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Mapping From Space
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Automatic Database Development Methods for a very Large Number of Satellite Images
2.2.1 Proposed Resampling Method
step 1. Represent the shapes of footprint of Pixels on a given coordinate system
By projecting pixel boundaries or four corners on the images plane onto the ground coordinate system where the grid cells are generated, the relationship between pixel and grid can be exactly/explicitly represented. (see fig 6)
Fig.6 Relationship between pixel and grid
Step 2. Representing footprint by combination of linear features
Pixel boundaries and line boundaries can be approximated by line segments with the same intervals. This enables processing very fast computation of intersection points with grid cell boundaries ( see fig 7).
Fig 7 Step2
2.2.2 Practice and Evaluations of this Model Practice :
We applied this method for overlaying the NOAA and TM data. See Fig .8.
Fig 8. Overlay TM and NOAA
Time Evaluation for Resampling
Fig shows the result of time for resampling. With the proposed method, computing time depends on the grid cell numbers, whereas, with the traditional method computing time are proportional to the squared number of the grid cells. That means, we can save the time for resampling larger size of images with this method.
Fig 9. Time Cost Evaluation for resampling
Conclusion
so , to integrate many varieties of and huge image/ raster data, we developed two methods of automatically managing image /raster database system.
- semi-automated geometric correction method for satellite images.
With this method, we can geo-code so many images semi-automatically
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Resampling method with high accuracy and high speed
We can save time for resampling while keeping high accuracy
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W.F.Webber, " Techniques for Images registration " Proceedings of the IEEE Conference on Machine Processing or Remotely Sensed Data ,pp.1B-1 B-7, October 1973.
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C.D.McGillen and M.Svedlow, " Digital Image Processing for Remote Sensing ", IEEE press, pp 168-173, 1978
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Keisuke Katsuta , " Block Adjustment of Stero Satellite Imagery" , Proceedings of the 15 th Asian Conference on Remote Sensing, pp : F-4-1-F-4-6, vol .1, 1994
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Koki Iwao, Ryosuke Shibasaki , " Semi-automated geometric correction for Mosaicking large number of satellite data " . Proceeding of the 17 the Asian Conference on Remote Sensing, pp. F-8-1-F-8-5.
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Taizo yamanoto, Ryosuke Shibasake, " Comparative study on Image Data Model for Integrating Multiple Resolution Image /Raster Data", Proceddings of the 18 the Asian Conference on Remote Sensing, pp. Q-4-1-Q-4-6, 1997.
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