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Remotesensing 20091205 (student preso)

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general physics
5 dec 2009

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Remotesensing 20091205 (student preso)

  1. 1. REMOTE SENSING: X-ray ,CT-Scan, Voxels<br />Group 2<br />Rishab, <br />Wattsuwach<br />
  2. 2. X-ray Tube<br />
  3. 3. Modern X-ray tube<br />
  4. 4.
  5. 5. The size of the aperture, produced by overlapping metal plates, through which the X-ray beam passes after leaving the tube<br />
  6. 6. The use of a lead grid in front of the photographic film to absorb scattered X-ray photons<br />
  7. 7. The variation with thickness x of an absorber of the percentage transmission of a parallel beam of X-ray<br />radiation is illustrated<br />
  8. 8. “Voxel”<br />
  9. 9. Principles<br />One area must have a difference in density.<br />Computers can collect the information(density) to create a 3-D picture<br />Pixel is a unit that tell you how much its dots per inch<br />Target material<br />
  10. 10. Reconstruction of Voxels<br />1<br />4<br />7<br />2<br />
  11. 11. 5<br />+<br /><br />9<br />+<br /><br />1<br />4<br />7<br />2<br />5<br />5<br />5<br />9<br />9<br />9<br />
  12. 12. 1<br />4<br />45°<br /><br />+<br />1<br />7<br />2<br /><br /><br />11<br />2<br />
  13. 13. 1<br />11<br />2<br />+<br />5<br />5<br /><br />9<br />9<br />6<br />16<br />11<br />20<br />
  14. 14. 6<br />8<br />6<br />16<br />1<br />4<br />11<br />20<br />+<br />+<br /><br />7<br />2<br /><br /><br />14<br />22<br />8<br />6<br />17<br />28<br />
  15. 15. 4<br />3<br />7<br />+<br />4<br />1<br />4<br />14<br />22<br />3<br />17<br />28<br />7<br />7<br />2<br /><br />17<br />26<br />20<br />35<br />
  16. 16. Divide <br />by 3<br />17<br />3<br />Deduct 14<br />26<br />12<br />1<br />4<br /><br /><br />20<br />35<br />6<br />21<br />2<br />7<br />Reconstruction of each pixel require millions of computations<br />7<br />4<br />= 14<br />+<br />+<br />3<br />The 3-D image can be constructed through storing all the reconstructed pixel on the memory.<br />Background Radiation<br />
  17. 17. Comparison<br />Old technologies<br />X-ray film transparency<br />Ultrasound<br />Its application<br />CT scan<br />Used in medical work<br />Used in the airport (destructive objects)<br />
  18. 18. Ultrasound<br />Disadvantages<br /><ul><li>Requires a coupling medium
  19. 19. 2-D and it’s not consistent</li></ul>Processes<br />
  20. 20. Examples<br />
  21. 21. Reference<br />A Level Science Applications<br />Support Booklet: Physics (University of Cambridge)<br />http://www.nlm.nih.gov/medlineplus/ency/article/003330.htm<br />http://www.radiologyinfo.org/en/info.cfm?PG=bodyct<br />http://www.emedicinehealth.com/ct_scan/article_em.htm<br />
  22. 22. Task<br />Rishab<br />Reconstruction of Voxel<br />Slide preparation<br />Watsuwach<br />Principles of X-ray <br />Applications and comparisons<br />Ultrasound<br />

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