Aghagolzadeh M.,Michigan State University |
Segall A.,Sharp Laboratories of America
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2013
In this paper, we consider the problem of removing jaggy artifacts from images. We consider the kernel regression framework and propose a reduced-rank quadratic adaptive method that adapts to the local gradient direction. The proposed technique is effective in shrinking isophote fluctuations, and the result is smooth edges. We observe that it is critical to differentiate jaggy artifacts from texture, junctions and corners, so that meaningful image structure is preserved. Here, we demonstrate that the spectrum of the local covariance matrix of gradients, also known as the structure tensor, is well suited for differentiation of jaggy artifacts from image structure, and we incorporate this into the kernel regression framework. Results show the efficacy of the approach. Namely, that the method is effective in reducing jaggy artifacts without blurring meaningful image structure. © 2013 IEEE.
Deshpande S.,Sharp Laboratories of America
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013
Adaptive media playout techniques are used to avoid buffer underflow in a dynamic streaming environment where the available bandwidth may be fluctuating. In this paper we report human perceptions from audio quality studies that we performed on speech and music samples for adaptive audio playout. Test methods based on ITU-R BS. 1534-1 recommendation were used. Studies were conducted for both slow playout and fast playout. Two scales-a coarse scale and a finer scale was used for the slow and fast audio playout factors. Results from our study can be used to determine acceptable slow and fast playout factors for speech and music content. An adaptive media playout algorithm could use knowledge of these upper and lower bounds on playback speeds to decide its adaptive playback schedule. © 2013 SPIE-IS&T.
Deshpande S.,Sharp Laboratories of America
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
Perceived video quality studies were performed on a number of key classes of noise removal algorithms to determine viewer preference. The noise removal algorithm classes represent increase in complexity from linear filter to nonlinear filter to adaptive filter to spatio-temporal filter. The subjective results quantify the perceived quality improvements that can be obtained with increasing complexity. The specific algorithm classes tested include: linear spatial one channel filter, nonlinear spatial two-channel filter, adaptive nonlinear spatial filter, multi-frame spatio-temporal adaptive filter. All algorithms were applied on full HD (1080P) content. Our subjective results show that spatio-temporal (multi-frame) noise removal algorithm performs best amongst the various algorithm classes. The spatio-temporal algorithm improvement compared to original video sequences is statistically significant. On the average, noise-removed video sequences are preferred over original (noisy) video sequences. The Adaptive bilateral and non-adaptive bilateral two channel noise removal algorithms perform similarly on the average thus suggesting that a non-adaptive parameter tuned algorithm may be adequate. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Sullivan G.J.,Microsoft |
Boyce J.M.,Vidyo Inc. |
Chen Y.,Qualcomm |
Ohm J.-R.,RWTH Aachen |
And 2 more authors.
IEEE Journal on Selected Topics in Signal Processing | Year: 2013
This paper describes extensions to the High Efficiency Video Coding (HEVC) standard that are active areas of current development in the relevant international standardization committees. While the first version of HEVC is sufficient to cover a wide range of applications, needs for enhancing the standard in several ways have been identified, including work on range extensions for color format and bit depth enhancement, embedded-bitstream scalability, and 3D video. The standardization of extensions in each of these areas will be completed in 2014, and further work is also planned. The design for these extensions represents the latest state of the art for video coding and its applications. © 2007-2012 IEEE.
Rodriguez-Pardo C.E.,University of Rochester |
Sharma G.,University of Rochester |
Feng X.-F.,Sharp Laboratories of America
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014
Traditional methodologies for primary selection usually consider the optimization of parameters that characterize the global performance of the display system, such as the luminance of the white point, gamut volume, and power consumption. We propose a methodology for primary design that optimizes a figure of merit designed to favor gamuts for which maximum luminance at each chromaticity is uniformly related to the corresponding maximum luminance over the set of optimal colors. We contrast the results obtained with the proposed methodology with those obtained by an alternative strategy based on the optimization of gamut volume, and analyze differences in performance between these approaches for both three and four primary systems. Results indicate that the global vs local design choices result in significantly different primary designs. © 2014 SPIE-IS&T.