
[1] He Anzhi, Yan Dapeng, Ni Xiaowu. Optical Engineering, 1988, 27(10): 841. [2] Wang Zhendong, Wang Zhixing, Li Zhenhua, et al. Microwave and Optical Technology Letters, 2001, 31(1): 57. [3] Song Yizhong, Zhang Bin, Fu Lin, et al. Optoelectronics Letters, 2006, 2(1): 63. [4] Soller C, Wenskus R, Middendorf P, et al. Applied Optics, 1994, 33(14): 2921. [5] Watt David W, Gross Todd S, Hening S D. Applied Optics, 1991, 30(13): 1617. [6] Stricker J, Kerent E, Kafri O. AIAA J, 1983, 21(12): 1767. [7] Yan Depang, Cha Soyoung Stephend. Applied Optics, 1998, 37(7): 1159. [8] Yao W, He A Z. Journal of the Optical Society of America, A, 1999, 12(2): 121. [9] Wu Donglou, Wang Zhendong, Yao wei, et al. Optical Engineering, 1998, 37(8): 2255. [10] Yan Dapeng, Zhang Jiajun, He Anzhi, et al. Applied Optics, 1994, 33(11): 2121. [11] Wu Donglou, He Anzhi. Applied Optics, 1999, 38(16): 3468. [12] ZHANG Bin, SONG Yang, SONG Yi-zhong, et al(张 斌,宋 旸,宋一中,等). Journal of Optoelectronics·Laser(光电子·激光), 2007, 18(2): 224. [13] ZHANG Bin, SONG Yang, SONG Yi-zhong, et al(张 斌,宋 旸,宋一中,等). Chinese Journal of Lasers(中国激光), 2006, 33(4): 531. [14] YAO Wei, YOU Hai-hang, WANG Zhen-dong, et al(姚 卫,尤海航,王振东,等). Laser Technology(激光技术), 1998, 22(4): 221. [15] ZHANG Bin, HE An-zhi, SONG Yang(张 斌,贺安之,宋 旸). Chinese Journal of Lasers(中国激光), 2006, 33(12): 1665. [16] SONG Yi-zhong, HE An-zhi(宋一中,贺安之). Journal of Optoelectronics·Laser (光电子·激光), 2006, 17(4): 484. [17] SONG Yi-zhong, HU Guo-ying, HE An-zhi(宋一中,胡国英,贺安之). Journal of Optoelectronics·Laser(光电子·激光), 2006, 17(5): 616. [18] SONG Yi-zhong, SUN Tao, HU Guo-ying, et al(宋一中,孙 涛,胡国英,等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2006, 26(8): 1411. [19] SONG Yi-zhong, YANG Xiang-jun, LIU Xue-mei, et al(宋一中,阳向军,刘学梅,等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2006, 26(10): 1918. [20] SONG Yi-zhong, HU Guo-ying, HE An-zhi(宋一中,胡国英,贺安之). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2006, 26(12): 2364. [21] SONG Yi-zhong, HE An-zhi(宋一中,贺安之). Journal of Optoelectronics·Laser (光电子·激光), 2006, 17(3): 352.