1. Digital Data Introduction to Remote Sensing Instructor: Dr. Cheng-Chien LiuCheng-Chien Liu Department of Earth Sciences National Cheng Kung University Last updated: 20 October 2004 Chapter 4

2. Outline  Introduction  Acquisition  Format  Storage  Display  Terminology

3. Introduction  Comparison between photographic and electronic imaging (Table 2.3) Electronic imaging  wider range  Higher exposure latitude Digital signal  storage, process, transmit, distribution, duplication Rapid turnaround time  Images are immediately available & computer-ready

4. Acquisition  Digital sensor AC  DC Gain Compression Transmission Storage Distribution Duplication

5. Format  Structure (Fig 4.12 in Campbell 2002) Raster format Vector format  Interleave (Fig 4.13 – 4.15 in Campbell 2002) Band interleaved by pixel (BIP) Band interleaved by line (BIL) Band sequential (BSQ)

6. Format (cont.)  Interchange bmp GIF (graphics interchange format) jpeg TIFF (tagged image file format)  Remote sensing HDF GeoTIFF jpeg2000

7. Format (cont.)  HDF (Hierarchical Data Format) Created by National Centre for Supercomputing Applications  NCSA HDF home page NCSA HDF home page Mission  Support for the types of data and metadata commonly used by scientists  Efficient storage of and access to large data sets  Platform independence  Extensibility for future enhancements and compatibility with other standard formats Documents and Tools Example  ASTER, MODIS, SeaWiFS, …

8. Format (cont.)  GeoTIFF Created by over 160 different remote sensing, GIS, cartographic, and surveying related companies and organizations TIFF based interchange format for georeferenced raster imagery Web Page Documents and Tools Example:  ROCSAT-2

9. Format (cont.)  JPEG2000 Created by the JPEG committee Based on wavelet technology Compress and transmit without any distortion or loss lossy image  clear image Web page

10. Storage  Unit Bit, Byte, Kilobyte, Megabyte, Gigabyte, Terabyte  Media CDROM/DVDROM Tape Disk array  Future media Super-resolution near field structure Quantum/biological storage

11. Display  Size  Radiometric resolution  Rendition of color

12. Terminology  Signal-to-noise ratio (S/N ratio) See Fig 4.9 in Campbell 2002  Full width half maximum (FWHM) e.g. linklink  Image cube e.g. linklink

13. Homework  Make a table to compare the difference among BMP, GIF, JPEG and TIFF format