Figure 2:

Overview of common HSI techniques: 3 different HSI set-ups are commonly used. Push broom cameras (yellow) are line scanners that are moved over the object or alternatively use a mirror; filter-based systems (green) scan single wavelengths according to the filters one after the other; and whisk broom cameras (blue) scan the full spectrum pixel by pixel. All set-ups result in a 3D hypercube (purple) showing 2 spatial axes and 1 spectral axis.