Time filter

Source Type

Saint-Jean-de-Losne, France

Gucunski N.,Rutgers University | Yan M.,Siemens AG | Wang Z.,Thomson Corporate Research | Fang T.,Siemens AG | Maher A.,Rutgers University
Journal of Infrastructure Systems | Year: 2012

Ultrasonic seismic methods can be used in the condition assessment of bridge decks by evaluating changes in material characteristics and detecting the development of defects and zones of deterioration. The impact-echo method is of special benefit in the evaluation of corrosion-induced deck delamination because of its nondestructive nature and ability to detect delaminated zones at various stages of deterioration: from initial to progressed and developed. The traditional approach in the condition assessment of bridge decks by impact-echo is based on a review of individual test-point records. A new approach based on three-dimensional data visualization is proposed. The developed three-dimensional visualization platform allows for both the advanced presentation and an automated interpretation of impact-echo data. The data presentation is provided in terms of three-dimensional translucent visualizations of reflectors in a bridge deck section and horizontal and vertical cross sections through all distinctive zones, including a zone of delamination. The associated interpretation platform enables the overall assessment of the condition of the deck, through cumulative distributions of reflection intensity of different reflective layers, and the identification of deteriorated zones of the deck to be repaired or rehabilitated in an efficient and intuitive way. © 2012 American Society of Civil Engineers.

Yang H.,Thomson Corporate Research | Rose K.,University of California at Santa Barbara
IEEE Transactions on Image Processing | Year: 2010

This paper is concerned with optimization of the motion compensated prediction framework to improve the error resilience of video coding for transmission over lossy networks. First, accurate end-to-end distortion estimation is employed to optimize both motion estimation and prediction within an overall rate-distortion framework. Low complexity practical variants are proposed: a method to approximate the optimal motion via simple distortion and source coding rate models, and a source-channel prediction method that uses the expected decoder reference frame for prediction. Second, reference frame generation is revisited as a problem of filter design to optimize the error resilience versus coding efficiency tradeoff. The special cases of leaky prediction and weighted prediction (i.e., finite impulse response filtering), are analyzed. A novel reference frame generation approach, called "generalized source-channel prediction", is proposed, which involves infinite impulse response filtering. Experimental results show significant performance gains and substantiate the effectiveness of the proposed encoder optimization approaches. © 2009 IEEE.

Guo L.,Thomson Corporate Research | Au O.C.,Hong Kong University of Science and Technology | Ma M.,Hong Kong University of Science and Technology | Liang Z.,Harmonic Inc.
Journal of Signal Processing Systems | Year: 2010

Multi-Hypothesis motion compensated filter (MHMCF) utilizes a number of hypotheses (temporal predictions) to estimate the current pixel which is corrupted with noise. While showing remarkable denoising results, MHMCF is computationally intensive as full search is employed in the expectation of finding good temporal predictions in the presence of noise. In the frame of MHMCF, a fast denoising algorithm FMHMCF is proposed in this paper. With edge preserved low-pass prefiltering and noise-robust fast multihypothesis search, FMHMCF could find reliable hypotheses while checking very few search locations, so that the denoising process can be dramatically accelerated. Experimental results show that FMHMCF can be 10 to 14 times faster than MHMCF, while achieving the same or even better denoising performance with up to 1.93 dB PSNR (peak-signal-noise-ratio) improvement. © 2009 Springer Science + Business Media, LLC. Manufactured in The United States.

Gu X.,Thomson Corporate Research | Qiu G.,University of Nottingham | Feng X.,Thomson Corporate Research | Liu D.,Thomson Corporate Research | Chen Z.,Thomson Corporate Research
Telecommunication Systems | Year: 2012

The objective video quality metrics have been researched for years and many methods have been proposed. As a main feature of the Human Visual System (HVS), visual attention (or Region of Interest-ROI) will influence viewer's subjective feeling since artifacts on a ROI is much more annoying than those appearing on an inconspicuous area. However, little study has been taken on identifying how and to what extent ROI will influence video quality measurements. In this paper, we propose a fully automatic region of interest weighted pooling strategy considering the influence of visual attention, which is then evaluated on VQEG Phase I FR-TV test dataset. Apparent and coherent performance improvement is achieved by applying the proposed pooling strategy on PSNR and SSIM, together with a highly reduction in computation complexity. © Springer Science+Business Media, LLC 2010.

Vo D.T.,Samsung | Sole J.,Thomson Corporate Research | Yin P.,Thomson Corporate Research | Gomila C.,Thomson Corporate Research | Nguyen T.Q.,University of California at San Diego
IEEE Transactions on Image Processing | Year: 2010

This paper proposes a selective data pruning-based compression scheme to improve the rate-distortion relation of compressed images and video sequences. The original frames are pruned to a smaller size before compression. After decoding, they are interpolated back to their original size by an edge-directed interpolation method. The data pruning phase is optimized to obtain the minimal distortion in the interpolation phase. Furthermore, a novel high-order interpolation is proposed to adapt the interpolation to several edge directions in the current frame. This high-order filtering uses more surrounding pixels in the frame than the fourth-order edge-directed method and it is more robust. The algorithm is also considered for multiframe-based interpolation by using spatio-temporally surrounding pixels coming from the previous frame. Simulation results are shown for both image interpolation and coding applications to validate the effectiveness of the proposed methods. © 2010 IEEE.

Discover hidden collaborations