Before revision:  To overcome limited available backscatter X-ray data for training, we compare three alternatives for training  : i)  non-plant-root images, ii)  plant-root images, and iii) pretraining the model with non-plant-root images and fine-tuning with plant-root images and two deep learning approaches i) Fast Super Resolution Convolutional Neural Network and ii) Super Resolution Generative Adversarial Network).
After revision:  To overcome limited available backscatter X-ray data for training, we compare three alternatives for training the SR model : i) non-plant-root images, ii) plant-root images, and iii) pretraining the model with non-plant-root images and fine-tuning with plant-root images and two deep learning approaches i) Fast Super Resolution Convolutional Neural Network and ii) Super Resolution Generative Adversarial Network).