西瓜品质检测系统的光热环境测试

目的 掌握西瓜品质检测试验台光照箱内部光热环境变化。方法 在西瓜品质检测试验台的光源开启后30 min内, 每隔1 min采集光照箱的温度和光源的光谱。对光照箱的温度变化过程采用一阶系统的阶跃响应过程进行分析, 将光谱分为可见光波段(400~700 nm)和近红外波(700~1100 nm), 通过对其光谱值积分得到其光谱能量, 并对光谱能量随时间变化的情况进行分析。结果 采用一阶系统的阶跃响应公式计算得到各观测时刻的温度计算值与实测值的相关系数为0.9997, 西瓜品质检测试验台光照箱内温度稳定时间小于15 min, 光源的光谱稳定时间小于1 min。结论 西瓜品质检测试验台光照箱温度升高过程为一阶系统的阶跃响应过程, 西瓜品质检测试验台光照箱内光热环境稳定时间不大于15 min, 西瓜品质检测试验可在光源开启15 min之后进行。

Test for the changes of illumination and thermal environmental in the chamber of a watermelon quality inspection system

Objective To investigate illumination and thermal environmental changes in the chamber of a watermelon quality inspection system. Methods The spectrum and temperature of the chamber were determined every 1 min within 30 min after the light source was turned on. The data of temperature changes in the light box were regressed using a first-order system step response. The spectrum values in the visible band (400~700 nm) and NIR band (700~1100 nm) were integrated to get a value which was used as luminous flux value respectively, the luminous flux values were analyzed over time. Results The correlation coefficient value between the temperature calculated by first-order system step response and the data measured was 0.997. The stabilization time of temperature in the chamber was less than 15 min, and the stabilization time of spectrum in the chamber was less than 1 min. Conclusion The process of temperature increases in the chamber is step response of a first-order system. The changes of illumination and thermal in the chamber are less than 15 min. It is necessary to wait for 15 min after the light source turned on before the inspection of watermelon quality.