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1.
基于局域最大值法单木位置探测的适宜模型研究 总被引：2，自引：0，他引：2
以凉水自然保护区为研究区域,基于机载激光雷达数据,采用动态窗口局部最大值法对郁闭度较高的针叶林进行单木位置自动提取。采用树冠高度模型(CHM)和树冠最大模型(CMM)配合两种动态窗口,即树高--树冠大小回归方程和该方程的95%预测下限来探测树冠顶点,用探测百分比、1∶1对应关系的单木个数、生产者精度和用户精度进行了精度评价。结果表明:利用CMM能够抑制树冠内部枝杈产生的错判现象;利用树高--树冠大小回归方程95%的预测下限做动态窗口,能够有效防止在局部最大值方法中产生的小树漏测现象。因此,利用CMM和95%的预测下限做动态窗口的局域最大值法有利于提高单木位置探测的精度,为密林中自动地探测单木位置提供依据。 相似文献
2.
基于深度学习的5种树皮纹理图像识别研究 总被引：1，自引：0，他引：1
3.
Lack of automatic weed detection tools has hampered the adoption of site-specific weed control in cereals. An initial object-oriented
algorithm for the automatic detection of broad-leaved weeds in cereals developed by SINTEF ICT (Oslo, Norway) was evaluated.
The algorithm (“WeedFinder”) estimates total density and cover of broad-leaved weed seedlings in cereal fields from near-ground red–green–blue images.
The ability of “WeedFinder” to predict ‘spray’/‘no spray’ decisions according to a previously suggested spray decision model for spring cereals was
tested with images from two wheat fields sown with the normal row spacing of the region, 0.125 m. Applying the decision model
as a simple look-up table, “WeedFinder” gave correct spray decisions in 65–85% of the test images. With discriminant analysis, corresponding mean rates were 84–90%.
Future versions of “WeedFinder” must be more accurate and accommodate weed species recognition. 相似文献
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Iran supports five different vegetation zones. One of those is the Irano-Touranian zone that is located in the northeast of
Iran. This vegetation zone includes arid and semi-arid lands, and its area is about 3.5 million hm2. It supports growth of pistachio (Pistacia vera), a deciduous-broadleaved species, which is one of the ecologically and economically most important native species. In this
study, we analyzed three images acquired by ALOS satellite, including 10m resolution multispectral band (AVNIR-2), 2.5 m resolution
“Backward” PRISM image, and 2.5 m resolution “Nadir” PRISM image, based on a provided rational polynomial coefficient (RPC).
Using the “Backward” and “Nadir” images, a 2.5 m resolution digital elevation model (DEM) was produced. Four methods with
AVNIR-2 and PRISM data were used to produce pan-sharpening images and conduct an object-based feature extraction process.
Normalized Difference Vegetation Index (NDVI) was used to determine the maximum distribution of pistachio in related elevation.
The accuracy of the DEM was tested on 28 ground control points in the pair image as tie points, with the value of parallax
error of 0.9027 m. The created elevation map indicated that pistachio trees grow up at 650m above sea level (a.s.l.). The
result from NDVI in the related elevation showed the maximum density of pistachio at 800m a.s.l. In addition, the result of
feature extraction in the forest showed the area of each target element calculated. The results of this research will improve
decision-making and lead to sustainable management in general. 相似文献
6.
有效了解森林生长变化信息对森林资源的保护以及生态环境的研究具有重要意义。近年来,激光雷达数据是森林清查中主要的LiDAR数据源。但是现有机载LiDAR数据单木分割算法在密集林区应用精度较低,尤其在中下层冠层单木提取精度不高,存在漏检的现象。针对以上问题,采用归一化割（normalized cut,Ncut）方法直接对激光点云数据进行初始分割,然后设定冠层的形状参数与点云数量阈值,利用全局最大值重复Ncut方法,对林区下层冠层进行探测,实现单木的精确提取。结果表明,与只利用归一化割方法提取单木结果相比,本研究方法使单木提取误判率由22.66%降至3.9%,识别率由原先的68.49%提升至86.63%,有效规避了上层冠木对下层遮盖导致的下层单木漏检情况,提高了在冠层中间层和下层树木的识别率,可为今后森林清查、森林资源管理提供分割方法的选择,也为森林分类、单木分割提供样例。 相似文献
7.
Raphael Linker 《Precision Agriculture》2017,18(1):59-75
A procedure for estimating the number of mature apples in orchard images captured at night-time with artificial illumination was developed and its potential for estimating yield was investigated. The procedure was tested using four datasets totaling more than 800 images taken with cameras positioned at three heights. The procedure for detecting apples was based on the observation that the light distribution on apples follows a simple pattern in which the perceived light intensity decreases with the distance from a local maximum due to specular reflection. Accordingly, apple detection was achieved by detecting concentric circles (or parts of circles) in binary images obtained via threshold operations. For each dataset, after calibration of the procedure using 12 images, the estimates of the number of apples were within a few percent of the number of apples counted by visual inspection. Yield estimations were obtained via multi-linear models that used between two and six images per tree. The results obtained using all three cameras were only slightly better than those obtained using only two cameras. Using images from only one side of the tree did not worsen the results significantly. Overall, the yield estimated by the best models was within \(\pm\)10 % of the actual yield. However, the standard deviation of the yield estimation errors corresponded to ~26–37 % of the average tree yield, indicating that improvements are still needed in order to achieve accurate yield estimation at the single-tree level. 相似文献
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基于HSV空间的玉米果穗性状的检测 总被引：2，自引：0，他引：2
为高效检测玉米果穗性状,建立了基于HSV(色调、饱和度、明度值)空间的玉米果穗性状的检测方法:使用机器视觉技术采集绿色背景玉米果穗图像,用HSV直方图阈值算法去除绿色背景,用FFT滤波器去除尖锐边缘和噪声,运用粒子滤波分离单一图像中的多个玉米果穗图像,并采用形态学腐蚀方法,经过4次迭代腐蚀,得到玉米果穗中间3行;检测玉米果穗的大小、形状、纹理和颜色4个特征的性状。随机检测67张玉米果穗样本图像的结果表明,果穗大小和形状特征检测的准确率为100%,果穗颜色和纹理特征检测的准确率分别为98.55%和96.25%,平均每果穗检测时间为0.1 s。 相似文献
10.
Lettuce calcium deficiency detection with machine vision computed plant features in controlled environments 总被引：1，自引：0，他引：1
Conventional greenhouse environmental conditions are determined by observation. However, destructive or invasive contact measurements are not practical for real-time monitoring and control applications. At the canopy scale, machine vision has the potential to identify emerging stresses and guide sampling for identification of the stressor. A machine vision-guided plant sensing and monitoring system was used to detect calcium deficiency in lettuce crops grown in greenhouse conditions using temporal, color and morphological changes of the plant. The machine vision system consisted of two main components: a robotic camera positioning system and an image processing module. The machine vision system extracted plant features to determine overall plant growth and health status, including top projected canopy area (TPCA) as a morphological feature; red-green-blue (RGB) and hue-saturation-luminance (HSL) values as color features; and entropy, energy, contrast, and homogeneity as textural features. The machine vision-guided system was capable of extracting plant morphological, textural and temporal features autonomously. The methodology developed was capable of identifying calcium-deficient lettuce plants 1 day prior to visual stress detection by human vision. Of the extracted plant features, TPCA, energy, entropy, and homogeneity were the most promising markers for timely detection of calcium deficiency in the lettuce crop studied. 相似文献
11.
拟合并选择云南红豆杉单木生物量模型,明确树冠结构调控技术。以3年生福建省明溪县云南红豆杉原料林为对象,采用4种自变量类型模型,并导入树冠结构特征变量拟合生物量模型;经配对t检验、偏差检验与估算预测精度,优选系列单木生物量模型。比较导入树冠结构特征前后模型的拟合与预测效果,明确并验证树冠结构调控技术。结果表明,采用D2H变量拟合的模型效果最优,其次为DH变量,然后是D2变量,最后是D、H变量。采用D2H变量较D、H变量明显提高模型的拟合与预测效果。导入树冠结构特征后明显提高模型拟合与预测效果。冠幅、冠形率显著影响红豆杉系列单株生物量,促进系列生物量的树冠结构调控重点与方向是促进冠幅宽大;经验证,树冠结构调控技术显著提高系列单木生物量是可行的。自变量类型显著影响模型的拟合与预测效果,选择自变量类型以优化红豆杉单木生物量模型是必要和可行的。导入树冠结构特征因子明显提高单木生物量模型的拟合效果与预测精度。选出4个最优红豆杉单木生物量模型,其决定系数不小于0.862,预测精度均不小于95.18%,MAPE均不大于16.95%,可以用于生产中的生物量预测。 相似文献
12.
Keiko Tanaka 《Agriculture and Human Values》2008,25(4):567-580
Using the case of food safety governance reform in Japan between 2001 and 2003, this paper examines the relationship between
science and trust. The paper explains how the discovery of the first BSE positive cow and consequent food safety scandals
in 2001 politicized the role of science in protecting the safety of the food supply. The analysis of the Parliamentary debate
focuses on the contestation among legislators and other participants over three dimensions of risk science, including “knowledge,”
“objects,” and “beneficiaries.” The metaphor of “seven samurai” and the relationally situated roles of “samurai,” “bandits,”
and “beneficiaries” are used to show that in the process of policy making certain moral and ethical expectations on a new
expert institution for food safety were contested and negotiated to frame responsibilities and commitments of social actors for creating the food
system based on trust.
相似文献
| Keiko TanakaEmail: |
13.
This paper examines the discourses and practices of pedigree livestock breeding, focusing on beef cattle and sheep in the
UK, concentrating on an under-examined aspect of this—the deselection and rejection of some animals from future breeding populations.
In the context of exploring how animals are valued and represented in different ways in relation to particular agricultural
knowledge-practices, it focuses on deselecting particular animals from breeding populations, drawing attention to shifts in
such knowledge-practices related to the emergence of “genetic” techniques in livestock breeding which are arguably displacing
“traditional” visual and experiential knowledge’s of livestock animals. The paper situates this discussion in the analytical
framework provided by Foucault’s conception of “biopower,” exploring how interventions in livestock populations aimed at the
fostering of domestic animal life are necessarily also associated with the imperative that certain animals must die and not
contribute to the future reproduction of their breed. The “geneticization” of livestock breeding produces new articulations
of this process associated with different understandings of animal life and the possibilities of different modes of intervention
in livestock populations. Genetic techniques increasingly quantify and rationalize processes of selection and deselection,
and affect how animals are perceived and valued both as groups and as individuals. The paper concludes by emphasizing that
the valuation of livestock animals is contested, and that the entanglement of “traditional” and “genetic” modes of valuation
means that there are multiple layers of valuation and (de)selection involved in breeding knowledge-practices. 相似文献
14.
Delineating productivity zones in a citrus grove using citrus production,tree growth and temporally stable soil data 总被引：1，自引：0，他引：1
The productivity of a citrus grove with variation in tree growth was mapped to delineate zones of productivity based on several
indicator properties. These properties were fruit yield, ultrasonically measured tree canopy volume, normalized difference
vegetation index (NDVI), elevation and apparent electrical conductivity (ECa). The spatial patterns of soil series, soil color and ECa, and their correspondence with the variation in yield emphasized the importance of variation in the soil in differentiating
the productivity of the grove. Citrus fruit yield was positively correlated with canopy volume, NDVI and ECa, and yield was negatively correlated with elevation. Although all the properties were strongly correlated with yield and
were able to explain the productivity of the grove, citrus tree canopy volume was most strongly correlated (r = 0.85) with yield, explaining 73% of its variation. Tree canopy volume was used to classify the citrus grove into five productivity
zones termed as ‘very poor’, ‘poor’, ‘medium’, ‘good’ and ‘very good’ zones. The study showed that productivity of citrus
groves can be mapped using various attributes that directly or indirectly affect citrus production. The productivity zones
identified could be used successfully to plan soil sampling and characterize soil variation in new fields. 相似文献
15.
Over the course of the 1990s, donor enthusiasm for participation came to be institutionalized in a variety of ways. One particular
methodology—Participatory Rural Appraisal (PRA)—came to enjoy phenomenal popularity. New aid modalities may have shifted donor
and lender concern away from the grassroots towards “policy dialogue.” But “civil society participation,” “social accountability,”
and “empowerment”—some of the issues PRA grapples with—retain a place in the new aid discourse. PRA and its variants also
continue to be used by government agencies, non-governmental, and community-based organizations in local-level assessment,
planning, monitoring, and evaluation, as well as in national-level poverty assessments. It has sometimes been conflated, by
donors and critics alike, with doing participatory development, and has elicited critiques that often go far beyond the bounds
of the methodological. Yet these critics have tended to be academics with little experience as practitioners or facilitators.
In this article, we draw on an action research project with PRA practitioners. We explore, through their critical reflections,
some of the conundrums and contradictions faced by those who were active as PRA practitioners in the early 1990s. We suggest
that the story of PRA’s success and of subsequent concerns about abuse and misuse by mainstream development institutions offers
broader lessons with continued salience for development. 相似文献
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该文应用机载激光雷达数据,获得了高精度的树冠底部地形信息及树高信息,提取了包含植被冠层高度的数字表面模型,即林冠层三维信息模型(DCM),结合研究区的数字高程模型(DEM)可以获得用常规方法很难准确获取的森林植被参数,如冠层垂直结构、森林高度、郁闭度等.在此基础上,制作了研究区的林木高度图,具有直观、形象等特点,有助于林业部门及时、准确地掌握森林资源相关信息,并可利用DCM获得森林密度、胸高断面积、蓄积量(生物量)及单木参数等森林植被参数. 相似文献
18.
准确提取单木树冠边界是获取森林数量参数的重要基础,是高分辨率遥感图像林业应用的技术难题。基于DOM航空影像数据源,采用面向对象的方法对研究区内的2个树种的林分进行了单木树冠边界提取研究。首先利用桉树和杉木的空间分布矢量数据对DOM航空影像进行掩膜处理,在掩膜区域内进行多层次多尺度图像分割得到初步树冠分割结果,并剔除非树冠信息;再以树冠信息种子对象为基础,使用区域增长算法对树冠信息种子对象增长得到单木树冠范围;最后使用形态学滤波的方法优化单木树冠边界,完成林区内桉树和杉木两类树种的单木树冠边界提取。结果表明,由于不同树种的树冠存在尺度和形态差异,进行单木树冠分割时需要设置不同的参数才能到达较好的分割效果。本研究中桉树和杉木的单木树冠提取总体精度分别为86.75%与89.21%,可满足林业部门获取森林单木树冠的精度需求。 相似文献
19.
【目的】提高苹果中克百威残留快速检测方法的灵敏度与准确度,确保苹果产品中克百威农药残留抽查的高效和准确性。【方法】以新疆阿克苏当地6个点位市售苹果为检测样品,采用行业标准NY/T 761-2008第3部分的液相色谱法为参比方法,分别选择3家快检试剂盒,根据《食品快速检测方法评价技术规范》对其快检适应性进行评估。【结果】利用参比方法和快检试剂盒均未从苹果样品中检出克百威残留。3家快检试剂盒可在0.01 mg/kg以上呈阳性显色反应,低于GB/T 2763-2019《食品安全国家标准食品中农药最大残留限量》中的限量要求;试剂盒灵敏度均为100%、特异性均为50%、假阴性率均为0、假阳性率均为50%、相对准确度均为90%。【结论】所测试剂盒适用于苹果中克百威残留量的快速筛查。 相似文献
20.
为提高果树病虫害危害程度分级精度进而更好地指导果园病虫害防治,采用迁移学习技术与GoogLeNet模型相结合的方法,对6种果园作物的25类病虫害样本进行识别与危害程度分级研究;同时,探究不同数据集大小以及不同优化算法对模型性能的影响;基于MATLAB平台设计了一款可视化的病虫害识别与分级系统。结果表明:1)基于迁移学习的GoogLeNet模型,对病虫害识别精度可达99.35%,危害程度分级精度可达92.78%;2)在相同训练参数下,本研究模型比AlexNet、VGG-16、ResNet-18、SqueezeNet、原GoogLeNet及MobileNet-v2模型验证精度提高了2.38%~11.44%,并且收敛速度最快;3)本研究模型识别精度随着数据集的增大而提高;在3种优化算法中SGDM算法耗时最短且精度最高,更适合本研究模型。通过拍摄果树叶片病害区域图像,本研究设计的系统能够在0.43 s左右准确识别出果树种类、病害类型以及危害等级等信息。 相似文献