An Effective Yet Fast Early Stopping Metric for Deep Image Prior in Image Denoising

The deep image prior (DIP) and its variants have demonstrated the ability to address image denoising in an unsupervised manner using only a noisy image as training data, but practical limitations arise due to overfitting in highly overparameterized models and the lack of robustness in the fixed iteration step of early stopping, which fails to adapt to varying noise levels and image contents, thereby affecting denoising effectiveness. In this work, we propose an effective yet fast early stopping metric (ESM) to overcome these limitations when applying DIP models to process synthetic or real noisy images. Specifically, our ESM measures the image quality of the output images generated by the DIP network. We split the output image from each iteration into two sub-images and calculate their distance as an ESM to evaluate image quality. When the ESM stops decreasing over several iterations, we end the training, ensuring near-optimal performance without needing the ground-truth image, thus reducing computational costs and making ESM suitable for application in the denoising of real noisy images.