Patents by Inventor Keman Yu

Keman Yu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20060088210
    Abstract: Video image quality may be improved by correcting exposure levels and/or enhancing contrast amounts on each frame. One or more of the following phases may be implemented: skin-color model building, face detecting, exposure level correcting, and contrast enhancing. In a described implementation, each pixel of an image frame is re-exposed using a ratio of contrast amount control variables (CACVs). More specifically, a pixel may be converted to a corresponding light intensity using a first CACV, and the corresponding light intensity may be reconverted to a pixel using a second CACV to enhance the contrast and possibly reduce fuzziness of the image frame. In another described implementation, a Gaussian skin-color model is built for each image frame during runtime. The Gaussian skin-color model is built with training pixels that are selected responsive to a defined skin color range, which is created offline from manually-selected skin pixels of multiple test sequences.
    Type: Application
    Filed: November 17, 2004
    Publication date: April 27, 2006
    Applicant: Microsoft Corporation
    Inventors: Keman Yu, Jiang Li, Shipeng Li
  • Publication number: 20060056719
    Abstract: Systems and methods for variable block size early termination for video coding are described. In one aspect a set of thresholds are selected based on block sizes in a video encoding scheme. The thresholds include a respective threshold for each block size used by the encoding scheme. For each macroblock of multiple macroblocks in a video data sequence, blocks in the macroblock are evaluated in view of respective threshold(s) to determine if motion estimation operations can be terminated prior to evaluating remaining blocks in the macroblock.
    Type: Application
    Filed: September 13, 2004
    Publication date: March 16, 2006
    Applicant: Microsoft Corporation
    Inventors: Keman Yu, Jiang Li, Shipeng Li
  • Publication number: 20050140674
    Abstract: Generation, coding and transmission of an effective video form, scalable portrait video. As an expansion to bi-level video, portrait video is composed of more gray levels, and therefore possesses higher visual quality while it maintains a low bit rate and low computational costs. Portrait video is a scalable video in that each video with a higher level always contains all the information of the video with a lower level. The bandwidths of 2-4 level portrait videos fit into the bandwidth range of 20-40 Kbps that GPRS and CDMA 1× can stably provide. Therefore, portrait video is very promising for video broadcast and communication on 2.5G wireless networks. With portrait video technology, this system and method is the first to enable two-way video conferencing on Pocket PCs and Handheld PCs.
    Type: Application
    Filed: February 25, 2005
    Publication date: June 30, 2005
    Applicant: Microsoft Corporation
    Inventors: Jiang Li, Keman Yu, Tielin He, Yunfeng Lin, Shipeng Li
  • Publication number: 20050069035
    Abstract: To encode image and video data using a transform having low computational complexity and high compression efficiency, all elements of the matrix can be expressed with power-of-2 elements, with a template of the matrix approximating a DCT matrix.
    Type: Application
    Filed: September 30, 2003
    Publication date: March 31, 2005
    Inventors: Shan Lu, Keman Yu, Jiang Li, Shipeng Li
  • Publication number: 20050053136
    Abstract: In a first exemplary media implementation, one or more processor-accessible media include processor-executable instructions that, when executed, direct a device to perform actions including: comparing an accuracy indicator to at least one threshold, the accuracy indicator corresponding to a reference macroblock selected for a target macroblock; ascertaining a refinement case from multiple refinement cases based on the comparing, each refinement case of the multiple refinement cases defining multiple test points in relation to the reference macroblock; and analyzing the ascertained refinement case with regard to the target macroblock.
    Type: Application
    Filed: September 9, 2003
    Publication date: March 10, 2005
    Inventors: Keman Yu, Jiang Li, Shipeng Li
  • Publication number: 20040233844
    Abstract: Systems and methods for video communication are described. In one aspect, network bandwidth conditions are estimated. Bi-level or full-color video is then transmitted over the network at transmission bit rates that are controlled as a function of the estimated bandwidth conditions. To this end, network bandwidth capability is periodically probed to identify similar, additional, or decreased bandwidth capabilities as compared to the estimated bandwidth conditions. Decisions to hold, decrease, or increase the video transmission bit rate are made based on the estimated bandwidth conditions in view of the probing operations. When the transmission bit rate is increased or decreased, the transmission bit rate is calculated to target an upper or lower bit rate, both of which are indicated by the estimated bandwidth conditions. Bi-level video communication is switched to full-color video transmission, or vice versa, when the video transmission bit rate respectively reaches the upper bit rate or the lower bit rate.
    Type: Application
    Filed: May 23, 2003
    Publication date: November 25, 2004
    Applicant: MICROSOFT CORPORATION
    Inventors: Keman Yu, Jiang Li, Shipeng Li
  • Publication number: 20040100586
    Abstract: Generation, coding and transmission of an effective video form, scalable portrait video. As an expansion to bi-level video, portrait video is composed of more gray levels, and therefore possesses higher visual quality while it maintains a low bit rate and low computational costs. Portrait video is a scalable video in that each video with a higher level always contains all the information of the video with a lower level. The bandwidths of 2-4 level portrait videos fit into the bandwidth range of 20-40 Kbps that GPRS and CDMA 1X can stably provide. Therefore, portrait video is very promising for video broadcast and communication on 2.5G wireless networks. With portrait video technology, this system and method is the first to enable two-way video conferencing on Pocket PCs and Handheld PCs.
    Type: Application
    Filed: November 22, 2002
    Publication date: May 27, 2004
    Inventors: Jiang Li, Keman Yu, Tielin He, Yunfeng Lin, Shipeng Li
  • Publication number: 20040101045
    Abstract: A video compression/decompression procedure that provides a reliable, low bit video bit stream with some color features over relatively low bandwidth wireless networks. The procedure provides some pleasing color features in a video bit stream without needing a large bandwidth network like those needed for example for a MPEG 4 bit stream. The procedure provides the color features by using a bi-level Y luminance component and a number of UV chrominance combinations. The bi-level Y-component outlines the features of the image, while the UV-combinations describe the basic color information of the image.
    Type: Application
    Filed: November 22, 2002
    Publication date: May 27, 2004
    Inventors: Keman Yu, Jiang Li, Jizheng Xu, Shipeng Li
  • Publication number: 20030182428
    Abstract: Techniques are provided for use in establishing and maintaining a contacting/communication service and/or network that does not necessarily require the use of dedicated server devices. For example, improved methods and apparatuses are provided that can be used to provide peer-to-peer (P2P) or other like forms of communication in such a manner that users can remain aware of others' online/offline statuses, search for other users, conduct audio/video talk and chat with others, exchange information, and/or communicate in other ways with one another.
    Type: Application
    Filed: March 19, 2002
    Publication date: September 25, 2003
    Inventors: Jiang Li, Keman Yu, Kaibo Wang, Yong Li, Shipeng Li