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41.
相位解包裹算法中基于调制度的新质量图 总被引:8,自引:1,他引:8
在移相法测量光学波面或物体形貌过程中,相位解包裹是条纹自动分析中的关键技术,而质量图对解包裹相位算法起着至关重要的作用。用计算机模拟干涉图获得相位导数偏差质量图,指出其在标识相位数据质量方面的不足,并根据调制度结合相位梯度构造出新的质量图(称之为调制度-相位梯度偏差质量图)来弥补此缺陷。再以新质量图数据为权值,采用加权最小二乘解包裹算法验证新质量图的可靠性。最后通过实验数据,比较新质量图和相位导数偏差质量图在解包裹相位算法中的作用,得到新质量图的解相结果均方根(RMS)值为2.652 rad,而相位导数偏差质量图的解相结果均方根值为5.151 rad,由此证明前者有更好的可靠性。 相似文献
42.
ZOUYi* HE Deping* & JIANG Jiaqiao Department of Material Science Engineering Southeast University Nanjing China 《中国科学B辑(英文版)》2004,47(5):407-413
The Ultra Light Metal Structure with variouskinds of pores (open, close) realizes the lightness andmultifunction of structural material. The functionsinclude lightness (ρ < 1), high specific strength, highenergy absorption, sound insulation, heat insulationand electromagnetism shield. It is one of the hotspotsin material research nowadays[1— . The requirements 6]of high speed movement and high technology make Alalloy foam, which has higher specific st… 相似文献
43.
对采用SBS调Q产生喇曼频移输出的激光器进行了理论分析,并对实验结果与染料调Q时的输出进行了对比,提出了改进该种激光器性能的方法。 相似文献
44.
V. Yu. Popov 《Mathematical Notes》2000,67(4):495-504
An example of a series of varieties of rings
with the finite basis property is constructed for which the word problem in the relatively free ring
of rankn in the variety
is decidable if and only ifn <p.
Translated fromMatematicheskie Zametki, Vol. 67, No. 4, pp. 582–594, April, 2000. 相似文献
45.
A. S. Sivatski 《Algebra Colloquium》2000,7(2):197-204
Let A be a commutative ring and n 3 a positive integer. In this paper, we consider unimodular rows (f1(x),..., fn(x)) over A[x]. We prove that, if the row of the leading coefficients of fi(x) is unimodular over A and a A, then there exists En(A[x]) such that (f1(x),...,fn(x)) = (f1(a),...,fn(a)). Also, if A is a Noetherian ring with finite Krull dimension and the row of leading coefficients satisfies the same condition, then we give a bound for the length of in terms of elementary transvections.Partially supported by INTAS 93–436EXT and DFG–RFBR grant No. 96–01–00092G.2000 Mathematics Subject Classification: 19A13, 19B14, 13C10, 13B25, 13F20 相似文献
46.
In this article, an inter-antenna inter-subblock shifting and inversion (IASSI) scheme is proposed to reduce the peak-to-average power ratio (PAPR) in multi-input multi- output orthogonal frequency division multiplexing (MIMO- OFDM) systems. It exploits multiple antennas and subblocks to provide additional degrees of freedom to benefit the system. To reduce the implementation complexity of the proposed scheme, two simple suboptimal schemes are further presented based on the minimum current maximum criterion; one adopts sequential search and the other employs random binary grouping. The simulation results exhibit the effectiveness of these proposed schemes. 相似文献
47.
Digital speckle pattern interferometry (DSPI) with increased sensitivity: Use of spatial phase shifting 总被引:1,自引:0,他引:1
Basanta Bhaduri 《Optics Communications》2007,272(1):9-14
This paper presents a real-time digital speckle pattern interferometry system with twofold increase in sensitivity for the measurement of in-plane displacement and first order derivative of out-of-plane displacement (slope). Spatial phase shifting technique has been used for quantitative fringe analysis. The system employs a double aperture arrangement in front of the imaging system that introduces spatial carrier fringes within the speckle for spatial phase shifting. For in-plane displacement measurement, the scattered fields from the object are collected independently along the direction of illumination beams, and combined at the image plane. For slope measurement, a shear is introduced between the two scattered fields. Experimental results on an edge clamped circular plate subjected to in-plane rotation for in-plane displacement measurement and central loading for slope measurement are presented. 相似文献
48.
In Fourier transform profilometry (FTP), the zero frequency of the imaged patterns will influence the measurement range and precision. The π phase shifting technique is usually used to eliminate the zero order component, but this method requires the capture of two fringe patterns with a π phase difference between them, which will impede the real time application of the method. In this paper, a novel method is proposed, in which a composite structured light pattern is projected onto the object. The composite structured light pattern is formed by modulating two separate fringe patterns with a π phase difference along the orthogonal direction of the two distinct carrier frequencies. This method can eliminate the zero frequency by using only one fringe pattern. Experiments show that there is no decrease in the precision of this novel method compared with the traditional π phase shifting technique. 相似文献
49.
50.
Let F= F(X) be a free group of rand n, A be a finite subset of F(X) and x∈X be a generator. The theorem states that x can be denoted as a rotation-inserting word of A if x is in the normal closure of A in F(X). Finally, an application of the theorem in Heegaard splitting of 3manifolds is given. 相似文献