# Fast Self-Adaptive Digital Camouflage Design Method Based on Deep Learning
## 2 Literature Review  
Military camouflage colors and patterns have evolved throughout history to improve their effectiveness, with each variant designed for a specific environment. Therefore, camouflage patterns are only effective in areas where the local background remains relatively constant. For a military system to operate in a variety of environments, its camouflage must be adjusted accordingly [32]. As a result, researchers around the world are beginning to design adaptive camouflage techniques that can change the color and texture of surfaces, like chameleons or octopuses, depending on their environment. Some researchers propose to project the collected background image on the surface of the target to achieve the purpose of camouflage. [PERSON] et al. [33; 34] designed an active camouflage system. The system first obtains the real-time background image through the image acquisition device installed on the back of the target and then projects the display scheme calculated from the observer's perspective onto the target surface with reflective materials. [PERSON] et al. [13] used microfluid network technology to prepare a soft camouflaging robot. It could change the color, contrast, pattern, apparent shape, luminescence, and surface temperature. The researchers changed the robot's color, pattern, and so on by filling the tiny tubes with different colored liquids. [PERSON] et al. [32] proposed the use of gray-level co-occurrence matrices to synthesize a texture similar to the background. Then, the texture is displayed on the surface of the battlefield reconnaissance robot by electronic paper display technology to achieve the purpose of camouflage. Inspired by the skin discoloration principle of cephalopods, [PERSON] et al. [35] used a thermochromic material to prepare a photoelectric camouflage demonstration system that could transform between black and white. The color-changing material is colorless and transparent when the temperature is higher than 47 \({}^{\circ}\)C, and black when the temperature is lower than 47 \({}^{\circ}\)C. By controlling the temperature of each unit, the researchers can display different patterns. Unfortunately, only black and white patterns can be displayed. [PERSON] et al. [14] used the adjustable plasmon technology to prepare a color-changing device that could cover the whole visible band and then developed a bionic mechanical chameleon. The mechanical chameleon could sense color changes in its environment and actively change its own color to match the color of its environment. It is a pity that the author did not study the design method of camouflage texture. So far, researchers have focused on how to design and implement color change, but few have studied how to design appropriate adaptive camouflage textures. The existing researches on camouflage texture mainly focus on traditional camouflage texture. For example, [PERSON] et al. [5] designed digital camouflage textures based on recursive overlapping of pattern templates. [PERSON] et al. [36] proposed a digital camouflage design method based on a space color mixing model. The model can simulate the color-mixing process in the aspects of color-mixing order, shape, and position of color-mixing spot. [PERSON] et al. [37] proposed a camouflage pattern design method based on spot combination. The core idea of the above design method is random or non-random arrangement of finite templates. Due to the simplicity of the template, these traditional design methods cannot meet the needs of the new generation of adaptive camouflage texture design. Therefore, it is necessary to study the design method of adaptive camouflage texture.