scholarly journals Large Area Robust Hybrid Tracking with Life-size Avatar in Mixed Reality Environment for Cultural and Historical Installation

2009 ◽  
Vol 8 (2) ◽  
pp. 13-18
Author(s):  
William Russell Pensyl ◽  
Tran C. T. Qui ◽  
Pei Fang Hsin ◽  
Shang Ping Lee ◽  
Daniel K. Jernigan
Keyword(s):  
Computer Vision ◽  
Mixed Reality ◽  
Inertial Sensors ◽  
Point Of View ◽  
Historical Narratives ◽  
Large Area ◽  
The Real ◽  
Lighting Conditions ◽  
Low Jitter ◽  
Present World

We have developed a system which enables us to track participant-observers accurately in a large area for the purpose of immersing them in a mixed reality environment. This system is robust even under uncompromising lighting conditions. Accurate tracking of the observer�s spatial and orientation point of view is achieved by using hybrid inertial sensors and computer vision techniques. We demonstrate our results by presenting a life-size, animated human avatar sitting in a real chair, in a stable and low-jitter manner. The system installation allows the observers to freely walk around and navigate themselves in the environment even while still being able to see the avatar from various angles. The project installation provides an exciting way for cultural and historical narratives to be presented vividly in the real present world.

scholarly journals Reconstruction Lighting Positions of a Scene for Mixed Reality Systems Using Convolutional Neural Network and Shadow Ray Tracing

2021 ◽  
pp. 1-18
Author(s):  
Maxim Igorevich Sorokin ◽  
Dmitry Dmitrievich Zhdanov ◽  
Ildar Vagizovich Valiev
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Computer Vision ◽  
Ray Tracing ◽  
Light Source ◽  
Virtual Worlds ◽  
Mixed Reality ◽  
The Real ◽  
Virtual Objects ◽  
Lighting Conditions

The paper examines the causes of visual discomfort in mixed reality systems and algorithmic solutions that eliminate one of the main causes of discomfort, namely, the mismatch between the lighting conditions of objects in the real and virtual worlds. To eliminate this cause of discomfort, the algorithm is proposed, which consists in constructing groups of shadow rays from points on the boundaries of shadows to points on the boundaries of objects. Part of the rays corresponding to the real lighting conditions form caustics in area of the real light source, which makes it possible to determine the source of illumination of virtual objects for their correct embedding into the mixed reality system. Convolutional neural networks and computer vision algorithms were used to classify shadows in the image. Examples of reconstructing the coordinates of a light source from RGBD data are presented.

scholarly journals Lighting parameter restoration method in mixed reality systems

2021 ◽  
pp. 1-17
Author(s):  
Andrew Fedorovich Lemeshev ◽  
Dmitry Dmitrievich Zhdanov ◽  
Boris Khaimovich Barladyan
Keyword(s):  
Real World ◽  
Virtual World ◽  
Mixed Reality ◽  
Light Sources ◽  
Effective Solution ◽  
The Real ◽  
Virtual Objects ◽  
Lighting Conditions ◽  
Restoration Method

The paper deals with the problem of visual perception discomfort inherent in mixed reality systems, more precisely, the determination of the lighting parameters of the objects of the virtual world, corresponding to the lighting conditions of the real world, into which the virtual objects are embedded. The paper proposes an effective solution to the problem of reconstructing the coordinates of a light source from an RGBD image of the real world. A detailed description of the algorithm and the results of a numerical experiment on reconstructing the coordinates of light sources in a model scene are given. The accuracy of coordinate recovery is analyzed and the limitations of the method are considered, associated with the inaccuracy of determining the boundaries of objects and their shadows, as well as the lack of interconnected areas of the boundaries of objects and their shadows in the RGBD image of the scene.

Real-world environment affects the color appearance of virtual stimuli produced by augmented reality

2019 ◽  
Vol 2019 (1) ◽  
pp. 237-242
Author(s):  
Siyuan Chen ◽  
Minchen Wei
Keyword(s):  
Augmented Reality ◽  
Real World ◽  
Mixed Reality ◽  
Rapid Development ◽  
Light Level ◽  
Color Appearance ◽  
Chromatic Adaptation ◽  
Lighting Condition ◽  
The Real ◽  
World Environment

Color appearance models have been extensively studied for characterizing and predicting the perceived color appearance of physical color stimuli under different viewing conditions. These stimuli are either surface colors reflecting illumination or self-luminous emitting radiations. With the rapid development of augmented reality (AR) and mixed reality (MR), it is critically important to understand how the color appearance of the objects that are produced by AR and MR are perceived, especially when these objects are overlaid on the real world. In this study, nine lighting conditions, with different correlated color temperature (CCT) levels and light levels, were created in a real-world environment. Under each lighting condition, human observers adjusted the color appearance of a virtual stimulus, which was overlaid on a real-world luminous environment, until it appeared the whitest. It was found that the CCT and light level of the real-world environment significantly affected the color appearance of the white stimulus, especially when the light level was high. Moreover, a lower degree of chromatic adaptation was found for viewing the virtual stimulus that was overlaid on the real world.

DEVELOPMENT OF COMPUTERIZED MONITORING AND CONTROL SYSTEM OF THE MOBILE ROBOT’S POSITIONING ON LARGE FERROMAGNETIC SURFACES BASED ON INTELLIGENT TECHNIQUES. COMPLEX OF TASKS OF MONITORING AND AUTOMATIC CONTROL OF MOBILE

2019 ◽  
pp. 37-47
Author(s):  
Yao Yueqin ◽  
Oleksiy Kozlov ◽  
Oleksandr Gerasin ◽  
Galyna Kondratenko
Keyword(s):  
Automatic Control ◽  
Point Of View ◽  
Monitoring And Control ◽  
Large Area ◽  
Monitoring And Control System ◽  
Technical Parameters ◽  
Automatic Control Systems ◽  
Current State ◽  
Computerized Monitoring ◽  
And Control

Analysis and formalization of the monitoring and automatic control tasks of the MR for the movement and execution of various types of technological operations on inclined and vertical ferromagnetic surfaces are obtained. Generalized structure of mobile robotic complex is shown with main subsystems consideration. Critical analysis of the current state of the problem of development of universal structures of mobile robots (MRs) for the various types of technological operations execution and elaborations of computerized systems for monitoring and control of MR movement is done. In particular, wheeled, walked and crawler type MRs with pneumatic, vacuum-propeller, magnetic and magnetically operated clamping devices to grip with vertical and ceiling surfaces are reviewed. The constructive features of the crawler MR with magnetic clamping devices capable of moving along sloping ferromagnetic surfaces are considered. The basic technical parameters of the MR are shown for the further synthesis of computerized monitoring and automatic control systems. Formalization of the tasks of monitoring and control of the MR positioning at the processing of large area ferromagnetic surfaces is considered from the point of view of control theory.

Developing Algorithms for a Berry Recognition System Used in Robotized Harvesting of Garden Strawberry

2020 ◽  
Vol 67 (1) ◽  
pp. 133-141
Author(s):  
Dmitriy O. Khort ◽  
Aleksei I. Kutyrev ◽  
Igor G. Smirnov ◽  
Rostislav A. Filippov ◽  
Roman V. Vershinin
Keyword(s):  
Computer Vision ◽  
Technological Process ◽  
Degrees Of Freedom ◽  
Computer Control ◽  
Recognition System ◽  
Raspberry Pi ◽  
Laser Sensors ◽  
Lighting Conditions ◽  
Systems Research ◽  
Degree Of Maturity

Technological capabilities of agricultural units cannot be optimally used without extensive automation of production processes and the use of advanced computer control systems. (Research purpose) To develop an algorithm for recognizing the coordinates of the location and ripeness of garden strawberries in different lighting conditions and describe the technological process of its harvesting in field conditions using a robotic actuator mounted on a self-propelled platform. (Materials and methods) The authors have developed a self-propelled platform with an automatic actuator for harvesting garden strawberry, which includes an actuator with six degrees of freedom, a co-axial gripper, mg966r servos, a PCA9685 controller, a Logitech HD C270 computer vision camera, a single-board Raspberry Pi 3 Model B+ computer, VL53L0X laser sensors, a SZBK07 300W voltage regulator, a Hubsan X4 Pro H109S Li-polymer battery. (Results and discussion) Using the Python programming language 3.7.2, the authors have developed a control algorithm for the automatic actuator, including operations to determine the X and Y coordinates of berries, their degree of maturity, as well as to calculate the distance to berries. It has been found that the effectiveness of detecting berries, their area and boundaries with a camera and the OpenCV library at the illumination of 300 Lux reaches 94.6 percent’s. With an increase in the robotic platform speed to 1.5 kilometre per hour and at the illumination of 300 Lux, the average area of the recognized berries decreased by 9 percent’s to 95.1 square centimeter, at the illumination of 200 Lux, the area of recognized berries decreased by 17.8 percent’s to 88 square centimeter, and at the illumination of 100 Lux, the area of recognized berries decreased by 36.4 percent’s to 76 square centimeter as compared to the real area of berries. (Conclusions) The authors have provided rationale for the technological process and developed an algorithm for harvesting garden strawberry using a robotic actuator mounted on a self-propelled platform. It has been proved that lighting conditions have a significant impact on the determination of the area, boundaries and ripeness of berries using a computer vision camera.

scholarly journals A Track Geometry Measuring System Based on Multibody Kinematics, Inertial Sensors and Computer Vision

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 683
Author(s):  
José L. Escalona ◽  
Pedro Urda ◽  
Sergio Muñoz
Keyword(s):  
Computer Vision ◽  
Inertial Sensors ◽  
Vision System ◽  
Accurate Method ◽  
Sensor Data ◽  
Measuring System ◽  
Railway Vehicles ◽  
Track Geometry ◽  
Video Cameras ◽  
Measuring Unit

This paper describes the kinematics used for the calculation of track geometric irregularities of a new Track Geometry Measuring System (TGMS) to be installed in railway vehicles. The TGMS includes a computer for data acquisition and process, a set of sensors including an inertial measuring unit (IMU, 3D gyroscope and 3D accelerometer), two video cameras and an encoder. The kinematic description, that is borrowed from the multibody dynamics analysis of railway vehicles used in computer simulation codes, is used to calculate the relative motion between the vehicle and the track, and also for the computer vision system and its calibration. The multibody framework is thus used to find the formulas that are needed to calculate the track irregularities (gauge, cross-level, alignment and vertical profile) as a function of sensor data. The TGMS has been experimentally tested in a 1:10 scaled vehicle and track specifically designed for this investigation. The geometric irregularities of a 90 m-scale track have been measured with an alternative and accurate method and the results are compared with the results of the TGMS. Results show a good agreement between both methods of calculation of the geometric irregularities.

MixAR

2019 ◽  
Vol 12 (4) ◽  
pp. 1-33 ◽  
Author(s):  
Telmo Adão ◽  
Luís Pádua ◽  
David Narciso ◽  
Joaquim João Sousa ◽  
Luís Agrellos ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Mixed Reality ◽  
The Real ◽  
Points Of Interest ◽  
Real Scene ◽  
The Future

MixAR, a full-stack system capable of providing visualization of virtual reconstructions seamlessly integrated in the real scene (e.g. upon ruins), with the possibility of being freely explored by visitors, in situ, is presented in this article. In addition to its ability to operate with several tracking approaches to be able to deal with a wide variety of environmental conditions, MixAR system also implements an extended environment feature that provides visitors with an insight on surrounding points-of-interest for visitation during mixed reality experiences (positional rough tracking). A procedural modelling tool mainstreams augmentation models production. Tests carried out with participants to ascertain comfort, satisfaction and presence/immersion based on an in-field MR experience and respective results are also presented. Ease to adapt to the experience, desire to see the system in museums and a raised curiosity and motivation contributed as positive points for evaluation. In what regards to sickness and comfort, the lowest number of complaints seems to be satisfactory. Models' illumination/re-lightning must be addressed in the future to improve the user's engagement with the experiences provided by the MixAR system.

Natural Locomotion Based on Foot-Mounted Inertial Sensors in a Wireless Virtual Reality System

2015 ◽  
Vol 24 (4) ◽  
pp. 298-321 ◽  
Author(s):  
Ernesto de la Rubia ◽  
Antonio Diaz-Estrella
Keyword(s):  
Virtual Reality ◽  
Gait Cycle ◽  
Inertial Sensors ◽  
Low Cost ◽  
Point Of View ◽  
Handheld Devices ◽  
Preliminary Evaluation ◽  
Virtual Reality System ◽  
Object Searching

Virtual reality has become a promising field in recent decades, and its potential now seems clearer than ever. With the development of handheld devices and wireless technologies, interest in virtual reality is also increasing. Therefore, there is an accompanying interest in inertial sensors, which can provide such advantages as small size and low cost. Such sensors can also operate wirelessly and be used in an increasing number of interactive applications. An example related to virtual reality is the ability to move naturally through virtual environments. This is the objective of the real-walking navigation technique, for which a number of advantages have previously been reported in terms of presence, object searching, and collision, among other concerns. In this article, we address the use of foot-mounted inertial sensors to achieve real-walking navigation in a wireless virtual reality system. First, an overall description of the problem is presented. Then, specific difficulties are identified, and a corresponding technique is proposed to overcome each: tracking of foot movements; determination of the user’s position; percentage estimation of the gait cycle, including oscillating movements of the head; stabilization of the velocity of the point of view; and synchronization of head and body yaw angles. Finally, a preliminary evaluation of the system is conducted in which data and comments from participants were collected.

Art. XIX.—An old Hebrew Romance of Alexander

1897 ◽  
Vol 29 (3) ◽  
pp. 485-549
Author(s):  
M. Gaster
Keyword(s):  
Middle Ages ◽  
Early Period ◽  
Point Of View ◽  
The Other ◽  
The West ◽  
The Real ◽  
History Of ◽  
Bibliographical Information ◽  
Ancient Times ◽  
Great Mass

More marvellous and more remarkable than the real conquests of Alexander are the stories circulated about him, and the legends which have clustered round his name and his exploits. The history of Alexander has, from a very early period, been embellished with legends and tales. They spread from nation to nation during the whole of the ancient times, and all through the Middle Ages. Many scholars have followed up the course of this dissemination of the fabulous history of Alexander. It would, therefore, be idle repetition of work admirably done by men like Zacher, Wesselofsky, Budge, and others, should I attempt it here. All interested in the legend of Alexander are familiar with those works, where also the fullest bibliographical information is to be found. I am concerned here with what may have appeared to some of these students as the bye-paths of the legend, and which, to my mind, has not received that attention which is due to it, from more than one point of view. Hitherto the histories of Alexander were divided into two categories; the first were those writings which pretended to give a true historical description of his life and adventures, to the exclusion of fabulous matter; the other included all those fabulous histories in which the true elements were smothered under a great mass of legendary matter, the chief representative of this class being the work ascribed to a certain Callisthenes. The study of the legend centred in the study of the vicissitudes to which this work of (Pseudo-) Callisthenes had been exposed, in the course of its dissemination from the East, probably from its native country, Egypt, to the countries of the West.

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