Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging

Table 3

Nonlinear regression analysis applied to the time as function of the chromatic coordinates.

Poplar samples
	B	Significance
Intercept	1732.326	***
𝐿^∗	−56.232	***
𝑎^∗	16.154	***
𝑏^∗	24.495	***
𝐿^∗2	0.381	***
𝑎^∗2	4.376	***
𝑏^∗2	−0.520	***

𝑅² adj. = 0.947; 𝑃<0.001.
𝑇=1732.3−56.2𝐿^∗+16.2𝑎^∗+24.5𝑏^∗+0.4𝐿^∗2+4.4𝑎^∗2.
∗Statistically significant.
∗∗∗Very high statistical significance.