Mr. Christofer R. Siemens Profile

Christofer R. Siemens

at HENSOLDT Optronics GmbH

SPIE Involvement:

Author

Area of Expertise:

Optical Metrology , Laser Communication , Cryogenic Optics , IR Imagers

Publications (6)

Proceedings Article | 27 May 2022 Presentation + Paper

Assembly and qualification of cryogenic infrared relay optics

Christofer Siemens, Martin Hinz, Torsten Gross, Nicolas Ummen, Anke Vogelgsang, Marcus Zimmermann, Torsten Antrack, Dirk Jahn

Proceedings Volume 12103, 121030G (2022) https://doi.org/10.1117/12.2620999

KEYWORDS: Interfaces, Optical testing, Data modeling, Relays, Cryogenics, Ocean optics, Infrared radiation

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Proceedings Article | 18 May 2020 Paper

Design and testing of cryogenic infrared relay optics

Christofer Siemens, Torsten Gross, Martin Hinz, Manfred Uebele, Lukas Kress, Denis Lober, Nicolas Ummen, Dirk Jahn, Hans Becker

Proceedings Volume 11388, 113880N (2020) https://doi.org/10.1117/12.2558819

KEYWORDS: Relays, Infrared imaging, Cryogenic lens design, Infrared lenses, Optical mounts, Testing and analysis

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Proceedings Article | 6 September 2019 Presentation + Paper

Airborne optical communication terminal: first successful link from Tenerife to the GEO Alphasat

Hubertus Haan, Christofer Siemens

Proceedings Volume 11133, 1113306 (2019) https://doi.org/10.1117/12.2529223

KEYWORDS: Satellites, Sun, Satellite communications, Calibration, Optical communications, Cameras, Free space optics, Mirrors, Data communications, Telecommunications

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Proceedings Article | 9 May 2018 Presentation + Paper

Colorimetry and multispectral imaging in the shortwave infrared

M. Gerken, H. Schlemmer, C. Siemens

Proceedings Volume 10624, 1062409 (2018) https://doi.org/10.1117/12.2305298

KEYWORDS: Short wave infrared radiation, Optical filters, Reflectivity, Cameras, Colorimetry, Sensors, Image filtering, Visible radiation, Multispectral imaging, Shortwaves

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Proceedings Article | 20 May 2016 Paper

Verification of sensitivity enhancement of SWIR imager technology in advanced multispectral SWIR/VIS zoom cameras with constant and variable F-number

M. Hübner, B. Achtner, M. Kraus, C. Siemens, M. Münzberg

Proceedings Volume 9819, 981905 (2016) https://doi.org/10.1117/12.2223440

KEYWORDS: Short wave infrared radiation, Imaging systems, Cameras, Zoom lenses, Sensors, Signal to noise ratio, Staring arrays, Integrating spheres, Tungsten, Light sources

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Proceedings Article | 29 May 2014 Paper

Characterization of SWIR cameras by MRC measurements

M. Gerken, H. Schlemmer, Hubertus Haan, Christofer Siemens, M. Münzberg

Proceedings Volume 9071, 907110 (2014) https://doi.org/10.1117/12.2052928

KEYWORDS: Short wave infrared radiation, Cameras, Sensors, Light sources, Imaging systems, Visible radiation, Visualization, Calibration, Lamps, Manufacturing

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Cameras for the SWIR wavelength range are becoming more and more important because of the better observation range for day-light operation under adverse weather conditions (haze, fog, rain). In order to choose the best suitable SWIR camera or to qualify a camera for a given application, characterization of the camera by means of the Minimum Resolvable Contrast MRC concept is favorable as the MRC comprises all relevant properties of the instrument. With the MRC known for a given camera device the achievable observation range can be calculated for every combination of target size, illumination level or weather conditions. MRC measurements in the SWIR wavelength band can be performed widely along the guidelines of the MRC measurements of a visual camera. Typically measurements are performed with a set of resolution targets (e.g. USAF 1951 target) manufactured with different contrast values from 50% down to less than 1%. For a given illumination level the achievable spatial resolution is then measured for each target. The resulting curve is showing the minimum contrast that is necessary to resolve the structure of a target as a function of spatial frequency. To perform MRC measurements for SWIR cameras at first the irradiation parameters have to be given in radiometric instead of photometric units which are limited in their use to the visible range. In order to do so, SWIR illumination levels for typical daylight and twilight conditions have to be defined. At second, a radiation source is necessary with appropriate emission in the SWIR range (e.g. incandescent lamp) and the irradiance has to be measured in W/m² instead of Lux = Lumen/m². At third, the contrast values of the targets have to be calibrated newly for the SWIR range because they typically differ from the values determined for the visual range. Measured MRC values of three cameras are compared to the specified performance data of the devices and the results of a multi-band in-house designed Vis-SWIR camera system are discussed.

Showing 5 of 6 publications

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