Prediction of the Freshness of Grass Carp during Storage with Electric Nose Based on Signal Sequence Merging and Wavelet Transform

Figure 6

PCA plot of DSSM and RSSM modes analyzed with and sequences for grass carp fillet from different storage time (: 0 d; +: 2 d; : 4 d; ▽: 6 d; : 8 d; •: 10 d; △: 12 d; □: 14 d; ✕: 16 d). represents approximation coefficients, represents detail coefficient, and j represents the decomposition level.