Christoffer Menk

Visualisation Techniques for Using Spatial Augmented Reality in the Design Process of a Car

If spatial augmented reality is used in the design process of a car, then one of the most important issues is that the virtual content is projected with a very high visual quality onto the real object, because based on this projection design decisions are made. Especially, the visualised colours on the real object should not be distinguishable from corresponding real reference colours. In this paper, we introduce a new approach for the augmentation of real objects which is able to match the requirements of a design process. We present a new rendering method with ray tracing which increases the visual quality of the projection images in comparison to existing methods. The desired values of these images have further to be adjusted according to the material, the ambient light and the local orientation of the projector. For this purpose, we develop a physically based computation which exactly determines the corresponding projection intensities for these values by using three‐dimensional lookup tables at every projector pixel. Since not all of the desired values can be represented with an intensity of the projector, an adjustment has to be computed for these values. Therefore, we conduct a user study with design experts who work in the automotive industry and use the results to propose a new adjustment method for such values. Finally, we compare our methods to existing procedures and conclude which ones are suitable for the design process of a car.

Truthful Color Reproduction in Spatial Augmented Reality Applications

Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized colors on the real object, because design decisions are made on basis of the projection. In this paper, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting colors on the real object are equally perceived as the real desired colors. Our approach computes the influences of the ambient light, the material, the pose and the color model of the projector to the resulting colors of the projected RGB values by using a physically based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable colors by moving the projector to arbitrary positions around the real object. We further extend the mentioned method so that it is applicable to multiple projectors. All methods are evaluated in a number of experiments.

Interactive visualization technique for truthful color reproduction in spatial augmented reality applications

Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized colors on the real object, because design decisions are made on basis of the projection. In this article, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting colors on the real object are equally perceived as the real desired colors. Our approach computes the influences of the ambient light, the material, the pose and the color model of the projector to the resulting colors of the projected RGB values by using a physically-based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable colors by moving the projector to arbitrary positions around the real object. The proposed method is evaluated in a number of experiments.

Physically-based augmentation of real objects with virtual content under the influence of ambient light

In this article, we introduce a new method for the augmentation of a real object with virtual content under the influence of ambient light. For this purpose, we use a physically-based simulation and spectral data which is recorded separately for each of the components: projector, ambient light and real object. Then the simulation computes the influence of every component to the scene and uses the results to compute an adjusted virtual content, which can then be displayed by a real projector in the given situation. The adjustment of the projection can therefore be computed by considering the full dynamic range of the scene and that of the virtual content. Additionally, the virtual content is visualized with informations from the environment and therefore hidden objects or reflections can be integrated into the projection. The proposed methods and the physically-based simulation are validated and visualized through different experiments.

Semi-automatic calibration of a projector-camera system using arbitrary objects with known geometry

We propose a new semi-automatic calibration approach for projector-camera systems that - unlike existing auto-calibration approaches - additionally recovers the necessary global scale by projecting on an arbitrary object of known geometry from one view. Our method therefore combines surface registration with bundle adjustment optimization on points reconstructed from structured light projections. In simulations on virtual data and experiments with real data we demonstrate that our approach estimates the global scale robustly and is furthermore able to improve incorrectly guessed intrinsic and extrinsic calibration parameters.

Fallbeispiele für VR/AR

Dieses Kapitel enthalt eine Sammlung von ausgewahlten erfolgreichen Fallbeispielen fur VR/AR aus Forschung und Praxis.