Reference Frame

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Jenqneng Hwang - One of the best experts on this subject based on the ideXlab platform.

  • scene context dependent Reference Frame placement for mpeg video coding
    IEEE Transactions on Circuits and Systems for Video Technology, 1999
    Co-Authors: A Y Lan, A G Nguyen, Jenqneng Hwang
    Abstract:

    The MPEG video-compression standard effectively exploits spatial, temporal, and coding redundancies in the algorithm. In its generic form, however, only a minimal amount of scene adaptation is performed. Video can be further compressed by taking advantage of scenes where the temporal statistics allow larger interReference-Frame distances. This paper proposes the use of motion analysis (MA) to adapt to scene content. The actual picture type [intracoded (I), predicted (P), or bidirectionally coded (B)] decision is made by examining the accumulation of motion measurements since the last Reference Frame (either I or P) was labeled. The proposed MA-based adaptive Reference Frame-placement scheme outperforms the standard fixed-Reference Frame-placement and adaptive schemes based on histogram of difference. When compared with the standard fixed scheme, depending on the video contents, this proposed algorithm can achieve from 2 to 13.9% savings in bits while maintaining similar quality.

  • scene context dependent Reference Frame placement for mpeg video coding
    International Conference on Acoustics Speech and Signal Processing, 1997
    Co-Authors: A Y Lan, Jenqneng Hwang
    Abstract:

    The MPEG video compression standard effectively exploits spatial, temporal, and coding redundancies in the algorithm. In its generic form, however, only a minimal amount of scene adaptation is performed. Video can be further compressed by taking advantage of scenes where the temporal statistics allow larger inter-Reference Frame distances. This paper proposes the use of motion analysis (MA) to adapt to scene content. The actual picture type (I, P, or B) decision is made by examining the accumulation of motion measurements since the last Reference Frame was labeled. Depending on the video content, this proposed algorithm can achieve from 2% to 13.9% savings in bits while maintaining similar quality.

P Charlot - One of the best experts on this subject based on the ideXlab platform.

  • the second realization of the international celestial Reference Frame by very long baseline interferometry
    The Astronomical Journal, 2015
    Co-Authors: D Gordon, E F Arias, Christopher S Jacobs, P Charlot, R A Gaume, G Bianco, D Boboltz, S Bockmann, S Bolotin, A Collioud
    Abstract:

    We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 μas and a directional stability of the Frame axes of ∼10 μas. A set of 295 new “defining” sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial Reference Frame, replacing ICRF1 as of 2010 January 1.

  • the international celestial Reference Frame as realized by very long baseline interferometry
    The Astronomical Journal, 1998
    Co-Authors: E F Arias, T M Eubanks, A L Fey, A M Gontier, Christopher S Jacobs, O J Sovers, B A Archinal, P Charlot
    Abstract:

    A quasi-inertial Reference Frame is defined based on the radio positions of 212 extragalactic sources distributed over the entire sky. The positional accuracy of these sources is better than about 1 mas in both coordinates. The radio positions are based upon a general solution for all applicable dual-frequency 2.3 and 8.4 GHz Mark III very long baseline interferometry data available through the middle of 1995, consisting of 1.6 million pairs of group delay and phase delay rate observations. Positions and details are also given for an additional 396 objects that either need further observation or are currently unsuitable for the definition of a high-accuracy Reference Frame. The final orientation of the Frame axes has been obtained by a rotation of the positions into the system of the International Celestial Reference System and is consistent with the FK5 J2000.0 optical system, within the limits of the link accuracy. The resulting International Celestial Reference Frame has been adopted by the International Astronomical Union as the fundamental celestial Reference Frame, replacing the FK5 optical Frame as of 1998 January 1.

E F Arias - One of the best experts on this subject based on the ideXlab platform.

  • the second realization of the international celestial Reference Frame by very long baseline interferometry
    The Astronomical Journal, 2015
    Co-Authors: D Gordon, E F Arias, Christopher S Jacobs, P Charlot, R A Gaume, G Bianco, D Boboltz, S Bockmann, S Bolotin, A Collioud
    Abstract:

    We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 μas and a directional stability of the Frame axes of ∼10 μas. A set of 295 new “defining” sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial Reference Frame, replacing ICRF1 as of 2010 January 1.

  • the international celestial Reference Frame as realized by very long baseline interferometry
    The Astronomical Journal, 1998
    Co-Authors: E F Arias, T M Eubanks, A L Fey, A M Gontier, Christopher S Jacobs, O J Sovers, B A Archinal, P Charlot
    Abstract:

    A quasi-inertial Reference Frame is defined based on the radio positions of 212 extragalactic sources distributed over the entire sky. The positional accuracy of these sources is better than about 1 mas in both coordinates. The radio positions are based upon a general solution for all applicable dual-frequency 2.3 and 8.4 GHz Mark III very long baseline interferometry data available through the middle of 1995, consisting of 1.6 million pairs of group delay and phase delay rate observations. Positions and details are also given for an additional 396 objects that either need further observation or are currently unsuitable for the definition of a high-accuracy Reference Frame. The final orientation of the Frame axes has been obtained by a rotation of the positions into the system of the International Celestial Reference System and is consistent with the FK5 J2000.0 optical system, within the limits of the link accuracy. The resulting International Celestial Reference Frame has been adopted by the International Astronomical Union as the fundamental celestial Reference Frame, replacing the FK5 optical Frame as of 1998 January 1.

Yeping Su - One of the best experts on this subject based on the ideXlab platform.

  • fast multiple Reference Frame motion estimation for h 264 avc
    IEEE Transactions on Circuits and Systems for Video Technology, 2006
    Co-Authors: Yeping Su
    Abstract:

    Multiple Reference Frame motion compensation is a new feature introduced in H.264/MPEG-4 AVC to improve video coding performance. However, the computational cost of multiple Reference Frame motion estimation (MRF-ME) is very high. In this paper, we propose an algorithm that takes into account the correlation/continuity of motion vectors among different Reference Frames. We show that the algorithm effectively reduces the computations of MRF-ME, and achieves similar coding gain compared to the motion search approaches in the Reference software

A Y Lan - One of the best experts on this subject based on the ideXlab platform.

  • scene context dependent Reference Frame placement for mpeg video coding
    IEEE Transactions on Circuits and Systems for Video Technology, 1999
    Co-Authors: A Y Lan, A G Nguyen, Jenqneng Hwang
    Abstract:

    The MPEG video-compression standard effectively exploits spatial, temporal, and coding redundancies in the algorithm. In its generic form, however, only a minimal amount of scene adaptation is performed. Video can be further compressed by taking advantage of scenes where the temporal statistics allow larger interReference-Frame distances. This paper proposes the use of motion analysis (MA) to adapt to scene content. The actual picture type [intracoded (I), predicted (P), or bidirectionally coded (B)] decision is made by examining the accumulation of motion measurements since the last Reference Frame (either I or P) was labeled. The proposed MA-based adaptive Reference Frame-placement scheme outperforms the standard fixed-Reference Frame-placement and adaptive schemes based on histogram of difference. When compared with the standard fixed scheme, depending on the video contents, this proposed algorithm can achieve from 2 to 13.9% savings in bits while maintaining similar quality.

  • scene context dependent Reference Frame placement for mpeg video coding
    International Conference on Acoustics Speech and Signal Processing, 1997
    Co-Authors: A Y Lan, Jenqneng Hwang
    Abstract:

    The MPEG video compression standard effectively exploits spatial, temporal, and coding redundancies in the algorithm. In its generic form, however, only a minimal amount of scene adaptation is performed. Video can be further compressed by taking advantage of scenes where the temporal statistics allow larger inter-Reference Frame distances. This paper proposes the use of motion analysis (MA) to adapt to scene content. The actual picture type (I, P, or B) decision is made by examining the accumulation of motion measurements since the last Reference Frame was labeled. Depending on the video content, this proposed algorithm can achieve from 2% to 13.9% savings in bits while maintaining similar quality.