Chapter 5 Digital Image Processing


5-1 Flow of Digital Image Processing

Digital image processing is required for the following cases in GIS.

- Integration of remote sensing and GIS, particularly with satellite imagery of Landsat, SPOT, JERS-1, ERS-1, Radarsat, IRS
   etc.
- Automated digitization from rasterized map data using scanners
- Computer mapping with color output in raster format
- Visualization in three dimensional bird’s eye view
- Editing of image database

Digital image processing includes the following procedures, as shown in Figure 5.1.

Image input: to acquire digital image data by scanning analog films or maps. Satellite imagery is provided in computer compatible tape (CCT) or CD-ROM.

Preprocessing: two procedures of radiometric correction and geometric correction are required.

Image Transformation: two procedures of image enhancement and feature extraction will be implemented depending on the specific purposes as shown in Figure 5.2

Classification: thematic maps such as land cover/land use, soil, forest, geology etc. will be produced.

Image output: two products of analog image out put and digital image database will be the result of digital image processing.