A low cost digital camera as thermal camera for volcanic applications

The lava temperature is an important characteristic quantity of a volcano. It is closely linked with the composition of the magma and the volcanic activity. It also partly affects the composition of volcanic gases, which are of great interest because of their influence on short therm atmospheric processes and climate. Thus, measurements of the temperature of lava are important for many volcanic studies. Most of the commercially available thermal cameras, which work in the relevant temperature range of about 600 to 1100°C, are rather expensive. This study shows, that with alternative approaches, that are based on the sensitivity of the silicon based sensors of consumer digital cameras in the near-infrared (up to about 1100 nm), temperatures of ca. 500°C and higher can be measured. In this thesis a compact digital consumer camera is used for the measurement of the temperature distribution of lava with high spatial resolution (16 MP). The camera was modified to block the visible spectrum and the characteristics of the remaining color filter (Bayer filter) are used to infer temperature from differential intensities. To do so a calibration with a heating wire is performed within the temperature range of 600 to 1100°C, which demonstrated the feasibility of temperature measurements with sufficient accuracy. Besides the low costs, superior mobility and simple handling, the high spatial resolution allows for temperature measurements even in highly dynamic situations