Browsing by Author "Wong, S."

Now showing 1 - 5 of 5

Citation - Scopus: 1
Hierarchical SNR Scalable Video Coding with Adaptive Quantization for Reduced Drift Error
(SciTePress, 2015) Choupani, R.; Wong, S.; Tolun, M.
In video coding, dependencies between frames are being exploited to achieve compression by only coding the differences. This dependency can potentially lead to decoding inaccuracies when there is a communication error, or a deliberate quality reduction due to reduced network or receiver capabilities. The dependency can start at the reference frame and progress through a chain of dependent frames within a group of pictures (GOP) resulting in the so-called drift error. Scalable video coding schemes should deal with such drift errors while maximizing the delivered video quality. In this paper, we present a multi-layer hierarchical structure for scalable video coding capable of reducing the drift error. Moreover, we propose an optimization to adaptively determine the quantization step size for the base and enhancement layers. In addition, we address the trade-off between the drift error and the coding efficiency. The improvements in terms of average PSNR values when one frame in a GOP is lost are 3.70(dB) when only the base layer is delivered, and 4.78(dB) when both the base and the enhancement layers are delivered. The improvements in presence of burst errors are 3.52(dB) when only the base layer is delivered, and 4.50(dB) when both base and enhancement layers are delivered. Copyright © 2015 SCITEPRESS - Science and Technology Publications All rights reserved.
Citation - Scopus: 0
Optimized Multiple Description Coding for Temporal Video Scalability
(Springer Verlag, 2013) Choupani, R.; Wong, S.; Tolun, M.
The vast application of video streaming over the Internet requires video adaptation to the fluctuations of the available bandwidth, and the rendering capabilities of the receiver device. On the other hand, the available video coding standards are designed for optimum bit rate which makes them susceptible to packet losses. A combination of video adaptation methods and error resilient methods can make the video stream more robust against networking problems. In this paper, an optimization for combining scalable video coding with multiple description coding schemes have been proposed. Our proposed method is capable of creating balanced descriptions with optimum coding efficiency.
Citation - Scopus: 3
Scalable video transmission over unreliable networks using multiple description wavelet coding
(2011) Choupany, R.; Wong, S.; Tolun, M.; 1863
Scalable video coding (SVC) and multiple description coding (MDC) are the two different adaptation schemes for video transmission over heterogenous and best-effort networks such as the Internet. We present a new approach to combine the advantages of SVC and MDC to provide reliable video communication over a wider range of communication networks and/or satisfy application requirements. Our proposed method utilizes 3D discrete wavelet transform and a modified embedded zero tree data structure to group the coefficients in different descriptions. The proposed method reduces the impact of the drift error by organizing the frames in a hierarchical structure. © 2011 AICIT.
Citation - Scopus: 18
Vision-based hand gesture recognition for human computer interaction: A review
(2008) Hassanpour, R.; Hassanpour, Reza; Wong, S.; Shahbahrami, A.; Yazılım Mühendisliği
Evolution of user interfaces shapes the change in the human-computer interaction. With the rapid emergence of threedimensional (3-D) applications; the need for a new type of interaction device arises as traditional devices such as mouse, keyboard, and joystick become inefficient and cumbersome within these virtual environments. Intuitive and naturalness characteristics of "Hand Gestures" in human computer interaction have been the driving force and motivation to develop an interaction device which can replace current unwieldy tools. This study is a survey on the methods of analyzing, modeling and recognizing hand gestures in the context of human-computer interaction. Taxonomy of the methods based on the applications that they have been developed for and the approaches that they have used to represent gestures is presented. Direction of future developments is also discussed. © 2008 IADIS.
Citation - Scopus: 0
Weighted embedded zero tree for scalable video compression
(2008) Choupani, R.; Wong, S.; Tolun, M.R.
Video streaming over the Internet has gained popularity during recent years mainly due to the revival of videoconferencing and videotelephony applications and the proliferation of (video) content providers. However, the heterogeneous, dynamic, and best-effort nature of the Internet cannot always guarantee a certain bandwidth for an application utilizing the Internet. Scalability has been introduced to deal with such issues (up to a certain point) by intelligently separating any information stream into multiple streams. The reception of one, several, or all stream influences the perceived quality of the information as basic, improved, or best, respectively. In addition, wavelet-based scalability combined with representation methods such as embedded zero trees (EZWs) improves the decode-ability of the stream even when only the initial part of the streams have been received. In this paper, we propose a method to improve on the compression rate of the EZW for scalability purposes by reducing the number of levels used in the tree. Therefore, the proposed method should be able to deal more efficiently with the mentioned scalability issues in low bandwidth network. Initial experimental show that the first two layers of the generated EZW are about 22.6% more concise.