Byung-Gook Lee

Hand tracking and gesture recognition system for human-computer interaction using low-cost hardware

Human-Computer Interaction (HCI) exists ubiquitously in our daily lives. It is usually achieved by using a physical controller such as a mouse, keyboard or touch screen. It hinders Natural User Interface (NUI) as there is a strong barrier between the user and computer. There are various hand tracking systems available on the market, but they are complex and expensive. In this paper, we present the design and development of a robust marker-less hand/finger tracking and gesture recognition system using low-cost hardware. We propose a simple but efficient method that allows robust and fast hand tracking despite complex background and motion blur. Our system is able to translate the detected hands or gestures into different functional inputs and interfaces with other applications via several methods. It enables intuitive HCI and interactive motion gaming. We also developed sample applications that can utilize the inputs from the hand tracking system. Our results show that an intuitive HCI and motion gaming system can be achieved with minimum hardware requirements.

Occlusion removal method of partially occluded 3D object using sub-image block matching in computational integral imaging

In this paper, we propose an occlusion removal method using sub-image block matching for improved recognition of partially occluded 3D objects in computational integral imaging (CII). When 3D plane images are reconstructed in CII, occlusion degrades the resolution of reconstructed images. To overcome this problem, we apply the sub-image transform to elemental image array (EIA) and these sub-images are employed using block matching method for depth estimation. Based on the estimated depth information, we remove the unknown occlusion. After completing the occlusion removal for all sub-images, we obtain the modified EIA without occlusion information through the inverse sub-image transform. Finally, the 3D plane images are reconstructed by using a computational integral imaging reconstruction method with the modified EIA. The proposed method can provide a substantial gain in terms of the visual quality of 3D reconstructed images. To show the usefulness of the proposed method we carry out some experiments and the results are presented.

Constrained polynomial degree reduction in the L 2 -norm equals best weighted Euclidean approximation of Bézier coefficients

In this paper we show that the best constrained degree reduction of a given Bezier curve f of degree from n to m with Cα-1-continuity at the boundary in L2-norm is equivalent to the best weighted Euclidean approximation of the vector of Bernstein-Bezier (BB) coefficients of f from the vector of degree raised BB coefficients of polynomials of degree m with Cα-1-continuity at the boundary.

Secure storage and access of data in cloud computing

Cloud computing is the most demanded advanced technology throughout the world. It is one of the most significant topic whose application is being researched in todays time. One of the prominent services offered in cloud computing is the cloud storage. With the cloud storage, data is stored on multiple third party servers, rather than on the dedicated server used in traditional networked data storage. All data stored on multiple third party servers is not cared by the user and no one knows where exactly data saved. It is cared by the cloud storage provider that claims that they can protect the data but no one believes them. Data stored over cloud and flow through network in the plain text format is security threat. This paper proposes a method that allows user to store and access the data securely from the cloud storage. It also guarantees that no one except the authenticated user can access the data neither the cloud storage provider. This method ensures the security and privacy of data stored on cloud. A further advantage of this method is that if there is security breach at the cloud provider, the users data will continue to be secure since all data is encrypted. Users also need not to worry about cloud providers gaining access to their data illegally.

A low complexity and lossless frame memory compression for display devices

In this paper, we introduce a new low complexity and lossless algorithm based on subband decomposition with the modified Hadamard transform (MHT) and adaptive Golomb-Rice (AGR) coding for display devices. The main goal of the proposed method is to reduce memory requirement for display devices. A basic unit of the proposed method is a line of the image so that the method is processed line by line. Also, MHT and AGR coding are utilized to achieve low complexity. The major improvement of the method is from the use of AGR and subband processing compared with exiting methods which are similar to the method in terms of complexity and applications. Simulation results show that the algorithm achieves a superior compression performance to the existing methods. In addition, the proposed method is hardware-friendly and could be easily implemented in any display devices.

A ternary 4-point approximating subdivision scheme

In the implementation of subdivision scheme, three of the most important issues are smoothness, size of support, and approximation order. Our objective is to introduce an improved ternary 4-point approximating subdivision scheme derived from cubic polynomial interpolation, which has smaller support and higher smoothness, comparing to binary 4-point and 6-point schemes, ternary 3-point and 4-point schemes (see Table 2). The method is easily generalized to ternary (2n + 2)point approximating subdivision schemes. We choose a ternary scheme because a way to get smaller support is to raise arity. And we use polynomial reproduction to get higher approximation order easily. 2007 Elsevier Inc. All rights reserved.

Application of Legendre--Bernstein basis transformations to degree elevation and degree reduction

We study the relationship of transformations between Legendre and Bernstein basis. Using the relationship, we present a simple and efficient method for optimal multiple degree reductions of Bezier curves with respect to the L2-norm.

Resolution-enhanced three-dimensional image reconstruction by use of smart pixel mapping in computational integral imaging

Computational integral imaging method can digitally provide a series of plane images of three-dimensional (3D) objects. However, the resolution of 3D reconstructed images is dramatically degraded as the distance from the lenslet array increases. In this paper, to overcome this problem, we propose a novel computational integral imaging reconstruction (CIIR) method based on smart pixel mapping (SPM). Since SPM is a computational process in which elemental images recorded at long distances are convertible to ones recorded near lenslet array, this can give us the improved resolution of plane images for 3D objects located at a long distance range from a lenslet array. For the effective use of the SPM-based CIIR method, we design a novel two-stage CIIR method by the combined use of the conventional CIIR and the SPM-based one. The conventional CIIR method is applied over a short distance range, while the SPM-based CIIR is used over a long distance range. We carry out some experiments to verify the performance of the two-stage CIIR system. From the experimental results, the proposed system can provide a substantial gain over a long distance range in terms of the resolution of reconstructed plane images.

Depth extraction of three-dimensional objects using block matching for slice images in synthetic aperture integral imaging.

We describe a computational method for depth extraction of three-dimensional (3D) objects using block matching for slice images in synthetic aperture integral imaging (SAII). SAII is capable of providing high-resolution 3D slice images for 3D objects because the picked-up elemental images are high-resolution ones. In the proposed method, the high-resolution elemental images are recorded by moving a camera; a computational reconstruction algorithm based on ray backprojection generates a set of 3D slice images from the recorded elemental images. To extract depth information of the 3D objects, we propose a new block-matching algorithm between a reference elemental image and a set of 3D slice images. The property of the slices images is that the focused areas are the right location for an object, whereas the blurred areas are considered to be empty space; thus, this can extract robust and accurate depth information of the 3D objects. To demonstrate our method, we carry out the preliminary experiments of 3D objects; the results indicate that our method is superior to a conventional method in terms of depth-map quality.

A simple matrix form for degree reduction of Bezier curves using Chebyshev-Bernstein basis transformations

We use the matrices of transformations between Chebyshev and Bernstein basis and the matrices of degree elevation and reduction of Chebyshev polynomials to present a simple and efficient method for r times degree elevation and optimal r times degree reduction of Bezier curves with respect to the weighted L2-norm for the interval [0, 1], using the weight function w(x)=1/4x-4x2. The error of the degree reduction scheme is given, and the degree reduction with continuity conditions is also considered.