Figure 5

The behavior of the concordance correlation coefficient$\widehat{\mathbf{\rho }}\left(\mathit{r}\right)$, through the interval 1 ≤ r  < 255. Increasing values of $\widehat{\rho }\left(r\right)$ through the interval 1 ≤ r < 128 are displayed. This means that the wider the interval of similarity ST(r) the greater the reproducibility of observed leaf areas by image proxies becomes. Interestingly through the domain 128 ≤ r < 178 values of $\widehat{\rho }\left(r\right)$ are maintained within a plateau of slight variation around $\widehat{\rho }\left(128\right)=0.90$. Afterwards, for 178 ≤ r ≤ 255 values of $\widehat{\rho }\left(r\right)$ decrease slightly until $\widehat{\rho }\left(r\right)$ drops to a value of 0.8464 attained at r = 255. Then for values of r larger than r = 128 reproducibility is not improved and coinciding with the criterion in the DCM for the present data, both an RGB color format and the ST(128) interval of tolerance of similarity could be used for image selection when noise due to humidity contents is present and efficient estimations of eelgrass leaf area taken from these images is required.