Finger pointer based human machine interaction for selected quality checks of industrial work pieces. - In: 52th International Symposium on Robotics, (2020), S. 121-126
Interaction between humans and machines, especially robots becomes more and more important in industrial production and quality managing processes. We developed a demonstrator system for selected quality checks of industrial work pieces using a special kind of human gesture, the finger pointer, for the communication with the robot-guided measurement system. The demonstrator consists of two optical 3D scanners, a six-axis-robot (mounted on a mobile platform) and a master system (PC and the necessary software modules which realises the communication between the components). The interaction between the human and the machine is realized using the so-called interaction sensor, which is one of the optical 3D scanners. The main feature of this scanner is the detection of the position on the surface of a work piece where the humans finger points to. The robust results of the pointer location determination show a good fitting for the application of the demonstrator system for selected quality checks of industrial work pieces.
Quantitative bildgebende Oberflächenanalyse mittels Multiparameter-Fluorometrie. - Ilmenau : Universitätsbibliothek, 2020. - 1 Online-Ressource (159 Seiten)
Technische Universität Ilmenau, Dissertation 2020
Ziel dieser Arbeit war die Erforschung sowie Entwicklung einer neuen Sensortechnologie zur quantitativen bildgebenden Analyse dünner Schmierstoffschichten auf Metallbauteilen. Der erste Teil der Arbeit beschreibt die Entwicklung eines Messsystems zur quantitativen bildgebenden Fluoreszenzanalyse. Es wurde sowohl ein 2D Laserscanner zur Anwendung als Laborsystem als auch ein 1D Inline-System entwickelt. Für das Laborsystem konnte eine Nachweisgrenze besser 0,05 g/m 2 für ein in Automobilpresswerken übliches Umformöl nachgewiesen werden. Der Inline-Laserscanner erlaubt die Analyse der Ölverteilung auf 2,2 m breiten Blechbahnen bei einem Bauraum von lediglich 1,52 m oberhalb des Blechs mit einer Zeilenrate von 400 Linien pro Sekunde. Das zweite Themengebiet umfasst die Entwicklung, Anwendung und Bewertung neuer Methoden zur Charakterisierung sowie zur Kalibrierung von Fluoreszenzsensoren. Hierbei konnte gezeigt werden, dass sich besonders die Analyse des Oberflächenkohlenstoffs sowie das Aufdrucken dünner Schmierstoffschichten zur Untersuchung der Nachweisgrenze in Laborumgebungen eignen. Des Weiteren wurden zwei neuartige Methoden zur Kalibrierung außerhalb sauberer Laborumgebungen vorgestellt. Als erste Möglichkeit konnte die Nutzung eines zuvor kalibrierten Infrarot-Absorptionssensors zur automatischen Kalibrierung von Fluoreszenzsensoren gezeigt werden. Als zweite Möglichkeit wurde erstmalig der Transfer von Kalibrierdaten zwischen verschiedenen optischen Aufbauten mittels eines Feststoff-Fluoreszenzstandards gezeigt. Das dritte Themengebiet beschreibt die theoretische sowie experimentelle Analyse von Einflussfaktoren auf die Fluoreszenzemission dünner Schichten. Untersucht wurden unter anderem der Einfluss der Eigenschaften des Substratmaterials unterhalb der Schicht, der Neigung der Probe sowie des Kontaktwinkels, also der Form der Öltropfen. Die Analyse von mit Öltropfen beschichteten Aluminiumproben zeigt beispielsweise einen Anstieg des detektierten Fluoreszenzsignals um über Faktor vier bei einer Neigung der Probe um 45˚. Erst die so gewonnenen Erkenntnisse erlauben die korrekte Interpretation von Fluoreszenzbildern dünner Schichten auf dreidimensionalen industriellen Bauteilen. Die erreichten Ergebnisse stellen einen signifikanten Beitrag zur Weiterentwicklung der verfügbaren Sensorik zur Qualitätssicherung im Bereich der Metallverarbeitung dar.
https://nbn-resolving.org/urn:nbn:de:gbv:ilm1-2020000561
Measurement, comparison, and evaluation of spectral sensitivity curves from different multispectral resolving snapshot-mosaic cameras. - In: Algorithms, Technologies, and Applications for Multispectral and Hyperspectral Imagery XXVI, (2020), insges. 1 S.
The combination of pixel-assigned spectral filter matrices and standardized CMOS sensors enables the production and application of miniaturized spatial and spectral resolving sensors which, when used in snapshot-mosaic cameras, represent an innovative solution in comparison to whiskbroom, staring or pushbroom cameras. These cameras are characterized by CMOS sensors where spectral filters are applied on the CMOS sensor in a matrix which is multiplied in the x- and y-direction over the entire CMOS sensor surface. Current multispectral resolving filter-on-chip snapshot-mosaic cameras, available on the market, work with 1.3, 2.0- or 4.0-megapixel CMOS sensors, which are equipped with 4, 9, 16 or 25 different spectrally selective filters in the visible (VIS) or near infrared (NIR) spectral range. The combination of pixel-assigned spectral filter matrices on CMOS sensors increases the integration density and system complexity of multispectral resolving snapshot-mosaic cameras many times compared to established cameras with monochromatic or RGB Bayer Pattern image sensors. For the objective comparison of multispectral resolving snapshot-mosaic cameras, it is necessary to describe their pixel-related spectral wavelength depended image acquisition channels by suitable parameters. Here especially the method for determination of spectral sensitivity curves in accordance with the EMVA1288 standard will be shown and explained. This method will be applied on different kinds of snapshot-mosaic cameras called monolithic and hybrid. The method also will be extended by multiple measurements, comparisons and evaluations of spectral sensitivity curves from different areas of the sensor. The paper will provide a systematic presentation of how to measure the spectral sensitivity curves from different multispectral resolving cameras, how to compare measured results and how to evaluate the results to choose possible more appropriate camera for desired applications. The EMVA1288 standard, developed by camera manufacturers and research institutes, distinguishes itself from other standards by considering the camera as a linear model. The camera is treated as a black box of which only pixel size and exposure time must be known. The recording of standardized test images is also omitted, allowing the camera to be described without optics. The only input variable of the linear camera model of the EMVA 1288 standard is the number of photons that hit a pixel of the image sensor during the exposure time. Therefore, the correct determination of the photon count is essential to calculate important camera parameters from the linear camera model, such as quantum efficiency or signal-to-noise ratio. To determine the number of photons, the irradiance of the radiation incident on the image sensor must be measured. This is usually accomplished using a radiometer instead of the camera. The number of photons per pixel during the exposure time can then be calculated from the irradiance, considering constants like the wavelength of the incident radiation, the area of the pixel and the exposure time of the camera.
https://doi.org/10.1117/12.2564690
3D shape measurement of objects with uncooperative surface by projection of aperiodic thermal patterns in simulation and experiment. - In: Optical engineering, ISSN 1560-2303, Bd. 59 (2020), 9, S. 094107-1-094107-17
3D shape measurement systems based on diffuse reflection of projected structured light are widely used. Unfortunately, this measurement principle does not work for uncooperative materials, i.e., materials with optical properties such as being glossy, transparent, absorbent, or translucent. Recently, it was shown that 3D reconstruction of an uncooperative object can be performed by a two-step process. In the first step, the object absorbs a projected thermal pattern. In the second step, after energy conversion, the object surface reemits a diffused thermal pattern according to Planck's law. To achieve high 3D result qualities in short measurement times, projection parameters such as irradiance pattern and irradiation period must be optimized depending on optical and thermal material properties, e.g., complex spectral refractive index, thermal conductivity, specific heat capacity, or emissivity. Therefore, we have developed a simulation tool to describe the entire measurement process beginning with the projection unit, followed by the interaction of the irradiation with the measurement object, reemission of thermal radiation and recording unit, and finally the 3D reconstruction. In this contribution, we present our simulation tool, verify it with measurement results, and apply it to investigations of the influence of projection and material parameters on the 3D result quality.
https://doi.org/10.1117/1.OE.59.9.094107
Enhanced contactless vital sign estimation from real-time multimodal 3D image data. - In: Journal of imaging, ISSN 2313-433X, Bd. 6 (2020), 11, 123, S. 1-15
https://doi.org/10.3390/jimaging6110123
A-priori calibration of a structured light underwater 3D sensor. - In: Journal of marine science and engineering, ISSN 2077-1312, Volume 8 (2020), 9, 635, Seite 1-13
In this study, we introduce a new calibration method for underwater optical stereo scanners. It uses air calibration, additional underwater parameters, and extended camera modeling. The new methodology can be applied to both passive photogrammetric and structured light three-dimensional (3D) scanning systems. The novel camera model uses a variable principal distance depending on the radial distance to the principal point instead of two-dimensional distortion functions. This allows for an initial improvement of 3D reconstruction quality. In a second step, certain underwater-specific parameters—such as refraction indices, glass thickness, and view-port distances—are determined. Finally, a correction function for the entire measurement volume can be obtained from a few underwater measurements. Its application further improves the measurement accuracy. Measurement examples show the performance of the new calibration method in comparison to current underwater calibration strategies. A discussion of the possibilities and limits of the new calibration method and an outlook for future work complete this work.
https://doi.org/10.3390/jmse8090635
"Hard- Softwarearchitekturen für die schnelle 3D-Bilddatenvorverarbeitung und Datenübermittlung für Weißlichtinterferometer-WLI-Systeme" im Verbundvorhaben "Echtzeitfähige 3D-Datenverarbeitung auf kaskadierten analog-digital customized System on a Chip (cSoC)-Architekturen" : Schlussbericht : Sachbericht zum Verwendungsnachweis : Berichtszeitraum: 01.05.2016-31.12.2019. - Ilmenau : Technische Universität Ilmenau. - 1 Online-Ressource (27 Seiten, 1,59 MB)Förderkennzeichen BMBF 03ZZ0427G
https://doi.org/10.2314/KXP:1734281626
Continuous low-latency 3D measurements using efficient freeform GOBO pattern projection and close-to-sensor image rectification. - In: Dimensional Optical Metrology and Inspection for Practical Applications IX, (2020), S. 1139705-1-1139705-8
https://doi.org/10.1117/12.2558466
Multi-channel supported surveying of industrial floor tiles. - In: I2MTC 2020, (2020), S. 1-6
https://doi.org/10.1109/I2MTC43012.2020.9128600
Investigations on industrial water detection on surfaces using multichannel imaging techniques. - In: I2MTC 2020, (2020), S. 1-6
https://doi.org/10.1109/I2MTC43012.2020.9128544