开花期番茄叶片含水率检测仪设计与试验

Design and Test of a Moisture Content Detecting Instrument for Tomato Leaves during Flowering Stage

为实时检测开花期番茄叶片含水率,基于阻抗检测原理设计了一种植物叶片含水率检测仪,可检测100Hz~113kHz频率范围内的叶片阻抗,主要由阻抗检测、输入/输出、微控制器和叶片夹等模块组成。使用自制检测仪检测不同含水率的开花期番茄叶片,建立基于阻抗特性的叶片含水率偏最小二乘预测模型并进行验证。结果表明:以组合数据为输入的预测模型验证集精度最高,决定系数R^(2)为0.8435,平均绝对误差为4.47%;将预测模型导入到检测仪后对仪器的性能进行了测试,发现在45%~88%含水率范围内,预测值与实际值的平均绝对误差为4.51%,检测时间约为4s,表明检测仪可以实现开花期番茄叶片含水率的实时检测。

To real-time detect the moisture content of tomato leaves during flowering stage,a plant leaf moisture content tester was designed based on impedance detection principle.This tester can detect leaf impedance within the frequency range of 100Hz~113kHz,and is mainly composed of impedance detection module,input/output module,microcontroller module,and leaf clamp.A self-made tester was used to detect tomato leaves with different moisture contents during flowering stage,and a partial least squares model for leaf moisture content was established based on impedance characteristics.The results showed that the model with combination data as input has the highest accuracy(R^(2)=0.8435,MAE=4.47%);After the prediction model was introduced into the tester,the performance of the instrument was tested.It was found that the average absolute error between the predicted value and the actual value was 4.51%within the range of 45%~88% moisture content,and the detection time was about 4s,indicating that the tester could realize real-time detection of tomato leaf moisture content during flowering stage.