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Search Publications by: John M. Libert (Assoc)

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Displaying 76 - 93 of 93

Perceptual Effects of Noise in Digital Video Compression

March 1, 2000
Author(s)
Charles D. Fenimore, John M. Libert, S. A. Wolf
This paper presents the results of subjective viewer assessment of the quality of MPEG-2 compressed video containing wideband Gaussian noise. The video test sequences consisted of seven test clips (both classical and new materials) to which noise with a

Algebraic Constraints Implying Monotonicity for Cubics

January 1, 2000
Author(s)
Charles D. Fenimore, John M. Libert, M. Brill
While it is straightforward to formulate constraints which ensure a cubic polynomial is monotonic on an interval, such constraints may not be in a form which is suitable for use in standard optimization software. The MATLAB package is typical; the required

Mosquito Noise in MPEG-compressed Video: Test Patterns and Metrics

January 1, 2000
Author(s)
Charles D. Fenimore, John M. Libert, Peter Roitman
Mosquito noise is a time dependent video compression impairment in which the high frequency spatial detail in video images having crisp edges is aliased intermittently. A new synthetic test pattern of moving spirals or circles is described which generates

Video Quality Experts Group: Current Results and Future Directions

January 1, 2000
Author(s)
A. M. Rohaly, P. Corriveau, John M. Libert, A. Webster, V. Baroncini, J. Beerends, J. L. Blin, L. Contin, T. Hamada, Diane Harrison, A. Hekstra, Jack Lubin, Y. Nishida, R. Ishihara, J Pearson, A. F. Pessoa, N. Pickford, A. Schertz, M. Visca, A. B. Watson, S. Winkler
Subjective assessment methods have been used reliably for many years to evaluate video quality. They continue to provide the most reliable assessments compared to objective methods. Some issues that arise with subjective assessment include the cost of

Video Quality Experts Group: The Quest for Valid Objective Methods

January 1, 2000
Author(s)
P. Corriveau, A. Webster, A. M. Rohaly, John M. Libert
Subjective assessment methods have been used reliably for many years to evaluate video quality. They continue to provide the most reliable assessments compared to objective methods. Some issues that arise with subjective assessment include the cost of

Perceptual Effects of Noise in Digital Video Compression

October 1, 1998
Author(s)
Charles D. Fenimore, John M. Libert, S. A. Wolf
We present results of subjective viewer assessment of video quality of MPEG-2 compressed video containing wide-band Gaussian noise. The video test sequences consisted of 7 test clips (both classical and new materials) to which noise with a peak-signal-to
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