Augmented Reality Markers Research Articles

Caracterización de marcadores de realidad aumentada para su uso en robótica

Pese a la amplia variedad de estudios e investigaciones en realidad aumentada aplicada en sistemas robóticos, en general no se aprecia un análisis del cómo afecta a la detección de los marcadores: la iluminación, las distancias, ni los ángulos de incidencia de la cámara de los robots, menospreciando la importancia de estos parámetros en la representación de objetos aumentados, por lo cual se dificulta hacer una comparación más objetiva del desempeño de las aplicaciones de realidad aumentada en los robots. Este articulo describe un procedimiento para analizar un conjunto de marcadores estándar de realidad aumentada teniendo en cuenta distancias, ángulos de detección e iluminación, al igual que el efecto del tamaño del marcador en la escala de los objetos aumentados, de forma que ayuden al lector a determinar que efecto tienen sobre el desempeño del sistema, y planteando una serie de recomendaciones originadas en los resultados de pruebas técnicas con el fin de mantener una detección óptima de los marcadores en ambientes in-door.

赤外光拡張現実マーカの認識精度に関する分光分析評価

赤外光拡張現実マーカの認識精度に関する分光分析評価

Penerapan Teknologi Augmented Reality untuk Pengenalan Komponen Jaringan dan Cara Kerja TCP/IP berbasis Android

Augmented reality is a term for combining real-world environment with virtual worlds. Augmented reality is becoming very popular today because besides interesting, also can be displayed in realtime. In general, augmented reality adds a digital object in reality with reference to specific objects in the real world, for example by using a marker. Therefore, in this thesis aims to create an application that displays a 3D object that contains information about the network components and the workings of TCP / IP by making use of the concept of augmented reality marker technique. A marker is a reference object in the real world as a marker so that the information can be displayed. The marker is made to function to call the 3D objects appear on the screen smartphone that uses the technique of introduction of basic colors of red, green and blue. The method used consists of several stages of research, namely data collection, analysis and system design and system implementation. Data collection method used is literature. Methods of analysis and design of systems using the Unified Modeling Language (UML). The programming language used for software development are C # (C-Sharp) with Unity applications and software SketcUp to create 3D objects as well as Android SDK to convert the file into the form of android. This application is successfully created by displaying a 3D object that can make users excited to get to know the physical network components and requires only an internet connection to download the initial marker.

A mobile augmented reality system to support machinery operations in scholar environments

ABSTRACTThis paper proposes a mobile augmented reality (MAR) system aimed to support students in the use of a milling and lathe machines at a university manufacturing laboratory. The system incorporates 3D models of machinery and tools, text instructions, animations and videos with real processes to enrich the information obtained from the real world. The elements are shown when the user points the camera of a mobile device to specific parts of the machinery, where augmented reality (AR) markers are placed. The main goals of the project were (1) create an AR system that guides inexperienced users in machinery handling and (2) measure the acceptance rate and performance of the system in the school manufacturing laboratory. The guidance is provided by means of virtual information about how to operate the machinery when the trainer is not present. The system was implemented as a mobile app for Android devices and it was tested by 16 students and teachers at the university manufacturing laboratory through a survey. The results of this study revealed that students, laboratory technicians, and teachers had positive opinions and good acceptance about the use of the MAR system in the manufacturing laboratory. © 2016 Wiley Periodicals, Inc. Comput Appl Eng Educ 24:967–981, 2016; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21772

Augmented Reality Marker Hiding with Texture Deformation.

Augmented reality (AR) marker hiding is a technique to visually remove AR markers in a real-time video stream. A conventional approach transforms a background image with a homography matrix calculated on the basis of a camera pose and overlays the transformed image on an AR marker region in a real-time frame, assuming that the AR marker is on a planar surface. However, this approach may cause discontinuities in textures around the boundary between the marker and its surrounding area when the planar surface assumption is not satisfied. This paper proposes a method for AR marker hiding without discontinuities around texture boundaries even under nonplanar background geometry without measuring it. For doing this, our method estimates the dense motion in the marker's background by analyzing the motion of sparse feature points around it, together with a smooth motion assumption, and deforms the background image according to it. Our experiments demonstrate the effectiveness of the proposed method in various environments with different background geometries and textures.

Three-dimensional sound-field visualization system using head mounted display and stereo camera

Visualization of a sound field helps us to intuitively understand various acoustic phenomena in sound design and education. The most straightforward method is to overlap the measured data onto a photographic image. However, in order to understand an entire three-dimensional (3D) sound field by using a conventional two-dimensional screen, it is necessary to move a camera and measure repeatedly. On the other hand, the augmented reality (AR) techniques such as an optical head mounted display (OHMD) have been rapidly developed. In this study, we propose a sound field visualization system using an OHMD and a handheld four-point microphone. This system calculates sound intensity from the four sound signals in real time. Then, the sound intensity distribution is depicted as arrows in the 3D display. The position and angle of the microphones and user’s head are acquired via AR markers and a gyro sensor of the OHMD. The system realizes simple and effective visualization of 3D sound field information from the vario...

L-split marker for augmented reality in aircraft assembly

In order to improve the performance of conventional square markers widely used by marker-based augmented reality systems in aircraft assembly environments, an L-split marker is proposed. Every marker consists of four separate L-shaped parts and each of them contains partial information about the marker. Geometric features of the L-shape, which are more discriminate than the symmetrical square shape adopted by conventional markers, are used to detect proposed markers from the camera images effectively. The marker is split into four separate parts in order to improve the robustness to occlusion and curvature to some extent. The registration process can be successfully completed as long as three parts are detected (up to about 80% of the area could be occluded). Moreover, when we attach the marker on nonplanar surfaces, the curvature status of the marker can be roughly analyzed with every part’s normal direction, which can be obtained since their six corners have been explicitly determined in the previous detection process. And based on the marker design, new detection and recognition algorithms are proposed and detailed. The experimental results show that the marker and the algorithms are effective.

Augmented Reality (AR) Applications for Supporting Human-robot Interactive Cooperation

The paper presents an Augmented Reality (AR) tool for supporting operators where humans and robots coexist in a shared industrial workplace. The system provides AR visualization of the assembly process, video and text based instructions and production status updates. The tool also enhances the operator's safety and acceptance of hybrid assembly environments through the immersion capabilities of AR technology. A hardware landscape including the AR equipment and markers, the handheld devices for user input and the network infrastructure for interfacing the robot and the storage database is provided. The software architecture for coordinating the AR tool with the assembly process and the data retrieval from the robot controller are also presented. The tool has been tested on a pilot case in the automotive sector. The results indicate that the approach can significantly enhance the operator's working conditions and their integration in the assembly process.

Reproduction of Highlights for Hiding an Augmented Reality Marker on a Plane

Reproduction of Highlights for Hiding an Augmented Reality Marker on a Plane

증강현실 콘텐츠의 이미지 인식 기법 효과성 연구

Recently augmented reality contents are variously used in public such as advertisements or exhibits as well as children`s books. Therefore, it is certain that the market, development of augmented reality contents, is gradually growing. Those who are the producer of augmented reality may be familiar with the skill where those images are used as a marker which is created by image recognition technique. In case of using image recognition technique, they usually use the augmented reality marker platform from Qualcomm since it is able to recognize self-produced images and 3-dimensional figures at no cost. This study was started when undergraduate students began to use those general techniques in their contents producing process. AR majoring students in Namseoul University applied image recognition technique to 3 AR contents exhibited in Sejong Center. Creating 3 different images, they have registered images at Image Target Manager provided by Vuforia to use as a marker. Moreover, they have modified the image producing method to raise the recognition rate by research. The higher recognition rate brings the more stable use of augmented reality contents. To achieve the satisfied rate, they have compared the elements of color contrast, pattern and etc. in the use of platform. Thus, the effective image creation method has been drawn. This study is aiming to suggest the production of stable contents by recognizing smart devices` limitation and producing educational contents. The purpose of this study is to help practically augmented reality contents developers by illustrating the application of augmented reality contents which are based on image recognition technique and also its effectiveness at the same time.

SlidAR: A 3D positioning method for SLAM-based handheld augmented reality

Handheld Augmented Reality (HAR) has the potential to introduce Augmented Reality (AR) to large audiences due to the widespread use of suitable handheld devices. However, many of the current HAR systems are not considered very practical and they do not fully answer to the needs of the users. One of the challenging areas in HAR is the in-situ AR content creation where the correct and accurate positioning of virtual objects to the real world is fundamental. Due to the hardware limitations of handheld devices and possible restrictions in the environment, the correct 3D positioning of objects can be difficult to achieve we are unable to use AR markers or correctly map the 3D structure of the environment.We present SlidAR, a 3D positioning for Simultaneous Localization And Mapping (SLAM) based HAR systems. SlidAR utilizes 3D ray-casting and epipolar geometry for virtual object positioning. It does not require a perfect 3D reconstruction of the environment nor any virtual depth cues. We have conducted a user experiment to evaluate the efficiency of SlidAR method against an existing device-centric positioning method that we call HoldAR. Results showed that SlidAR was significantly faster, required significantly less device movement, and also got significantly better subjective evaluation from the test participants. SlidAR also had higher positioning accuracy, although not significantly.

Using gradient-based ray and candidate shadow maps for environmental illumination distribution estimation

A method to estimate the environmental illumination distribution of a scene with gradient-based ray and candidate shadow maps is presented. In the shadow segmentation stage, we apply a Canny edge detector to the shadowed image by using a three-dimensional (3-D) augmented reality (AR) marker of a known size and shape. Then the hierarchical tree of the connected edge components representing the topological relation is constructed, and the connected components are merged, taking their hierarchical structures into consideration. A gradient-based ray that is perpendicular to the gradient of the edge pixel in the shadow image can be used to extract the shadow regions. In the light source detection stage, shadow regions with both a 3-D AR marker and the light sources are partitioned into candidate shadow maps. A simple logic operation between each candidate shadow map and the segmented shadow is used to efficiently compute the area ratio between them. The pro- posed method successively extracts the main light sources according to their relative contributions on the seg- mented shadows. The proposed method can reduce unwanted effects due to the sampling positions in the shadow region and the threshold values in the shadow edge detection. © The Authors. Published by SPIE under a

Providing IoT Services in Smart Cities through Dynamic Augmented Reality Markers.

Smart cities are expected to improve the quality of life of citizens by relying on new paradigms, such as the Internet of Things (IoT) and its capacity to manage and interconnect thousands of sensors and actuators scattered across the city. At the same time, mobile devices widely assist professional and personal everyday activities. A very good example of the potential of these devices for smart cities is their powerful support for intuitive service interfaces (such as those based on augmented reality (AR)) for non-expert users. In our work, we consider a scenario that combines IoT and AR within a smart city maintenance service to improve the accessibility of sensor and actuator devices in the field, where responsiveness is crucial. In it, depending on the location and needs of each service, data and commands will be transported by an urban communications network or consulted on the spot. Direct AR interaction with urban objects has already been described; it usually relies on 2D visual codes to deliver object identifiers (IDs) to the rendering device to identify object resources. These IDs allow information about the objects to be retrieved from a remote server. In this work, we present a novel solution that replaces static AR markers with dynamic markers based on LED communication, which can be decoded through cameras embedded in smartphones. These dynamic markers can directly deliver sensor information to the rendering device, on top of the object ID, without further network interaction.

Estimating Illumination Distribution to Generate Realistic Shadows in Augmented Reality

Mobile devices are becoming powerful enough to realize augmented reality (AR) application. This paper introduces two AR methods to estimate an environmental illumination distribution of a scene. In the first method, we extract the lighting direction and intensity from input images captured with a front-side camera of a mobile device, using its orientation sensor. The second method extracts shadow regions cast by three dimensional (3D) AR marker of known shape and size. Because previous methods examine per pixel shadow intensity, their performances are much affected by the number of sampling points, positions, and threshold values. By using a simple binary operation between the previously clustered shadow regions and the threshold real shadow regions, we can compute efficiently their relative area proportions according to threshold values. This area-based method can overcome point sampling problem and threshold value selection. Experiment results demonstrate that the proposed methods generate natural image with multiple smooth shadows in real-time.

Marker Hiding Methods: Applications in Augmented Reality

In augmented reality, the markers are noticeable by their simple design of a rectangular image with black and white areas that disturb the reality of the overall view. As the markerless techniques are not usually robust enough, hiding the markers has a valuable usage, which many researchers have focused on. Categorizing the marker hiding methods is the main motivation of this study, which explains each of them in detail and discusses the advantages and shortcomings of each. The main ideas, enhancements, and future works of the well-known techniques are also comprehensively summarized and analyzed in depth. The main goal of this study is to provide researchers who are interested in markerless or hiding-marker methods an easier approach for choosing the method that is best suited to their aims. This work reviews the different methods that hide the augmented reality marker by using information from its surrounding area. These methods have considerable differences in their smooth continuation of the textures that hide the marker area as well as their performance to hide the augmented reality marker in real time. It is also hoped that our analysis helps researchers find solutions to the drawbacks of each method.

Robust 3D object modeling with a low-cost RGBD-sensor and AR-markers for applications with untrained end-users

An approach for generating textured 3D models of objects without the need for complex infrastructure such as turn-tables or high-end sensors on precisely controlled rails is presented. The method is inexpensive as it uses only a low-cost RGBD sensor, e.g., Microsoft Kinect or ASUS Xtion, and Augmented Reality (AR) markers printed on paper sheets. The sensor can be moved by hand by an untrained person and the AR-markers can be arbitrarily placed in the scene, thus allowing the modeling of objects of a large range of sizes. Due to the use of the simple AR markers, the method is significantly more robust than just using the RGBD sensor or a monocular camera alone and it hence avoids the typical need for manual post-processing of alternative approaches like Kinect-Fusion, 123D Catch, Photosynth, or similar. This article has two main contributions: First, the development of a simple, inexpensive method for the quick and easy digitization of physical objects is presented. Second, the development of an uncertainty model for AR-marker pose estimation is introduced. The latter is of interest beyond the object modeling application presented here. The uncertainty model is used in a graph-based relaxation method to improve model-consistency. Realistic modeling of various objects, such as parcels, sport balls, coffee sacks, human dolls, etc., is experimentally demonstrated. Good model-accuracy is shown for several ground-truth objects with simple geometries and known dimensions. Furthermore, it is shown that the models obtained using the uncertainty model have fewer errors than the ones obtained without it.

MoP-32 Augmented-reality-marker-based picking system for efficient registration of part position

This paper presents an AR-marker-based picking system for efficient registration of parts' position. The system consists of a cart, cameras, an LED beam illuminator on a pan-tilt unit, a PC, and a shelf. The system observes augmented reality (AR) markers that are put near parts on warehouse shelves. These AR markers contain the IDs of the parts. The system detects the relative position of AR markers and generates a map of marker positions together with the parts IDs. The system estimates the cart position using the map and shows the part position to the user by projecting a light beam from the cart to the parts. Despite camera-based estimation, this system continues showing the part position even if the parts are outside the visual field of the camera. An experiment showed that the system generated a map automatically and showed the position to the user.

Development of Operating Instructional System Using AR Technology in Chemical Plants

In recent years, Japan's industrial accident rate has shown an increasing trend. This is especially remarkable due to chemical industrial complexes. As is well-known, many kinds of hazardous materials are being controlled in chemical facilities. If a serious accident occurs, there is the potential for severe damage to employees and the residents of local communities. A primary factor in these accidents is the lack of safety awareness, safety knowledge, safety management system deficiencies, and insufficiency of safety ethics. In addition, industrial technology is highly diversified and complicated. As a result, operators cannot grasp the whole situation of the abnormalities and potential crises present. In other words, operators are unable to take the appropriate safety measures to prevent accidents. In some cases, equipment failure shave developed into serious accidents due to incorrect operation by the operator. This paper presents systems that provide information to operators by using augmented reality (AR) technology in chemical plants. AR can enhance real-world environments using virtual objects such as computer graphics. This system can help plant operators to confirm procedures in order to ensure proper operation. Furthermore, the operator can recognize the equipment to be operated properly using a tablet PC with a built-in camera. The proposed system can provide the plant information based on the dynamic simulator (DS). In an emergency, chemical plant operators are required to make quick decisions to prevent the escalation of an accident. To convey accurate indication information of the work, it is useful to recognize target equipment using AR marker in addition to the output information by individual voice from control room. Our developed systems can support chemical plant operators to make quick decisions and to follow correct operating procedures.

Developing an interactive augmented reality system as a complement to plant education and comparing its effectiveness with video learning

The learning of plants has garnered considerable attention in recent years, but students often lack the motivation to learn about the process of plant growth. Also, students are not able to apply what they have learned in class in the form of observation, since plant growth takes a long time. In this study, we use augmented reality (AR) technology to develop the ARFlora system, which can assist students in observing the changes in plant growth while in the classroom. More specifically, students are able to use AR markers to manipulate various virtual objects (e.g. sunlight) and observe the changes they have on plant growth. Meanwhile, a quasi-experimental evaluation is in place to substantiate the effectiveness of ARFlora in the learning of plants and to compare it with digital video learning. In the quasi-experimental design, 55 elementary-school students participated in the study. The participants are divided into two groups, an “experimental group” and a “control group.” The experimental group was taught using the ARFlora system, while the control group was taught by employing the digital video. Results show that (1) ARFlora and digital video have the same effectiveness on student's learning outcomes; (2) ARFlora is more effective in helping students retain learned knowledge; and (3) ARFlora is comparatively more useful in motivating students to learn about plants.

Natural markers for augmented reality-based indoor navigation and facility maintenance

The longest phase in a facility's lifecycle is its maintenance period, during which operators perform activities to provide a comfortable living and working environment as well as to upkeep equipment to prevent functional failures. In current practice operators need a considerable amount of time to manually process dispersed and unformatted facility information to perform an actual task. Existing research approaches rely on expensive hardware infrastructure or use artificial, thus unesthetic Augmented Reality (AR) markers. In this paper we present a natural marker based AR framework that can digitally support facility maintenance (FM) operators when navigating to the FM item of interest and when actually performing the maintenance and repair actions. Marker detection performance experiments and case studies on our university campus indicate the feasibility and potential of natural markers for AR-based maintenance support.