title: [A method for auto-extraction of spectral lines based on convolution type of wavelet packet transformation].
abstract: The important astrophysical information is hidden in spectral lines of astronomical spectra. The presen paper presents a method for auto-extraction of spectral lines based on convolution type of wavelet packet. This method consists of four main steps: First, the observed spectra are transformed by convolution type of wavelet packet with 4th scale. Then, the noise with coefficients of the 4th scale is eliminated by the local correlation algorithm and threshold in the wavelet packet domain. After that, middle and high frequency coefficients are selected to reconstruct the feature of the spectral lines. Finally, with the reconstructed feature of the spectral lines, spectral lines in observed spectra are searched. The results of our experiments, which include the spectral lines of stars, normal galaxies and active galaxies, show that the method can robustly and accurately extract the spectral lines. The method was applied to extract the SDSS spectral lines and compute the redshifts with those lines. By comparing the redshifts with those given by SDSS, the extraction has proven successful and practical.
authors.affiliation: National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Zhong-Tian
authors.initials: ZT
authors.lastname: Liu
authors.forename: Fu-Chao
authors.initials: FC
authors.lastname: Wu
authors.forename: A-Li
authors.initials: AL
authors.lastname: Luo
authors.forename: Yong-Heng
authors.initials: YH
authors.lastname: Zhao