Design of movable remote crop monitoring system on fixed truss

Abstract: The image obtaining angle and scope for the fixed image acquisition device is limited for obtaining an image of the desired crop; with the high cost of running the system, a vehicle-mounted mobile multipoint access method needs to move the car as the carrier, and affects the image acquisition system automation level. In order to obtain a crop image in an enlarged acquisition scope, a crop image acquisition system was developed that the image acquisition device can move on a fixed truss. The system has five parts: an image acquisition device, rotation and pitching motion, vertical movement, horizontal movement, a remote control, and database management. The image color of crop growth information is at least 24 bit, and a resolution up to 640 ×480 pixels. A high-definition network camera was used as the image acquisition device. A comprehensive intelligent control Pan Tilt Zoom (PTZ) was selected as the rotation and pitching motion, in order to expand the scope of monitoring, to increase the space rotation and to add pitching motion. The image acquisition device was installed on the intelligent control PTZ to achieve 360° rotation and pitching movement. A helix four bar mechanism was designed for the vertical movement and the PTZ was fixed on it to achieve vertical movement for the camera. A sliding block guide mechanism was developed and the helix four bar mechanism was installed on it to achieve horizontal movement for the camera. Vertical movement and horizontal movement were driven by two stepper motors. Both stepper motors were checked, to ensure the system dynamics. In addition, the control software for the crop image remote acquisition system was developed. For the vertical movement and horizontal movement, the steering, speed, and step size control of stepper motor were realized by an intelligent stepper motor controller with a port of RJ45. For the rotation and pitching motion, the 360° rotation, the four directions moving of PTZ and pitch motion control of PTZ were realized, by an intelligent control PTZ. For the image acquisition device, the functions of the camera such as the lens, focus, action of the camera, adjustment of aperture and video recording, were realized. The crop image database and the remote management system were also established with the functions such as image storage, download and upload statistical inquiries and so on. The system in a greenhouse was carried out in five months, with the system running stably, with a clear crop image and video information. Response of the control system time was less than 1 s, with the precision reaching 96.2%, the control accuracy reaching 96.2%, the crop image transmission response time was less than 2.5 s, which satisfied the use requirement. The image database management system is mainly used for image storage, download and upload, statistical query, etc. This crop image acquisition system provides a platform to diagnose the water and fertilize remotely by the obtained image in different parts for all plants within the monitoring area.