光谱分辨率和信噪比对光谱线指数测量精度的影响  

Effects of Spectral Resolution and Noise on the Measurement of Indices

作　　者：杜薇[1,2,3] 罗阿理[1,2] 赵永恒[1,2] 

机构地区：[1]中国科学院国家天文台,北京100012 [2]中国科学院天文光学重点实验室(国家天文台),北京100012 [3]中国科学院研究生院,北京100049

出　　处：《光谱学与光谱分析》2012年第7期1886-1890,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(10973021)资助

摘　　要：分析光谱分辨率和信噪比对19个Lick原子吸收线指数测量精度的影响。采用高斯卷积方法,将光谱变换到不同分辨率下,通过测量并比较光谱在不同分辨率下的线指数值探究分辨率改变对线指数测量精度的影响;通过向光谱叠加符合不同高斯分布的随机噪声方法,将无噪理论光谱改变到不同信噪下,通过测量并比较光谱在不同信噪比时的线指数值分析信噪比对线指数测量精度的影响。结果表明:改变光谱分辨率能够引起线指数测量值的变化,此变化程度依赖于分辨率的改变程度,且此依赖关系对不同指数呈不同变化趋势;信噪比对线指数测量精度的影响随信噪比的降低而增大,当信噪比高于25时,此影响可忽略。In the present paper, we analysed the effects of spectral resolutions and signal-to-noise ratios （SNRs） on 19 atomic ab- sorption line indices of Lick index system. First of all, adopting method of convolving a spectrum with a Gaussian profile, we transformed spectra into those under different resolutions and then measured the line indices on therrL Comparisons of the indices under various resolutions allow to investigate the impact of spectral resolution change on the accuracy of measurements of indi- ces. Secondly, by adding random noises with different Gaussian distribution to a spectrum, the authors transformed theoretical spectra with no noises into those under diverse SNRs and then measured line indices on them. Comparisons of the indices under different SNRs greatly helped analyse the influence of SNR on the precision of the measurements of line indices. It comes from comparisons and analysis that the spectral resolution change can cause an index measurement change depending on the extent of the change of spectral resolution. Such a kind of change relationship varies with the indices. The lower the SNR, the less precise the measurements of indices. The effect of SNR on the measurements of indices can be ignored if SNR is larger than 25.

关 键 词：光谱线指数 光谱分辨率 信噪比 测量精度 统计 

分 类 号：TP29[自动化与计算机技术—检测技术与自动化装置]