It is difficult to understand how other species perceive the world since we humans see the world in our own way. Though we may never fully grasp how other species perceive the world, we can gain insights from scientific research. What does research tell us about how dolphins "see" things?

https://www.insightfulthinkersmedia.com/

References: 

Kremers, D., Célérier, A., Schaal, B., Campagna, S., Trabalon, M., Böye, M., . . . Lemasson, A. (2016). Sensory Perception in Cetaceans: Part I—Current Knowledge about Dolphin Senses as a Representative Species. Frontiers in Ecology and Evolution, 4.