基于声学特性的西瓜糖度检测系统

该研究优化了由包裹橡皮的金属小球、压电式加速度传感器、电荷放大器、光电式触发电路、数据采集卡和计算机等组成的西瓜声学特性测试系统。由所获取的声波信号幅值谱计算出声透过率,采用TQ软件中SMLR(逐步多元线性回归)函数选取6个特征频率:752、869、1001、4556、322、3950Hz,由其对应的声透过率值建立了西瓜品质检测的多元线性回归模型。对47个西瓜样本的试验数据分析表明:将敲击点和接收点分别放置在西瓜自然生长状态的中部对侧可获得最佳的测定模型,模型的校正相关系数R、校正均方根误差RMSEC和预测均方根误差RMSEP分别是0.80753、0.646和0.655。实现了西瓜糖度检测目的,为声学无损检测西瓜成熟度提供了参考。

Acoustic detecting system for sugar content of watermelon

An acoustic system was developed to detect the sugar content of watermelon nondestructively,which consists of a steel ball wrapped with rubber,6 piezoelectric accelerate sensors,an electricity amplifier,an optical trigger,a data acquisition card and a computer.Acoustic transmissivity can be calculated from the amplitude spectrum.And 6 characteristic frequencies,752、869、1001、4556、322、3950 Hz,were chosen with the function of SMLR (Stepwise Multiple Linear Regression) using TQ software.The acoustic transmissivity at frequencies were used to setup a multi regression models for the detection of watermelon sugar content.47 watermelons were tested,and the results showed that the best detection model can be obtained by tapping the equator part and receiving the signals from the opposite side with watermelon being put in its growing position,the R value was 0.80753,RMSEC was 0.646,RMSEP was 0.655.The research proved the possibility of the system in detection of sugar content of watermelon and can provide a reference for further research in this area.