# Remote Image Capture System to Improve Aerial Supervision for Precision Irrigation in Agriculture
## 1 Introduction
### ZigBee Wireless Protocol for Precision Agriculture  
The communication among nodes in a WSN allows for the integration of varied sensors types from the simplest (e.g., pressure, humidity and temperature) into the most complex ones (e.g., GPS location, micro-radars, tracking and image capture), thus allowing them to screen a wide area to obtain detailed information of the crops [35]. For this purpose, ZigBee, Bluetooth and WiFi wireless protocols, GPRS/3G/4G technology and Long Range Radio (LoRa) protocol are some of the communication technologies suitable for precision agriculture. Different works have compared these standards according to different parameters such as the communication range, power consumption, bandwidth speed, cost, system complexity, and other aspects [36].  
Among them, Zigbee has been adopted as the ideal wireless protocol for many agricultural applications due to its lower power consumption, the high number of nodes allowed (more than 65,000), its high reliability and low duty cycle [37; 38; 36]. The low duty cycle is important in domains as water quality management, watering supervision, and control of fertilizers and pesticides, requiring a frequent update of the information [39]. For this purpose, the ZigBee wireless protocol has been used for preserving energy by switching between the sleep and active states. Therefore, energy use is diminished and battery life of the motes is stretched. Some important aspects to investigate before applying ZigBee are the effects of signal strength on the spacing of the nodes, the height of the antenna in the base station and the leaf density. For example, in [40], different tests were performed in palm orchards to evaluate a model of the signal propagation using the received signal strength meter of the ZigBee protocol. They found that the wireless channel propagation model has to be adjusted before deploying the motes in the orchards to achieve the robust signal strength. ZigBee is also being used in smart beehives [41], orange orchards [42], automation in irrigation [43], and greenhouse monitoring systems [44], among many other applications.  
This paper describes the design, development and implementation of a remote image capture system controlled by a central processing coordinator node. The system includes a web-based application for accessing the information obtained from the capture nodes and measurement stations installed in the farm. It can be integrated with watering equipment, such as furrow and surface irrigation, different types of crop and production scales. It is designed to offer agronomists and owners updated and detailed information of the state of the crop, the weather conditions and the watering system, so better decisions can be taken to solve possible problems. The proposed structure contains multiple image capture nodes to get many observation zones representative of the entire area of plantation. They have autonomous power supply and wireless connection with the central unit, which takes the irrigation and harvesting decisions using the results of processing the images and other local sensors. This research opens the possibility for the development of a completely autonomous irrigation decision system, which is still an open problem. On the other hand, one of the objectives of the proposed system is to provide a technological tool that enhances the generation of irrigation specialists, giving them as much information as possible about the processes in the farm or field. This way, agricultural engineering schools could have powerful but inexpensive tools for the education of their students.