Andreas Wieser

Last Name

Wieser

First Name

Andreas

ORCID

0000-0001-5804-2164

Organisational unit

03964 - Wieser, Andreas / Wieser, Andreas

Show all metadata

Search Results

Publications 1 - 10 of 201

Supercontinuum-based hyperspectral LiDAR for precision laser scanning
Ray, Pabitro; Salido Monzú, David; Camenzind, Sandro L.; et al. (2023)
Optics Express
Hyperspectral LiDAR enables non-contact mapping of the 3D surface geometry of an object along with its spectral reflectance signature and has proved to be effective for automated point cloud segmentation in various remote sensing applications. The established hyperspectral LiDAR methods offer a range precision of a few mm to a few cm for distances exceeding several meters. We propose a novel approach to hyperspectral LiDAR scanning based on a supercontinuum (SC) coherently broadened from a 780 nm frequency comb. It provides high precision distance measurements along with target reflectance over the 570–970 nm range of the SC output. The distance measurements are carried out by monitoring the differential phase delay of intermode beat notes generated by direct photodetection, while the backscattered light spectrum is acquired using a commercial CCD spectrometer with 0.16 nm resolution across the 400 nm bandwidth of the SC output. We demonstrate a measurement precision below 0.1 mm for a stand-off range up to 50 m on a diffuse target with around 89% reflectance. The measured relative accuracy as compared to a reference interferometer is on the order of 10−5 for distances up to 50 m. Initial results also indicate spectrum-based material classification within a 3D point cloud using a linear support vector machine. The results highlight the potential of this approach for joint high-precision laser scanning and automated material classification.
Improvedpositioning accuracy with high-sensitivity GNSS receivers and SNR aided integrity monitoring of pseudo-range observations
Wieser, Andreas; Gaggl, Margrit; Hartinger, Horst (2005)
Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005)
Fusion of wireless and non-contact technologies for the dynamic testing of a historic RC bridge
Ferrari, Rosalba; Pioldi, Fabio; Rizzi, Egidio; et al. (2016)
Measurement Science and Technology
Influence of surface reflectivity on reflectorless electronic distance measurement and terrestrial laser scanning
Zámečníková, Miriam; Wieser, Andreas; Woschitz, Helmut; et al. (2014)
Journal of Applied Geodesy
Zur kontinuierlichen Überwachung von Bauwerken mit GPS
Brunner, Friedrich K.; Hartinger, Horst; Wieser, Andreas (2000)
Schriftreihe zur Wasserwirtschaft ~ Betrieb und Überwachung wasserbaulicher Anlagen
EDM 3.0 - mehr als nur Distanzen
Wieser, Andreas; Han, Yu; Ray, Pabitro; et al. (2023)
GeoNews
Moderne Lasertechnologie ermöglicht es, EDM-Messungen nicht nur genauer, sondern durch Anreicherung mit Material information auch informativer zu machen. Bis zur kommer ziellen Umsetzung wird es sicher noch eine Zeitlang dauern, aber die aktuelle Forschung zeigt vielversprechende Richtun gen auf, und man darf gespannt sein, wie die Reise weiter geht. Und ganz bestimmt lohnt es sich, von diesem EDM 3.0 zu träumen.
An UWB Based Indoor Compass for Accurate Heading Estimation in Buildings
Norrdine, Abdelmoumen; Grimm, David; Blankenbach, Joerg; et al. (2013)
4th International Conference on Indoor Positioning and Indoor Navigation (IPIN 2013)
Refractivity corrected distance measurement using the intermode beats derived from a supercontinuum
Ray, Pabitro; Salido Monzú, David; Presl, Robert; et al. (2024)
Optics Express
Simultaneous distance measurements on two or more optical wavelengths enable dispersion-based correction of deviations that result from insufficient knowledge of the refractive index along the signal propagation path. We demonstrate a supercontinuum-based approach for highly accurate distance measurements suitable for such an inline refractivity compensation. The distance is estimated from the phase delay observations on the intermode beats. We use a supercontinuum (SC) coherently broadened from a 780 nm frequency comb and spanning the spectral range of 570-970 nm. Experiments are performed on the 590 and 890 nm wavelength bands filtered from the SC spectrum. Results show distance measurements with standard deviations of around 0.01 mm at 50 m, and a distance-dependent component below 0.2 ppm on the individual spectral bands. Distance residuals compared to a reference interferometer are on the order of 0.1 ppm for displacements up to 50 m. Controlled pressure-induced refractivity variations are created over a length of 15 m, resulting in an optical path length change of 0.4 mm. Using the two-color method, we demonstrate refractivity-corrected distance measurement with a standard deviation of around 0.08 mm for a 60 s averaging window. The current experimental configuration can be easily extended to distance measurements on more than two wavelengths. The results highlight its potential for practical long-distance measurements through inline refractivity compensation.
MIMO-SAR Interferometric Measurements for Wind Turbine Tower Deformation Monitoring
Baumann-Ouyang, Andreas; Butt, Jemil Avers; Varga, Matej; et al. (2023)
Energies
Deformations affect the structural integrity of wind turbine towers. The health of such structures is thus assessed by monitoring. The majority of sensors used for this purpose are costly and require in situ installations. We investigated whether Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO-SAR) sensors can be used to monitor wind turbine towers. We used an automotive-grade, low-cost, off-the-shelf MIMO-SAR sensor operating in the W-band with an acquisition frequency of 100 (Formula presented.) to derive Line-Of-Sight (LOS) deformation measurements in ranges up to about 175 (Formula presented.). Time series of displacement measurements for areas at different heights of the tower were analyzed and compared to reference measurements acquired by processing video camera recordings and total station measurements. The results showed movements in the range of up to 1 (Formula presented.) at the top of the tower. We were able to detect the deformations also with the W-band MIMO-SAR sensor; for areas with sufficient radar backscattering, the results suggest a sub-mm noise level of the radar measurements and agreement with the reference measurements at the mm- to sub-mm level. We further applied Fourier transformation to detect the dominant vibration frequencies and identified values ranging from 0.17 to 24 (Formula presented.). The outcomes confirmed the potential of MIMO-SAR sensors for highly precise, cost-efficient, and time-efficient structural monitoring of wind turbine towers. The sensors are likely also applicable for monitoring other high-rise structures such as skyscrapers or chimneys.
Weakly Supervised Learning of Rigid 3D Scene Flow
Guibas, Leonidas J.; Birdal, Tolga; Gojcic, Zan; et al. (2021)
2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)
We propose a data-driven scene flow estimation algorithm exploiting the observation that many 3D scenes can be explained by a collection of agents moving as rigid bodies. At the core of our method lies a deep architecture able to reason at the object-level by considering 3D scene flow in conjunction with other 3D tasks. This object level abstraction enables us to relax the requirement for dense scene flow supervision with simpler binary background segmentation mask and ego-motion annotations. Our mild supervision requirements make our method well suited for recently released massive data collections for autonomous driving, which do not contain dense scene flow annotations. As output, our model provides low-level cues like pointwise flow and higher-level cues such as holistic scene understanding at the level of rigid objects. We further propose a test-time optimization refining the predicted rigid scene flow. We showcase the effectiveness and generalization capacity of our method on four different autonomous driving datasets. We release our source code and pre-trained models under github.com/zgojcic/Rigid3DSceneFlow.

Publications 1 - 10 of 201

Andreas Wieser

Last Name

First Name

ORCID

Organisational unit

Filters

Search Results