Friday, August 12, 2016

CHARACTERISTICS OF SENSORS

CHARACTERISTICS OF SENSORS

The characteristics of sensors are:
  • Spatial resolution
  • Spectral resolution
  • Radiometric resolution &
  • Temporal resolution
Spatial resolution Spatial resolution describes how much detail in a photographic image is visible to the human eye. The ability to distinguish between small details is one way to describe spatial resolution. Spatial resolution of images obtained from satellites sensor systems is usually expressed in m. 

Spectral resolution EMR patterns are recorded by sensors with separated spectral bands. Spectral reflectance curves or spectral signatures of different types of ground targets provide a knowledge base for extracting information. Spectral responses from ground targets are recorded in separate spectral bands by sensors. Spectral resolution refers to the number of bands and the width of each band. 

Radiometric resolution Radiometric resolution refers to the 'colour depth'. Higher radiometric resolution implies higher sensitivity of the sensor to detect minute changes in electromagnetic energy (sensitivity of sensor to detect differences in reflected or emitted energy). 

Temporal resolution Temporal resolution refers to the time (day or season) of image acquisition. A temporal resolution is helpful in evaluating the change, impacts and severity of the damage, if any. An important aspect in this regard is the revisit period.