# Underwater Stereo using Refraction-free Image Synthesized from Light Field Camera

## TL;DR

This paper introduces a novel method to synthesize refraction-free underwater images using light field cameras and employs stereo techniques for 3D reconstruction, outperforming previous approximation-based methods.

## Contribution

The paper presents an efficient ray selection technique for refraction-free image synthesis and a stereo method for 3D shape reconstruction from underwater light field images.

## Key findings

- Successfully synthesized refraction-free underwater images
- Achieved accurate 3D reconstructions using stereo from synthesized images
- Outperformed previous approximation-based techniques in experiments

## Abstract

There is a strong demand on capturing underwater scenes without distortions caused by refraction. Since a light field camera can capture several light rays at each point of an image plane from various directions, if geometrically correct rays are chosen, it is possible to synthesize a refraction-free image. In this paper, we propose a novel technique to efficiently select such rays to synthesize a refraction-free image from an underwater image captured by a light field camera. In addition, we propose a stereo technique to reconstruct 3D shapes using a pair of our refraction-free images, which are central projection. In the experiment, we captured several underwater scenes by two light field cameras, synthesized refraction free images and applied stereo technique to reconstruct 3D shapes. The results are compared with previous techniques which are based on approximation, showing the strength of our method.