Less is More: Skim Transformer for Light Field Image Super-resolution

A light field image captures scenes through an array of micro-lenses, providing a rich representation that encompasses spatial and angular information. While this richness comes at the cost of significant data redundancy, most existing light field methods still tend to indiscriminately utilize all the information from sub-aperture images (SAIs) in an attempt to harness every visual cue regardless of their disparity significance. However, this paradigm inevitably leads to disparity entanglement, a fundamental cause of inefficiency in light field image processing. To address this limitation, we introduce the Skim Transformer, a novel architecture inspired by the ``less is more" philosophy. Unlike conventional light field Transformers, our Skim Transformer features a multi-branch structure where each branch is dedicated to a specific disparity range by constructing its attention score matrix over a skimmed subset of SAIs, rather than all of them. Building upon this core component, we present SkimLFSR, an efficient yet powerful network for light field super-resolution (LFSR). Requiring only 67\% of parameters, SkimLFSR achieves state-of-the-art results surpassing the best existing method by an average of 0.59 dB and 0.35 dB in PSNR at the 2x and 4x tasks, respectively. Through in-depth analyses, we reveal that SkimLFSR, guided by the predefined skimmed SAI sets as prior knowledge, demonstrates distinct disparity-aware behaviors in attending to visual cues. These findings highlight its effectiveness and adaptability as a promising paradigm for light field image processing.