小波变换在激光诱导击穿光谱压缩中的应用

将小波变换应用于8种燃煤的激光诱导击穿光谱数据的压缩,并通过考察db小波阶数、分解层数和阈值化方法等参数对压缩效果的影响,总结了压缩参数选取的规律,确定了较好的压缩方案。以压缩分数、恢复分数、谱线强度相对误差为衡量准则,比较了压缩前后谱图的差异,评价了压缩的效果。结果表明,在所选的较优方案下,8个煤样其1,2,5通道的谱图恢复分数RS为81%~99.96%,压缩分数CS为79.02%~92.07%,谱线相对误差均在5%之内,重构光谱与原始光谱基本一致,存储量减小。

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.