Tobias Langlotz

Real-time panoramic mapping and tracking on mobile phones

We present a novel method for the real-time creation and tracking of panoramic maps on mobile phones. The maps generated with this technique are visually appealing, very accurate and allow drift-free rotation tracking. This method runs on mobile phones at 30Hz and has applications in the creation of panoramic images for offline browsing, for visual enhancements through environment mapping and for outdoor Augmented Reality on mobile phones.

Robust and unobtrusive marker tracking on mobile phones

Marker tracking has revolutionized augmented reality about a decade ago. However, this revolution came at the expense of visual clutter. In this paper, we propose several new marker techniques, which are less obtrusive than the usual black and white squares. Furthermore, we report methods that allow tracking beyond the visibility of these markers further improving robustness. All presented techniques are implemented in a single tracking library, are highly efficient in their memory and CPU usage and run at interactive frame rates on mobile phones.

Sketching up the world: in situ authoring for mobile Augmented Reality

We present a novel system allowing in situ content creation for mobile Augmented Reality in unprepared environments. This system targets smartphones and therefore allows a spontaneous authoring while in place. We describe two different scenarios, which are depending on the size of the working environment and consequently use different tracking techniques. A natural feature-based approach for planar targets is used for small working spaces whereas for larger working environments, such as in outdoor scenarios, a panoramic-based orientation tracking is deployed. Both are integrated into one system allowing the user to use the same interaction for creating the content applying a set of simple, yet powerful modeling functions for content creation. The resulting content for Augmented Reality can be shared with other users using a dedicated content server or kept in a private inventory for later use.

Image-driven view management for augmented reality browsers

In this paper, we introduce a novel view management technique for placing labels in Augmented Reality systems. A common issue in many Augmented Reality applications is the absence of knowledge of the real environment, limiting the efficient representation and optimal layout of the digital information augmented onto the real world. To overcome this problem, we introduce an image-based approach, which combines a visual saliency algorithm with edge analysis to identify potentially important image regions and geometric constraints for placing labels. Our proposed solution also includes adaptive rendering techniques that allow a designer to control the appearance of depth cues. We describe the results obtained from a user study considering different scenarios, which we performed for validating our approach. Our technique will provide special benefits to Augmented Reality browsers that usually lack scene knowledge, but also to many other applications in the domain of Augmented Reality such as cultural heritage and maintenance applications.

Online Creation of Panoramic Augmented Reality Annotations on Mobile Phones

A novel application lets users create panoramic images in real time on a mobile phone and annotate the physical environment using an augmented-reality interface. Annotations can be accurately mapped to the correct objects, despite varying user positions.

Augmented Reality 2.0

Augmented Reality (AR) was first demonstrated in the 1960s, but only recently have technologies emerged that can be used to easily deploy AR applications to many users. Camera-equipped cell phones with significant processing power and graphics abilities provide an inexpensive and versatile platform for AR applications, while the social networking technology of Web 2.0 provides a large-scale infrastructure for collaboratively producing and distributing geo-referenced AR content. This combination of widely used mobile hardware and Web 2.0 software allows the development of a new type of AR platform that can be used on a global scale. In this paper we describe the Augmented Reality 2.0 concept and present existing work on mobile AR and web technologies that could be used to create AR 2.0 applications.

Next-Generation Augmented Reality Browsers: Rich, Seamless, and Adaptive

As low-level hardware will soon allow us to visualize virtual content anywhere in the real world, managing it in a more structured manner still needs to be addressed. Augmented reality (AR) browser technology is the gateway to such structured software platform and an anywhere AR user experience. AR browsers are the substitute of Web browsers in the real world, permitting overlay of interactive multimedia content on the physical world or objects they refer to. As the current generation allows us to barely see floating virtual items in the physical world, a tighter coupling with our reality has not yet been explored. This paper presents our recent effort to create rich, seamless, and adaptive AR browsers. We discuss major challenges in the area and present an agenda on future research directions for an everyday augmented world.

Mobile Augmented Reality: Robust detection and tracking of annotations for outdoor augmented reality browsing

A common goal of outdoor augmented reality (AR) is the presentation of annotations that are registered to anchor points in the real world. We present an enhanced approach for registering and tracking such anchor points, which is suitable for current generation mobile phones and can also successfully deal with the wide variety of viewing conditions encountered in real life outdoor use. The approach is based on on-the-fly generation of panoramic images by sweeping the camera over the scene. The panoramas are then used for stable orientation tracking, while the user is performing only rotational movements. This basic approach is improved by several new techniques for the re-detection and tracking of anchor points. For the re-detection, specifically after temporal variations, we first compute a panoramic image with extended dynamic range, which can better represent varying illumination conditions. The panorama is then searched for known anchor points, while orientation tracking continues uninterrupted. We then use information from an internal orientation sensor to prime an active search scheme for the anchor points, which improves matching results. Finally, global consistency is enhanced by statistical estimation of a global rotation that minimizes the overall position error of anchor points when transforming them from the source panorama in which they were created, to the current view represented by a new panorama. Once the anchor points are redetected, we track the users movement using a novel 3-degree-of-freedom orientation tracking approach that combines vision tracking with the absolute orientation from inertial and magnetic sensors. We tested our system using an AR campus guide as an example application and provide detailed results for our approach using an off-the-shelf smartphone. Results show that the re-detection rate is improved by a factor of 2 compared to previous work and reaches almost 90% for a wide variety of test cases while still keeping the ability to run at interactive frame rates.

Unsynchronized 4D Barcodes

We present a novel technique for optical data transfer between public displays and mobile devices based on unsynchronized 4D barcodes. We assume that no direct (electromagnetic or other) connection between the devices can exist. Time-multiplexed, 2D color barcodes are displayed on screens and recorded with camera equipped mobile phones. This allows to transmit information optically between both devices. Our approach maximizes the data throughput and the robustness of the barcode recognition, while no immediate synchronization exists. Although the transfer rate is much smaller than it can be achieved with electromagnetic techniques (e.g., Bluetooth or WiFi), we envision to apply such a technique wherever no direct connection is available. 4D barcodes can, for instance, be integrated into public web-pages, movie sequences, advertisement presentations or information displays, and they encode and transmit more information than possible with single 2D or 3D barcodes.

Augmented reality browsers: essential products or only gadgets?

How lessons learned from the evolution of the Web and Web browsers can influence the development of AR browsers.