• Title/Summary/Keyword: remote

Search Result 11,818, Processing Time 0.036 seconds

DETECTION AND MASKING OF CLOUD CONTAMINATION IN HIGH-RESOLUTION SST IMAGERY: A PRACTICAL AND EFFECTIVE METHOD FOR AUTOMATION

  • Hu, Chuanmin;Muller-Karger, Frank;Murch, Brock;Myhre, Douglas;Taylor, Judd;Luerssen, Remy;Moses, Christopher;Zhang, Caiyun
    • Proceedings of the KSRS Conference
    • /
    • v.2
    • /
    • pp.1011-1014
    • /
    • 2006
  • Coarse resolution (9 - 50 km pixels) Sea Surface Temperature satellite data are frequently considered adequate for open ocean research. However, coastal regions, including coral reef, estuarine and mesoscale upwelling regions require high-resolution (1-km pixel) SST data. The AVHRR SST data often suffer from navigation errors of several kilometres and still require manual navigation adjustments. The second serious problem is faulty and ineffective cloud-detection algorithms used operationally; many of these are based on radiance thresholds and moving window tests. With these methods, increasing sensitivity leads to masking of valid pixels. These errors lead to significant cold pixel biases and hamper image compositing, anomaly detection, and time-series analysis. Here, after manual navigation of over 40,000 AVHRR images, we implemented a new cloud filter that differs from other published methods. The filter first compares a pixel value with a climatological value built from the historical database, and then tests it against a time-based median value derived for that pixel from all satellite passes collected within ${\pm}3$ days. If the difference is larger than a predefined threshold, the pixel is flagged as cloud. We tested the method and compared to in situ SST from several shallow water buoys in the Florida Keys. Cloud statistics from all satellite sensors (AVHRR, MODIS) shows that a climatology filter with a $4^{\circ}C$ threshold and a median filter threshold of $2^{\circ}C$ are effective and accurate to filter clouds without masking good data. RMS difference between concurrent in situ and satellite SST data for the shallow waters (< 10 m bottom depth) is < $1^{\circ}C$, with only a small bias. The filter has been applied to the entire series of high-resolution SST data since1993 (including MODIS SST data since 2003), and a climatology is constructed to serve as the baseline to detect anomaly events.

  • PDF

REMOTE SENSING AND GIS INTEGRATION FOR HOUSE MANAGEMENT

  • Wu, Mu-Lin;Wang, Yu-Ming;Wong, Deng-Ching;Chiou, Fu-Shen
    • Proceedings of the KSRS Conference
    • /
    • v.2
    • /
    • pp.551-554
    • /
    • 2006
  • House management is very important in water resource protection in order to provide sustainable drinking water for about four millions population in northern Taiwan. House management can be a simple job that can be done without any ingredient of remote sensing or geographic information systems. Remote sensing and GIS integration for house management can provide more efficient management prescription when land use enforcement, soil and water conservation, sewage management, garbage collection, and reforestation have to be managed simultaneously. The objective of this paper was to integrate remote sensing and GIS to manage houses in a water resource protection district. More than four thousand houses have been surveyed and created as a house data base. Site map of every single house and very detail information consisting of address, ownership, date of creation, building materials, acreages floor by floor, parcel information, and types of house condition. Some houses have their photos in different directions. One house has its own card consists these information and these attributes were created into a house data base. Site maps of all houses were created with the same coordinates system as parcel maps, topographic maps, sewage maps, and city planning maps. Visual Basic.NET, Visual C#.NET have been implemented to develop computer programs for house information inquiry and maps overlay among house maps and other GIS map layers. Remote sensing techniques have been implemented to generate the background information of a single house in the past 15 years. Digital orthophoto maps at a scale of 1:5000 overlay with house site maps are very useful in determination of a house was there or not for a given year. Satellite images if their resolutions good enough are also very useful in this type of daily government operations. The developed house management systems can work with commercial GIS software such as ArcView and ArcPad. Remote sensing provided image information of a single house whether it was there or not in a given year. GIS provided overlay and inquiry functions to automatically extract attributes of a given house by ownership, address, and so on when certain house management prescriptions have to be made by government agency. File format is the key component that makes remote sensing and GIS integration smoothly. The developed house management systems are user friendly and can be modified to meet needs encountered in a single task of a government technician.

  • PDF

A Study on Radiotechnologic Students' Satisfaction in Blended Learning (블렌디드 러닝 수업에 대한 방사선과 학생의 만족도 조사)

  • Park, Jeongkyu
    • Journal of the Korean Society of Radiology
    • /
    • v.14 no.4
    • /
    • pp.405-413
    • /
    • 2020
  • Expectations and interests in blended learning are increasing as universities respond to the educational flow of transition to e-learning. This study analyzed the difference between the satisfaction of students in the first grade of radiology and the general characteristics of the subjects when applying blended learning. First, the satisfaction according to the class type was the highest in blended learning classes at 47.2%, followed by lecture room classes at 30.6% and remote classes at 22.2%. Second, the place where the remote lecture was watched by viewing the remote class according to the general characteristics was the highest at 94.4%. The most common medium for attending the remote class was using a PC, with 72.2%, and there was no significant difference in the remote class viewing method (p>0.05). Third, the appropriateness of the blended learning, "Remote lectures and lecture room lectures were properly conducted," had the highest score of 4.27±0.70. In addition, there was no significant difference in response to the teaching method according to gender and age (p>0.05). Fourth, the technology and system support,'Technical support and system support must be done when taking a remote lecture,' showed the highest score of 3.41±0.96. The lack of communication between professors and students,'In the remote class, communication between professors and students is insufficient' was the lowest with 2.88±1.00. In addition, there was no significant difference in the improvement of class according to gender and age (p>0.05). Through this study, it was intended to serve as a basis for the plans of blended classes and the policies of schools that introduced blended classes.

Current status and prospects of plant diagnosis and phenomics research by using ICT remote sensing system (ICT 원격제어 system 이용 식물진단, Phenomics 연구현황 및 전망)

  • Jung, Yu Jin;Nou, Ill Sup;Kim, Yong Kwon;Kim, Hoy Taek;Kang, Kwon Kyoo
    • Journal of Plant Biotechnology
    • /
    • v.43 no.1
    • /
    • pp.21-29
    • /
    • 2016
  • Remote Sensing (RS) is a technique to obtain necessary information in a non-contact and non-destructive method by using various sensors on the surface, water or atmospheric phenomena. These techniques combine elements such as sensors, and platform and information communication technology (ICT) for mounting the sensor. ICT has contributed significantly to the success of smart agriculture through quantification and measurement of environmental factors and information such as weather, crop and soil management to distribution and consumption stage, as well as the production stage by the cloud computer. Remote sensing techniques, including non-destructive non-contact bioimaging (remote imaging) is required to measure the plant function. In addition, bioimaging study in plant science is performed at the gene, cellular and individual plant level. Recently, bioimaging technology is considered the latest phenomics that identifies the relationship between the genotype and environment for distinguishing phenotypes. In this review, trends in remote sensing in plants, plants diagnostics and response to environment and status of plants phonemics research were presented.

Current Status of Hyperspectral Remote Sensing: Principle, Data Processing Techniques, and Applications (초분광 원격탐사의 특성, 처리기법 및 활용 현용)

  • Kim Sun-Hwa;Ma Jung-Rim;Kook Min-Jung;Lee Kyu-Sung
    • Korean Journal of Remote Sensing
    • /
    • v.21 no.4
    • /
    • pp.341-369
    • /
    • 2005
  • Hyperspectral images have emerged as a new and promising remote sensing data that can overcome the limitations of existing optical image data. This study was designed to provide a comprehensive review on definition, data processing methods, and applications of hyperspectral data. Various types of airborne, spaceborne, and field hyperspectral image sensors were surveyed from the available literatures and internet search. To understand the current status of hyperspectral remote sensing technology and research development, we collected several hundreds research papers from international journals (IEEE Transactions on Geoscience and Remote Sensing, International Journal of Remote Sensing, Remote Sensing of Environment and AVIRIS Workshop Proceedings), and categorized them by sensor types, data processing techniques, and applications. Although several hyperspectral sensors have been developing, AVIRIS has been a primary data source that the most hyperspectral remote sensing researches were relied on. Since hyperspectral data have very large data volume with many spectral bands, several data processing techniques that are particularly oriented to hyperspectral data have been developed. Although atmospheric correction, spectral mixture analysis, and spectral feature extraction are among those processing techniques, they are still in experimental stage and need further refinement until the fully operational adaptation. Geology and mineral exploration were major application in early stage of hyperspectral sensing because of the distinct spectral features of rock and minerals that could be easily observed with hyperspectral data. The applications of hyperspectral sensing have been expanding to vegetation, water resources, and military areas where the multispectral sensing was not very effective to extract necessary information.