Severely Degraded Underwater Image Enhancement with a Wavelet-based Network

Abstract

Underwater images are important in marine science and ocean engineering fields owing to giving color information, low cost, and compact. Yet obtained underwater images are often degraded and restoring and enhancing wavelength selective signal attenuation of underwater images depending on complex underwater physical process is essential in practical application. While recently developed deep learning is a promising choice, constructing sufficiently large dataset covering whole real images is challenging, peculiar to underwater image processing. In order to supplement relatively small dataset, previous studies alternatively construct an artificial underwater image dataset based on a physical model or Generative Adversarial Network. Also, incorporating traditional signal processing methods into the network architecture has shown promising success, though enhancement of severely degraded underwater images remains to be a big issue. In this paper, we tackle underwater image enhancement based on an encoder-decoder based deep learning model incorporating discrete wavelet transform and whitening and coloring transform. We also construct a severely degraded real underwater image dataset. The presented model shows excellent results both qualitatively and quantitatively in the artificial and real image dataset. Constructed dataset is available at https://github.com/tkswalk/2022-IJACSA.