Patents Assigned to Information Technologies Research Inc.
  • Patent number: 5067152
    Abstract: A method of and apparatus for vector quantizaiton operates on binary signal vectors. Each signal vector contains a plurality of sample elements of a signal to be compressed. Each of the signal vectors is hashed to generate a value identifying one of at least three different subsets of code words collectively constituting a set of binary code words. Each of the signal vectors is hashed a second time to generate a value identifying one of at least three different subsets of code words collectively constituting a second different set of binary code words. Each code word is equal in length to the length of each of the signal vectors and has associated with it a unique binary code of a lesser length. The vector quantizer performs a distortion comparison search through the code words of the selected subset to identify the one code word and its uniquely associated code which has the least distortion of all of the code words of the one subset with respect to the hashed signal vector.
    Type: Grant
    Filed: March 16, 1990
    Date of Patent: November 19, 1991
    Assignee: Information Technologies Research, Inc.
    Inventors: Gregory H. Kisor, Edward J. King
  • Patent number: 4979039
    Abstract: A method of and apparatus for vector quantization operates on binary signal vectors. Each signal vector contains a plurality of sample elements of a signal to be compressed. Each of the signal vectors is hashed to generate a value identifying one of at least three different subsets of code words collectively constituting a set of binary code words. Each code word is equal in length to the length of each of the signal vectors and has associated with it a unique binary code of a lesser length. The vector quantizer performs a distortion comparison search through the code words of the selected subset to identify the one code word and its uniquely associated code which has the least distortion of all of the code words of the one subset with respect to the hashed signal vector. That one code is outputted to represent the hashed signal vector. The subsets may be mutually exclusive and include a plurality of code words.
    Type: Grant
    Filed: January 30, 1989
    Date of Patent: December 18, 1990
    Assignee: Information Technologies Research Inc.
    Inventors: Gregory H. Kisor, James F. Parker, Edward J. King