The influence of the fundamental parameters on the performance of the RCT method is given in Table 1. The evaluations presented in this table are measured using the PRI. The expanse Ex is the similarity tolerance among the features used and is the size of the neighborhood to analyze. The value of Ex has influence on the dilatation or contraction of the boundary region between the histogram and the histon, and therefore, on the value of the roughness index. If Ex is high, the association of similar pixels becomes more flexible, leading to undersegmentation issues. If Ex is small, the association becomes more rigid, making highly similar pixels to be considered as different regions, resulting in an oversegmentation. The parameter has a direct impact on the computation time of the histon, since it defines the neighborhood size of the analysis for each pixel. It can be seen in Table 1 that the performance remains stable when Ex is small and the PRI starts to decrease when . This decrement in the performance is caused by the fact that the ground-truth images from the BSD are, in general, undersegmented. Such fact has been also observed by Ilea and Whelan.15 The lowest PRI value of 0.7480 is obtained with the parameters (9, 350) and the best performance, , is found for (7, 150). Other parameters, like the value of for the texture extraction and the weights in the Eq. (9), were also obtained in such exhaustive search. The window size for the texture extraction was searched in the set and the weights in the set . A window size of , meaning a , and the set of weights have been found to provide the best results.