China TopRS Technology Co.

Beijing, China

China TopRS Technology Co.

Beijing, China
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Bai J.,Beijing Normal University | Bai J.,China TopRS Technology Co. | Jia L.,CAS Institute of Remote Sensing | Liu S.,Beijing Normal University | And 4 more authors.
IEEE Geoscience and Remote Sensing Letters | Year: 2015

To validate satellite-based surface fluxes by ground measurements properly, several numerical simulations were carried out at a homogeneous alpine meadow site and mixed cropland site, considering various atmospheric conditions and different land cover distribution types. By comparing various pixel selection methods, the results showed that footprint was significant in insuring a consistent spatial scale between ground measurements and satellite-based surface fluxes, particularly for heterogeneous surface and high-resolution remote sensing data. Because large aperture scintillometer measurements cover larger areas than eddy covariance (EC) system measurements, the spatial heterogeneity at a subpixel scale in complicated surface should be further considered in validating coarse satellite data. Thus, more accurate validation data and scaling methods must be developed, such as measuring surface fluxes at the satellite pixel scale by a flux measurement matrix or airborne EC measurements. © 2014 IEEE.

Deng J.,Wuhan University | Cheng X.,Wuhan SumMap RS Technology Co. | Liao M.,China TopRS Technology Co.
Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010 | Year: 2010

As a new type instruments of aerial remote sensing, the low-altitude unmanned aerial vehicle(UAV) mapping systems with its flexible, convenient and efficient advantages make up the deficiencies of the traditional aerial photography in a small area of large scale mapping, emergency and a new countryside surveying, urban rapid updating, focused region monitoring and so on. For the characteristics of unequal overlap, big swing-tilt angle, using the matching technique that combine SIFT feature matching with least squares matching to achieve automatic and high-precise matching, and availably resolve aerial triangulation difficulty of UAV images. Basing on an analysis of UAV remote sensing system, DPGrid (Digital Photogrammetry Grid) system is presented, the tests showed that matching algorithm of the module is advanced, reliable and accurate adjustment, can meet requirements of production. © 2010 IEEE.

Sheng L.,China TOPRS Technology Co. | Sheng L.,Henan Polytechnic University | Bai J.,China TOPRS Technology Co. | Zhou G.-W.,China TOPRS Technology Co. | And 4 more authors.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2015

South Sea Islands of China are far away from the mainland, the reefs takes more than 95% of south sea, and most reefs scatter over interested dispute sensitive area. Thus, the methods of obtaining the reefs bathymetry accurately are urgent to be developed. Common used method, including sonar, airborne laser and remote sensing estimation, are limited by the long distance, large area and sensitive location. Remote sensing data provides an effective way for bathymetry estimation without touching over large area, by the relationship between spectrum information and bathymetry. Aimed at the water quality of the south sea of China, our paper develops a bathymetry estimation method without measured water depth. Firstly the semi-analytical optimization model of the theoretical interpretation models has been studied based on the genetic algorithm to optimize the model. Meanwhile, OpenMP parallel computing algorithm has been introduced to greatly increase the speed of the semi-analytical optimization model. One island of south sea in China is selected as our study area, the measured water depth are used to evaluate the accuracy of bathymetry estimation from Worldview-2 multispectral images. The results show that: the semi-analytical optimization model based on genetic algorithm has good results in our study area; the accuracy of estimated bathymetry in the 0-20 meters shallow water area is accepted. Semi-analytical optimization model based on genetic algorithm solves the problem of the bathymetry estimation without water depth measurement. Generally, our paper provides a new bathymetry estimation method for the sensitive reefs far away from mainland.

Bai J.,China TOPRS Technology Co. | Zhao Y.,China TOPRS Technology Co. | Lin S.,China TOPRS Technology Co. | Lin S.,Henan Polytechnic University | And 2 more authors.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2015

To fully grasp the nature and human geography situation information, solve the problem of ecological environment, economic and social development of the country, monitoring the state of geographic condition by uniform index system has great significance. By collecting the existing standard documents, our paper established a suit of index system considering the characteristics of long time series remote sensing data. The index system includes basic, subject, composite statistical indexes, and statistical indexes based on basic geographic element. The spatial and temporal distribution of geographic condition with Landsat TM image in Haidian district of Beijing from 1983 to 2013 are studies. Results show that farmland decreases by 28.60%, build-up land increases by 38.95% in this period. The amount of land resources in different elevation/slope shows that, with the increase of elevation/slope, farmland and build-up land is gradually reduced, while grassland area is gradually increasing. In plains areas of elevation less than 50m and within the scope of the 0 to 3° slope, farmland and build-up land are the main land cover types, and both show the characteristic of tradeoffs. Urban area extended to the west and the north, meanwhile mass center of Haidian also moves to the northwest. The urban compactness decreases and the fractal index increased gradually, reflecting the city saturation degree become reduced, the city boundary becomes complicated gradually. Thecomprehensive land cover dynamic degree after the first decrease and then increases. Finally, based on the above statistic results, the spatial distribution of land cover in 2015 is predicted.

Pei L.,China TopRS Technology Co. | Yingcheng L.,China TopRS Technology Co. | Yingcheng L.,Chinese Academy of Surveying and Mapping | Yanli X.,China TopRS Technology Co. | And 3 more authors.
IOP Conference Series: Earth and Environmental Science | Year: 2014

In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized.

Li Y.,China University of Mining and Technology | Li Y.,China TopRS Technology Co. | Deng K.,China University of Mining and Technology | Liu P.,China TopRS Technology Co. | Gu L.,China TopRS Technology Co.
2011 International Symposium on Image and Data Fusion, ISIDF 2011 | Year: 2011

By LIDAR raw data to obtain high-precision digital elevation model, the first and most important step is to carry out the filtering of point cloud data, which is the key step of point cloud data generating to the digital terrain model (DTM). The algorithm in the article carries the special space index out to the point cloud, and builds the topology relation between the points. Organize the Light Detection and Ranging (LIDAR) cloud point used quadtree. The algorithm is based on stream and judge the ground point with the principle of slope and the point under the triangle. LIDAR data in ANYANG for the study area are used to test the algorithm. Results show that the method can efficiently extract ground points from LIDAR points cloud on urban area. © 2011 IEEE.

Zeng Y.,Chinese Academy of Surveying and Mapping | Van Genderen J.L.,University of Twente | Zhang J.,Chinese Academy of Surveying and Mapping | Wang G.,Chinese Academy of Surveying and Mapping | Wang G.,China TopRS Technology Co.
Proceedings of the 2012 International Conference on Industrial Control and Electronics Engineering, ICICEE 2012 | Year: 2012

Image and data fusion is a process dealing with data and information from multiple sources to achieve refined or improved information for decision making. It has wide applications. When images with a similar acquisition time are used, the expected result is to obtain a fused image that retains the spatial resolution from the panchromatic image and color content from the multi-spectral image, to perform land use/cover classification, or to extract geo-spatial information, which can be used in thematic mapping, as well as the establishment and update of geo-spatial databases; when images with different dates are used, the main purpose of image fusion is to detect the changes over a period of time, which can be employed in disaster monitoring, environmental monitoring, land use/cover change detection, etc. Aiming at the two types of applications, this paper discusses and summarizes the evaluation methods for image fusion performance in the level of pixel-based processing and decision-based processing. It also develops a quantitative analysis method for assessment of the pixel-level image fusion for change detection. This method integrates spectral features and spatial texture features which constitute the most important visual content of an image. The main idea of this method is to compare the image similarity between the regions where changed parcels are located and the regions where there is no change using the similarity measure. The practical application examples of the evaluation criteria are also given. © 2012 IEEE.

Gu L.,China TopRS Technology Co. | Li Y.,China TopRS Technology Co. | Liu P.,China TopRS Technology Co. | Teng C.,China TopRS Technology Co.
2011 International Symposium on Image and Data Fusion, ISIDF 2011 | Year: 2011

Traditional shading theory is based on DEM. For DSM, because of the complex manmade and natural ground objects such as buildings and vegetation, the elevation of DSM has the characteristic of discontinuity and abrupt, and the resulted shading map is poor in artistry and practicality. Color of terrain, construction, vegetation and other features may be similar on the shading map in certain area, and it's difficult to recognize them from each other. Based on relief shading theory, this paper does an in-depth analysis in the issue above, and two relief shading methods are designed for DSM, one is based on LiDAR points and the other is based on nDSM. On the experiment result, it can be seen that the quality of shading map has been improved significantly. Both methods considered about the representation of terrain and features, terrain and features are distinguishable obviously on the shading map. Besides, based on classification of airborne LiDAR points, the two methods are useful for the application requirements of power, highway and other departments, and have important reference value in emergency management as well. © 2011 IEEE.

Li Y.-C.,China TopRS Technology Co. | Ye D.-M.,China TopRS Technology Co. | Ding X.-B.,China TopRS Technology Co. | Teng C.-S.,China TopRS Technology Co. | And 2 more authors.
2011 International Symposium on Image and Data Fusion, ISIDF 2011 | Year: 2011

The paper analyze the key technology of lowaltitude UAV aerial photographic system in island topographic mapping, including exposure control auto excursion angle rectification and exposure point calculate by differential GPS and the flight plan considering the characteristic of island and so on. Then give a typical example of the island photography and topographic mapping. The results present that the UAV aerial photographic technology can satisfy the island topographic mapping at large-scale with only a few control points, which fills the blank of Chinese island topographic mapping. © 2011 IEEE.

Ye D.,ZheJiang TopRS Technology Co. | Liao M.,ZheJiang TopRS Technology Co. | Nan A.,ZheJiang TopRS Technology Co. | Wang E.,China TopRS Technology Co. | Zhou G.,China TopRS Technology Co.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2016

This paper is based on the principles of two-medium photogrammetry, with the purpose to perform a bathymetric survey of a reef in the South China Sea, using aerial imagery acquired by UAV. The first objectives are to introduce the basic principles of two-medium photogrammetry, discuss the technical requirements of this methodology to determine an accurate refractive index of sea water, and propose a new method to calculate seawater refraction and calculate corrected reef elevations. The second objective is to analyse and integrate the elevation and depth datum for both the land mass and the undersea reef. The final objective of this paper is performing stereoscopic mensuration on the UAV photography in order to transform reef elevation and depth datum. Our test shows that aerial two-medium photogrammetry is feasible in practical application, but requires relatively high aerial photography conditions.

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