Analysis for the Near Infrared Spectrum Characteristic of Tea Based on Orthogonal Wavelet Packet
Lü Jin1, 2，LIN Min2,ZHUANG Song-lin1
1. College of Optics and Electronics Engineering, University of Shanghai for Science and Technology，Shanghai 200093, China 2. College of Metrology Technology and Engineering, China Institute of Metrology, Hangzhou 310018, China
Abstract：According to the high co-linearity and dimension in the near infrared(NIR) spectrum of tea, the present paper describes quantitatively the characteristic of tea NIR spectra with wavelet packet by introducing the retained energy and number of zeros, based on the decorrelation capacity of orthogonal wavelet packet. Results show that the energy retained is as high as 99.98% after compressing, while the percentage for number of zeros is 95.87%. It was concluded that orthogonal wavelet packet has a good compressibility for NIR spectra, which has significance in storing, searching and processing the NIR spectrogram.
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