Marine remote sensing toolkit

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BRG The University of Queensland
Fundamentals

- Main page
- Pre-processing
- Field data collection
- Mapping approaches
- Change and trends
  - About
  - Image requirements
  - Mapping change
  - Trend detection
  - Example time series
  - Example change maps
- Delivery

# Image requirements

For a bi-temporal or multi-date image series to be subjected to change detection and time series analysis requires that the data area subject to:

### Geometric

- Spatial resolution
  - Pixel size must be the same
  - If not, apply re-sampling algorithm if not (to largest common pixel size)
- Spatial registration between images
  - R.M.S.E. between each image must be < 0.5 pixel
  - Mis-registration will produce "false" change signals
- Images must have the same datum, projection and coordinates
- Image acquisition look angles must be the same

### Spectral

- Ensure spectral band-widths and band-centres between dates match

### Radiometric

- Ensure sensor quantisation between dates is identical
- Work with calibrated and corrected image data (radiance, reflectance)
- Ensure processing history of the data is known TEMPORAL
- Solar geometry needs to match
- Fully calibrated and corrected data to remove these effects (illumination, viewing & slope geometry)
- Variations in environmental conditions unable to be corrected for:

- atmospheric
- water bodies
- vegetation
- urban areas

If mis-registration and radiometric errors between images are reduced then change detection can be successful and is then depending on the quality of the individual mapping approach of a specific environmental parameter.