The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Xinbo Ruan - One of the best experts on this subject based on the ideXlab platform.

  • zero voltage switching pwm hybrid full bridge three level converter
    IEEE Transactions on Power Electronics, 2005
    Co-Authors: Xinbo Ruan, Zhiying Chen, Wu Chen
    Abstract:

    This paper proposes a zero-voltage-switching (ZVS) pulse-width modulation (PWM) hybrid full-bridge three-level converter, which has a three-level leg and a two-level leg. The switches of the three-level leg sustain only the half of the input voltage, and they can realize ZVS in a wide load range. The switches of the two-level leg sustain the input voltage, and they can realize ZVS with the use of the resonant inductance. The secondary rectified voltage is a three-level waveform having lower High-Frequency Content compared with that of the traditional full-bridge converters, which can reduce the output filter, and as a result, the dynamic response of the converter is improved. The voltage stress of the rectifier diode is reduced also. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results.

  • Zero-voltage and zero-current-switching PWM hybrid full-bridge three-level converter
    IEEE Transactions on Industrial Electronics, 2005
    Co-Authors: Xinbo Ruan
    Abstract:

    This paper proposes a zero-voltage and zero-current-switching pulsewidth modulation hybrid full-bridge three-level (ZVZCS PWM H-FB TL) converter, which has a TL leg and a two-level leg. The voltage stress of the switches of the TL leg is half of the input voltage, and the switches can realize ZVS, so MOSFETs can be adopted; the voltage stress of the switches of the two-level leg is the input voltage, and the switches can realize ZCS, so IGBT can be adopted. The secondary rectified voltage is a TL waveform having lower High-Frequency Content compared with that of the traditional FB converters, which leads to the reduction of the output filter inductance. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results. Several ZVZCS PWM H-FB TL converters are also proposed in this paper.

  • Zero-voltage and zero-current-switching PWM hybrid full-bridge three-level converter
    2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289), 2002
    Co-Authors: Xinbo Ruan
    Abstract:

    This paper proposes a zero-voltage and zero-current-switching PWM hybrid full-bridge three-level converter (ZVZCS PWM H-FB TL converter), which has a three level (TL) leg and a two-level leg. The voltage stress of the switches of the TL leg is half of the input voltage, and the switches can realize ZVS, so the MOSFET can be adopted. The voltage stress of the switches of the two-level leg is the input voltage, and the switches can realize ZCS, so IGBT can be adopted. The secondary rectified voltage is a TL waveform having lower High-Frequency Content compared with that of the traditional FB converters, which leads to the reduction of the output filter inductance. The input current of the converter has quite low ripple, the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results. Several ZVZCS PWM H-FB TL converters are also proposed in this paper.

Wu Chen - One of the best experts on this subject based on the ideXlab platform.

  • zero voltage switching pwm hybrid full bridge three level converter
    IEEE Transactions on Power Electronics, 2005
    Co-Authors: Xinbo Ruan, Zhiying Chen, Wu Chen
    Abstract:

    This paper proposes a zero-voltage-switching (ZVS) pulse-width modulation (PWM) hybrid full-bridge three-level converter, which has a three-level leg and a two-level leg. The switches of the three-level leg sustain only the half of the input voltage, and they can realize ZVS in a wide load range. The switches of the two-level leg sustain the input voltage, and they can realize ZVS with the use of the resonant inductance. The secondary rectified voltage is a three-level waveform having lower High-Frequency Content compared with that of the traditional full-bridge converters, which can reduce the output filter, and as a result, the dynamic response of the converter is improved. The voltage stress of the rectifier diode is reduced also. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results.

Yappeng Tan - One of the best experts on this subject based on the ideXlab platform.

  • edge preserving image denoising via optimal color space projection
    IEEE Transactions on Image Processing, 2006
    Co-Authors: Naixiang Lian, V Zagorodnov, Yappeng Tan
    Abstract:

    Denoising of color images can be done on each color component independently. Recent work has shown that exploiting strong correlation between High-Frequency Content of different color components can improve the denoising performance. We show that for typical color images High correlation also means similarity, and propose to exploit this strong intercolor dependency using an optimal luminance/color-difference space projection. Experimental results confirm that performing denoising on the projected color components yields superior denoising performance, both in peak signal-to-noise ratio and visual quality sense, compared to that of existing solutions. We also develop a novel approach to estimate directly from the noisy image data the image and noise statistics, which are required to determine the optimal projection

  • image denoising using optimal color space projection
    International Conference on Acoustics Speech and Signal Processing, 2006
    Co-Authors: Naixiong Lian, V Zagorodnov, Yappeng Tan
    Abstract:

    Denoising of color images can be improved by exploiting strong correlation between High-Frequency Content of different color components. We show that for typical color images High correlation also means similarity, and propose to exploit this property using an optimal luminance/color-difference space projection. Experimental results confirm that denoising in the proposed color space yields superior performance, both in PSNR and visual quality sense, compared to that of existing solutions.

Wojciech Matusik - One of the best experts on this subject based on the ideXlab platform.

  • display pre filtering for multi view video compression
    ACM Multimedia, 2007
    Co-Authors: Matthias Zwicker, Wojciech Matusik, Anthony Vetro, Clifton Forlines, Hanspeter Pfister
    Abstract:

    Multi-view 3D displays are preferable to other stereoscopic display technologies because they provide autostereoscopic viewing from any viewpoint without special glasses. However, they require a large number of pixels to achieve High image quality. Therefore, data compression is a major issue for this approach. In this paper, we present a framework for efficient compression of multi-view video streams for multi-view 3D displays. Our goal is to optimize image quality without increasing the required data bandwidth. We achieve this by taking into account a precise notion of the multi-dimensional display bandwidth. The display bandwidth implies that scene elements that appear at a given distance from the display become increasingly blurry as the distance grows. Our main contribution is to enhance conventional multi-view compression pipelines with an additional pre-filtering step that bandlimits the multi-view signal to the display bandwidth. This imposes a shallow depth of field on the input images, thereby removing High Frequency Content. We show that this pre-filtering step leads to increased image quality compared to state-of-the-art multi-view coding at equal bitrate. We present results of an extensive user study that corroborate the benefits of our approach. Our work suggests that display pre-filtering will be a fundamental component in signal processing for 3D displays, and that any multi-view compression scheme will benefit from our pre-filtering technique.

  • Texture design using a simplicial complex of morphable textures
    ACM Transactions on Graphics, 2005
    Co-Authors: Wojciech Matusik, Matthias Zwicker, Frédo Durand
    Abstract:

    We present a system for designing novel textures in the space of textures induced by an input database. We capture the structure of the induced space by a simplicial complex where vertices of the simplices represent input textures. A user can generate new textures by interpolating within individual simplices. We propose a morphable interpolation for textures, which also defines a metric used to build the simplicial complex. To guarantee sharpness in interpolated textures, we enforce histograms of High-Frequency Content using a novel method for histogram interpolation. We allow users to continuously navigate in the simplicial complex and design new textures using a simple and efficient user interface. We demonstrate the usefulness of our system by integrating it with a 3D texture painting application, where the user interactively designs desired textures.

Matthias Zwicker - One of the best experts on this subject based on the ideXlab platform.

  • display pre filtering for multi view video compression
    ACM Multimedia, 2007
    Co-Authors: Matthias Zwicker, Wojciech Matusik, Anthony Vetro, Clifton Forlines, Hanspeter Pfister
    Abstract:

    Multi-view 3D displays are preferable to other stereoscopic display technologies because they provide autostereoscopic viewing from any viewpoint without special glasses. However, they require a large number of pixels to achieve High image quality. Therefore, data compression is a major issue for this approach. In this paper, we present a framework for efficient compression of multi-view video streams for multi-view 3D displays. Our goal is to optimize image quality without increasing the required data bandwidth. We achieve this by taking into account a precise notion of the multi-dimensional display bandwidth. The display bandwidth implies that scene elements that appear at a given distance from the display become increasingly blurry as the distance grows. Our main contribution is to enhance conventional multi-view compression pipelines with an additional pre-filtering step that bandlimits the multi-view signal to the display bandwidth. This imposes a shallow depth of field on the input images, thereby removing High Frequency Content. We show that this pre-filtering step leads to increased image quality compared to state-of-the-art multi-view coding at equal bitrate. We present results of an extensive user study that corroborate the benefits of our approach. Our work suggests that display pre-filtering will be a fundamental component in signal processing for 3D displays, and that any multi-view compression scheme will benefit from our pre-filtering technique.

  • Texture design using a simplicial complex of morphable textures
    ACM Transactions on Graphics, 2005
    Co-Authors: Wojciech Matusik, Matthias Zwicker, Frédo Durand
    Abstract:

    We present a system for designing novel textures in the space of textures induced by an input database. We capture the structure of the induced space by a simplicial complex where vertices of the simplices represent input textures. A user can generate new textures by interpolating within individual simplices. We propose a morphable interpolation for textures, which also defines a metric used to build the simplicial complex. To guarantee sharpness in interpolated textures, we enforce histograms of High-Frequency Content using a novel method for histogram interpolation. We allow users to continuously navigate in the simplicial complex and design new textures using a simple and efficient user interface. We demonstrate the usefulness of our system by integrating it with a 3D texture painting application, where the user interactively designs desired textures.