Remote sensing [compatibility mode]

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Remote sensing [compatibility mode]

  1. 1. Introduction to Remote Sensing Prof. Sumanta Das Dept. of civil Engg. Engg. MEFGI, Rajkot Image: NASA 2005
  2. 2. Outline       Remote Sensing Defined Resolution Electromagnetic Energy (EMR) Types Interpretation Applications ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  3. 3. Remote Sensing Defined  Remote Sensing is:  “The art and science of obtaining information about an object without being in direct contact with the object” (Jensen 2000).  There is a medium of transmission involved. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  4. 4. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  5. 5. Remote Sensing Defined  Environmental Remote Sensing:  … the collection of information about Earth surfaces and phenomena using sensors not in physical contact with the surfaces and phenomena of interest.  We will focus on data collected from an overhead perspective via transmission of electromagnetic radiation. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  6. 6. ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Source: Jensen (2000)
  7. 7. Remote Sensing Defined  Remote Sensing Includes:  A) The mission plan and choice of sensors;  B) The reception, recording, and processing of the signal data; and  C) The analysis of the resultant data. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  8. 8.  Types of Remote Sensing:Sensing:Based on Range of Electromagnetic Spectrum:Spectrum:1. Optical Remote Sensing. 2. Thermal Remote Sensing.  3. Microwave Remote Sensing.  Based on the source of the energy:energy:Active remote sensing. Passive remote sensing. 1. 2.
  9. 9.  Based on Range of Electro magnetic Spectrum:Spectrum:   Optical Remote Sensing:Sensing:The optical remote sensing devices operate in the visible, near infrared, middle infrared and short wave infrared portion of the electromagnetic spectrum. These devices are sensitive to the wavelengths ranging from 300 nm to 3000 nm.
  10. 10.  Thermal Remote Sensing:Sensing: The sensors, which operate in thermal range of electromagnetic spectrum record, the energy emitted from the earth features in the wavelength range of 3000 nm to 5000 nm and 8000 nm to 14000 nm.
  11. 11.  Microwave Remote Sensing:Sensing: A microwave remote sensor records the backscattered microwaves in the wavelength range of 1 mm to 1 m of electromagnetic spectrum.  Most of the microwave sensors are active sensors, having there own sources of energy.
  12. 12. Depending on the source of the energy:energy:      Active remote sensing:sensing:Active remote sensing uses an artificial source for energy. For example the satellite itself can send a pulse of energy which can interact with the target. In active remote sensing, humans can control the nature (wavelength, power, duration) of the source energy. Active remote sensing can be carried out during day and night and in all weather conditions. ExampleExample- RADAR
  13. 13.  Passive remote sensing:sensing: Passive remote sensing depends on a natural source to provide energy.  The sun is the most powerful and commonly used source of energy for passive remote sensing.  The satellite sensor in this case records primarily the radiation that is reflected from the target.
  14. 14. Fig. active & passive remote sensing.
  15. 15. Remote Sensing Process Components Energy Source or Illumination (A) Radiation and the Atmosphere (B) Interaction with the Target (C) Recording of Energy by the Sensor (D) Transmission, Reception, and Processing (E) Interpretation and Analysis (F) Source: Canadian Centre for Remote Sensing ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Application (G)
  16. 16. EM energy interaction of earth surface:
  17. 17.  Advantages of remote sensing:sensing:      Provides a regional view (large areas). Provides repetitive looks at the same area. Remote sensors "see" over a broader. portion of the spectrum than the human eye. Provides geo-referenced, digital, data. geoSome remote sensors operate in all seasons, at night, and in bad weather. Give information of inaccessible area.
  18. 18.  DISADVANTAGE OF REMOTE SENSING:SENSING:• Expensive to build and operate. • Measurement uncertainty can be large. • Data interpretation can be difficult.
  19. 19.  Applications of Remote Sensing:Sensing:      Agriculture:Agriculture:Crop type classification. Crop condition assessment. Crop yield estimation. Mapping of soil characteristic. Soil moisture estimation.
  20. 20.         Geology:Geology:Lithological mapping. Mineral exploration. Environmental geology. Sedimentation mapping and monitoring. GeoGeo-hazard mapping. Glacier mapping. Hydrocarbon exploration and mine exploration
  21. 21.      Urban Planning:Planning:Land parcel mapping. Infrastructure mapping. Land use change detection. Future urban expansion planning.
  22. 22.          Hydrology:Hydrology:Watershed mapping and management. Flood delineation and mapping. Ground water targeting. Land Use/Land Cover mapping:mapping:Natural resource management. Wildlife protection. Encroachment. LULC change detection & analysis
  23. 23.         Ocean applications:applications:Storm forecasting. Water quality monitoring. Aquaculture inventory and monitoring. Navigation routing. Coastal vegetation mapping. Oil spill. Coastal hazard monitoring & assessment.
  24. 24.        Civil Engineering:Engineering:Building construction(ICONOS,LIDAR) City and Town planning & development Surveying Ground water exploration and mapping Site investigation Land information system(LIS)
  25. 25. Resolution  All remote sensing systems have four types of resolution:  Spatial  Spectral  Temporal  Radiometric ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  26. 26. Spatial Resolution High vs. Low? ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Source: Jensen (2000)
  27. 27. Spectral Resolution ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Source: Jensen (2000)
  28. 28. Temporal Resolution July 2 July 18 August 3 16 days Time 11 days July 1 ND GIS Users Workshop Bismarck, ND October 24-26, 242005 July 12 July 23 August 3
  29. 29. Radiometric Resolution 6-bit range 0 63 8-bit range 0 255 10-bit range 0 1023 ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  30. 30. Electromagnetic Radiation ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  31. 31. Electromagnetic Spectrum ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  32. 32. Signature Spectra ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  33. 33. RS Data- AVHRR (Advanced Very DataHigh Resolution Radiometer) NASA ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  34. 34. GOES (Geostationary Operational Environmental Satellites) IR 4 ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  35. 35. MODIS (250 m) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  36. 36. Landsat TM (False Color Composite) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  37. 37. SPOT (2.5 m) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  38. 38. QUICKBIRD (0.6 m) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  39. 39. IKONOS (4 m Multispectral) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  40. 40. IKONOS (1 m Panchromatic) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  41. 41. RADAR (Radio Detection and Ranging) Image: NASA 2005 ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  42. 42. LIDAR (Light Detection and Ranging) Image: Bainbridge Island, WA courtesy Pudget Sound LIDAR Consortium, 2005
  43. 43. Elements of Image Interpretation  Shape:  Many natural and human-made features have humanunique shapes.  Often used are adjectives like linear, curvilinear, circular, elliptical, radial, square, rectangular, triangular, hexagonal, star, elongated, and amorphous. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  44. 44. Shape Jensen (2000) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  45. 45. Elements of Image Interpretation  Shadow:  Shadow reduction is of concern in remote sensing because shadows tend to obscure objects that might otherwise be detected.  However, the shadow cast by an object may be the only real clue to its identity.  Shadows can also provide information on the height of an object either qualitatively or quantitatively. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  46. 46. Shadow Jensen (2000) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  47. 47. Elements of Image Interpretation  Tone and Color:  A band of EMR recorded by a remote sensing instrument can be displayed on an image in shades of gray ranging from black to white.  These shades are called “tones”, and can be qualitatively referred to as dark, light, or intermediate (humans can see 40-50 tones). 40-  Tone is related to the amount of light reflected from the scene in a specific wavelength interval (band). ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  48. 48. Tone and Color Jensen (2000) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  49. 49. Elements of Image Interpretation  Texture:  Texture refers to the arrangement of tone or color in an image.  Useful because Earth features that exhibit similar tones often exhibit different textures.  Adjectives include smooth (uniform, homogeneous), intermediate, and rough (coarse, heterogeneous). ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  50. 50. Texture ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Jensen (2000)
  51. 51. Elements of Image Interpretation  Pattern:  Pattern is the spatial arrangement of objects on the landscape.  General descriptions include random and systematic; natural and human-made. human-  More specific descriptions include circular, oval, curvilinear, linear, radiating, rectangular, etc. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  52. 52. Pattern ND GIS Users Workshop Bismarck, ND October 24-26, 242005 Jensen (2000)
  53. 53. Elements of Image Interpretation  Height and Depth:  As discussed, shadows can often offer clues to the height of objects.  In turn, relative heights can be used to interpret objects.  In a similar fashion, relative depths can often be interpreted.  Descriptions include tall, intermediate, and short; deep, intermediate, and shallow. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  54. 54. Height and Depth ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  55. 55. Elements of Image Interpretation  Association:  This is very important when trying to interpret an object or activity. Association refers to the fact that certain features and activities are almost always related to the presence of certain other features and activities. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  56. 56. Association Jensen (2000) ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  57. 57. Digital Image processing    1. 2. 3. Correction of data Digital enhancement for the purpose of better visual interpretation. It involves three basic steps: Image preprocessing Image processing Post processing & transformation ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  58. 58. Why do we need image processing? o o o Improvement of pictorial information for human perception Image processing for autonomous machine application Efficient storage and transmission ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  59. 59. Color Image Processing Wavelet & multiresolution processing Compression Image Restoration Image Filtering & Enhancement Image Acquisition Morphological Processing Segmentation Knowledge base Representation & Description Object Recognition
  60. 60. Image preprocessing   Geometric correction Radiometric correction ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  61. 61. Geometric correction  Geometric corrections are made to correct the inaccuracy between the location coordinates of the picture elements in the image data, and the actual location coordinates on the ground. Several types of ground. geometric corrections include system, precision, and terrain corrections. corrections.
  62. 62. Radiometric correction  Radiometric corrections are made to the raw digital image data to correct for brightness values, of the object on the ground, that have been distorted because of sensor calibration or sensor malfunction problems. The problems. distortion of images is caused by the scattering of reflected electromagnetic light energy due to a constantly changing atmosphere. This is one source of atmosphere. sensor calibration error. error. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  63. 63. Image processing   Enhancing an image or extracting information or features from an image Computerized routines for information extraction (eg, pattern recognition, (eg, classification) from remotely sensed images to obtain categories of information about specific features. ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  64. 64.  Spatial filtering  Image quality and statistical evaluation Image contrast enhancement and sharpening Image classification     Pixel based ObjectObject-oriented based ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  65. 65. Post processing & transformation    Accuracy assessment of classification PostPost-classification and GIS Change detection ND GIS Users Workshop Bismarck, ND October 24-26, 242005
  66. 66. Clouds in ETM+
  67. 67. Striping Noise and Removal CPCA Combined Principle Component Analysis Xie et al. 2004
  68. 68. Speckle Noise and Removal Blurred objects and boundary G-MAP Gamma Maximum A Posteriori Filter
  69. 69. ND GIS Users Workshop Bismarck, ND October 24-26, 242005

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