Technology

Image-based Ghostings for Single Layer Occlusions in Augmented Reality

In augmented reality displays, X-Ray visualization techniques make hidden objects visible through combining the physical view with an artificial rendering of the hidden information. An important step in X-Ray visualization is to decide which parts of the physical scene should be kept and which should be replaced by overlays. The combination should provide users with essential perceptual cues to understand the relationship of depth between hidden information and the physical scene. In this paper we present an approach that addresses this decision in unknown environments by analyzing camera images of the physical scene and using the extracted information for occlusion management. Pixels are grouped into perceptually coherent image regions and a set of parameters is determined for each region. The parameters change the X-Ray visualization for either preserving existing structures or generating synthetic structures. Finally, users can customize the overall opacity of foreground regions to adapt the visualization.

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Compact Explosion Diagrams

This paper presents a system to automatically generate compact explosion diagrams. Inspired by handmade illustrations, our approach reduces the complexity of an explosion diagram by rendering an exploded view only for a subset of the assemblies of an object. However, the exploded views are chosen so that they allow inference of the remaining unexploded assemblies of the entire 3D model. In particular, our approach demonstrates the assembly of a set of identical groups of parts, by presenting an exploded view only for a single representative. In order to identify the representatives, our system automatically searches for recurring subassemblies. It selects representatives depending on a quality evaluation of their potential exploded view. Our system takes into account visibility information of both the exploded view of a potential representative as well as visibility information of the remaining unexploded assemblies. This allows rendering a balanced compact explosion diagram, consisting of a clear presentation of the exploded representatives as well as the unexploded remaining assemblies. Since representatives may interfere with one another, our system furthermore optimizes combinations of representatives. Throughout this paper we show a number of examples, which have all been rendered from unmodified 3D CAD models.

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Focus and Context in Mixed Reality by Modulating First Order Salient Features

We present a technique for dynamically directing a viewer's attention to a focus object by analyzing and modulating bottom-up salient features of a video feed. Rather than applying a static modulation strategy, we inspect the original image's saliency map, and modify the image automatically to favor the focus object. Image fragments are adaptively darkened, lightened and manipulated in hue according to local contrast information rather than global parameters. The goal is to suggest rather than force the attention of the user towards a specific location. The technique's goal is to apply only minimal changes to an image, while achieving a desired difference of saliency between focus and context regions of the image. Our technique exhibits temporal and spatial coherence and runs at interactive frame rates using GPU shaders. We present several application examples from the field of Mixed Reality, or more precisely Mediated Reality.

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Importance Masks for Revealing Occluded Objects in Augmented Reality

When simulating X-ray vision in Augmented Reality, a critical aspect is ensuring correct perception of the occluded objects position. Naive overlay rendering of occluded objects on top of realworld occluders can lead to a misunderstanding of the visual scene and a poor perception of the depth. We present a simple technique to enhance the perception of the spatial arrangements in the scene. An importance mask associated with occluders informs the rendering what information can be overlaid and what should be preserved. This technique is independent of scene properties such as illumination and surface properties, which may be unknown. The proposed solution is computed efficiently in a single-pass fragment shaders on the GPU.

[paper] [video1] [video2] [screenshots]

Explosion Diagrams for Augmented Reality

This article introduces explosion diagrams to Augmented Reality (AR) applications. It presents algorithms to seamlessly integrate an object's explosion diagram into a real world environment, including the AR rendering of relocated objects textured with live video and the restoration of visual information which are hidden behind relocated objects. It demonstrates several types of visualizations for convincing AR explosion diagrams and it discusses visualizations of exploded parts as well as visual links conveying their relocation direction. Furthermore, we show the integration of our rendering and visualization techniques in an AR framework, which is able to automatically compute a diagram's layout and an animation of its corresponding explosion.

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Comprehensible X-Ray Visualization for Augmented Reality

This article presents interactive visualizations to support the comprehension of spatial relationships between virtual and real-world objects for Augmented Reality (AR) applications. To enhance the clarity of such relationships, we discuss visualization techniques and their suitability for AR. We apply them on different AR applications with different goals, e.g., in x-ray vision or in applications that draw a user's attention to an object of interest. We demonstrate how Focus and Context (F+C) visualizations are used to affect the user's perception of hidden or nearby objects by presenting contextual information in the area of augmentation.

Featured article, IEEE TVCG

[paper] [video] [screenshots]

Interactive Focus and Context Visualization for Augmented Reality

In this article we present interactive Focus and Context (F+C) visualizations for Augmented Reality (AR) applications. We demonstrate how F+C visualizations are used to affect the user's perception of hidden objects by presenting contextual information in the area of augmentation. We carefully overlay synthetic data on top of the real world imagery by taking into account the information that is about to be occluded. Furthermore, we present operations to control the amount of augmented information. Additionally, we developed an interaction tool, based on the Magic Lens technique, which allows for interactive separation of focus from context.

[paper] [video] [screenshots]

Compositing on the Tegra

We got an nvidia Tegra and we decided to try some of our AR techniques on it. These are the first results. The first example modifies the image's HSV values. The second example applies a more elaborated compositing technique similar to that of the Comprehensible Augmented Reality.

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Cutaways for Augmented Reality

Cutaways are an alternative to ghostings, which have the advantage of fully revealing the occluded object through the cutout. We are experimenting with various styles and approaches for cutouts.

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Labeling for Augmented Reality

Providing textual and other labels for real world objects is an important component of so-called AR browsers. The layout of the labels can easily go wrong, in particular if too many labels clutter the screen. In this research, we are therefore concerned with automated optimal placement of labels.

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