Deep convolutional neural networks as a geological image classification tool

A convolutional neural network (CNN) is a deep learning (DL) method that has been widely and successfully applied to computer vision tasks including object localization, detection, and image classification. DL for supervised learning tasks is a method that uses the raw data to determine the classification features, in contrast to other machine learning (ML) techniques that require pre-selection of the input features (or attributes). In the geosciences, we hypothesize that deep learning will facilitate the analysis of uninterpreted images that have been neglected due to a limited number of experts, such as fossil images, slabbed cores, or petrographic thin sections. We use transfer learning, which employs previously trained models to shorten the development time for subsequent models, to address a suite of geologic interpretation tasks that may benefit from ML. Using two different base models, MobileNet V2 and Inception V3, we illustrate the successful classification of microfossils, core images, petrographic photomicrographs, and rock and mineral hand sample images. ML does not replace the expert geoscientist. The expert defines the labels (interpretations) needed to train the algorithm and also monitors the results to address incorrect or ambiguous classifications. ML techniques provide a means to apply the expertise of skilled geoscientists to much larger volumes of data.