Articles | Volume 15, issue 2
https://doi.org/10.5194/jsss-15-155-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/jsss-15-155-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
High-resolution characterization of the size-of-source effect via a continuously variable aperture
Miguel-David Mendez-Bohorquez
CORRESPONDING AUTHOR
Measurement and Control Research Group, University of Kassel, Mönchebergstraße 7, 34125 Kassel, Germany
Robert Schmoll
Measurement and Control Research Group, University of Kassel, Mönchebergstraße 7, 34125 Kassel, Germany
Andreas Kroll
Measurement and Control Research Group, University of Kassel, Mönchebergstraße 7, 34125 Kassel, Germany
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During the geometric calibration of infrared cameras, the parameters that describe where object points are mapped onto thermal images are determined. The required reference data is obtained by capturing so-called calibration targets. In established approaches, it is difficult to estimate the lens distortions precisely. A newly developed target and its evaluation algorithm make it possible to increase the sensitivity of the calibration by finding reference points close to image borders.
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Short summary
The size-of-source effect (SSE) is a systematic error requiring slow labor-intensive measurements. We propose a continuous approach using an iris diaphragm. Our method matched the accuracy of the traditional discrete method while providing more data and a reduction in measurement time. The method has no significant sensitivity to frame rate changes. Transient responses were observed using a neutral density filter, raising questions on how to measure and correct SSE in such configurations.
The size-of-source effect (SSE) is a systematic error requiring slow labor-intensive...
Special issue