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1.
水稻遥感动力估产模拟初探   总被引:3,自引:0,他引:3  
将遥感手感和动力估产模型相结合,即通过NOAA卫星获得有效绿度模式;通过绿度-叶面积关系式,估算水稻群体叶面积指数;依据水稻生物量分配规律及环境条件对其的影响,估算水稻各器官的干重,取得了较好的模拟效果。  相似文献   

2.
遥感绿度指数图像处理是农作物遥感综合估产的基础,对其软件进行软件改进是作物产量报业务技术进步的表现。近年来,作者着手对旧版遥感绿度指数图像处理系统的改进工作,研制了新版软件,定名为GPS2.0。  相似文献   

3.
卫星遥感绿度值的特点及其应用   总被引:1,自引:0,他引:1  
谭凯琰  李郁竹 《遥感信息》1991,(4):16-18,32
引言应用气象卫星遥感绿度值资料估测大面积冬小麦产量和面积已经取得成功。绿度值(也称为植被指数)已被较广泛地应用于描述宏观地表植被状况。作为一种卫星遥感特征参数,其应用的方面越来越多,因此,对其特点、影响因素和变化规律的研究是有益的。本文结合卫星遥感绿度值在冬小麦遥感估产研究中的应用实践,粗浅地探讨一下它的特点及其应用。  相似文献   

4.
根据冬小麦和土壤地面反射波谱测试数据,计算了在卫星高度上与卫星磁带数据相对应波段的辐亮度值,对NOAAAVHRR和TM某些通道的差值绿度植被指数DVI、归一化绿度植被指数NDVI和比值绿度植被指数RVI的分析,从理论上证明了目前采用TMDVI_(4,3)提取冬小麦种植面积和NOAANDVI_(2,1)区分植被和土壤背景的有效性。同时在冬小麦种植面积和长势监测方面提出了一些新建议。  相似文献   

5.
李京  陈云浩  潘耀忠  赵静 《遥感信息》2003,387(3):8-11,T001
论述了基于遥感手段的生态资产定量遥感评估的模型和方法,包括遥感测量参数的选取,遥感评估模型的建立及模型各生态参数的遥感测量方法等,最终借助于多尺度遥感对地观测技术,利用所建立的遥感评估模型对典型研究区的生态资产现状进行了评估和比较,取得了较好的效果。  相似文献   

6.
以贵阳市中心城区为试验区,建立城市资源环境信息系统空间数据库。用遥感和地理信息系统技术,进行城市资源综合评价,为城市规划与管理提供信息服务。该数据库的设计和建立是以地理信息系统PAMAPGIS软件为基本工具,在数据的采集过程中,以遥感数据作为充实和更新数据库的主要信息源。数据库由两部分组成:①基础地理数据库,包括数字高程模型和基础地理图件;②资源环境数据库,主要由常规专题图和遥感专题图组成。  相似文献   

7.
具有部分监督的遥感影像模糊聚类方法研究及应用   总被引:7,自引:0,他引:7  
遥感信息主要反映的是地球表层信息。由于地球表层系统的复杂性和开放性,地表信息是多维的、无限的,遥感信息传递过程中的局限性以及遥感信息之间的复杂相关性,决定了遥感信息其结果的不确定性和多解性。模糊分类是遥感影像分类研究的重要趋势。在Fuzzy-ISODATA 方法的基础上,探讨如何在样本数据集中融合部分知识和随机样本,通过聚类分析获得目标类别的模糊隶属度矩阵和特征空间的特征模式的方法。提出了基于该方法的遥感影像模糊分类模型  相似文献   

8.
用NOAA卫星资料作冬作物冻害分析   总被引:4,自引:0,他引:4  
对于严重的农作物灾害,领导部门迫切希望能尽快了解受灾程度和受灾范围,以便及时组织抗灾救灾。为此,我们探索了应用气象卫星遥感资料进行作物宏观受害程度调查的方法,并作了1987年冬作物冻害程度的分析。一、灾害分布图的生成首先根据卫星气象中心提供的光谱资料合成绿度值,并进行绿度稳定性的检验和处理,生成受灾前和受灾后两个时相的绿度数值图。  相似文献   

9.
针对当前地表覆盖分类结果精度低的问题,提出基于多源遥感数据融合的地表覆盖分类方法。首先,将红-绿-蓝(Red Green Blue,RBG)、数字表面模型(Digital Surface Model,DSM)和归一化植被指数(Normalized Differential Vegetation Index,NDVI)作为编码器的3个分支,生成地表覆盖遥感影像语义分割网络;其次,利用多源遥感数据融合技术构建地表覆盖分类模型;最后,通过对模型的训练和优化,输出空白域自适应与影像地表覆盖分类结果。实验结果表明,该方法可以实现对多种地表覆盖类型的高精度划分,具有一定的应用价值。  相似文献   

10.
长春净月潭遥感实验区玉米遥感估产模式研究   总被引:2,自引:0,他引:2       下载免费PDF全文
以长春净月潭遥感试验区和吉林省梨树县为主要试验区,研究建立玉米遥感估产模式。利用多种图像处理方法提取玉米播种面积,建立单产估产模型,对试验区1992年玉米产量进行了估算预报,结果较好。  相似文献   

11.
Abstract

For the last 10 years the U.S. National Oceanic and Atmospheric Administration has produced an experimental Global Vegetation Index (GVI) data set for terrestrial vegetation research. These data, sampled from advanced very high resolution radiometer (AVHRR) observations, have served as a primary stimulus for global-scale vegetation research but have, so far, not been adequately evaluated. This study reviews the GVI production procedures and compares the resultant observations with a more comprehensive compilation of the AVHRR data being produced at the NASA Goddard Space Flight Center. There are many aspects of the GVI production procedures which could be improved to achieve the desired objectives. In particular, the mapping and sampling procedures employed provide measurements which only approximate the observed GAC measurements. The GVI NDVI record varies more than ±NDVI units (~ 7 per cent of signal) from the GAC record and, in general, seriously underestimates the GAC NDVI measurements. The NDVI portion of the GVI record is compromised through use of digital numbers rather than calibrated reflectance. NDVI measurements from the calibrated channels of the GVI data set produces values that compare favourably with the GAC measurements, but with considerable residual variance. Calculation of a 3 by 3 pixel average of the GVI NDVI measurements reduces residual variance between the data sets to ±0.018 NDVI units (~3 per cent of signal). Decay of sensor calibration and orbital overpass time, experienced by all the AVHRR sensors, as well as differences in these parameters between the sensors are not addressed but the results suggest the importance of accounting for these factors. These results indicate that GVI data sets, following adequate reprocessing, provide reasonable estimates of major regional contrasts in vegetation activity but should not be employed to evaluate local or minor trends.  相似文献   

12.
Global Vegetation Index (GVI) data from the Advanced Very High Resolution Radiometer (AVHRR) was used to identify macro-scale vegetation/ land cover regions in the former Soviet Union (FSU). These regions are a better representation of surface vegetation and land cover than can be obtained from existing thematic maps of the FSU. Image classes were identified through cluster analysis using the ISODATA clustering algorithm and a maximum likelihood classifier. Qualitative analysis of the image variants produced with different input parameters indicated that an image with 42 classes best represented significant details in vegetation and land cover patterns without producing uninterpretable levels of details that represent artefacts of the clustering algorithm. Initial identification of image classes has been made by considering the weight of evidence provided by quantitative and qualitative analysis of existing maps, analytical tools from class statistics, ancillary data from a variety of sources and expert assessment by Russian scientists with extensive field experience in the FSU. Overall, this method of image classification using GVI data appears to describe accurately regions with similar vegetation and hind cover across the FSU. Some questions regarding the identification of wetlands and potential problems with classification in the Russian high arctic are discussed. The products of this research will help improve carbon budget estimates of the FSU by providing accurate delineation and definition of carbon quantifiable regions.  相似文献   

13.
Abstract

The aims of this presentation were (i) to simulate the solar zenith angle effect on the Global Vegetation Index (GVI), (ii) to derive an expression for removing such an effect from the GVI data by the above simulation procedure and (iii) to apply this relation to the GVI data obtained from the NOAA-AVHRR imagery.  相似文献   

14.
A signal processing technique is presented and applied to annual patterns of the Global Vegetation Index (GVI) derived from the Advanced Very High Resolution Radiometer (AVHRR) to examine the frequency distribution of the multi-temporal signal. It is shown that frequencies of the signal are linked to integrated GVI, seasonal variability and subseasonal variability of the land cover type. These characteristics are used to derive a land cover classification.  相似文献   

15.
We present a simple method to obtain a stable correlated color temperature (CCT) for the variation in light output power (LOP) of a light-emitting diode (LED) comprising a trichromatic LED-based white light source. A mathematical model was developed to determine the condition for the stable CCT operation using colorimetric analyses, and the stable CCT condition can be obtained by taking the derivative of the CCT with respect to the power ratio between the LEDs. Specifically, the stable CCT point that is invariant to the change in the LOP of a green LED can be uniquely determined at a certain value of the power ratio between red and blue LEDs. It was found that the chromaticity coordinate of the mixed white light moves along the isoCCT line of the Planckian locus as the LOP of a green LED varied under the stable CCT condition. The existence of the stable CCT point was also verified experimentally. The proposed method is expected to be advantageously employed in optimizing trichromatic LED-based white illumination sources for improved color stability.  相似文献   

16.
Abstract

The weekly global vegetation index (GVI) derived from the NOAA AVHRR instrument has been analysed for the 1982-1985 period over a wide range of vegetation formations of Asia. Temporal development curves of the index are presented for environments ranging from the desert of central Asia to the tropical forest of Borneo. The paper shows that, despite the coarse resolution of the GVI product, a large set of useful information on ecosystem dynamics and cropping practices can be consistently derived from time series of such data. In addition, it is shown that the impact of the 1982-1983 El Nino Southern Oscillation-related drought can be detected in the GVI data through an analysis of anomalies in the development of selected vegetation formations. The relevance of such analysis for global vegetation monitoring and change detection is then underlined.  相似文献   

17.
Abstract— A dynamic adaptation model (DAM), based on the variations in the luminance levels under the same chromaticity viewing conditions and equal‐whiteness correlated‐color‐temperature (CCT) curves (EWCCs) derived by using the proposed DAM, is proposed. The proposed model was obtained by the transformation of the test colors for high luminance into the corresponding colors for low luminance. In the proposed model, the optimal coefficients are obtained from the corresponding color data from Breneman's experiments. From the experimental results, it was confirmed that the chromaticity errors between the predicted colors by the proposed model and the corresponding colors of Breneman's experiments are 0.004 in uv′ chromaticity coordinates. The prediction performance of the proposed model is excellent because this error is the threshold value that distinguishes two adjacent color patches. Equal‐whiteness CCT curves (EWCs) are also proposed using the proposed DAM. By using the proposed EWCCs, an analysis of the difference between the selected video‐display‐unit reference‐white CCT values can be made. Additionally, the proposed EWCCs can be used as the theoretical standard which determines the reference white of the color video display units.  相似文献   

18.
A type of fast response time (RT) liquid crystal (LC) was developed to adopt in fringe‐field switching (FFS) mode for shutter glass 3D display device, the average gray to gray level (GTG) RT can reduce from 7.43 ms to 4.48 ms at a refreshing rate of 60 Hz, and the transmittance can increase by 15.4% compared with conventional LC based on the same cell gap. Meanwhile, the correlation among optical efficiency, correlative color temperature (CCT) of module and retardation of LC for FFS mode was studied. Transmittance is proportional to the retardation of LC; however, the CCT is inversely proportional to the retardation. The fast response LC can keep almost the original optical efficiency and CCT.  相似文献   

19.
Staff of the University of Maryland, Laboratory for Global Remote Sensing Studies have reprocessed the National Oceanic and Atmospheric Administration (NOAA) Global Vegetation Index (GVI) data record. Observations from April 1983 to June 1991 were mapped to a consistent projection (Plate Carreé) and radiometrically calibrated to spectral reflectance. Sensor degradation with time was taken into account. The normalized difference vegetation index (NVDI) was computed and bi-weekly composites formed to reduce residual cloud contamination. In addition, a set of data quality indicators were compiled during processing. Inspection of the reprocessed observations indicates that they are a significant improvement over the original GVI data. The temporal patterns in the observations appear consistent over time and between sensor systems. Considerable local variance is still evident in the observations, particularly in humid, cloud-prone regions of the globe. This is indicative of inherent limitations in the GVI data files. The ancillary data files in the reprocessed record may assist in addressing this atmospheric contamination problem. These reprocessed measurements should be of value in current efforts to study biospheric dynamics and in the design of future remote sensing missions to study global change.  相似文献   

20.
Coflow作为并行计算框架的典型流量模型,降低Coflow的完成时间(CCT)成为云计算领域的研究热点。现有Coflow调度机制未考虑云数据中心内网络瓶颈问题,容易造成网络拥塞,导致CCT增加。针对该问题,构建基于瓶颈感知的Coflow调度机制Bamq。利用Lagrange对偶优化Coflow调度模型,以加快Coflow流速并增大吞吐量,从而降低CCT。通过设计多级反馈队列机制,降低吞吐量对网络拥塞产生的影响,根据已发流的大小、宽度和流速信息,构建瓶颈因子以动态调整多级队列的优先级,实现拥塞感知,提高Coflow调度性能。在Facebook真实数据集上进行实验,结果表明,相比Baraat、Varys、Aalo机制,该机制的CCT平均缩短21.3%,吞吐量平均提高17.9%,能够有效提高链路的利用率。  相似文献   

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