Application of Wavelet Transform in Laser-Induced Breakdown Spectra Compression

A method based on the wavelet transform (WT) was developed for the compression of laser-induced breakdown coal spectral data. By studing the impacts of main parameters such as the order of db wavelet, decompose level and threshold method on compression performance, it can summarize the compression parameter selection rule and select the proper compression scheme. The scheme was evaluated by compression scores and relative deviation of each spectral line between original and reconstructed. By choosing proper parameters for channel 1, channel 2 and channel 5 of LIBS spectrum of coal sample (No.1-No.8), the restore score RS and compress score CS are respectively 81%-92.11% and 79.02%-92.07%, with the spectral line relative deviation under 5%. It indicates that the storage space is reduced while the main characteristic of original spectrum is maintained. The result shows that this method is very effective.