2013
2013
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Record 109 of
Title:Rapid measurement of spatial azimuth by using polarized light
Author(s):Lu, Wei-Guo(1,2); Wu, Yi-Ming(1); Gao, Li-Min(1); Xiao, Mao-Sen(1); Wang, Hai-Xia(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 21 Issue: 3 DOI: 10.3788/OPE.20132103.0539 Published: March 2013Abstract:To measure the spatial azimuths of different instruments in the upper and lower planes rapidly, an angle-measuring system based on magneto-optical modulation and a polarization splitter was proposed. An angle-measuring model of the system was deduced by describing the Jones vector of polarized light, and the influence of light source fluctuation on the angle-measuring precision was eliminated through signal processing method of "difference divided by addition". Then, the relationships between the transmittance and the incidence angle, azimuth for the two pathways of optical signals from the Wollaston prism were analyzed, as well as their effects on the measurement results. Furthermore, the dependence of gain differences from optical signal attenuations, device drifts, and circuit performance of opto-electronic elements in two optical paths on the measurement precision were discussed. Finally, a magneto-optical modulation method was proposed to eliminate the difference of transmittances and gain coefficients of the two signals for the achievement of high-precision measurement. The experimental observation demonstrates that the measurement time is 15 s and angle-measuring accuracy is better than 5" within +8~-8°. These results show that the proposed method has some advantages on the fast angular measurement velocity, high precision, and so on.Accession Number: 20131616213797 -
Record 110 of
Title:A novel weighted-direction color interpolation
Author(s):Tao, Jin-You(1,2); Yang, Jian-Feng(1); Xue, Bin(1); Liang, Xiao-Fen(1,2); Qi, Yong-Hong(1,2); Wang, Feng(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8908 Issue: DOI: 10.1117/12.2032500 Published: 2013Abstract:A digital camera capture images by covering the sensor surface with a color filter array (CFA), only get a color sample at pixel location. Demosaicking is a process by estimating the missing color components of each pixel to get a full resolution image. In this paper, a new algorithm based on edge adaptive and different weighting factors is proposed. Our method can effectively suppress undesirable artifacts. Experimental results based on Kodak images show that the proposed algorithm obtain higher quality images compared to other methods in numerical and visual aspects. ? 2013 SPIE.Accession Number: 20134216857646 -
Record 111 of
Title:A new primary mirror based on topology optimization
Author(s):Wang, Xin(1,2); Wang, Wei(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8908 Issue: DOI: 10.1117/12.2032227 Published: 2013Abstract:The impact of the mirror self-weight or other structural stress may cause bad optical imaging quality. The large-diameter primary mirror was optimized based on variable density topology optimization method and in the condition of gravity to satisfy the design requirements. A new primary mirror has been designed, comparing which with the traditional lightweight primary mirror in the method of finite element analysis, the results prove that the new primary mirror is superior to the traditional model in the lightweight rate, surface accuracy and structural rigidity, so the paper puts forward a new idea in the lightweight design. ? 2013 SPIE.Accession Number: 20134216857639 -
Record 112 of
Title:A doubly-scale adaptive non-local means image denoising algorithm
Author(s):Zhao, Jingjuan(1,2); Zhou, Zuofeng(1); Cao, Jianzhong(1); Wang, Hua(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: SUPPL.1 DOI: Published: 2013Abstract:By analyzing the effect of parameter of the original non-local means (NLM) and the classification error problems which exist in several improved pixel-classification-based adaptive NLM in image denoising application, a doubly-scale adaptive NLM image denoising algorithm is proposed. The proposed algorithm first use NLM-based 'roughly denoising' mainly on the smooth regions with large-scale similarity window and search window; and then regard the firstly roughly 'less denoisied' image as containing totally texture regions, and apply the second NLM-based 'finely denoising' with small-scale similarity window and search window mainly on these texture regions to get the final adaptive denoising result. Experimental results demonstrate the great superiority of the proposed algorithm to the original NLM algorithm, and the certain advantage over the several improved NLM algorithms.Accession Number: 20134416940653 -
Record 113 of
Title:Optical system of a four spectral bands sea-infrared radiometer
Author(s):Wang, Feng(1,2); Zhang, Jian(1); Fan, Zheyuan(1,2); Yan, Aqi(1,2); Qu, Enshi(1); Cao, Jianzhong(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: SUPPL.2 DOI: Published: December 2013Abstract:An automatic four spectral bands infrared radiometer system was designed for measuring the sea surface temperature. The principle of temperature measurement was given and the optical system was designed, which was divided into long-wave and medium-wave infrared optical system by using a spectroscope. Three long-wave infrared spectral bands were obtained through three long-wave infrared filters in the long-wave infrared optical system, respectively, which were 8-13 μm, 10.3-11.3 μm and 11.5-12.5 μm. Similarly, a medium-wave infrared spectral band (3.5-4.0 μm) was acquired by a medium-wave infrared filter in the medium-wave infrared optical system. The film system transmittance curves of the four infrared spectral bands were given, showing that the desired effect about narrow-band light pass was achieved. Furthermore, the modulation reticles in the long-wave and medium-wave infrared optical system were designed to modulate the object infrared radiation. The accuracy of the system was better than 0.5 K.Accession Number: 20140317216008 -
Record 114 of
Title:Improved design of a pseudo-cassegrain optical system
Author(s):Yang, Huanli(1,2); Chen, Rongli(1); Liu, Kai(1); Lei, Guangzhi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8908 Issue: DOI: 10.1117/12.2034464 Published: 2013Abstract:This paper uses a pseudo-cassegrain system as the initial structure, whose full field of view and F number are 5.6 and 1.63, respectively. Then the authors make further improvements and optimization in large weights and serious central obscuration. The final system is designed with preference of smaller central obscuration, lower manufacturing difficulty, lighter, simpler configuration and lower cost compared with the initial pseudo-cassegrain optical system. In addition, what is different from the previous modified cassegrain system is that secondary mirror of the final system is a plane mirror which is easier to fabricate and install. At the same time, the final system has three significant characteristics of these three systems: cassegrain, maksutov and schmidt. At last, the dissertation certificates the feasibility of the new system in the angle of aberration analysis, spot diagram analysis and energy analysis. It also provides a new design method for the optical system of moderate field, large relative aperture and wide spectral. ? 2013 SPIE.Accession Number: 20134216857689 -
Record 115 of
Title:Alignment off-axis optical system using nodal aberration theory
Author(s):Jiang, Bo(1,2); Zhou, Si-Zhong(1); Jiang, Kai(1,2); Fu, Huai-Yang(1,2); Mei, Chao(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8910 Issue: DOI: 10.1117/12.2032379 Published: 2013Abstract:We present the Fringe Zernike coefficients of the parent system pupil can be converted into coefficients of off-axis system, it is show that the coefficients of the Fringe Zernike polynomials in the off-axis pupil only contain orders equal to or lower than the Fringe Zernike polynomials originally placed on the parent pupil, and for the 3rd aberration the pupil transformation matrix has been finding. Using nodal aberration, we get the misaligned matrix of rotational symmetry parent optical system. Then with the pupil transformation matrix, the misaligned matrix of off-axis two-mirror system was found, the amounts of the misalignments are calculated by the off-axis misaligned matrix. ? 2013 SPIE.Accession Number: 20141317516357 -
Record 116 of
Title:Infrared and visible image fusion based on region growing and contourlet transform
Author(s):Zhao, Bingjie(1,2); Gao, Wei(1); Song, Zongxi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8907 Issue: DOI: 10.1117/12.2031627 Published: 2013Abstract:According to the characteristics of infrared and visible images, a new image fusion method based on region growing and contourlet transform is proposed in this paper. To obtain more complementary information, the method is designed as a two-stage procedure. Firstly, the input infrared image is processed with region growing to segment the thermal target. Different fusion rules are adopted in target and background regions, respectively. For the target region, local energy is utilized as the fusion rule of the first fusion to fuse the thermal target and the visible image, while for the non-target region, we reserve the visible background information. Secondly, in order to fully add original information of the source images and avoid loss of information caused by segmentation, we make the second fusion between the visible image and the result image of the one-stage fusion. For good properties of localization, directionality and anisotropy, we adopt contourlet transform as the second fusion method. Experiments are carried out and the results show that our method is clearer in visual quality and effective in quantitative evaluations and the fused images are better than those resulting of using wavelet transform and contourlet transform. ? 2013 Copyright SPIE.Accession Number: 20141317510090 -
Record 117 of
Title:Calculation of signal-to-noise ratio (SNR) of infrared detection system based on MODTRAN model
Author(s):Lu, Xue(1,2); Li, Chuang(1); Fan, Xuewu(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8907 Issue: DOI: 10.1117/12.2033048 Published: 2013Abstract:Signal-to-noise ratio (SNR) is an important parameter of infrared detection system. SNR of infrared detection system is determined by the target infrared radiation, atmospheric transmittance, background infrared radiation and the detector noise. The infrared radiation flux in the atmosphere is determined by the selective absorption of the gas molecules, the atmospheric environment, and the transmission distance of the radiation, etc, so the atmospheric transmittance and infrared radiance flux are intricate parameters. A radiometric model for the calculation of SNR of infrared detection system is developed and used to evaluate the effects of various parameters on signal-to-noise ratio (SNR). An atmospheric modeling tool, MODTRAN, is used to model wavelength-dependent atmospheric transmission and sky background radiance. Then a new expression of SNR is deduced. Instead of using constants such as average atmospheric transmission and average wavelength in traditional method, it uses discrete values for atmospheric transmission and sky background radiance. The integrals in general expression of SNR are converted to summations. The accuracy of SNR obtained from the new method can be improved. By adopting atmospheric condition of the 1976 US standard, no clouds urban aerosols, fall-winter aerosol profiles, the typical spectrum characters of sky background radiance and transmittance are computed by MODTRON. Then the operating ranges corresponding to the threshold quantity of SNR are calculated with the new method. The calculated operating ranges are more close to the measured operating range than those calculated with the traditional method. ? 2013 Copyright SPIE.Accession Number: 20141317510148 -
Record 118 of
Title:Survey on reconstruction algorithm based on compressive sensing
Author(s):Li, Shen(1,2); Ma, Caiwen(1); Li, Yan(1); Chen, Ping(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: SUPPL.1 DOI: Published: 2013Abstract:With the rapid demanding for information, the existing systems are very difficult to meet the challenges of high speed sampling, large volume data transmission and storage. Recently, a new sampling theory called compressive sensing (CS) provides a golden opportunity for solving this problem. CS theory asserts that a signal or image, unknown but supposed to be sparse or compressible in some basis, can be subjected to fewer measurements than traditional methods, and be accurately reconstructed. Firstly, a brief overview of the CS theory framework was given in this paper and the sampling process about signal compression was discussed. Next, the reconstruction algorithm of CS theory was reviewed. Especially, the basis pursuit algorithm and greedy algorithms were introduced and the difference between them was explored. In the end, possible implication in the areas of CS data reconstruction was briefly discussed. This paper provides theory basis for the improvement and application of compressed sensing reconstruction algorithm.Accession Number: 20134416940654 -
Record 119 of
Title:Output performance of gain guided and index antiguided fiber lasers pumped by different methods
Author(s):Zhu, Yonggang(1); Duan, Kailiang(1); Zhao, Baoying(1); Yang, Hening(1); Zhang, Entao(1); Zhao, Wei(1)Source: Proceedings - 2013 Wireless and Optical Communications Conference, WOCC 2013 Volume: Issue: DOI: 10.1109/WOCC.2013.6676416 Published: 2013Abstract:The output performance of Yb3+ doped gain guided and index antiguided (GG-IAG) fiber lasers pumped by different methods are compared by numerically solving rate equations (REs) with additional leakage losses. Three pump models, including forward pump, backward pump and bidirectional pump are established combined with REs model. Calculation results show that the output powers and slope efficiencies of GG-IAG fiber from high to low under the same condition are obtained by bidirectional pump, backward pump and forward pump in sequence. The upper energy level particle population density N2(z) and thermal distribution along the fiber generated by bidirectional pump are more uniform than that by other two pump methods. It benefits the lasing of GG-IAG fiber most. ? 2013 IEEE.Accession Number: 20140717299193 -
Record 120 of
Title:A multi-exposure image fusion method based on wavelet packet transform
Author(s):Wang, Qi(1,2); Song, Zongxi(1); Gao, Wei(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8907 Issue: DOI: 10.1117/12.2031837 Published: 2013Abstract:This paper presents a method for multi-exposure images fusion based on wavelet packet transform, combining the local energy distributions of multi-exposure images with the edge detection. After decomposing two images involved in fusion into sub images in low-frequency and high-frequency with wavelet packet transform, we use different methods for low-frequency and high-frequency to obtain fusion coefficients. In low frequency processing, the method that threshold value is set for local energy is used while the edge detection method is used in high frequency, where the edge detection operator help compute the information quantity of different high frequency images. Then the coefficients for fusion are selected according to different strategies adopted for low- and high-frequency. Finally, the fusion image is reconstructed through inverse wavelet packet transform. The result shows that the fusion method is effective and the fusion image can preserve the details of the each input image successfully. ? 2013 Copyright SPIE.Accession Number: 20141317510097