Evaluation of a UAV-mounted consumer grade camera with different spectral modifications and two handheld spectral sensors for rapeseed growth monitoring: performance and influencing factors     

Zhang  Jian  Wang  Chufeng  Yang  Chenghai  Jiang  Zhao  Zhou  Guangsheng  Wang  Bo  Shi  Yeyin  Zhang  Dongyan  You  Liangzhi  Xie  Jing 《Precision Agriculture》2020,21(5):1092-1120

The objective of this study was to evaluate the crop monitoring performance of a consumer-grade camera with non-modified and modified spectral ranges which are commonly used in low-altitude unmanned aerial vehicle (UAV) platforms. The camera was fixed sequentially with seven types of filters for collecting visible images and near-infrared (NIR) images with different center band locations and bandwidths. Meanwhile, field-based hyperspectral data and normalized difference vegetation index (NDVI) measured by a GreenSeeker handheld crop sensor (GS-NDVI) were collected to examine the accuracy of rapeseed growth monitoring in terms of vegetation indices (VIs) derived from UAV images. Results showed that the UAV-based RGB-VIs and optimal NIR-VIs had similar accuracy for predicting GS-NDVI. Moreover, similar results were achieved based on the hyperspectral data, indicating the importance of spectral characteristics for GS-NDVI estimation. However, the UAV-based results also indicated that the performance of VIs derived from the band combinations containing longer NIR center wavelengths and narrower bandwidths was obviously poorer than that of the RGB-VIs. The image quality of the NIR band was also found to be inferior to the visible band based on quantitative analysis, which also revealed that image quality had great impact on UAV-based results. Image quality was then related to the effects of camera exposure, spectral sensitivity, soil background and dark areas. The results from this study provide useful information for camera modifications by selecting appropriate filters that not only are sensitive to crop growth, but also ensure image quality.

  相似文献   

滨海盐土柑桔园行间生草草种影响土壤养分的试验     

杨储丰  虞秀明  郑洁 《中国南方果树》2022,(1):40-46

为研究不同生草处理对柑桔园土壤养分的影响,在上海市崇明区长兴岛滨海盐土宫川温州蜜柑园,于9月开始设置行间自然生草及黑麦草、野豌豆、黄花苜蓿、菊苣、高羊茅和鼠茅草等6个草种人工生草处理,翌年对不同草种地上部的生物量及0～20 cm土层的pH值、有机质、矿质元素有效含量等指标进行测定分析。结果表明:(1)野豌豆和黑麦草地上部干鲜质量比低于其他草种处理,不同处理之间土壤pH值差异无显著性;(2)行间种植黑麦草和野豌豆促进春秋季桔园土壤有机质累积的作用较好;(3)与其他处理相比,行间种植野豌豆春秋季土壤水解性氮、有效磷和速效钾含量均较高;(4)行间种植黑麦草和野豌豆对秋季土壤中交换性钙含量的提升效果优于其他草种,而行间种植黑麦草和黄花苜蓿对秋季土壤中交换性镁含量的提升效果较好;(5)行间种植野豌豆春季土壤有效锰、有效锌、有效铜含量及秋季土壤有效硼含量均高于其他草种;种植野豌豆和菊苣对秋季土壤有效铁含量、种植黑麦草对秋季土壤有效锌和有效铜含量、自然生草和野豌豆对秋季土壤有效钼含量分别具有更明显的提升效果。桔园行间生草可有效调节土壤有机质、大量元素、中量元素和微量元素的供给能力,但不同生草类型的调...  相似文献   

单行马铃薯中耕追肥机的设计与试验     

孔皓  宁楚峰  张永华  姚忠志  沈东华  魏富德 《农机化研究》2022,44(9):74-79

  相似文献