LOW-cost high-accuracy measurement system of plant height based in infrared photosensitive tube sensing

摘要

Crop growth information is the basis of acquiring crop nutrition status, water status, diseases, insect pests, weeds, and physiological information and scientific management according to the growing conditions of crops. Plant height (PH) is one of thekey indicators of crop growth information and a core technology for realizing agricultural modernization. Therefore, acquiring real-time information of PH is important for farmland automation management. The objectives of this study are to provide a novel low-cost high-accuracy system for PH measurement based on infrared photosensitive tube sensors and to realize real-time, on-line, and rapid PH measurement. On the basis of providing the arrangements of IPT and modulation wave driven circuit, the measurement system is designed. The algorithm for PH calculation together with software procedures is designed. To monitor the PH of crops with various heights, a height adjusting device was designed. To validate the performance of the developed system for PHmeasurement, experiments are conducted on tomatoes planted in a Venlo greenhouse. During experiments, the mobile platform is moved at three different velocities of 0.320, 0.410 and 0.525 ms~(-1). The sampling time of the measurement system was set as 1ms. The system for PH measurement driven by the mobile platform was moved along the direction of crop rows. Results suggest that the designed measurement system presents high accuracy with an absolute error less than ±4 mm as well as relative error lessthan 0.1% and can be conveniently applied to the measurement of PH.