Current Issue : April - June Volume : 2012 Issue Number : 2 Articles : 6 Articles
This article addresses the problem of low dynamic range image enhancement for commercial digital cameras. A\r\nnovel simultaneous dynamic range compression and local contrast enhancement algorithm (SDRCLCE) is presented\r\nto resolve this problem in a single-stage procedure. The proposed SDRCLCE algorithm is able to combine with\r\nmany existent intensity transfer functions, which greatly increases the applicability of the proposed method. An\r\nadaptive intensity transfer function is also proposed to combine with SDRCLCE algorithm that provides the\r\ncapability to adjustably control the level of overall lightness and contrast achieved at the enhanced output.\r\nMoreover, the proposed method is amenable to parallel processing implementation that allows us to improve the\r\nprocessing speed of SDRCLCE algorithm. Experimental results show that the performance of the proposed method\r\noutperforms three state-of-the-art methods in terms of dynamic range compression and local contrast\r\nenhancement....
A revolutionary feature of emerging media services over the Internet is their ability to account for human\r\nperception during service delivery processes, which surely increases their popularity and incomes. In such a\r\nsituation, it is necessary to understand the users� perception, what should obviously be done using standardized\r\nsubjective experiences. However, it is also important to develop artificial quality assessors that enable to\r\nautomatically quantify the perceived quality. This efficiently helps performing optimal network and service\r\nmanagement at the core and edges of the delivery systems. In our article, we explore the behavior rating of new\r\nemerging artificial speech quality assessors of VoIP calls subject to moderately bursty packet loss processes. The\r\nexamined Speech Quality Assessment (SQA) algorithms are able to estimate speech quality of live VoIP calls at runtime\r\nusing control information extracted from header content of received packets. They are especially designed to\r\nbe sensitive to packet loss burstiness. The performance evaluation study is performed using a dedicated set-up\r\nsoftware-based SQA framework. It offers a specialized packet killer and includes the implementation of four SQA\r\nalgorithms. A speech quality database, which covers a wide range of bursty packet loss conditions, has been\r\ncreated and then thoroughly analyzed. Our main findings are the following: (1) all examined automatic bursty-loss\r\naware speech quality assessors achieve a satisfactory correlation under upper (> 20%) and lower (< 10%) ranges of\r\npacket loss processes; (2) they exhibit a clear weakness to assess speech quality under a moderated packet loss\r\nprocess; (3) the accuracy of sequence-by-sequence basis of examined SQA algorithms should be addressed in\r\ndetail for further precision....
Video quality assessment is essential for the performance analysis of visual communication applications. Objective\r\nmetrics can be used for estimating the relative quality differences, but they typically give reliable results only if the\r\ncompared videos contain similar types of quality distortion. However, video compression typically produces\r\ndifferent kinds of visual artifacts than transmission errors. In this article, we focus on a novel subjective quality\r\nassessment method that is suitable for comparing different types of quality distortions. The proposed method has\r\nbeen used to evaluate how well different objective quality metrics estimate the relative subjective quality levels for\r\ncontent with different types of quality distortions. Our conclusion is that none of the studied objective metrics\r\nworks reliably for assessing the co-impact of compression artifacts and transmission errors on the subjective quality.\r\nNevertheless, we have observed that the objective metrics� tendency to either over- or underestimate the\r\nperceived impact of transmission errors has a high correlation with the spatial and temporal activity levels of the\r\ncontent. Therefore, our results can be useful for improving the performance of objective metrics in the presence of\r\nboth source and channel distortions....
In this article, a novel scheme is proposed for switching among multiple bitrate video streams over Internet, to\r\nachieve best quality of service (QoS). The research is focused on selecting the best switching points inside the precoded\r\nvariable bit rate video streams, to facilitate bandwidth scalability among the non-scalable multiple\r\nbitstreams. With a stepwise monotonically decreasing (downstairs) bandwidth reservation scheme, it is shown that\r\nif switching occurs at the transition points in the ââ?¬Å?downstairsââ?¬Â, then the best QoS can be achieved. However,\r\ninsertion of switching pictures at these transition points may change the characteristics of the ââ?¬Å?downstairsââ?¬Â\r\nfunction and hence the bandwidth requirement. Here, we propose a scheme for proper management of the\r\nallocated resources to facilitate the stream switching in the ââ?¬Å?downstairsââ?¬Â through SP-frames. The performance is\r\nmeasured in terms of the wastage of bits in the receiver buffer and bandwidth utilization at the switching\r\ninstances....
In this paper, the performances of appearance-based statistical method called Principal Component Analysis (PCA) is tested for the recognition of face images. Principal Component Analysis is most successful technique to recognize faces. PCA performs well when the size of the database is small. Mathematical formulation of eigenface calculation and PCA algorithm is discussed. The training set with 9 images with N x N size is tested. Results of experiment are also presented. The coding is implemented on MATLAB software and also on GUI (Graphic User Interface)....
The televisions today are all showing the two dimensional display. And we are heading on for increasing the pixels, both in computer monitors and Television sets, for increasing the resolution. Looking forward for implementing the third dimensional display in existing setup of televisions, without adding additional devices will be a revolution in the present media world. If we solve it with a method there is yet another problem of bandwidth for various channels at high such high resolution. So, the new methodology is attempted to be at the same bandwidth of videos, but with a high texture and resolution details. The protocol described here indicates the development of technique to display 3D videos on television sets, without any extra gadgets. The videos from three cameras, kept diagonally to three axes, can be linked by an integrator tool, considering the pixel details and can then develop a three dimensional video with highest pixel details...
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