An investigation of the spectral and radiometric characteristics of low-cost digital cameras for use in UAV remote sensing

The foundation of all quantitative remote sensing is based on the ability of sensors to convert energy into digital signals. This process requires an understanding of the radiometric and spectral behaviour of the instrument. This information is rarely available for the consumer-grade digital cameras commonly used in unmanned aerial vehicle (UAV) systems. This study measured the spectral and radiometric characteristics of consumer-grade digital cameras in laboratory-based experiments. The spectral characteristics showed broad overlapping spectral bands in the visible and near-infrared wavelengths with spectral band widths between 70 and 100 nm. The radiometric response functions were non-linear in nature. The nonlinearity resulted in the inability of reliable spectral reflectance calculations. When compared to the spectral reflectance values computed from an ASD FieldSpec-3, differences were as high as 42% from the true value with average deviations between 23% and 32%. When characterized, the spectral reflectance values compared more favourably to ASD-computed spectral reflectance.