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131.
Non-uniformity correction is the key issue for the image quality improvement of infrared focal panel array (IRFPA) imaging. A non-uniformity correction (NUC) algorithm for IRFPA based on motion controllable micro-scanning platform and perimeter diaphragm strips is presented. We initially execute one-point calibration to the perimeter detectors, then based on controllable motion of adjacent frames, a special algebraic algorithm is proposed to transport the calibration of the perimeter detectors to those interior un-corrected ones. In this way, the bias parameter of the whole field of view (FOV) is calculated. The algorithm can be easily combined with sub-pixel imaging, thereby improving the quality of thermal imaging system (image spatial resolution and uniformity). All calculations are algebraic, with a low computation load. The algorithm can realize adaptive one point calibration without covering the central FOV rapidly. Experiments on simulated infrared data demonstrate that this algorithm requires only dozens of frames to obtain high quality corrections. 相似文献
132.
针对基于DSP的高功率TEA CO2激光器控制系统直接利用DSP F2812内置A/D转换器(ADC)进行模拟量采样时存在转换误差较大,且模拟量易受电磁干扰等问题,从硬件和软件两个角度提出了校正DSP2812内置ADC的方法。硬件上采用硬件模拟滤波和隔离等手段对输入的模拟量进行处理;软件校正则通过将两路给定的参考电压值送入DSPF2812内置A/D转换器的两个转换通道,计算出ADC的偏置误差和增益误差,以此误差对其它通道A/D转换器进行校正。最后,实验分析了参考电压和A/D采样时钟频率对A/D转换精度的影响。结果表明,提出的方法能有效地提高A/D转换器的精度,A/D转换误差达到±3 LSB,特别是在对腔压值精度要求很高的0~12 000 Pa区段,A/D转换精度达±1 LSB,可以保证TEA CO2激光器的可靠运行。 相似文献
133.
Spectroscopic investigations on NO+(x1∑+,a3∑+,A1Ⅱ) ion using multi-reference configuration interaction method and correlation-consistent sextuple b 下载免费PDF全文
Three low-lying electronic states (x1∑+,a3∑+,and A1Ⅱ) of NO+ ion are studied using the complete active space self-consistent-field (CASSCF) method followed by highly accurate valence internally contracted multi-reference configuration interaction (MRCI) approach in combination of the correlation-consistent sextuple basis set augmented with diffuse functions, aug-cc-pV6Z. The potential energy curves (PECs) of the NO+(x1∑+,a3∑+,A1Ⅱ) are calculated. Based on the PECs, the spectroscopic parameters Re, De, ωe, ωeχe, α e, Be, and D0 are reproduced, which are in excellent agreement with the available measurements. By numerically solving the radial Schrödinger equation of nuclear motion using the Numerov method, the first 20 vibrational levels, inertial rotation and centrifugal distortion constants of NO+(x1∑+,a3∑+,A1Ⅱ) ion are derived when the rotational quantum number J is equal to zero (J = 0) for the first time, which accord well with the available measurements. Finally, the analytical potential energy functions of these states are fitted, which are used to accurately derive the first 20 classical turning points when J = 0. These results are compared in detail with those of previous investigations reported in the literature. 相似文献
134.
本文基于绝热近似和群论导出了电声耦合系统的哈密顿量的一般形式,讨论了电声耦合系统中的电子算符和活跃的声子模式. 应用幺正平移变换和能量最小化方法,进一步计算了正四面体群下T*(e+t2)杨-泰勒系统中的激发态能量,从对称性的角度分析了T1电子态的能级分裂以及晶格体系的对称性破缺,得出了对称性的破缺方式和电声耦合系统密切相关的结论. 结果表明:通过群论与对称性分析完全可以定性地解释由于电声耦合所造成的简并电子
关键词:
电声耦合
杨-泰勒畸变
活跃的杨-泰勒声子模式
电声耦合哈密顿量 相似文献
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137.
大视场星敏感器标定技术研究 总被引:7,自引:1,他引:6
大视场星敏感器光学系统,由于畸变量较大,在轨标定过程中,直接采用最小二乘最优估计(LMS)或扩展卡尔曼滤波方法(EKF)无法精确求解其标定参数。在深入分析星敏感器测量误差因素的基础上,对考虑畸变和不考虑畸变两种情况的在轨标定结果进行了仿真对比;指出了标定焦距之前需先标定光学畸变的必要性,并介绍了4种可用于在轨校正光学畸变的方法;提出先标定主点偏差,再标定光学畸变参数,最后标定焦距的标定方法。仿真结果表明,可以采用像面旋转法求取主点偏差,利用高阶多项式方法求取光学畸变参数,畸变校正后,采用LMS和EKF标定算法估计焦距,标定精度达到了3.1μm和2.2μm。对100幅模拟星图处理后,星间角距统计偏差约为传统在轨标定方法的1/10~1/8。 相似文献
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139.
This study quantitatively assesses the effectiveness of retrospective beat-to-beat respiratory motion correction (B2B-RMC) at near 100% efficiency using high-resolution coronary artery imaging. Three-dimensional (3D) spiral images were obtained in a coronary respiratory motion phantom with B2B-RMC and navigator gating. In vivo, targeted 3D coronary imaging was performed in 10 healthy subjects using B2B-RMC spiral and navigator gated balanced steady-state free-precession (nav-bSSFP) techniques. Vessel diameter and sharpness in proximal and mid arteries were used as a measure of respiratory motion compensation effectiveness and compared between techniques. Phantom acquisitions with B2B-RMC were sharper than those acquired with navigator gating (B2B-RMC vs. navigator gating: 1.01±0.02 mm−1 vs. 0.86±0.08 mm−1, P<.05). In vivo B2B-RMC respiratory efficiency was significantly and substantially higher (99.7%±0.5%) than nav-bSSFP (44.0%±8.9%, P<.0001). Proximal and mid vessel sharpnesses were similar (B2B-RMC vs. nav-bSSFP, proximal: 1.00±0.14 mm−1 vs. 1.08±0.11 mm−1, mid: 1.01±0.11 mm−1 vs. 1.05±0.12 mm−1; both P=not significant [ns]). Mid vessel diameters were not significantly different (2.85±0.39 mm vs. 2.80±0.35 mm, P=ns), but proximal B2B-RMC diameters were slightly higher (2.85±0.38 mm vs. 2.70±0.34 mm, P<.05), possibly due to contrast differences. The respiratory efficiency of B2B-RMC is less variable and significantly higher than navigator gating. Phantom and in vivo vessel sharpness and diameter values suggest that respiratory motion compensation is equally effective. 相似文献
140.
Chang Yu Guo 《数学学报(英文版)》2014,30(12):1999-2013
Let f:Ω→ f(Ω) R~n be a W~(1,1)-homeomorphism with L~1-integrable inner distortion.We show that finiteness of min{lip_f(x),k_f/(x)},for every x ∈Ω\E,implies that f~(-1) ∈ W~(1,n)and has finite distortion,provided that the exceptional set E has cr-finite H~1-measure.Moreover,/ has finite distortion,differentiable a.e.and the Jacobian J_f 0 a.e. 相似文献