Spectral signature

The spectral signature of an object is a function of the incidental EM wavelength and material interaction with that section of the electromagnetic spectrum.

The measurements can be made with various instruments, including a task specific spectrometer, although the most common method is separation of the red, green, blue and near infrared portion of the EM spectrum as acquired by digital cameras.

Calibrating spectral signatures under specific illumination are collected in order to apply a correction to airborne or satellite imagery digital images.

The user sees specific lines of colour falling on a graduated scale.

As a last step, they assign a class to each group (classification) by comparing with known spectral signatures.