ABSTRACT
Images obtained underwater generally suffer from colour distortion, blurred details, poor contrast, and a blue or greenish hue as a result of light dispersion and underwater image absorption. As a result, the accessibility is severely impaired. In the last few decades, researchers have come up with a lot of quality improvement in underwater images by making them easier to see and bringing out more details. This chapter gives an overview of different ways to improve underwater image. This chapter provides an overview of methods for enhancing and restoring underwater image and its types. Every type is explored in brief. In conclusion, the performance of contemporary current techniques and standard quantitative measures are compared with their elements. In addition, underwater image datasets that are used to improve and restore that are examined in depth. Various evaluation criteria necessary for assessment of underwater images and current uses are presented here. This work broadens the scope for other researchers to comprehend the essential aspects of various strategies for enhancing the contrast of underwater images and also gives ideas for future research.
