A method of extending the capabilities of multispectral interference-filter cameras for planetary exploration and similar applications

The capabilities and benefits of hyperspectral imaging in remote sensing applications are well established and routinely exploited in terrestrial imaging applications. However the restrictions imposed on mass and power consumption and the extreme operating conditions encountered on other planets have limited its widespread use in planetary exploration robots. Instead multispectral camera systems using a small number of optical filters (typically 10-12) are employed, providing only coarse spectral information. By exploiting the properties of interference filters at non normal angles of incidence it is possible to obtain additional spectral information using established multispectral filter wheel camera technology. This additional information can help in identification of mineralogical species present by inferring the existence of spectral features missed between filter wavelengths. Examples of the implementation and capabilities are presented using simulated data for the PanCam instrument under development for the ESA / NASA ExoMars 2018 mission. By extension of the technique and with recent advances in interference filter technology it is possible to develop a simple and lightweight hyperspectral wide angle camera employing a filter wheel. The theory of operation and early test results from a prototype camera system are presented.