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[ACM Press the 2018 ACM International Conference - Tokyo, Japan (2018.11.25-2018.11.28)] Proceedings of the 2018 ACM International Conference on Interactive Surfaces and Spaces - ISS '18 - Floor-Projected Guidance Cues for Collaborative Exploration of Spatial Augmented Reality Setups
摘要： In this paper we present a floor-based user interface (UI) that allows multiple users to explore a spatial augmented reality (SAR) environment with both monoscopic and stereoscopic projections. Such environments are characterized by a low level of user instrumentation and the capability of providing a shared interaction space for multiple users. However, projector-based systems using stereoscopic display are usually single-user setups, since they can provide the correct perspective for only one tracked person. To address this problem, we developed a set of guidance cues, which are projected onto the floor in order to assist multiple users regarding (i) the interaction with the SAR system, (ii) the identification of regions of interest and ideal viewpoints, and (iii) the collaboration with each other. In a user study with 40 participants all cues were evaluated and a set of feedback elements, which are essential to guarantee an intuitive self-explaining interaction, was identified. The results of the study also indicate that the developed UI guides users to more favorable viewpoints and therefore is able to improve the experience in a multi-user SAR environment.
关键词： floor based user interfaces,Spatial augmented reality
更新于2025-09-23 15:22:29
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An interactive cameraless projector calibration method
摘要： The geometric calibration of projectors is a demanding task in many areas related to computer vision, virtual reality or augmented reality, to name some. Up to date, different methods have been proposed to retrieve the intrinsic and extrinsic parameters of projectors. During the last 20 years, researchers have used cameras as means to calibrate projectors in order to automatize the process. However, this might add: (1) complexity in terms of mathematical formulation; (2) restrictions in terms of camera locations relative to projectors; and (3) additional errors (those due to the camera calibration itself). Most of these camera-based methods make use of planar homographies, and others require an extended calibration process (for both the camera and the projector). In this paper, we present an approach that combines a direct transformation method (DLT) with projected augmented reality to perform an interactive calibration of projectors without the need for cameras. This method is based on non-coplanar points and 2D/3D correspondences, which are interactively established. Intrinsic and extrinsic calibration is achieved in a single step, making use of the DLT. The method rescues old approaches to calibrate projectors, but brings the new capabilities of interactive systems, all integrated in a single software solution. We conduct different experiments by considering two projector setups and two different sets of control points, proving that the accuracy of the method in the real space can be between one and two pixels.
关键词： Photogrammetry,Augmented reality,DLT,Cameraless,Interactive,Calibration,Projector
更新于2025-09-23 15:22:29
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Camera localization for augmented reality and indoor positioning: a vision-based 3D feature database approach
摘要： The recent fast development in computer vision and mobile sensor technology such as mobile LiDAR and RGB-D cameras is pushing the boundary of the technology to suit the need of real-life applications in the fields of Augmented Reality (AR), robotics, indoor GIS and self-driving. Camera localization is often a key and enabling technology among these applications. In this paper, we developed a novel camera localization workflow based on a highly accurate 3D prior map optimized by our RGB-D SLAM method in conjunction with a deep learning routine trained using consecutive video frames labeled with high precision camera pose. Furthermore, an AR registration method tightly coupled with a game engine is proposed, which incorporates the proposed localization algorithm and aligns the real Kinetic camera with a virtual camera of the game engine to facilitate AR application development in an integrated manner. The experimental results show that the localization accuracy can achieve an average error of 35 cm based on a fine-tuned prior 3D feature database at 3 cm accuracy compared against the ground-truth 3D LiDAR map. The influence of the localization accuracy on the visual effect of AR overlay is also demonstrated and the alignment of the real and virtual camera streamlines the implementation of AR fire emergency response demo in a Virtual Geographic Environment.
关键词： LiDAR,virtual geographic environment (VGE),localization,indoor positioning,camera pose,Augmented reality (AR),indoor GIS,3D reconstruction
更新于2025-09-23 15:22:29
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A Comparison of Predictive Spatial Augmented Reality Cues for Procedural Tasks
摘要： Previous research has demonstrated that Augmented Reality can reduce a user's task response time and mental effort when completing a procedural task. This paper investigates techniques to improve user performance and reduce mental effort by providing projector-based Spatial Augmented Reality predictive cues for future responses. The objective of the two experiments conducted in this study was to isolate the performance and mental effort differences from several different annotation cueing techniques for simple (Experiment 1) and complex (Experiment 2) button-pressing tasks. Comporting with existing cognitive neuroscience literature on prediction, attentional orienting, and interference, we hypothesized that for both simple procedural tasks and complex search-based tasks, having a visual cue guiding to the next task's location would positively impact performance relative to a baseline, no-cue condition. Additionally, we predicted that direction-based cues would provide a more significant positive impact than target-based cues. The results indicated that providing a line to the next task was the most effective technique for improving the users' task time and mental effort in both the simple and complex tasks.
关键词： Spatial augmented reality,mental effort,predictive cue,procedural task
更新于2025-09-23 15:21:21
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Identifying the Optimal 3D Display Technology for Hands-On Virtual Experiential Learning: A Comparison Study
摘要： The purpose of this study was to test different 3D display technologies in a hands-on virtual experiential learning environment (VELE) and determine the optimal 3D display technology. A conceptual framework was firstly proposed to explain the mechanism of how VR display features affect virtual experiential learning. Then, a single-factor within-subject experimental design was adopted for testing. The within-subject factor was three types of 3D display technology: fully immersive virtual reality (VR) mode [VR head-mounted display (HMD)], partially immersive VR mode (3D projection), and augmented reality (AR) mode (AR HMD). The dependent variables were visual comfort, interaction experience, learning experience, and outcome. A virtual math learning environment was established, and the aforementioned display technologies were tested in two hands-on virtual experiential learning scenarios. Results showed that different display technologies significantly affected users’ visual comfort, interaction experience, learning experience, and outcome in experiential learning (ps < 0.05). User ratings on these aspects for the VR HMD were significantly higher than those for the 3D projection and AR HMD. Thus, the VR HMD contributes to a best viewing experience and learning experience in terms of hands-on virtual experiential learning in the scenarios tested. Whether the study results still hold reliably in terms of more complex learning activities and long-term learning needs to be further studied.
关键词： visual comfort,Experiential learning,augmented reality,hands-on learning,virtual reality
更新于2025-09-23 15:21:01
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Chirped polarization volume grating for wide FOV and higha??efficiency waveguidea??based AR displays
摘要： We demonstrate a reflective chirped polarization volume grating as a strong contender for wide field-of-view augmented reality display systems. By introducing gradient pitch along the beam propagation direction, the angular bandwidth extends dramatically from 18(cid:1) to 54(cid:1) while keeping over 80% average efficiency and 95% peak efficiency.
关键词： liquid crystals,augmented reality,polarization volume grating,gradient pitch structure
更新于2025-09-23 15:21:01
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[ACM Press the 12th International Conference - Eindhoven, Netherlands (2018.09.03-2018.09.04)] Proceedings of the 12th International Conference on Distributed Smart Cameras - ICDSC '18 - Hand-Eye Camera Calibration with an Optical Tracking System
摘要： This paper presents a method for hand-eye camera calibration via an optical tracking system (OTS) faciltating robotic applications. The camera pose cannot be directly tracked via the OTS. Because of this, a transformation matrix between a marker-plate pose, tracked via the OTS, and the camera pose needs to be estimated. To this end, we evaluate two different approaches for hand-eye calibration. In the first approach, the camera is in a fixed position and a 2D calibration plate is displaced. In the second approach, the camera is also fixed, but now a 3D calibration object is moved. The first step of our method consists of collecting N views of the marker-plate pose and the calibration plates, acquired via OTS. This is achieved by keeping the camera fixed and moving the calibration plate, while taking a picture of the calibration plate using the camera. A dataset is constructed that contains marker-plate poses and the relative camera poses. Afterwards, the transformation matrix is then computed, following a least-squares minimization. Accuracy in hand-eye calibration is computed in terms of re-projection error, calculated based on camera homography transformations. For both approaches, we measure the changes in accuracy as a function of the number of poses used for each calibration, while we define the minimum number of poses required to obtain a good camera calibration. Results of the experiments show similar performances for the two evaluated methods, achieving a median value of the re-projection error at N = 25 poses of 0.76 mm for the 2D calibration plate and 0.70 mm for the 3D calibration object. Also, we have found that minimally 15 poses are required to achieve a good camera calibration.
关键词： optical tracking system,neurosurgery,augmented reality,Hand-eye calibration,endoscope,tracking
更新于2025-09-23 15:21:01
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Real-Time Texture-less Object Recognition on Mobile Devices
摘要： This paper presents a technique for real-time texture-less object recognition and tracking on mobile devices. Our proposed algorithm is an even lighter-weight version of the recent state-of-the-art binary-based texture-less object detector BIND (Binary Integrated Net Descriptor), primarily customized for mobile device applications. This modification, termed BIND-Lite, employs various techniques to overcome the low-computational power of current mobile devices, while mostly retaining the texture-less object detection robustness of the original BIND. On current generation mobile devices, BIND-Lite was able to achieve runtime rates of up to 30 frames per second. To evaluate our algorithm, we have also designed a mobile augmented reality application coined IMPRINT, which renders logos/images onto detected objects to showcase BIND-Lite in a real-time mobile augmented reality setting.
关键词： mobile augmented reality,Real Time,object detection,binary descriptor,texture-less,binary matching
更新于2025-09-23 15:21:01
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Light source estimation using feature points from specular highlights and cast shadows
摘要： A method for light sources estimation is proposed in this paper. The method utilizes feature points in cast shadows to estimate near light source positions from estimated source directions using specular highlights. There are several methods that can be used to estimate light sources from scene images, using either cast shadows or specular highlights. However, most of them are limited to directional light sources. The proposed method can estimate the positions and intensities of multiple near point light sources. Specular highlights on an object of known geometry are first used for light source direction estimation. Then, a discontinuity point in the object shape and the corresponding cast shadow on a ground plane are used for light source position estimation. Feature points obtained from an image of the cast shadow, however, can be inaccurate due to various factors. Information on diffused light reflected from Lambertian ground-plane surface is subsequently used to improve estimation accuracy. Experimental results were used to evaluate the performance of the proposed method.
关键词： light source recovery,augmented reality,Light source estimation
更新于2025-09-23 15:21:01
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Study on the adaptability of augmented reality smartglasses for astigmatism based on holographic waveguide grating
摘要： Background Augmented reality (AR) smartglasses are considered as the next generation of smart devices to replace mobile phones, and are widely concerned. But at present, AR smartglasses are usually designed according to the human normal eyes. In order to experience AR smartglasses perfectly, abnormal eye users must first wear diopters. Methods For people with astigmatism to use AR smartglasses without wearing a diopter lens, a cylindrical lens waveguide grating is designed in this study based on the principle of holographic waveguide grating. First, a cylindrical lens waveguide substrate is constructed for external light deflection to satisfy the users' normal viewing of the real world. Further, a variable period grating structure is established based on the cylindrical lens waveguide substrate to normally emit the light from the virtual world in the optical machine to the human eyes. Finally, the structural parameters of grating are optimized to improve the diffraction efficiency. Results The results show that the structure of cylindrical lens waveguide grating allows people with astigmatism to wear AR smartglasses directly. The total light utilization rate reaches 90% with excellent imaging uniformity. The brightness difference is less than 0.92% and the vertical field of view is 10°. Conclusions This research serves as a guide for AR product designs for people with long/short sightedness and promotes the development of such products.
关键词： Astigmatism,Augmented reality smartglasses,Holographic waveguide grating,Cylindrical lens
更新于2025-09-23 15:19:57