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Error concealment in digital television signals

  • US 4,381,519 A
  • Filed: 09/14/1981
  • Issued: 04/26/1983
  • Est. Priority Date: 09/18/1980
  • Status: Expired due to Term
First Claim
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1. A method of concealing errors in a composite PAL or NTSC digital television signal, which television signal comprises a plurality of sample signals corresponding respectively to sample positions along a horizontal scan line of a television picture made up of a plurality of said horizontal lines, the method comprising, in respect of each said sample signal:

  • using a first algorithm to calculate a first expected value of said sample signal, said first algorithm using actual values of adjacent sample signals in the same horizontal line as said sample signal for said calculation;

    performing a first comparison between said first expected value and the actual value of said sample signal;

    using a second algorithm to calculate a second expected value of said sample signal, said second algorithm using actual values of adjacent sample signals in the same horizontal line as said sample signal and actual values of adjacent sample signals in the horizontal lines preceding and following the horizontal line of said sample signal;

    performing a second comparison between said second expected value and the actual value of said sample signal;

    continuously storing an indication as to which of said first and second comparisons gives a result closer to zero; and

    on occurrence of an error sample signal substituting a corrected sample signal for said error sample signal so as to conceal the error, said corrected sample signal being generated using said first or second algorithm in dependence on said indication.

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