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Aufsatz
Iterative feature detection of a coded checkerboard target for the geometric calibration of infrared cameras
(2021-08-11)
The geometric calibration of cameras becomes necessary when images should be undistorted, geometric image information is needed or data from more than one camera have to be fused. This process is often done using a target with a checkerboard or circular pattern and a given geometry. In this work, a coded checkerboard target for thermal imaging cameras and the corresponding image processing algorithm for iterative feature detection are presented. It is shown that, due in particular to the resulting better feature ...
Aufsatz
Rigorous 3D modeling of confocal microscopy on 2D surface topographies
(2021-06-07)
Although optical 3D topography measurement instruments are widespread, measured profiles suffer from systematic deviations occurring due to the wave characteristics of light. These deviations can be analyzed by numerical simulations. We present a 3D modeling of the image formation of confocal microscopes. For this, the light-surface interaction is simulated using two different rigorous methods, the finite element method and the rigorous coupled-wave analysis. The image formation in the confocal microscope is simulated ...
Aufsatz
Microstructure and Physicochemical Properties of Light Ice Cream: Effects of Extruded Microparticulated Whey Proteins and Process Design
(2021-06-21)
This study aimed to understand the influence of extruded microparticulated whey proteins (eMWPs) and process design in light ice cream processing by evaluating the microstructure and physicochemical properties. The inulin (T1), a commercial microparticulated whey protein (MWP) called simplesse (T2), a combination (T3), as well as eMWPs (as 50% volume of total particles): d50 < 3 µm (T4), and d50 > 5 µm (T5) were used as fat replacers. The first process design was pasteurization with subsequent homogenization (PH). ...
Aufsatz
Three-dimensional transfer function of optical microscopes in reflection mode
(2021-06-16)
Three-dimensional (3D) transfer functions build the basis for a comprehensive characterization of optical imaging systems in the spatial frequency domain. Utilizing the projection-slice theorem, the 2D modulation transfer function of an incoherent imaging system can be derived from a 3D transfer function by integration with respect to the axial spatial frequency. For a diffraction limited microscope with homogeneous incoherent pupil illumination, the modulation transfer function equals the 2D autocorrelation function ...
Aufsatz
Velocity-Dependent Perception Threshold for Discrete Imperceptible Repositioning in a Virtual Environment During Eye Blinks
(2021-07-02)
In this study, the relationship between a person’s walking speed and the perception threshold for discrete implicit repositioning during eyeblinks in a virtual environment is investigated. The aim is to estimate the perception thresholds for forward and backward repositioning during forward translation following eyeblink occurrences. A psychophysical method called Staircase Transformed and Weighted up/down is utilized to quantify the perception thresholds for forward and backward repositioning. The perception thresholds ...
Aufsatz
On the Expressive Power of Stateless Ordered Restart-Delete Automata
(2021-03-13)
Stateless ordered restart-delete automata (stl-ORD-automata) are studied. These are obtained from the stateless ordered restarting automata (stl-ORWW-automata) by introducing an additional restart-delete operation, which, based on the surrounding context, deletes a single letter. While the stl-ORWW-automata accept the regular languages, we show that the swift stl-ORD-automata yield a characterization for the class of context-free languages. Here a stl-ORD-automaton is called swift if it can move its window to any ...
Aufsatz
Augmented-Reality-basierte Assistenz für das Anlernen manueller und roboterunterstützter Montageprozesse
(2021-10-14)
Durch eine zunehmend flexibilisierte Produktion und relativ hohe Personalfluktuation bei einfachen Tätigkeiten wird das Anlernen neuer Mitarbeitender bzw. für neue oder geänderte Produktionsprozesse zunehmend relevanter. Konventionelle Anlernmethoden, bspw. durch Demonstration oder Arbeitspläne, haben Schwächen (bspw. binden sie zusätzliche Arbeitskraft oder sind kognitiv anspruchsvoll), die durch ein Augmented-Reality-(AR-)basiertes Assistenzsystem kompensiert werden können. Ein AR-Assistenzsystem zum Anlernen eines ...
Aufsatz
Optical Quality of InAs/InP Quantum Dots on Distributed Bragg Reflector Emitting at 3rd Telecom Window Grown by Molecular Beam Epitaxy
(2021-10-21)
We present an experimental study on the optical quality of InAs/InP quantum dots (QDs). Investigated structures have application relevance due to emission in the 3rd telecommunication window. The nanostructures are grown by ripening-assisted molecular beam epitaxy. This leads to their unique properties, i.e., low spatial density and in-plane shape symmetry. These are advantageous for non-classical light generation for quantum technologies applications. As a measure of the internal quantum efficiency, the discrepancy ...
Aufsatz
Potentials and Limitations of WorldView-3 Data for the Detection of Invasive Lupinus polyphyllus Lindl. in Semi-Natural Grasslands
(2021-10-28)
Semi-natural grasslands contribute highly to biodiversity and other ecosystem services, but they are at risk by the spread of invasive plant species, which alter their habitat structure. Large area grassland monitoring can be a powerful tool to manage invaded ecosystems. Therefore, WorldView-3 multispectral sensor data was utilized to train multiple machine learning algorithms in an automatic machine learning workflow called ‘H2O AutoML’ to detect L. polyphyllus in a nature protection grassland ecosystem. Different ...
Aufsatz
Comparison of Spaceborne and UAV-Borne Remote Sensing Spectral Data for Estimating Monsoon Crop Vegetation Parameters
(2021-04-20)
Various remote sensing data have been successfully applied to monitor crop vegetation parameters for different crop types. Those successful applications mostly focused on one sensor system or a single crop type. This study compares how two different sensor data (spaceborne multispectral vs unmanned aerial vehicle borne hyperspectral) can estimate crop vegetation parameters from three monsoon crops in tropical regions: finger millet, maize, and lablab. The study was conducted in two experimental field layouts (irrigated ...