Diffeomorphic Template Registration for Atmospheric Turbulence Mitigation

We describe a method for recovering the irradiance underlying a collection of images corrupted by atmospheric turbulence. Since supervised data is often technically impossible to obtain, assumptions and biases have to be imposed, and we choose to model them explicitly. Rather than initializing a latent irradiance (``template'') by heuristics to estimate deformation, we select one of the images as a reference, and model the deformation in this image by the aggregation of the optical flow from it to other images, exploiting a prior imposed by Central Limit Theorem. Then with a novel flow inversion module, the model registers each image TO the template but WITHOUT the template, avoiding artifacts related to poor template initialization. To illustrate the simplicity and robustness of the method, we simply select the first frame as the reference and use the simplest optical flow to estimate the warpings, yet the improvement in registration is decisive in the final reconstruction, as we achieve state-of-the-art performance despite its simplicity. The method establishes a strong baseline that can be improved by integrating it with more sophisticated pipelines, or with domain-specific methods if so desired.