Figure 4
(a) Main co-variations from sensory exploration (3) mapped by cross-validated PLSR bi-plot in which the design parameters θ D , θ N , p D , p N , μ , M , and s and selected interactions are related to the sensory image descriptors for 32 solution images from the fractional factorial design, plotted in the subspace of Pattern Descriptor Space spanned by the two first PLS components PC 1 and PC 2 (orthogonal linear combinations of the 12 sensory descriptors). Sensory descriptor variables, design parameters and 32 solution score indicators are positioned according to their correlations to PC1 and PC2. The origin represents zero correlation; outer ellipsis represents locus of variables with variance explained 100% by PC1 and PC2. Variables close to the ellipsis and close to (or opposite) each other are positively (or negatively) correlated to each other. Only the most salient variables are marked. Some correlations are illustrated in (b)-(e). Ellipses show approximate boundaries of the four classes I-IV; the coloured markers represent the classes. (b) Values of Sharpness vs. Contrast for the 32 images, r = 0.98. (c) Curls vs. θD, r = -0.84. (d) Regular vs. the four-factor interaction term pII = [θD+, θN+, pD ≠ pN], i.e. θD is high,θN is high, and pD is high for low pN and vice versa, r = 0.98. (e) PatternWhite and PatternBlack are anti-correlated, r = -0.82. Plot symbols: black asterisk = class I, yellow square = class II, blue circle = class III, cyan/magenta/white triangles = class IV (see Additonal file 1: Table S-T6). Abbreviations for sensory descriptors: PW = PatternWhite, PB = PatternBlack, Co = Contrast, Cu = Curls, Re = Regular, MS = MultiShade. (see Additonal file 1: Table S-T5). Higher-order interaction terms: pI = [θD-], pII = [θD +, θN+, pD ≠ pN], pIII = [θD+, θN-, pD+].