• Title/Summary/Keyword: Imagery

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A Worldview-2 satellite imagery pansharpening algorithm for minimizing the effects of local displacement (지역적 변위에 따른 영향을 최소화하기 위한 Worldview-2 위성영상의 융합 기법)

  • Choi, Jae-Wan
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.6
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    • pp.577-582
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    • 2011
  • In remote sensing, spatial/spectral distortions are recognized as two of the main problems in the pansharpening algorithm. Most pansharpening methodologies show a tendency to distort spatial information from objects such as buildings and vehicles because there are local spatial dissimilarities among multispectral bands in Worldview-2 satellite imagery. In this paper, we propose a new pansharpening algorithm in order to minimize the effects of the local displacement of spatial information in the pansharpening process. In experiments using Worldview-2 images, our method provided better spectral and spatial quality than pre-existing pansharpening methods.

Estimating Leaf Area Index of Paddy Rice from RapidEye Imagery to Assess Evapotranspiration in Korean Paddy Fields

  • Na, Sang-Il;Hong, Suk Young;Kim, Yi-Hyun;Lee, Kyoung-Do;Jang, So-Young
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.4
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    • pp.245-252
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    • 2013
  • Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam-do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

Analysis of sideward footprint of Multi-view imagery by sidelap changing (횡중복도 변화에 따른 다각사진 Sideward Footprint 분석)

  • Seo, Sang-Il;Park, Seon-Dong;Kim, Jong-In;Yoon, Jong-Seong
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.53-56
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    • 2010
  • An aerial multi-looking camera system equips itself with five separate cameras which enables acquiring one vertical image and four oblique images at the same time. This provides diverse information about the site compared to aerial photographs vertically. However, multi-looking Aerial Camera for building a 3D spatial information don't use a large-size CCD camera, do uses a medium-size CCD camera, if acquiring forward, backward, left and right imagery of Certain objects, Aerial photographing set overlap and sidelap must be considered. Especially, Sideward-looking camera set up by the sidelap to determine whether a particular object can be acquisition Through our research we analyzed of sideward footprint and aerial photographing efficiency of Multi-view imagery by sidelap changing.

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The Acquisition of Urban Information by using the Aerial polyhedral Oblique Imagery (항공 다면 경사 영상을 이용한 도시 정보 취득)

  • Kim, Won-Dae;Song, Young-Sun
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.295-299
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    • 2010
  • The vertical photographs of the existing production role of aerial photogrammetry was sufficient for the purpose. The current variety of purposes, such as image maps are used. However, a 3-D stereoscopic mapping, three-dimensional modeling and obtaining the side information of objects are difficult with limitations. In this study, aerial polyhedral oblique imagery are used for obtaining the a vertical and the side information of buildings at the same time to get used to the urban information. The results of this study, various urban information was available, the existing vertical photos can overcome the limitations of the techniques.

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A Study on the Analysis of Accuracy of SPOT Photos According to the Preprocessing Level (전처리 수준에 따른 SPOT 위성사진의 정확도 분석에 관한 연구)

  • 유복모;이현직
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.9 no.1
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    • pp.83-96
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    • 1991
  • The use of SPOT Imagery is a growing trend in the field of small and middle scale mapping, as well as in establishing topographic database. This study is about 3-D positioning using the SPOT Imagery, where the accuracy and the gemetric characteristics of SPOT photos are analysed according to the preprocessing level (level 1AP,1B). As a result of this study the following could be determined, i. e 1) the geometric characteristics of SPOT Imagery according to the preprocessing level, 2) the optimal polynomial type for exterior orientations of each preprocessing level, and 3) the type of significant additional parameters. It was found that both the geometric precision and accuracy of level 1AP is higher than those of level 1B, which implies that level 1AP is more suitable for precise 3-D positioning and map production.

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Development of Feature-based Classification Software for High Resolution Satellite Imagery (고해상도 위성영상의 분류를 위한 형상 기반 분류 소프트웨어 개발)

  • Jeong, Soo;Lee, Chang-No
    • Journal of Korean Society for Geospatial Information Science
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    • v.12 no.2 s.29
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    • pp.53-59
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    • 2004
  • In this paper, we investigated a method for feature-based classification to develop a software which is suitable for the classification of high resolution satellite imagery. We developed algorithms for image segmentation and fuzzy-based classification required for feature-based classification and designed user interfaces to support interaction with user, considering various elements required for the feature-based classification. Evaluation of the software was accomplished using real image. Classification results were compared and analysed with eCognition software which is unique commercial software for feature-based classification. The classification results from both softwares showed essentially same results and the developed software showed better result in the processing speed.

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Image-Based Cadastral Mapping with Fusion of Cadastre and Image Information (영상정보와 지적정보에의 융복합에 의한 영상응용지적도 개발)

  • Lee, In Su;Chang, Cheong Hwa;Seo, Yong Cheol
    • Journal of Korean Society for Geospatial Information Science
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    • v.20 no.4
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    • pp.45-54
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    • 2012
  • Nowadays, a variety of efforts, such as the open of SPACEN, the enactment of law related to Spatial Information and the improvement of institute in order to encourage of the Spatial Information Industry in domestic, are fulfilled. At this moment, it is expected that spatial information market will be vigorous, with the development of image-based cadastral map with combining cadastral information(vector) with Imagery information (raster). Hence, this study deals with the Image-Based Cadastral mapping and its application.

Effects of Motor Imagery Practice in Conjunction with Repetitive Transcranial Magnetic Stimulation on Stroke Patients

  • Ji, Sang-Goo;Cha, Hyun-Gyu;Kim, Ki-Jong;Kim, Myoung-Kwon
    • Journal of Magnetics
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    • v.19 no.2
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    • pp.181-184
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    • 2014
  • The aim of the present study was to examine whether motor imagery (MI) practice in conjunction with repetitive transcranial magnetic stimulation (rTMS) applied to stroke patients could improve theirgait ability. This study was conducted with 29 subjects diagnosed with hemiparesis due to stroke.The experimental group consisted of 15 members who were performed MI practice in conjunction with repetitive transcranial magnetic stimulation, while the control group consisted of 14 members who were performed MI practice and sham therapy. Both groups received traditional physical therapy for 30 minutes a day, 5 days a week, for 6 weeks; additionally, they received mental practice for 15 minutes. The experimental group was instructed to perform rTMS and the control group was instructed to apply sham stimulation for 15 minutes. Gait analysis was performed using a three-dimensional motion capture system, which is a real-time tracking device that delivers data via infrared reflective markers using six cameras. Results showed that the velocity, step length, and cadence of both groups were significantly improved after the practice (p<0.05). Significant differences were found between the groups in velocity and cadence (p<0.05) as well as with respect to the change rate (p<0.05) after practice. The results showed that MI practice in conjunction with rTMS is more effective in improving gait ability than MI practice alone.

Definition and Generation of Level 0 Product for KOMPSAT-2

  • Shin, Ji-Hyeon;Kim, Moon-Gyu;Park, Sung-Og
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.810-814
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    • 2002
  • According to the image level definition for KOMPSAT-2 in KOMPSAT-2 Ground Station Specification, the level 0 is frame formatted, unprocessed data at full resolution; any and all communications artifacts (e.g., synchronization frames, communications headers) removed. The level 0 is used for two purposes: 1) exchange of imagery between image receiving & processing element (IRPE), and 2) image transfer from the Receiving & Archiving Subsystem to Search & Processing Subsystem. On-board processing of imagery data of KOMPSAT-2 includes JPEG-like compression and encryption besides conventional CCSDS packetization. The encryption is used to secure imagery data from any intervention during downlink and compression allows real-time downlink of image data reducing data rate produced from the camera. While developing ground receiving system for KOMPSAT-2, it was necessarily to define level 0 products. In this paper, we will suggest level 0 product definition for KOMPSAT-2 and explain reasons of the decisions made. The key factor used while defining the level 0 products is the efficiency of whole ground receiving system. The latter half of the paper will explain the implementation of software that generates level 0 products. The necessary steps to produce level 0 products will be explained, and the performance achieved will be presented.

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The Comparison of the SIFT Image Descriptor by Contrast Enhancement Algorithms with Various Types of High-resolution Satellite Imagery

  • Choi, Jaw-Wan;Kim, Dae-Sung;Kim, Yong-Min;Han, Dong-Yeob;Kim, Yong-Il
    • Korean Journal of Remote Sensing
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    • v.26 no.3
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    • pp.325-333
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    • 2010
  • Image registration involves overlapping images of an identical region and assigning the data into one coordinate system. Image registration has proved important in remote sensing, enabling registered satellite imagery to be used in various applications such as image fusion, change detection and the generation of digital maps. The image descriptor, which extracts matching points from each image, is necessary for automatic registration of remotely sensed data. Using contrast enhancement algorithms such as histogram equalization and image stretching, the normalized data are applied to the image descriptor. Drawing on the different spectral characteristics of high resolution satellite imagery based on sensor type and acquisition date, the applied normalization method can be used to change the results of matching interest point descriptors. In this paper, the matching points by scale invariant feature transformation (SIFT) are extracted using various contrast enhancement algorithms and injection of Gaussian noise. The results of the extracted matching points are compared with the number of correct matching points and matching rates for each point.