Stefan Schwarzer


Limits to calibration: Engineers against nature's stubbornness

Calibration is, by definition, the act of comparison of the indications of an instrument to corresponding quantity values as provided by measurement standards under specified conditions. Surprise and progress in instrument design lurk in the often underestimated adverbial  phrase »specified conditions« which supposedly guarantees the repeatability of the measurement process. In fact, what is described as  calibration in this definition could also serve in turn as the definition of a quantitative physical experiment. In this sense, complex instruments are »experiments« which constantly push our understanding to higher levels and finer details, and where we finally encounter the fundamental limitations to our measurement procedure. I will take you on a short journey through the calibration of (a) laser based distance measurement device(s) and let you know where specifications need to be taken with a grain of salt.

Curriculum Vitae

The author has studied statistical physics, fluid- and thermodynamis at Hamburg and Boston University and graduated with a Ph.D. in Theoretical Physics in Boston 1993. Since then he has collected work experience in modeling chemical engineering problems and teaching (Paris, Stuttgart), building large atmospheric Doppler radars and sodars (sound radar) for meteorological research (Tübingen). He joined Fraunhofer IPM in 2006 and has since then taken part in the development of several laser scanner devices, learning about challenges, possibilities and fundamental limits in the process.