“…Moreover, choosing the appropriate feature extraction approach that has a strong capacity to extract significant features from such complicated patterns and textures ( Xie et al, 2019 ). Feature extraction is the main step in the accurate diagnosis of medical conditions ( Baraka et al, 2019 ) such as BC ( Ragab, Sharkas & Attallah, 2019 ), gastrointestinal diseases ( Khan et al, 2020 ; Ali et al, 2019 ; Khan et al, 2019 ; Attallah & Sharkas, 2021 ), heart diseases ( Attallah et al, 2017a ; Attallah & Ma, 2014 ; Karthikesalingam et al, 2015 ; Attallah & Ma, 2015 ), and brain disorders ( Attallah, 2020 ; Ceschin et al, 2018 ; Attallah, Sharkas & Gadelkarim, 2019 ; Attallah, Gadelkarim & Sharkas, 2018 ). Accordingly, CADx systems are characterized into two categories.…”