Neural Spline Fields for Burst Image Fusion and Layer Separation
Authors: Ilya Chugunov, David Shustin, Ruyu Yan, Chenyang Lei, Felix Heide

Each photo in an image burst can be considered a sample of a complex 3D scene: the product of parallax diffuse and specular materials scene motion and illuminant variation. While decomposing all of these effects from a stack of misaligned images is a highly ill-conditioned task the conventional align-and-merge burst pipeline takes the other extreme: blending them into a single image. In this work we propose a versatile intermediate representation: a two-layer alpha-composited image plus flow model constructed with neural spline fields -- networks trained to map input coordinates to spline control points. Our method is able to during test-time optimization jointly fuse a burst image capture into one high-resolution reconstruction and decompose it into transmission and obstruction layers. Then by discarding the obstruction layer we can perform a range of tasks including seeing through occlusions reflection suppression and shadow removal. Tested on complex in-the-wild captures we find that with no post-processing steps or learned priors our generalizable model is able to outperform existing dedicated single-image and multi-view obstruction removal approaches.