3S技术在水利工程中的应用-遥感.ppt

1、Remote Sensing遥 感,Remote Sensing Systems 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Remote Sensing Systems 1. Passive,Introduction Remote se

2、nsing systems use three different sources of radiation,Remote Sensing Systems 1. Passive,Introduction Remote sensing systems use three different sources of radiation Reflected solar radiation Emitted thermal or microwave radiation Artifical radiation A variety of instruments can be used to sample an

3、d measure this radiation These can be either passive (simply samples ambient EMR), or active (generates own artificial ERM),Remote Sensing Systems 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Remote Sensing Systems 1. Passive,Cameras Pass

4、ive system Device to focus EMR to form an image onto sensitive film Analogous to human eye,Remote Sensing Systems 1. Passive,Cameras Main system for aerial photography,Remote Sensing Systems 1. Passive,Cameras Also on manned orbital missions such as Space Shuttle,Remote Sensing Systems 1. Passive,Ca

5、meras Also on manned orbital missions such as Space Shuttle Cairo from the Space Shuttle,Remote Sensing Systems 1. Passive,Cameras Advantages Higher spatial resolution than other systems for any given altitude Disadvantages Retrieval of film in satellite missions is problematic,Remote Sensing System

6、s 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Remote Sensing Systems 1. Passive,Remote Sensing Systems 1. Passive,Scanning radiometers(扫描辐射仪） Passive system Produces digital images,Scanning radiometers Mirror scans across-track (swath),R

7、emote Sensing Systems 1. Passive,Scanning radiometers 2-D image formed by platform forward motion,Remote Sensing Systems 1. Passive,Scanning radiometers Multiple spectral bands sampled simultaneously,Remote Sensing Systems 1. Passive,Scanning radiometers Advantages Digital data can be telemetered to

8、 Earth Data are machine readable Data can be multispectral Disadvantages Limited spatial resolution Distortion and noise,Remote Sensing Systems 1. Passive,Scanning radiometers Examples Landsat Thematic Mapper Death Valley, California,Remote Sensing Systems 1. Passive,Scanning radiometers Examples NO

9、AA AVHRR （Advances Very High Resolution Radiometer) Scandinavia,Remote Sensing Systems 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Remote Sensing Systems 1. Passive,CCD arrays (线阵列推扫式扫描仪） Passive system Line or block of CCDs instead of s

10、canning mirror Senses entire swath (or block) simultaneously,Remote Sensing Systems 1. Passive,CCD arrays Advantages Small, low power, cheap Long life (no moving parts) High geometric/radiometric accuracy High spatial resolution Disadvantages Many detectors to calibrate Limited spectral range of CCD

11、s,Remote Sensing Systems 1. Passive,CCD arrays Examples SPOT,Remote Sensing Systems 1. Passive,CCD arrays Examples MOMS,Remote Sensing Systems 1. Passive,CCD arrays Examples IKONOS,Remote Sensing Systems 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy C

12、onclusions,Remote Sensing Systems 1. Passive,Imaging spectroscopy（成象分光计）,Complex optics and electronics,Imaging spectroscopy,Remote Sensing Systems 1. Passive,Imaging spectroscopy Many more narrow spectral bands (hyperspectral) Can resolve individual mineral absorptions Mostly used for geology or ve

13、getation health studies Mostly airborne systems, but experimental system (Hyperion) flown on EO-1 satellite mission,Remote Sensing Systems 1. Passive,Imaging spectroscopy Strengths Excellent for diagnostic mapping Sensitive to subtle spectral features Weaknesses Very large datasets Signal-to-noise（信

14、噪比） low on some systems,Remote Sensing Systems 1. Passive,Imaging spectroscopy Examples HyMap infrared image of Mt Fitton, South Australia,Remote Sensing Systems 1. Passive,Imaging spectroscopy Examples AVIRIS data of Jasper Ridge, California, displayed as a hyperspectral data cube,Remote Sensing Sy

15、stems 1. Passive,Imaging spectroscopy Examples Mineral map of Cuprite, Nevada, from AVIRIS hyperspectral data,Remote Sensing Systems 1. Passive,Structure Introduction Cameras Scanning radiometers CCD arrays Imaging spectroscopy Conclusions,Remote Sensing Systems 1. Passive,Conclusions Passive remote sensing systems measure ambient EMR They use optical systems (telescopes, prisms, mirrors et