The images below are displayed according to the following order:
(a) Segmentation-challenging images. (b) Results obtained with the native code of [51]. (c) [51] +BCI. (d) [51] +SQWT [11]. (e) [51] +sRGB [13]. (f) [51] +aRGB [13]. (g) [51] +imadjust. (h) [51] +CLAHE [9]. (i) [51] +BPDFHE [12]. (j) [51] +AGCWD [14]. (k) [51] +LIME [16]. (l) [51] +WVM [15].