Semantic dictionary. Semantic dictionary generated using the intermediate outputs of global average pooling (GAP) layer. (a) Mean GAP output of 200 images of tomato early blight from the test dataset was multiplied by the weights of the CNN and sorted based on its value. (b) Neurons that correspond to the top five output values were selected and feature visualization was, respectively, applied. (c) Representative images of disease symptoms selected from the indicated class. Bottom row is a magnified view of the red inset in the top row.