Vineet R. Kamat

Visualization of construction graphics in outdoor augmented reality

This paper describes research that investigates the application of augmented reality (AR) in 3D animation of simulated construction operations. The objective is an AR-based platform that can be used together with corresponding equipment (HMD, GPS receiver, and a portable computer) to generate a mixed view of the real world and superimposed virtual simulation objects in an outdoor environment. The characteristic that distinguishes the presented work from indoor AR applications is the capability to produce real time updated output as the user moves around while applying minimum constraints over the users position and orientation. The ability to operate independently of environmental factors (e.g. lighting conditions and terrain variations) makes the described framework a powerful tool for outdoor AR applications. This paper presents initial results and an AR platform prototype (UM-AR-GPS-ROVER) that is able to place 3D graphical objects at any desired location in outdoor augmented space.

Validating complex construction simulation models using 3D visualization

One of primary impediments in the use of discrete-event simulation to plan and design construction operations is that decision-makers often do not have the means, the knowledge, and/or the time to check the veracity and the validity of simulation models and thus have little confidence in the results. Visualizing simulated operations in 3D can be of substantial help in the verification, validation, and accreditation of simulation models. In addition, visualization can provide valuable insight into subtleties of modeled operations that are otherwise non-quantifiable and presentable. This paper investigates the efficacy of 3D visualization in verifying and validating discrete-event construction simulation models. The paper presents a case study of a simulation model of an earthmoving operation with fairly complex control logic that was verified and validated by visualizing the operation in 3D. The simulation model for the example was developed using Stroboscope and was visualized using the Dynamic Construction Visualizer.

General-purpose modular hardware and software framework for mobile outdoor augmented reality applications in engineering

This paper presents a reusable, general-purpose, mobile augmented reality (AR) framework developed to address the critical and repetitive challenges specific to visualization in outdoor AR. In all engineering applications of AR developed thus far, basic functionality that supports accurate user registration, maximizes the range of user motion, and enables data input and output has had to be repeatedly re-implemented. This is primarily due to the fact that designed methods have been traditionally custom created for their respective applications and are not generic enough to be readily shared and reused by others. The objective of this research was to remedy this situation by designing and implementing a reusable and pluggable hardware and software framework that can be used in any AR application without the need to re-implement low-level communication interfaces with selected hardware. The underlying methods of hardware communication as well as the object-oriented design (OOD) of the reusable interface are presented. Details on the validation of framework reusability and pluggability are also described.

Fast plane extraction in organized point clouds using agglomerative hierarchical clustering.

Real-time plane extraction in 3D point clouds is crucial to many robotics applications. We present a novel algorithm for reliably detecting multiple planes in real time in organized point clouds obtained from devices such as Kinect sensors. By uniformly dividing such a point cloud into non-overlapping groups of points in the image space, we first construct a graph whose node and edge represent a group of points and their neighborhood respectively. We then perform an agglomerative hierarchical clustering on this graph to systematically merge nodes belonging to the same plane until the plane fitting mean squared error exceeds a threshold. Finally we refine the extracted planes using pixel-wise region growing. Our experiments demonstrate that the proposed algorithm can reliably detect all major planes in the scene at a frame rate of more than 35Hz for 640×480 point clouds, which to the best of our knowledge is much faster than state-of-the-art algorithms.

Collaborative visualization of engineering processes using tabletop augmented reality

3D computer visualization has emerged as an advanced problem-solving tool for engineering education and practice. For example in civil engineering, the integration of 3D/4D CAD models in the construction process helps to minimize the misinterpretation of the spatial, temporal, and logical aspects of construction planning information. Yet despite the advances made in visualization, the lack of collaborative problem-solving abilities leaves outstanding challenges that need to be addressed before 3D visualization can become widely accepted in the classroom and in professional practice. The ability to smoothly and naturally interact in a shared workspace characterizes a collaborative learning process. This paper introduces tabletop Augmented Reality to accommodate the need to collaboratively visualize computer-generated models. A new software program named ARVita is developed to validate this idea, where multiple users wearing Head-Mounted Displays and sitting around a table can all observe and interact with dynamic visual simulations of engineering processes. The applications of collaborative visualization using Augmented Reality are reviewed, the technical implementation is covered, and the programs underlying tracking libraries are presented.

SMART: scalable and modular augmented reality template for rapid development of engineering visualization applications

BackgroundThe visualization of civil infrastructure systems and processes is critical for the validation and communication of computer generated models to decision-makers. Augmented Reality (AR) visualization blends real-world information with graphical 3D models to create informative composite views that are difficult to create or replicate on the computer alone.MethodsThis paper presents a scalable and extensible mobile computing framework that allows users to readily create complex outdoor AR visual applications. The technical challenges of building this reusable framework from the software and hardware perspectives are described.ResultsSMART is a generic and loosely-coupled software computing framework for creating AR visual applications with accurate registration algorithms and visually credible occlusion effects. While SMART is independent of any specific hardware realization, ARMOR is built as a hardware implementation of SMART to test its algorithm correctness and its adaption to engineering applications. In particular, ARMOR is a modular mobile hardware platform designed for user position and orientation tracking, as well as augmented view display.ConclusionThe framework has been validated in several case studies, including the visualization of underground utilities for excavator control and collision avoidance to demonstrate SMART’s rapid creation of complex AR visual applications.

Integration of infrastructure based positioning systems and inertial navigation for ubiquitous context-aware engineering applications

This paper presents research that investigated and implemented a hybrid integrated location tracking framework that was developed by integrating infrastructure based positioning systems and inertial navigation. The authors implemented this research by using the Personal Dead Reckoning positioning system to serve as the inertial navigation based positioning system. The primary contribution of the presented work is the development and implementation of the Integrated Tracking System algorithm which was implemented in two levels. At the first level, the Integrated Tracking System (ITS) was developed by integrating Global Positioning System (GPS) and Personal Dead Reckoning (PDR) system to ubiquitously track a mobile user, in dynamic environments where GPS coverage may be uncertain. At the second level, the PDR system was integrated with a database of pre-determined known indoor location points in order to correct the accumulated drift error during a mobile users navigation in an indoor environment. Finally, a hybrid tracking system was developed and implemented by integrating the PDR system with the mobile users intervention and discernment of the environment. The implementation and the results obtained from validation experiments performed on the aforementioned hybrid tracking systems demonstrate the potential of using hybrid tracking for determining the spatial context of mobile users in ubiquitous context-aware engineering applications.

SCENE GRAPH AND FRAME UPDATE ALGORITHMS FOR SMOOTH AND SCALABLE 3D VISUALIZATION OF SIMULATED CONSTRUCTION OPERATIONS

One of the prime reasons inhibiting the widespread use of discrete-event simulation in construction planning is the absence of appropriate visual communication tools. Visualizing modeled operations in 3D is arguably the best form of communicating the logic and the inner working of simulation models and can be of immense help in establishing the credibility of analyses. New software development technologies emerge at incredible rates that allow engineers and scientists to create novel, domain-specific applications. The authors capitalized on a computer graphics technology based on the concept of the scene graph to design and implement a general-purpose 3D visualization system that is simulation and CAD-software independent. This system, the Dynamic Construction Visualizer, enables realistic visualization of modeled construction operations and the resulting products and can be used in conjunction with a wide variety of simulation tools. This paper describes the scene graph architecture and the frame updating algorithms used in designing the Dynamic Construction Visualizer.

Automated Generation of Operations Level Construction Animations in Outdoor Augmented Reality

Three-dimensional 3D visualization is an effective tool for communicating, verifying, and validating the results of a simulated operation. Traditional visualization tools used for this purpose are typically based on the paradigm of virtual reality. Augmented reality AR is a relatively newer visualization paradigm whose engineering applications have been explored by a limited number of researchers. In this paper, the problem of generating smooth and continuous AR animations from the results of running discrete event simulation models and a general purpose methodology to overcome this challenge are discussed. The structure of an AR animation authoring language developed by the writers to create a logical link between a running simulation model and its corresponding 3D visualization in AR is described. In order to validate the functionality and effectiveness of the designed methods and animation language, an AR-based visualization application was developed and the designed algorithms were successfully tested using different simulation scenarios of varying visual and operational complexity. DOI: 10.1061/ ASCE 0887-3801 2009 23:6 405 CE Database subject headings: Construction sites; Graphic methods; Computer applications; Simulation; Computer graphics; Automation.

Scalable Algorithm for Resolving Incorrect Occlusion in Dynamic Augmented Reality Engineering Environments

@Augmented reality (AR) offers significant potential in construction, manufacturing, and other en- gineering disciplines that employ graphical visualization to plan and design their operations. As a result of intro- ducing real-world objects into the visualization, less vir- tual models have to be deployed to create a realistic visual output that directly translates into less time and effort re- quired to create, render, manipulate, manage, and update three-dimensional (3D) virtual contents (CAD model en- gineering) of the animated scene. At the same time, us- ing the existing layout of land or plant as the background of visualization significantly alleviates the need to collect data about the surrounding environment prior to creat- ing the final visualization while providing visually con- vincing representations of the processes being studied. In an AR animation, virtual and real objects must be simultaneously managed and accurately displayed to a user to create a visually convincing illusion of their co- existence and interaction. A critical challenge impeding this objective is the problem of incorrect occlusion that manifests itself when real objects in an AR scene par- tially or wholly block the view of virtual objects. In the ∗ To whom correspondence should be addressed. E-mail: vkamat