Dr. Rolf Kaufmann Profile

Dr. Rolf Kaufmann

at EMPA

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Publications (8)

Proceedings Article | 25 September 2017 Paper

Comparison of different phase retrieval algorithms

Rolf Kaufmann, Mathieu Plamondon, Jürgen Hofmann, Antonia Neels

Proceedings Volume 10391, 1039115 (2017) https://doi.org/10.1117/12.2275144

KEYWORDS: Phase measurement, Interferometers, Phase retrieval, X-rays, Sensors, Image processing, X-ray technology, Phase contrast, Synchrotrons, Materials science

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Proceedings Article | 21 October 2016 Presentation + Paper

Advancing the visualization of pure water transport in porous materials by fast, talbot interferometry-based multi-contrast x-ray micro-tomography

Fei Yang, Michele Griffa, Alexander Hipp, Hannelore Derluyn, Peter Moonen, Rolf Kaufmann, Matthieu Boone, Felix Beckmann, Pietro Lura

Proceedings Volume 9967, 99670L (2016) https://doi.org/10.1117/12.2236221

KEYWORDS: X-rays, Visualization, Spatial resolution, X-ray imaging, Water, Cements, X-ray imaging, Phase contrast, Tomography, Image segmentation, Signal attenuation

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Proceedings Article | 20 May 2009 Paper

8 Gb/s 0.5 V integrated Ge-on-SOI photodetector

Johann Osmond, Giovanni Isella, Daniel Chrastina, Hans von Känel, Rolf Kaufmann, Laurent Vivien, Gilles Rasigade, Delphine Marris-Morini, Paul Crozat, Eric Cassan, Suzanne Laval

Proceedings Volume 7366, 73660B (2009) https://doi.org/10.1117/12.821714

KEYWORDS: Photodetectors, Germanium, Diodes, Silicon, Optical communications, Integrated optics, Plasma, Ions, External quantum efficiency, Eye

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Proceedings Article | 26 January 2006 Paper

High-speed and high-sensitive demodulation pixel for 3D imaging

Bernhard Büttgen, Thierry Oggier, Michael Lehmann, Rolf Kaufmann, Simon Neukom, Michael Richter, Matthias Schweizer, David Beyeler, Roger Cook, Christiane Gimkiewicz, Claus Urban, Peter Metzler, Peter Seitz, Felix Lustenberger

Proceedings Volume 6056, 605603 (2006) https://doi.org/10.1117/12.642305

KEYWORDS: Modulation, Sensors, Demodulation, Cameras, Signal detection, Distance measurement, Diffusion, Electrons, Head, Image processing

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Proceedings Article | 17 January 2005 Paper

Novel pixel architecture with inherent background suppression for 3D time-of-flight imaging

Thierry Oggier, Rolf Kaufmann, Michael Lehmann, Bernhard Buttgen, Simon Neukom, Michael Richter, Matthias Schweizer, Peter Metzler, Felix Lustenberger, Nicolas Blanc

Proceedings Volume 5665, 566501 (2005) https://doi.org/10.1117/12.586933

KEYWORDS: 3D-TOF imaging, Sensors, 3D image processing, Time of flight imaging, Cameras, Sun, Modulation, Solid state electronics, Image sensors, Time metrology

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The time-of-flight (TOF) principle is a well known principle to acquire a scene in all three dimensions. The advantages of the knowledge of the third dimension are obvious for many kinds of applications. The distance information within the scene renders automatic systems more robust and much less complex or even enables completely new solutions. A solid-state image sensor containing 124 x 160 pixels and the corresponding 3D-camera, the so-called SwissRanger camera, has already been presented in detail in [1]. It has been shown that the SwissRanger camera achieves depth resolutions in the sub-centimeter range, corresponding to a measured time resolution of a few tens of picoseconds with respect to the speed of light (c~3•108 m/s). However, one main drawback of these so-called lock-in TOF pixels is their limited capacity to handle background illumination. Keeping in mind that in outdoor applications the optical power on the sensor originating from background illumination (e.g., sun light) may be up to a few 100 times higher than the power of the modulated illumination, the sensor requires new pixel structures eliminating or at least reducing the currently experienced restrictions in terms of background illumination. Based on a 0.6 µm CMOS/CCD technology, four new pixel architectures suppressing background illumination and/or improving the ratio of modulated signal to background signal at the pixel-output level were developed and will be presented in this paper. The theoretical principle of operation and the expected performance are described in detail, together with a sketch of the implementation of the different pixel designs at silicon level. Furthermore, test results obtained in a laboratory environment are published. The sensor structures are characterized in a high background-light environment with up to sun light conditions. The distance linearity over a range of a few meters with the mentioned light conditions is measured. At the same time, the distance resolution is plotted as a function of the target distance, the integration time and the background illumination power. This in-depth evaluation leads to a comparison of the various background suppression approaches; it also includes a comparison with the traditional pixel structure in order to highlight the benefits of the new approaches. The paper concludes by providing parameter estimations which enables the outlook to build a sensor with a high lateral resolution containing the most promising pixel.

Proceedings Article | 1 September 2004 Paper

A time-of-flight line sensor: development and application

Rolf Kaufmann, Michael Lehmann, Matthias Schweizer, Michael Richter, Peter Metzler, Graham Lang, Thierry Oggier, Nicolas Blanc, Peter Seitz, Gabriel Gruener, Urs Zbinden

Proceedings Volume 5459, (2004) https://doi.org/10.1117/12.545571

KEYWORDS: Sensors, Distance measurement, Electrons, Phase measurement, Modulation, Cameras, Charge-coupled devices, Laser range finders, Imaging systems, Mobile robots

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Proceedings Article | 16 April 2004 Paper

Demonstration of a novel drift field pixel structure for the demodulation of modulated light waves with application in three-dimensional image capture

Bernhard Buttgen, Thierry Oggier, Rolf Kaufmann, Peter Seitz, Nicolas Blanc

Proceedings Volume 5302, (2004) https://doi.org/10.1117/12.525654

KEYWORDS: Demodulation, Modulation, Signal detection, Distance measurement, Electrons, Sensors, Camera shutters, Signal processing, 3D image processing, Diffusion

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Proceedings Article | 18 February 2004 Paper

An all-solid-state optical range camera for 3D real-time imaging with sub-centimeter depth resolution (SwissRanger)

Thierry Oggier, Michael Lehmann, Rolf Kaufmann, Matthias Schweizer, Michael Richter, Peter Metzler, Graham Lang, Felix Lustenberger, Nicolas Blanc

Proceedings Volume 5249, (2004) https://doi.org/10.1117/12.513307

KEYWORDS: Sensors, Cameras, Imaging systems, Modulation, 3D image processing, Stereoscopic cameras, Optics manufacturing, Distance measurement, Demodulation, Image resolution

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Showing 5 of 8 publications

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