基于低空遥感的消费级相机油菜苗期长势监测最优波段选取

无人机遥感作为卫星和航空遥感平台的有力补充，在低空遥感观测领域发挥越来越重要的作用.对于农作物长势监测而言，选择合适的光谱波段有利于更加准确地反映作物长势情况.该研究借助水稻—油菜氮素养分试验，针对其油菜季开展基于无人机遥感的消费级相机油菜苗期长势监测最优波段选取问题研究.试验采用经红外改造后的消费级相机，逐次搭配lp680、lp720、lp850 3种近红外长通滤波片和RGB红外截止滤波片来获取不同光谱位置的近红外波段影像和可见光波段影像.在此基础上计算多波段影像的多种植被指数，同时结合油菜地面冠层高光谱数据和滤波片光谱响应特性模拟计算相同的植被指数.结果表明，使用可见光波段影像计算的归一化差指数(NDI)与地面实测归一化差植被指数(NDVI)之间的相关性最高，其R2达到0.945，该结果与基于油菜地面冠层高光谱数据所得结果呈现出较好的一致性.同时该NDI值与油菜氮素养分试验中不同氮素施用水平之间的相关性也较好，其R2达0.963.该研究结果表明选取常规消费级相机可见光波段也能准确地获取作物长势信息，为其用于作物长势监测提供了科学依据.

Optimal band selection for seedling rape growth monitoring with consumer-grade camera based on low-altitude Remote Sensing

Remote Sensing based on unmanned aerial vehicle (UAV) is a powerful supplement to satellite and aerial remote sensing platforms. It is playing a more important role in low-altitude remote sensing observation field. Furthermore， optimal selection of spectral bands and vegetation index will raise the accuracy of response to crop growth monitoring. Therefore， the research on the optimal band selection for growth monitoring of rape was carried out based on low-altitude UAV platform， which contained a consumer-grade camera after infrared reconstruction. The camera was fixed with one IR-cut (RGB) and three IR long pass (lp680， lp720， lp850) filters. Then visible image was obtained by IR-cut (RGB) filter， and the near infrared images from different spectral position were obtained by lp680， lp720， lp850 filters. After that， some common vegetation indexes were calculated based on different band images. Meanwhile， the same vegetation index was also calculated by synchronous canopy spectrum of rape based on spectral response of each filter. The results showed that the correlation between the vegetation index based on RGB image information and the normalized difference vegetation index(NDVI) in ground measurement was high. The normalized difference index (NDI) was the best VIs， the R2 of which has reached 0.945. At the same time， the results based on images were consistent with that based on synchronous canopy spectrum of rape. On this basis， the correlation between NDI and nitrogen application in the rape planting experiment was calculated， and the R2 was 0.963. The study showed that the visible spectrum of conventional consumer-grade camera could also accurately obtain the crop growth information without infrared reconstruction. In general， the study provides a scientific reference for crop monitoring with consumer-grade camera.