ohne Studienabschlussarbeiten

Junger, Christina; Fütterer, Richard; Rosenberger, Maik; Notni, Gunther
Characterisation of a FPGA-based multi-view stereo system with linear measuring arrangement. - In: Measurement: sensors, ISSN 2665-9174, Bd. 18 (2021), 100322, S. 1-4

In recent years, stereoscopic image processing algorithms have gained importance for a variety of applications. To capture larger measurement volumes, multiple stereo systems are combined into a multi-view stereo system (MVS). To reduce the amount of data and the data rate, calculation steps close to the sensors are outsourced to field programmable gate arrays (FPGAs) as upstream computing units. In this paper a FPGA-based MVS system with linear camera arrangement and part overlapping field of view is presented. The system consists of four FPGA-based passive stereoscopic systems and a downstream processing unit (Zynq Ultrascale ZU9EG SoC). This synchronizes the pre-processing modules and receives the disparity maps via HDMI. A subsequent computing unit calculates a coherent 3d point cloud. Basic investigation of the system is shown to use this system for road damage detection in the future.

https://doi.org/10.1016/j.measen.2021.100322

Horn, Robin; Rosenberger, Maik; Notni, Gunther; Golomoz, Andrei; Fütterer, Richard; Dittrich, Paul-Gerald
Investigation on chromatic aberrations and its potential for application in depth measurement. - In: Measurement: sensors, ISSN 2665-9174, Bd. 18 (2021), 100113, S. 1-4

Chromatic aberrations are mostly supressed in typical industrial lenses to ensure a well-defined colour image. Beside the main wavelengths which are recognizable for the human eye, multispectral cameras can sample with a more detailed chromatic (spectral) resolution. This leads to a partial wavelength depended unsharpness in the images. If the imaging system can be well defined out of these imperfections, a depth information can be calculated. In this paper the theoretical model as well as a method for the 3D-reconstruction out of different colour (spectral) channels will be discussed.

https://doi.org/10.1016/j.measen.2021.100113

Zhang, Chen; Gebhart, Ingo; Kühmstedt, Peter; Rosenberger, Maik; Notni, Gunther
Real-time multimodal 3D imaging system for remote estimation of vital signs. - In: Multimodal Sensing and Artificial Intelligence: Technologies and Applications II, (2021), S. 117850F-1-117850F-14

The contactless estimation of vital signs based on conventional color cameras and ambient light can be affected by motions of patients and changes in ambient light. In this work, a multimodal 3D imaging system with an irritation-free controlled illumination was developed in order to mitigate these both problems. In the developed system the real-time high-precision 3D imaging is combined with VIS-NIR multispectral imaging and thermal imaging. Based on 3D data and color images, an approach was proposed for the efficient compensation of head motions, and novel approaches based on 3D regions of interest were developed for the estimation of heart rate, oxygen saturation, respiration rate, and body temperature from NIR multispectral video data and thermal video data. A proof-of-concept for the developed imaging system and algorithms can be delivered with first experimental results.

https://doi.org/10.1117/12.2592660

Munkelt, Christoph; Heinze, Matthias; Schindwolf, Simon; Heist, Stefan; Notni, Gunther
Irritation-free optical 3D-based measurement of tidal volume. - In: Automated Visual Inspection and Machine Vision IV, (2021), S. 117870A-1-117870A-7

The measurement of breathing biomechanics, such as tidal volume, can be used to assess both the breathing performance and the respiratory health of individuals. State-of-the-art methods like spirometry or body plethysmography require a mouthpiece or facemask., which can be uncomfortable to the test person. As an alternative, we propose to use the change of the geometric shape of the subjects torso while breathing. By acquiring 3D point clouds of the person with a real-time near-infrared (NIR) 3D scanner, we measure those changes in a comfortable, irritation-free, and contact-free manner. Accordingly, two continuously measuring structured light 3D sensors, using a GOBO-based aperiodic sinusoidal pattern projector at a wavelength of 850 nm, simultaneously capture the upper front and side torso of the subject at a frame rate of 200 Hz. Both 3D scanners are calibrated and operated in a sensor network fashion, yielding a unified data stream within a global coordinate system. This results in increased coverage and reduced occlusion of the patient's body shape, enabling robust measurements even in the presence of loose clothing and varying body figure. We collected data from 16 healthy participants in an upright sitting position, wearing everyday clothing during the measurements. For reference, we simultaneously recorded spirometry readings. An algorithm ("OpTidal") tracks the volume of the subject's torso from the 3D data. Comparison whith the reference data shows high correlation and low mean error for the absolute tidal volume readings. As such, our method is a viable, safe, and accurate alternative to spirometry and plethysmography.

https://doi.org/10.1117/12.2592714

Schmidt, Leander; Junger, Christina; Schricker, Klaus; Bergmann, Jean Pierre; Notni, Gunther
Echtzeitfähige Ansätze zum Monitoring der dehnungsfeldbasierten Spaltentstehung und resultierender Nahtqualität beim Laserstrahlschweißen. - In: Innovative Verfahren der Lasermaterialbearbeitung, (2021), S. 44-55