# Research Progress and Prospects of Agricultural Aero-Bionic Technology in China
## 2 Biological Perception and Agricultural Aviation
### Compound Eye Bionics  
In 1826, [PERSON] [40] proposed the Mosaic theory of compound eye. By the middle and late 20 th century, as researchers from various countries began to explore the theory and experiment of compound eyes, people's understanding of compound eyes gradually shifted from a biological perspective to an optical perspective. The compound eyes of insects are composed of thousands of sub-eyes, and each sub-eye has an independent optical system, which is finally spliced to obtain a large field-of-view image. A bionic compound eye can obtain the space, position, speed, and other information of the target object by imitating the mechanism of the insect compound eye, so as to achieve the purpose of image acquisition, spatial positioning, and fast obstacle avoidance of the target object. It has the advantages of high sensitivity, fast information acquisition, high time resolution, and large field-of-view [41]. In recent years, the bionic application and research of compound eyes has mainly focused on two aspects: curved array and camera array. However, because the existing curved surface technology is not perfect, the research on curved compound eyes is still in the theoretical stage. [PERSON] [42] used 7 CCD cameras to simulate the compound eyes of flies and designed a bionic compound eye vision system to improve real-time and high-quality image mosaic requirements, which effectively solved the problem of mosaic image misalignment and enhanced the real-time performance of the system. However, this method requires high alignment accuracy of two adjacent sub-images, which is the focus of improvement in the future. [PERSON] [43] imitated the structural characteristics of biological compound eyes and arranged 16 CCD sensors into a curved surface to realize image acquisition without blind spots in the 180 \(\times\) 75\({}^{\circ}\) field-of-view, and to improve the resolution. Aiming at the shortcomings of small drone-borne cameras, such as small field-of-view and narrow imaging range, [PERSON] [44] designed a small size, field angle of up to 106\({}^{\circ}\), micro-miniature bionic compound eye camera. The curved arrangement of the small lens array, optical transformation subsystem, and the data processing unit is composed of three parts. The lens arrangement is shown in Figure 3. In order to increase the overlap rate of the potential fields of adjacent lenses, the lens array in the center A area adopts a regular pentagonal arrangement. The rest of the area is arranged in a hexagonal shape, and the system can collect a target of 0.5 m on the ground at a height of 500 m to achieve a large field-of-view and a high-resolution imaging effect. Figure 2: MATRICE M300 RTK six-way sensing system: (**a**) function annotation, and (**b**) product in kind [39]. Note: 1 front vision system, 2 left vision and right vision infrared perception system, 3 left vision and right vision system, 4 top vision system, 5 top vision infrared perception system, 6 FPV camera, and 7 front vision infrared perception system. The bionic compound eye sensor has the characteristics of high sensitivity, compact structure, large field-of-view, and high resolution. It has broad application prospects in the fields of aviation, detection, robot vision, target recognition, and tracking. Due to the slow progress in optical micro-processing technology, equipment debugging, image acquisition, splicing, etc., in the application of agricultural aviation, the accuracy of the bionic compound eye sensor is easily affected by factors such as harsh environments, and there are still many deficiencies to be improved. The application development in agricultural aviation is still in its infancy. The future development of compound eye bionic technology in agricultural aviation will include fast-precision measurement, real-time obstacle avoidance, a bionic compound eye manufacturing system, and micro-integration.