| The morphological characteristics of crops,such as plant height,stem thickness and leaf area index,directly affect the final yield of crops.With the change of crop variety growth and development stage and planting density,these characteristics will be changed.The morphological characteristics of crops need to be obtained accurately and timely at different growth stages,which is of great significance for in-depth study of crop biological characteristics,optimal breeding,growth monitoring and so on.At present,it mainly relies on artificial measurement method to obtain the morphological characteristics of crops with some defects,such as slow speed,strong subjectivity and large labor intensity.In this paper,a crawler car image acquisition system is designed and equipped,which can satisfy the image acquisition in different growth stages of different dry field crops,and provides a new image acquisition method for phenotypic researchers.The main research contents and results are as follows:(1)The design of the overall scheme of the system.Based on the characteristics of geographical and spatial distribution of complex terrestrial environment and crop growth in dry field,crawler chassis and T-type bracket is establishedas the main hardware structure on the car.Forthe research on the guidance mode of the car in the field,it is decided to use the magnetic guidance sensor to induce the navigation magnetic strip to realize the automatic walking of the car in the field according to the path.Wireless communication technology is used to monitor the running track state of the car remotely.The solar panel is installed on the top of the system to provide electric energy for the car when it is running.By studying the system image acquisition scheme,it is established that the top view and side view cameras are installed on both sides of the t-shaped bracket,and the digital camera is automatically controlled by the computer software to simultaneously collect the growth images of the two crops.(2)Research on automatic walking method of small car.The CCF-D16 type Magnetic guidance sensor and CCF-DB1 Magnetic landmark sensor are determined as the key parts of car automatic guidance and landmark recognition.Through the analysis of the application principle and the response state of the two,it is determined that the crawler car adopts the differential principle to realize the small line walking and steering,in which the continuous magnetic landmark signal can be used as the site indication to trigger the remote monitoring,and a single landmark signal can be used as a trigger background cloth to lift or locate a single plant.Using drip method to record the running track of the car,it is found that the maximum operating deviation is less than ±3.5cm when the running speed of the car is less than 0.3m/s.(3)Research on control method based on PLC.Omron CP1 H series XA model PLC as the core controller,the crawler car Control Ladder diagram program is designed around its switching input and output and analog signal output scheme.Mainly includes the serial communication programbetween PLC and computer,touch screen.PLC can accept switching signal from magnetic guidance sensor and magnetic landmark sensor,then analyzes andjudges response signal,finally controls drive motor,background cloth motor,image Acquisition camera to complete the corresponding action procedures.(4)Research on image acquisition method.Complete the image acquisition software in the computer and the design of the digital camera control scheme.Fixed point and continuous image acquisition control schemes are put forward,and the acquisition efficiency of single camera in continuous shooting acquisition mode is 30 sheets per minute,and the acquisition efficiency of single camera in fixed-point acquisition mode is 20 per minute.In order to verify the feasibility of the image system,60 pots of maize plants were tested by continuous acquisition mode,and the test showed that the system could collect the crop growth images stably and reliably. |
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