IV - FROM DATA TO INFORMATION
Remote sensing data provide useful information to better understand our environment, make choices and act.
However, the raw data recorded by sensors are not immediately ready for use. They require several pre-processing steps to enhance and transform them before they can finally be analysed or classified to extract the necessary information.
1- PREPARE AN IMAGE FOR ANALYSIS (PRE-PROCESSING)
Before the actual analysis and extraction of information can take place, the acquired images must undergo preprocessing to correct various distortions and disruptions. During this calibration, specific methods are applied to correct:
- irregularities of the sensor or changes in exposure between images acquired at different times (radiometric corrections);
- interactions between the atmosphere and the energy reflected or emitted by the earth (atmospheric corrections);
- geometric distortions due to variations in satellite positioning, Earth rotation, oblique viewing angle, topography, etc. (geometric corrections).