Clemens Arth

Graz University of Technology | TU Graz · Institute of Computer Graphics and Knowledge Visualisation

We present a registration method relying on geometric constraints extracted from parametric primitives contained in 3D parametric models. Our method solves the registration in closed-form from three line-to-line, line-to-plane or plane-to-plane correspondences. The approach either works with semantically segmented RGB-D scans of the scene or with t...

In this paper we present an improved version of MAUI [9] (MAUI - Maintenance Assistance User Interface), extending the user-study, giving detailed insight into the implementations and introducing a new User-Interface for mobile use. MAUI is a novel take on tele-assisted tasks on cyber-physical systems. In its core we do not only provide real-time c...

Civil engineering is a primary domain for new augmented reality technologies. In this work, the area of subsurface utility engineering is revisited, and new methods tackling well-known, yet unsolved problems are presented. We describe our solution to the outdoor localization problem, which is deemed one of the most critical issues in outdoor augmen...

This paper presents a novel 7 DOF (i.e., orientation, translation, and scale) visual simultaneous localization and mapping (vSLAM) system for mobile robots in outdoor environments. In the front end of this vSLAM system, a fast initialization method is designed for different vSLAM backbones, which upgrades the accuracy of trajectory and reconstructi...

The rise of IoT-ready devices is supported through well-established web concepts for communication and analytics, but interaction yet remains in the world of web browsers and screen-based 2D interaction during times of tablet and smartphone popularity. Transforming IoT interaction concepts into 3D for future exploitation with head-worn XR devices i...

Augmented reality for medical applications allows physicians to obtain an inside view into the patient without surgery. In this context , we present an augmented reality application running on a standard smartphone or tablet computer, providing visualizations of medical image data, overlaid with the patient, in a video see-through fashion. Our syst...

Indoor reconstruction using depth camera algorithms (e.g., InfiniTAMv3) is becoming increasingly popular. Simple reconstruction methods solely use the frames of the depth camera, leaving any imagery from the adjunct RGB camera untouched. Recent approaches also incorporate color camera information to improve consistency. However, the results heavily...

Development and verification of real-time algorithms for robotic total stations usually require hard-ware-in-the-loop approaches, which can be complex and time-consuming. Simulator-in-the-loop can be used instead, but the design of a simulation environment and sufficient detailed modeling of the hardware are required. Typically, device specificatio...

Performing accurate measurements on non-planar targets using a robotic total station in reflectorless mode is prone to errors. Besides requiring a fully reflected laser beam of the electronic distance meter, a proper orientation of the pan-tilt unit is required for each individual accurate 3D point measurement. Dominant physical 3D structures like...

We propose an efficient physics-based method for dexterous ’real hand’-’virtual object’ interaction in Virtual Reality environments. Our method is based on the Coulomb friction model, and we show how to efficiently implement it in a commodity VR engine for realtime performance. This model enables very convincing simulations of many types of actions s...

In this paper, we present a new 3D tracking approach for self-localization in urban environments. In particular, we build on existing tracking approaches (i.e., visual odometry tracking and SLAM), additionally using the information provided by 2.5D maps of the environment. Since this combination is not straightforward, we adopt ideas from semantic...

In this position paper, we argue about a concept for collaborative outdoor reconstruction using SLAM clients and a scalable SfM engine running in the cloud. Based on previous observations and results, we discuss issues like illumination changes, overall scalability or the dacay of buildings, having a serious impact on the practical feasibility of s...

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, optically variable devices such as holograms are important, but difficult to inspect. Augmented Reality can provide all relevant information on standard mobile devices. However, hologram verification on mobiles still take...

In this work, we propose a multi-user system for tracking and map-ping, which accommodates mobile clients with different capabili-ties, mediated by a server capable of providing real-time structurefrom motion. Clients share their observations of the scene accord-ing to their individual capabilities. This can involve only keyframetracking, but also...

We present a method for large-scale geo-localization and global tracking of mobile devices in urban outdoor environments. In contrast to existing methods, we instantaneously initialize and globally register a SLAM map by localizing the first keyframe with respect to widely available untextured 2.5D maps. Given a single image frame and a coarse sens...

A mobile device uses vision and orientation sensor data jointly for six degree of freedom localization, e.g., in wide-area environments. An image or video stream is captured while receiving geographic orientation data and may be used to generate a panoramic cylindrical map of an environment. A bin of model features stored in a database is accessed...

This document summarizes the major milestones in mobile Augmented Reality between 1968 and 2014. Major parts of the list were compiled by the member of the Christian Doppler Laboratory for Handheld Augmented Reality in 2010 (author list in alphabetical order) for the ISMAR society. Later in 2013 it was updated, and more recent work was added during...

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, view-dependent elements such as holograms are interesting, but the expertise of individuals performing the task varies greatly. Augmented Reality systems can provide all relevant information on standard mobile devices. Ho...

We propose simple and efficient methods for estimating the camera motion between two images when this motion is small. While current solutions are still either slow, or unstable in case of small translation, we show how to considerably speed up a recent stable but slow method. The reasons for this speed-up are twofold. First, by approximating the r...

We propose a method for estimating the 3D pose for the camera of a mobile device in outdoor conditions, using only an untextured 2D model. Previous methods compute only a relative pose using a SLAM algorithm, or require many registered images, which are cumbersome to acquire. By contrast, our method returns an accurate, absolute camera pose in an a...

Pose estimation is performed using a scene structure captured in a query image and reference images from a database. Each of the reference images has an associated position estimate. Direction vectors are generated that describe directions between an unknown position of a camera center for the query image and a reference camera center for each refe...

Many security documents contain machine readable zones (MRZ) for automatic inspection. An MRZ is intended to be read by dedicated machinery, which often requires a stationary setup. Although MRZ information can also be read using camera phones, current solutions require the user to align the document, which is rather tedious. We propose a real-time...

Holograms are used frequently in creating fraud resistant security documents, such as passports, ID cards or banknotes. The key contribution of this paper is a real time method to automatically detect holograms in images acquired with a standard smartphone. Following a robust algorithm for creating a tracking target, our approach evaluates an evolv...

We propose a novel solution to the generalized camera pose problem which includes the internal scale of the generalized camera as an unknown parameter. This further generalization of the well-known absolute camera pose problem has applications in multi-frame loop closure. While a well-calibrated camera rig has a fixed and known scale, camera trajec...

We propose the combination of a keyframe-based monocular SLAM system and a global localization method. The SLAM system runs locally on a camera-equipped mobile client and provides continuous, relative 6DoF pose estimation as well as keyframe images with computed camera locations. As the local map expands, a server process localizes the keyframes wi...

Creating panoramic images in real-time is an expensive operation for mobile devices. Mapping of individual pixels into the panoramic image is the main focus of this paper, since it is one of the most time consuming parts. The pixel-mapping process is transferred from the Central Processing Unit (CPU) to the Graphics Processing Unit (GPU). The indep...

In this work we describe our approach to efficiently create, handle and organize large-scale Structure-from-Motion reconstructions of urban environments. For acquiring vast amounts of data, we use a Point Grey Ladybug 3 omni directional camera and a custom backpack system with a differential GPS sensor. Sparse point cloud reconstructions are genera...

In this paper, we discuss how the sensors available in modern smartphones can improve 6-degree-of-freedom (6DOF) localization in wide-area environments. In our research, we focus on phones as a platform for large-scale Augmented Reality (AR) applications. Thus, our aim is to estimate the position and orientation of the device accurately and fast -...

Estimating the external calibration --- the pose --- of a camera with respect to its environment is a fundamental task in Computer Vision (CV). In this paper, we propose a novel method for estimating the unknown 6DOF pose of a camera with known intrinsic parameters from epipolar geometry only. For a set of geo-located reference images, we assume th...

Self-localization in large environments is a vital task for accurately registered information visualization in outdoor Augmented Reality (AR) applications. In this work, we present a system for self-localization on mobile phones using a GPS prior and an online-generated panoramic view of the user's environment. The approach is suitable for executin...

Rapid D reconstruction of environments has become an active research topic due to the importance of 3D models in a huge number of applications, be it in Augmented Reality (AR), architecture or other commercial areas. In this paper we present a novel system that allows for the generation of a coarse D model of the environment within several seconds...

Augmented Reality (AR) on mobile phones is receiving more and more attention recently, becoming a popular research topic and an important commercial field. In this paper we present a lightweight method to create coarse 3D models of small-scale objects. The goal is to give the users the possibility to create and maintain AR content themselves withou...

Smartphones have attracted a lot of interest recently as they are becoming more and more computationally powerful platforms for all kinds of tasks in mobile environments. Due to the availability of high quality mobile phone cameras, the use of these platforms even for critical applications leveraging Computer Vision techniques is justified. In this...

Rapid 3D reconstruction of environments has many applications for mobile augmented reality, ranging from creating models for visual tracking systems, interaction models for placing annotations and environment maps for realistic rendering of virtual objects. Ideally, a single user should be able to rapidly generate a coarse model of their surroundin...

We present a fast and memory efficient method for localizing a mobile user's 6DOF pose from a single camera image. Our approach registers a view with respect to a sparse 3D point reconstruction. The 3D point dataset is partitioned into pieces based on visibility constraints and occlusion culling, making it scalable and efficient to handle. Starting...

In recent years many powerful computer vision algorithms have been proposed, making feasible automatic or semi-automatic solutions to many popular vision tasks, such as camera calibration and visual object recognition. In particular, the driving force was the development of new powerful algorithms, especially in the area of local features. On the o...

In the last few years, object recognition has become one of the most popular tasks in computer vision. In particular, this was driven by the development of new powerful algorithms for local appearance based object recognition. So-called “smart cameras” with enough power for decentralized image processing became more and more popular for all kinds o...

This paper introduces a novel real-time framework which enables detection, tracking and recognition of license plates from video sequences. An efficient algorithm based on analysis of Maximally Stable Extremal Region (MSER) detection results allows localization of international license plates in single images without the need of any learning scheme...

Object reacquisition or reidentification is the process of matching objects between images taken from separate cameras. In this paper, we present our work on feature based object reidentification performed on autonomous embedded smart cameras and applied to traffic scenarios. We present a novel approach based on PCA-SIFT features and a vocabulary t...

Abstract In this paper we present a full-featured license plate detection and recognition system. The system is imple- mented,on an embedded,DSP platform and processes a video stream in real-time. It consists of a detection and a character recognition module. The detector is based on the AdaBoost approach presented by Viola and Jones. Detected lice...

In recent years many powerful Computer Vision algo- rithms have been invented, making automatic or semi- automatic solutions to many popular vision tasks, such as visual object recognition or camera calibration, possible. On the other hand embedded vision platforms and solutions such as smart cameras have successfully emerged, however, only offerin...

This paper introduces an efficient method to substantially increase the recognition performance of a vocabulary tree based recognition system. We propose to combine the hy-pothesis obtained by a standard inverse object voting al-gorithm with reliable descriptor co-occurrences. The al-gorithm operates on different depths of a standard k-means tree,...

In this paper we present a novel embedded platform, dedicated especially to the surveillance of remote locations under harsh environmental conditions, featuring various video and audio compression algorithms as well as support for local systems and devices. The presented solution follows a radically decentralized approach and is able to act as an a...

Smartphones have been identified as most promising future devices for an Augmented Reality (AR) mass market. However, their use puts considerable constraints on the design and composition of AR applications. The key problem is to find a registration mechanism for accurate six degree of freedom (6DOF) self-localization with respect to the environmen...