Dissertation in the field of Measurement Science and Technology, Maksim Shpak
”Applications of Radiometric Measurements in Non-Contact Thermometry and Mesopic Photometry”.
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Optical measurement of temperature is a widely use method, which relies on studying the radiation emitted by the measured object. In the thesis, this method is applied to measure the temperatures of microscopic light emitters. The emitters were about 400 µm long and 25 µm wide silicon filaments that shine visibly when heated with electrical current. The main measurement challenge was the determination of emissivity of the objects, which was solved by measuring optical parameters of materials and by constructing a model for the spectral emissivity. Microscopic wideband light emitters can be used, for example, in the spectroscopic sensors.
Photometry is a field of metrology that deals with measurement of light in accordance with human vision. Although typically only cone cell responsivity curve is used in practical measurements, corresponding to the so called day vision, in reality the eye adapts to lower light levels by using both cone and rod cells. The dusk region between daylight and dark is called mesopic vision, and it’s an important measurement range, for example, for traffic safety. This work presents a new type of a two-channel photometer, that was developed and characterized for measurements in the mesopic range. Additionally, the mathematical model for calculation of mesopic quantities, published by the International Commission on Illumination (CIE), was studied for its suitability in all theoretical lighting conditions. Two problematic areas were identified at the edges of the mesopic range, and a solution was presented in the form of parameterized equations that offer a continuous response.
Opponents: Dr. Mohamed Sadli, Laboratoire commun de métrologie LNE-Cnam, France ja Dr. Yoshi Ohno, National Institute of Standards and Technology, USA
Supervisor: Professor Erkki Ikonen, Aalto University School of Electrical Engineering, Department of Signal Processing and Acoustics
Contact information:
Maksim Shpak
p. 050 4155976
maksim.shpak@vtt.fi