lossy compression

2 definitions found

lossy compression - Collaborative International Dictionary of English v.0.48 :

  Compression \Com*pres"sion\, n. [L. compressio: cf. F.
     compression.]
     1. The act of compressing, or state of being compressed.
        "Compression of thought." --Johnson.
        [1913 Webster]
  
     2. (Computers) reduction of the space required for storage
        (of binary data) by an algorithm which converts the data
        to a smaller number of bits while preserving the
        information content. The act of compressing [3].
  
     Note: Compression may be lossless compression, in which all
           of the information in the original data is preserved,
           and the original data may be recovered in form
           identical to its original form; or lossy compression,
           in which some of the information in the original data
           is lost, and decompression results in a data form
           slightly different from the original. Lossy compression
            is used, for example, to compress audio or
           video recordings, and sometimes images, where the
           slight differences in the original data and the data
           recovered after lossy compression may be
           imperceptable to the human eye or ear. The JPEG
           format is produced by a lossy compression algorithm.
           [PJC]

  lossy compression \los"sy com*pres"sion\, n. (Computers)
     The compression of binary data into a form which, when it is
     re-expanded, has most, but not all, of the original
     information. It is used primarily for compression of images
     and sounds, and is designed to provide a high degree of
     compression at the cost of a slight loss of data. It is
     expemplified by the JPEG compression standard. Images
     compressed by a lossy compression algorithm are re-expanded
     into an image close, but not identical to the original image;
     the difference between the original and the reconstructed
     image may be imperceptible to normal viewing by the eye.
     [PJC]