Figure 4.

Domain knowledge enhanced yield (Domain-KEY)-based classifier for the presence of perineural invasion. Correct (A, B) and incorrect (C, D) identification of nerve fibers. Incorrect classification resulted from the presence of similar patterns (C) or noisy signals (D). Correct (E, F) and incorrect (G, H) identification of perineural invasion. Incorrect classification resulted from the presence of fibroblasts surrounding the nerve and inappropriate separation of nerve fibers (G) or noisy signals (H). The purple color denotes the recognition of nerve structures, whereas normal nerves are marked in red. Areas of perineural invasion are highlighted in green with a black/blue background. The yellow rectangle denotes an area of incorrect classification.