Multispectral cameras, which are divided into linear and matrix cameras, provide images that allow us to see beyond the visible range. They mainly exploit two technologies: the first uses a prism, placed immediately after the optic, which separates the components of different wavelengths and directs them towards independent sensors. The second technology uses Bandpass Filters equipped sensors, which permit to collect only the information relating to certain spectral bands. The returned image is therefore composed of the contents of all the sensors. The main difference between the Multispectral and the Hyperspectal images is represented by the number and width of the bands shown in the graph. In this way the Hyperspectral images allow us to obtain a large amount of useful and accurate information, such as the Spectral Signature, which uniquely identifies a material. This feature is also used in the Chemical Color Imaging (CCI), in which the chemical properties of interest become easily recognizable as represented in different colors. All this allows, for example during an inspection, to identify unwanted contamination. Other fields of application of the Multispectral and Hyperspectral images include the forensic sciences, the food industry, the pharmaceutical industry and waste collection, treatment and disposal activities.
CCI image of different materials (left) with their spectral bands (right)