Evaluation of a lightweigth UAS-prototype for hyperspectral imaging. K. Nackaerts a , B. Delauré a , J. Everaerts a ,B. Michiels a , C. Holmlund b , J. Mäkynen b , H. Saari b a Flemish Institute for Technological Research - VITO, Boeretang 200, BE-2400 Mol, Belgium b Technical Research Centre of Finland - VTT, P.O. Box 1000, FI-02044 VTT, Finland ICWG I/V KEY WORDS: hyperspectral imaging, Fabry-Perot, rotorcraft, mapping, light-weight UAS ABSTRACT: Recent developments in the area of miniaturisation have boosted the development of a wide range of Unmanned Aerial Systems (UAS). In terms of hyperspectral imaging, no appropriate sensors are available for light weight UAS. Available sensors are in general too heavy, produce an overload on data, and are mainly 1D line sensors. Given the attitude instability of a light weight UAV in com- bination with inferior miniaturized attitude sensors, accurate image reconstruction becomes an exceptional challenge for such line sensors mounted on a UAS. The first trials with a novel UAS equipped with an hyperspectral frame imager are presented. The imager was integrated and operat- ed on a six-rotor rotorcraft type UAV of VITO, the Flemisch Institute for Technological Research. This system provides an answer to the above mentioned issues: two dimensional imaging, low weight and with user definable (application specific) spectral sensitivity. The hyperspectral imager was developed by VTT Technical Research Centre of Finland and is based on the Piezo actuated Fabry- Perot Interferometer to enable recording of 2D spatial images at the selected wavelength bands simultaneously and to reduce the size of the hyperspectral spectrometer to be compatible with light weight UAV platforms. The prototype is capable of recording 2D im- ages within the range of 400 – 1100 nm at a spectral resolution of 5 – 10 nm @ FWHM. The full sensor system (sensor, storage, bat- tery and triggering) weighted less than 500 grams. The results and key issues for improvement for different aspects of the UAS will be presented during the symposium. 1. INTRODUCTION One of the main challenges for small low altitude Unmanned Aerial Systems hereby is the development, testing and calibra- tion of suitable sensors that provide information of interest to the end user. Weight and power consumption are the most limit- ing factor and put new constraints on sensor development. The potential of available technology is surfacing on a regular basis. Aerial imaging is feasible today by means of standard digital consumer camera’s. Grenzdörffer et al. (2008) describes the po- tential of low cost UAVs equipped with such cameras for pho- togrammetric applications. Eisenbeiss et al. (2008) and Lambers et al. (2007) complemented photogrammetry based on a stan- dard DSLR camera successfully. This work has been continued by Eisenbeiss et al. (2008) and tested to create an accurate 3D reconstruction of an historical building illustrating the technol- ogy’s full potential for very high resolution applications. Ma- cArthur et al. (2006) use an industrial mini stereo RGB vision system to map citrus yields. The results were promising, but a higher spectral resolution was necessary. When adding narrow bandwidth optical filters to a digital cam- era, multispectral imaging becomes available, allowing to ex- tract specific surface properties of interest. This can be per- formed by using consumer or industrial cameras as used by Chao et al. (2008) in a research project to study the feasibility of a UVS for real-time water management and irrigation con- trol. Nebiker et al. (2008) demonstrate the use of industrial smart cameras for multispectral imaging. A more dedicated sys- tem –a combination of multiple CMOS cameras in a fixed frame setup with exchangeable filters- was used by Suarez et al. (2009) for crop monitoring. This work demonstrate that results obtained with a low-cost UAS for agricultural applications yielded comparable estimations than those obtained by tradi- International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XXXVIII, Part 5 Commission V Symposium, Newcastle upon Tyne, UK. 2010 478