Mr. Uwe Adomeit Profile

Uwe Adomeit

at Fraunhofer IOSB

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Author

Publications (10)

Proceedings Article | 23 October 2023 Presentation + Paper

Thermal imagers with boost: range prediction with the Johnson criteria

Uwe Adomeit

Proceedings Volume 12737, 127370J (2023) https://doi.org/10.1117/12.2680255

KEYWORDS: Thermography, Cameras, Minimum resolvable temperature difference, Imaging systems, Spatial frequencies, Temperature metrology, Image filtering, Signal filtering

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Proceedings Article | 12 September 2021 Presentation + Paper

A standard target for triangles or how to transfer TOD to MTDP

Uwe Adomeit

Proceedings Volume 11866, 118660E (2021) https://doi.org/10.1117/12.2599731

KEYWORDS: Spatial frequencies, Cameras, Imaging systems, Thermography, Temperature metrology, Minimum resolvable temperature difference, Sensors, Data modeling, Modulation transfer functions

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Triangle Orientation Discrimination (TOD) developed by TNO Human Factors and Minimum Temperature Difference Perceived (MTDP) developed by Fraunhofer IOSB are competitive measurement methods for the assessment of well and under sampled thermal imagers. Key differences between the two methods are the different targets, bars for MTDP and equilateral triangles for TOD, and the measurement methodology. MTDP bases on a threshold measurement whereas TOD uses a psychophysical approach. All advantages and disadvantages of the methods trace back on these differences. The European Computer Model for Optronic System Performance Prediction (ECOMOS) includes range performance assessments according to both methods. This triggered work at Fraunhofer IOSB to do comparative TOD and MTDP measurements. Idea was checking if TOD- and MTDP-curves fall together when transferring the two target descriptive parameters, reciprocal angular subtense (one over triangle size expressed in angular units) and spatial frequency respectively, into each other using a conversion factor or function. Surprisingly, literature does not include such a measurement-based comparison to date. Extending IOSBs existing MTDP set-up with triangle targets and the associated turntable and shutter enabled the comparative measurements. The applied TOD measurement process uses the guidelines found in literature with some necessary adaptions. Both measurements included the same components (blackbody, collimator, monitor etc.) except the targets. Additionally the trained MTDP-observer also did the TOD measurements. Only the methods itself thus should cause differences in the results. Four thermal imagers with different magnitude of under sampling (MTF at Nyquist frequencies about 8 %, 14 %, 32 %, and 73 %) are the basis for the comparison. Their measurements allowed deriving a standard target for triangles according to the process known from target acquisition assessment. These calculations result in 1.5±0.2 line pairs on target. Multiplying reciprocal angular subtense with this factor gives corresponding MTDP and TOD curves when TOD is based 62.5 % instead of the standard 75 % probability. 62.5 % corrected for chance are 50 % probability and thus in correspondence with the threshold assumption of the MTDP. Deviations occur, when reciprocal angular subtense is near the cut-off because of unaccounted sampling effects. The proposed way to overcome this is normalizing spatial frequency and reciprocal angular subtense with camera line spread function full width at half maximum. A sigmoidal transition function is able to describe the resulting connection. This function could be valid for all thermal imagers, as indicated by the assessment of two additional ones. However, as the assessment bases only on six thermal imagers and one observer further comparative measurements by a larger number of observers or, alternatively, modeling is necessary.

Proceedings Article | 9 October 2019 Paper

Assessing detection performance of night vision VIS/LWIR-fusion

Uwe Adomeit

Proceedings Volume 11159, 111590P (2019) https://doi.org/10.1117/12.2533170

KEYWORDS: Night vision, Long wavelength infrared, Image fusion, Visualization, Situational awareness sensors, Thermography, Low light imagers, Night vision goggles, Goggles, Bolometers

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Proceedings Article | 29 September 2017 Paper

Shortwave infrared for night vision applications at Fraunhofer IOSB

Uwe Adomeit, Jürgen Krieg

Proceedings Volume 10425, 104250F (2017) https://doi.org/10.1117/12.2282357

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Proceedings Article | 21 October 2016 Paper

SWIR, VIS and LWIR observer performance against handheld objects: a comparison

Uwe Adomeit

Proceedings Volume 9987, 99870L (2016) https://doi.org/10.1117/12.2241086

KEYWORDS: Short wave infrared radiation, Long wavelength infrared, Cameras, Visualization, Infrared imaging, Spatial resolution, Thermography, Infrared radiation, Reflectivity, Data acquisition

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The short wave infrared spectral range caused interest to be used in day and night time military and security applications in the last years. This necessitates performance assessment of SWIR imaging equipment in comparison to the one operating in the visual (VIS) and thermal infrared (LWIR) spectral range. In the military context (nominal) range is the main performance criteria. Discriminating friend from foe is one of the main tasks in today’s asymmetric scenarios and so personnel, human activities and handheld objects are used as targets to estimate ranges. The later was also used for an experiment at Fraunhofer IOSB to get a first impression how the SWIR performs compared to VIS and LWIR. A human consecutively carrying one of nine different civil or military objects was recorded from five different ranges in the three spectral ranges. For the visual spectral range a 3-chip color-camera was used, the SWIR range was covered by an InGaAs-camera and the LWIR by an uncooled bolometer. It was ascertained that the nominal spatial resolution of the three cameras was in the same magnitude in order to enable an unbiased assessment. Daytime conditions were selected for data acquisition to separate the observer performance from illumination conditions and to some extend also camera performance. From the recorded data, a perception experiment was prepared. It was conducted as a nine-alternative forced choice, unlimited observation time test with 15 observers participating. Before the experiment, the observers were trained on close range target data. Outcome of the experiment was the average probability of identification versus range between camera and target. The comparison of the range performance achieved in the three spectral bands gave a mixed result. On one hand a ranking VIS / SWIR / LWIR in decreasing order can be seen in the data, but on the other hand only the difference between VIS and the other bands is statistically significant. Additionally it was not possible to explain the outcome with typical contrast metrics. Probably form is more important than contrast here as long as the contrast is generally high enough. These results were unexpected and need further exploration.

Proceedings Article | 8 October 2015 Paper

Shortwave infrared for night vision applications: illumination levels and sensor performance

Uwe Adomeit, Jürgen Krieg

Proceedings Volume 9641, 964104 (2015) https://doi.org/10.1117/12.2193738

KEYWORDS: Short wave infrared radiation, Visualization, Airglow, Cameras, Night vision, Indium gallium arsenide, Infrared radiation, Sensors, Astronomy, Clouds

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Proceedings Article | 24 October 2012 Paper

Infrared detection, recognition and identification of handheld objects

Uwe Adomeit

Proceedings Volume 8541, 85410O (2012) https://doi.org/10.1117/12.979288

KEYWORDS: Weapons, Cameras, Mid-IR, Long wavelength infrared, Thermography, Target recognition, Target detection, Infrared detection, Chest, Temperature metrology

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A main criterion for comparison and selection of thermal imagers for military applications is their nominal range performance. This nominal range performance is calculated for a defined task and standardized target and environmental conditions. The only standardization available to date is STANAG 4347. The target defined there is based on a main battle tank in front view. Because of modified military requirements, this target is no longer up-to-date. Today, different topics of interest are of interest, especially differentiation between friend and foe and identification of humans. There is no direct way to differentiate between friend and foe in asymmetric scenarios, but one clue can be that someone is carrying a weapon. This clue can be transformed in the observer tasks detection: a person is carrying or is not carrying an object, recognition: the object is a long / medium / short range weapon or civil equipment and identification: the object can be named (e. g. AK-47, M-4, G36, RPG7, Axe, Shovel etc.). These tasks can be assessed experimentally and from the results of such an assessment, a standard target for handheld objects may be derived. For a first assessment, a human carrying 13 different handheld objects in front of his chest was recorded at four different ranges with an IR-dual-band camera. From the recorded data, a perception experiment was prepared. It was conducted with 17 observers in a 13-alternative forced choice, unlimited observation time arrangement. The results of the test together with Minimum Temperature Difference Perceived measurements of the camera and temperature difference and critical dimension derived from the recorded imagery allowed defining a first standard target according to the above tasks. This standard target consist of 2.5 / 3.5 / 5 DRI line pairs on target, 0.24 m critical size and 1 K temperature difference. The values are preliminary and have to be refined in the future. Necessary are different aspect angles, different carriage and movement.

Proceedings Article | 18 May 2012 Paper

A standard data set for performance analysis of advanced IR image processing techniques

A. Robert Weiß, Uwe Adomeit, Philippe Chevalier, Stéphane Landeau, Piet Bijl, Frédéric Champagnat, Judith Dijk, Benjamin Göhler, Stefano Landini, Joseph Reynolds, Leslie Smith

Proceedings Volume 8355, 835512 (2012) https://doi.org/10.1117/12.919004

KEYWORDS: Cameras, Super resolution, Detection and tracking algorithms, Image processing, Image fusion, Thermography, Imaging systems, Mid-IR, Image compression, Black bodies

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Proceedings Article | 24 September 2009 Paper

Improved target detection by IR dual-band image fusion

U. Adomeit, R. Ebert

Proceedings Volume 7481, 74810B (2009) https://doi.org/10.1117/12.832294

KEYWORDS: Image fusion, Target detection, Long wavelength infrared, Mid-IR, Thermography, Infrared imaging, Cameras, Calibration, Climatology, Imaging systems

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Proceedings Article | 6 October 2007 Paper

IR-dual-band-camera demonstrator: experimental assessment, practical applications

U. Adomeit, R. Ebert

Proceedings Volume 6737, 673703 (2007) https://doi.org/10.1117/12.737725

KEYWORDS: Mid-IR, Modulation transfer functions, Long wavelength infrared, Image fusion, Temperature metrology, Quantum well infrared photodetectors, Sensors, Thermography, Calibration, Cameras

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