(e.g., printer toner or specialized paper)? Backup software ?
A 2019 NeurIPS paper titled "Training Image Estimators without Image Ground Truth" proposes a method to train neural networks without needing a "ground-truth" (true) image, useful in image restoration.
A July 2024 paper, "True image construction in quantum-secured single-pixel imaging," describes a method to recover a genuine image ("true image") while under a spoofing attack.
