Dr. Marina Kolesnik Profile

Dr. Marina Kolesnik

at Fraunhofer IMK

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Publications (5)

Proceedings Article | 18 March 2005 Paper

Virtual odometry from visual flow

Markus Lappe, Harald Frenz, Thomas Buehrmann, Marina Kolesnik

Proceedings Volume 5666, (2005) https://doi.org/10.1117/12.610863

KEYWORDS: Visualization, Virtual reality, Error analysis, Distance measurement, Visual optics, Calibration, Eye, Human subjects, Glasses, Camera shutters

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We investigate how visual motion registered during one's own movement through a structured world can be used to gauge travel distance. Estimating absolute travel distance from the visual flow induced in the optic array of a moving observer is problematic because optic flow speeds co-vary with the dimensions of the environment and are thus subject to an environment specific scale factor. Discrimination of the distances of two simulated self-motions of different speed and duration is reliably possible from optic flow, however, if the visual environment is the same for both motions, because the scale factors cancel in this case. Here, we ask whether a distance estimate obtained from optic flow can be transformed into a spatial interval in the same visual environment. Subjects viewed a simulated self-motion sequence on a large (90 by 90 deg) projection screen or in a computer animated virtual environment (CAVE) with completely immersive, stereographic, head-yoked projection, that extended 180deg horizontally and included the floor space in front of the observer. The sequence depicted self-motion over a ground plane covered with random dots. Simulated distances ranged from 1.5 to 13 meters with variable speed and duration of the movement. After the movement stopped, the screen depicted a stationary view of the scene and two horizontal lines appeared on the ground in front of the observer. The subject had to adjust one of these lines such that the spatial interval between the lines matched the distance traveled during the movement simulation. Adjusted interval size was linearly related to simulated travel distance, suggesting that observers could obtain a measure of distance from the optic flow. The slope of the regression was 0.7. Thus, subjects underestimated distance by 30%. This result was similar for stereoscopic and monoscopic conditions. We conclude that optic flow can be used to derive an estimate of travel distance, but this estimate is subject to scaling when compared to static intervals in the environment, irrespective of steroscopic depth cues.

Proceedings Article | 12 May 2004 Paper

Segmentation of wounds in the combined color-texture feature space

Marina Kolesnik, Alex Fexa

Proceedings Volume 5370, (2004) https://doi.org/10.1117/12.535041

KEYWORDS: Image segmentation, Skin, Tissues, Wound healing, RGB color model, Image classification, Standards development, 3D image processing, Video, Feature extraction

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Proceedings Article | 1 April 2003 Paper

Perceptual user interface in virtual shopping environment

Weidong Geng, Wolfgang Strauss, Monika Fleischmann, Vladimir Elistratov, Thomas Kulessa, Marina Kolesnik

Proceedings Volume 4756, (2003) https://doi.org/10.1117/12.497765

KEYWORDS: Human-machine interfaces, Virtual reality, Control systems, Navigation systems, 3D modeling, Visual process modeling, Cameras, 3D displays, Prototyping, Infrared radiation

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Proceedings Article | 12 March 1999 Paper

View-based method for relative orientation in a pipe

Marina Kolesnik

Proceedings Volume 3719, (1999) https://doi.org/10.1117/12.341372

KEYWORDS: Cameras, Imaging systems, Reticles, Projection systems, Fluctuations and noise, Optical simulations, Laser based displays, Head, Lithium, Robotic systems

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Proceedings Article | 30 July 1998 Paper

Algorithmic solution for autonomous vision-based off-road navigation

Marina Kolesnik, Gerhard Paar, Arnold Bauer, Michael Ulm

Proceedings Volume 3364, (1998) https://doi.org/10.1117/12.317474

KEYWORDS: Calibration, Cameras, Sensors, Navigation systems, 3D modeling, Stereoscopic cameras, Reconstruction algorithms, Stereo vision systems, Image sensors, 3D image reconstruction

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