Multi-spectral images are images of the same object (Earth or planetary surface), taken in different bands of visible or infrared region of electromagnetic continuum. This is the main type of images acquired by Remote sensing (RS) radiometers. Multi-spectral is the opposite of panchromatic. Usually satellites have 3 to 7 or more radiometers (France's SPOT has 3, Landsat has 7). Each one acquires one digital image (in remote sensing, called a scene) in a small band of visible spectra, ranging 0.7 μm to 0.4 μm, called red-green-blue (RGB) region, and going to infra-red wavelengths of 0.7 μm to 10 or more μm, classified as NIR-Near InfraRed, MIR-Midle InfraRed and FIR-Far InfraRed or Thermal. In the Landsat case there are 7 scenes comprising a 7 band multi spectral image.

Imaging | Cartography | Geology | Imagem multiespectral