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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (19): 153-158.doi: 10.11924/j.issn.1000-6850.casb2023-0171

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Design and Experiments of Nondestructive Moisture Content Testing System Based on Near-infrared Spectroscopy

GUO Xindong(), SUN Yu(), ZHANG Yongmei   

  1. College of Information Science and Engineering, Shanxi Agriculture University, Taigu, Shanxi 030801
  • Received:2023-03-03 Revised:2023-05-12 Online:2023-07-05 Published:2023-07-03

Abstract:

The moisture content of corn leaves is an important physiological index in the process of crop growth. Near-infrared moisture meter can effectively detect the moisture content of corn leaves. Since the traditional near- infrared moisture meter has the disadvantages of high power consumption and high cost, we design a portable near-infrared crop leaf moisture nondestructive testing system based on STM32 by using a LED light source with 1450 nm. First, we designed the testing system consisting of light source circuit, signal processing circuit, STM32 minimum system, power circuit, etc. Then the calibration of the system was performed, which included collecting the reflected light and water content of the leaves, establishing linear fitting model of leaf water content and light segment. Finally, the portable moisture detector was tested to measure and display the leaf moisture content in real time. The results shows that the correlation coefficient of leaf moisture content and light absorption of the portable moisture detector is 0.8019 with RMSEC of 0.51, and the maximum measurement error of the test set is 1.80%, and the average measurement error is 0.964%, which meet the need of agricultural industry. This system has the advantages of fast detection speed, small size and low cost, which provides theoretical reference and technical support for the study of near infrared spectrum detection instruments.

Key words: near-infrared spectroscopy, nondestructive testing, maize leaves, moisture content, STM32