I. Introduction
Camouflage is a function that both predators and preys conceal themselves to deceive the visual perception systems of each other [1]. Although the concept of camouflage was first proposed by biologists in 1918 [1], more than 100 years later, sensory ecologists and cognitive scientists are still enthusiastic about this field, since camouflaged object detection (COD) has very practically meaningful applications including polyp segmentation [2], military anti-camouflage, search and rescue in extreme weather and discovery of endangered species, etc.