Digital DataDigital Data

Introduction to Remote SensingInstructor: Dr. Cheng-Chien Liu

Department of Earth Sciences

National Cheng Kung University

Last updated: 20 October 2004

Chapter 4Chapter 4

OutlineOutline

IntroductionIntroduction AcquisitionAcquisition FormatFormat StorageStorage DisplayDisplay TerminologyTerminology

IntroductionIntroduction

Comparison between photographic and Comparison between photographic and electronic imaging (Table 2.3)electronic imaging (Table 2.3)• Electronic imaging wider range

Higher exposure latitude

• Digital signal storage, process, transmit, distribution, duplication

• Rapid turnaround timeImages are immediately available & computer-ready

AcquisitionAcquisition

Digital sensorDigital sensor• AC DC

• Gain

• Compression

• Transmission

• Storage

• Distribution

• Duplication

FormatFormat

Structure (Fig 4.12 in Campbell 2002)Structure (Fig 4.12 in Campbell 2002)• Raster format

• Vector format

Interleave Interleave (Fig 4.13 – 4.15 in Campbell (Fig 4.13 – 4.15 in Campbell 2002)2002)• Band interleaved by pixel (BIP)

• Band interleaved by line (BIL)

• Band sequential (BSQ)

Format (cont.)Format (cont.)

InterchangeInterchange• bmp• GIF (graphics interchange format)• jpeg• TIFF (tagged image file format)

Remote sensingRemote sensing• HDF• GeoTIFF• jpeg2000

Format (cont.)Format (cont.)

HDF (HDF (Hierarchical Data Format)Hierarchical Data Format)• Created by National Centre for Supercomputing

ApplicationsNCSA HDF home page

• MissionSupport 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, …

Format (cont.)Format (cont.)

GeoTIFFGeoTIFF• 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

Format (cont.)Format (cont.)

JPEG2000JPEG2000• Created by the JPEG committee

• Based on wavelet technology

• Compress and transmit without any distortion or loss

• lossy image clear image

• Web page

StorageStorage

UnitUnit• Bit, Byte, Kilobyte, Megabyte, Gigabyte, Terabyte

MediaMedia• CDROM/DVDROM• Tape• Disk array

Future mediaFuture media• Super-resolution near field structure• Quantum/biological storage

DisplayDisplay

SizeSize Radiometric resolutionRadiometric resolution Rendition of colorRendition of color

TerminologyTerminology

Signal-to-noise ratio (S/N ratio)Signal-to-noise ratio (S/N ratio)• See Fig 4.9 in Campbell 2002

Full width half maximum (FWHM)Full width half maximum (FWHM)• e.g. link

Image cubeImage cube• e.g. link

HomeworkHomework

Make a table to compare the difference Make a table to compare the difference among BMP, GIF, JPEG and TIFF among BMP, GIF, JPEG and TIFF formatformat