• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.11-18
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• 2018

To interact with a virtual object in immersive virtual environment, the target object should be selected quickly and accurately. Conventional 3D ray casting method using a direction of user's hand or head allows the user to select an object quickly. However, accuracy problem occurs when selecting an object using conventional methods among occlusion of objects. In this paper, we propose a region of interest based selection method that enables to select an object among occlusion of objects using a combination of gaze tracking and hand gesture recognition. When a user looks at a group of occlusion of objects, the proposed method recognizes user's gaze input, and then region of interest is set by gaze input. If the user wants to select an object among them, the user gives an activation hand gesture. Then, the proposed system relocates and visualizes all objects on a virtual active window. The user can select an object by a selecting hand gesture. Our experiment verified that the user can select an object correctly and accurately.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.896-908
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• 2003

Interaction technique in .3D virtual environment is a decisive factor that affects the immersion and presence felt by users in virtual space. Especially, in fields that require exquisite manipulation of objects such as electronic manuals in desktop environment, interaction technique that supports effective and natural manipulation of object is in demand. In this paper, 3D scene graph can be internally divided and reconstructed to a list defending on the users selection and through moving focus among the selection candidate objects list, the user can select 3D object more accurately Also, by providing various feedbacks for each manipulation stage, more effective manipulation is possible. The proposed technique can be used as 3D user interface in areas that require exquisite object manipulation.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.666-673
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• 2019

In the immersive virtual reality environment, we can select and manipulate various virtual objects. in order to select a virtual object, we generally use Ray-casting method that fires a virtual line in user's view and selects an object when the line and the object match, or Cone-casting method that is widely used to select multiple objects at the same time. However, since the virtual objects used in CAD are composed of small and complex objects in detail, when selecting an object in the user's view by existing methods, there occurs a ambiguity problem that needs additional realignment operation even though an object is selected as a group. in this paper, even if a virtual object is composed of several small virtual objects, it calculates the spatial and logical relationship among objects and expands or shrinks desired objects, so that the user can quickly and accurately select a desired object. in order to evaluate the proposed method, performance comparison were performed using Our and Ray-Casting and Cone-Casting methods. Experimental results show that the proposed method has the fastest speed and the highest accuracy when selecting the desired objects.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.704-713
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• 2021

This paper proposes a method to prioritize the virtual objects to be selected, considering both the user's hand and the geometric relationship with the virtual objects and the user's intention which is recognized in advance. Picking up virtual objects in VR content is an essential and most commonly used interaction. When virtual objects are located close to each other in VR, a situation occurs in which virtual objects that are different from the user's intention are selected. To address this issue, this paper provides different weights for user intentions and distance between user's hand and virtual objects to derive priorities in order to generate interactions appropriately according to the situation. We conducted the experiment in the situation where the number of virtual objects and the distance between virtual objects are diversified. Experiments demonstrate the effectiveness of the proposed method when the density between virtual objects is high and the distance between each other is close, user satisfaction increases to 20.34% by increasing the weight ratio of the situation awareness. We expect the proposed method to contribute to improving interaction skills that can reflect users' intentions.

• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.9-17
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• 2017

This study proposes a third-person virtual reality content production pipeline to provide users with a new experience and presence in a new virtual reality environment. For this purpose, we first create third-person virtual reality content, which includes a story, fun factors, and game characteristic. It consists of a tutorial scene in which a user can pre-learn the proposed interface suitable for a third person different from existing virtual reality content and a content scene that achieves its purpose by using game factors based on the background story. Next, we design an interface suitable for the third-person virtual reality content. This study proposes an interface in which users can interact with a virtual environment or object by using their hand. The proposed interface consists of three steps: character movement, virtual object selection with multiple selection, and 3D menu control using virtual space. Finally, through the survey experiment, third-person virtual reality content produced based on the proposed interface was confirmed to be easily controlled while ensuring high satisfaction.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.492-497
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• 2009

Computer-Generated Hologram (CGH) is made for three dimensional image of a virtual object. Error diffusion method is used for the phase quantization of CGH, and it is known to be effective to the image quality improvement of the reconstructed image. However, the image quality of the reconstructed image from the CGH using error diffusion method depends on the selection of error diffusion coefficient. In this paper, we derived the relational expression to obtain the error diffusion coefficient from the position of the input object and size of the input object for CGH. As a result, the method of this thesis was able to obtain an excellent reconstructed image compared with the case to derive the error diffusion coefficient from only the position of the input image.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.207-212
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• 1999

In VEs (virtual environments) such as a CAVE system, there are three important operations : executive command decision, object selection and 3-D (three-dimensional) pointing. It is necessary to implement these operations in VEs intuitively and accessibly. In CAVE, it is possible for examines to walk and change their viewpoints freely. Then, the input devices which have excellent portability and rich expression are desired. Speech input satisfies both requirements. It is, however, very difficult for the speech input to indicate an exact point in 3-D space. Therefore, an extendable virtual stick is employed and it supports speech input. This paper proposes a user friendly interface using speech and a virtual stick in CAVE system. In this paper, several applications appropriate for the proposed interface are developed. Some problems are pointed out from the applications.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.499-506
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• 2006

This Paper describes a fast and stable camera pose estimation method for real-time augmented reality systems. From the feature tracking results of a marker on a single frame, we estimate the camera rotation matrix and the translation vector. For the camera pose estimation, we use the shape factorization method based on the scaled orthographic Projection model. In the scaled orthographic factorization method, all feature points of an object are assumed roughly at the same distance from the camera, which means the selected reference point and the object shape affect the accuracy of the estimation. This paper proposes a flexible and stable selection method for the reference point. Based on the proposed method, we implemented a video augmentation system that inserts virtual 3D objects into the input video frames. Experimental results showed that the proposed camera pose estimation method is fast and robust relative to the previous methods and it is applicable to various augmented reality applications.

• Journal of the Korea Computer Graphics Society
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• v.3 no.2
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• pp.1-13
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• 1997

Two factors are required for a virtual reality system; realism and immersion. Since realism is determined primarily by the realistic image, objects in a virtual environment should be represented with details by their own characteristics. Also, reflection on light must be considered. On the other hand, immersion is defined as realistic movements and fast interactions. Thus, virtual environment should be rendered as fast as possibl. Regular frame rate should also be kept to make moves as intended by the user. In a complex virtual environment composed of objects with various levels, the appropriate level for individual object should be assigned according to the view point, in other words, the selection of level-of-detail is needed. In this paper, the problem of determining the levels of detail is formalized in terms of error, cost and L -distance. Error is defined as the difference between the current level image and the highest level image, cost as rendering time, and L-distance as the level difference between the previous and the current level. To solve this problem, a new method called the well-distributed adaptive algorithmis proposed.