Investigating ancient agricultural field systems in Sweden from airborne LIDAR data by using convolutional neural network

Abstract

Today, the advances in airborne LIDAR technology provide high-resolution datasets that allow specialists to detect archaeological features hidden under wooded areas more efficiently. Still, the complexity and large scale of these datasets require automated analysis. In this respect, artificial intelligence (AI)-based analysis has recently created an alternative approach for interpreting remote sensing data. In this study, a convolutional neural network (CNN) is proposed to detect clearance cairns, which are visible in today's landscape and act as important markers of past agricultural activities. For this aim, the U-shape network architecture is adapted, trained from scratch with an original labelled dataset and tested in various field sites, focusing on southern Sweden. Although it is challenging to tune the hyperparameters and decide on the proper network architecture to obtain reliable prediction, long-running experimental tests with this model produced promising results, with training and validation metrics of 0.8406 Dice-coefficient, 0.7469 Val-dice coefficient, and 0.7350 IuO and 0.6034 Val-IoU values, once trained with the best parameters. Thus, the proposed CNN model in this study made data interpretation quicker and guided scholars to focus on the location of the target objects, opening a new frontier for future landscape analysis and archaeological research.