As a multi- spectral image data sets are referred to in the remote sensing, which are composed of several spectral bands. The recording is made with so-called multispectral cameras.
Thus multispectral contain information about reflected or emitted electromagnetic radiation of different wavelengths. The simplest example of multi-spectral data is a digital color photograph which contains information of red, green and blue light. The term multi-spectral camera but is used primarily for sensors that green, absorb red and near infrared light for research purposes. These remote sensing data can also contain medium infrared, and some thermal infrared wavelengths.
Examples of remote sensing satellites with multispectral sensors are Landsat, Spot and ASTER. Best known is the German-speaking developed in the GDR camera MKF 6; Other examples are the HRSC and the WAOSS.
Sensors that have very many close and continuous spectral channels are referred to as hyperspectral sensors; those who receive only light of a single wavelength range, depending on the width of the region as a mono-or panchromatic.
Scientific and commercial applications
Based on the comparison with the conventional digital photography increased number of spectral channels arise from, among other things, in professional photography a number of application fields for Multispectral. If the spectral channels arranged in a suitable manner in the visible range of the electromagnetic spectrum, as can be derived from the sensor signals, the spectra of the recorded objects mathematically reconstructed. This is a great advantage over the conventional digital photography, which is only three channels available. From the spectra known in each pixel the appearance of the captured object can be calculated under any type of light with very high accuracy. Due to their color fastness multispectral imaging technique, which is significantly superior to conventional digital photography.
In astrophotography color photographs are increasingly being replaced by multi-spectral images, which are obtained by superposition of filtered images of the sky in 3-4 color areas.