07-11-2013 дата публикации
Номер: US20130293400A1
A method for differential compression of a sequence of digital values adapted to avoid error propagation during restoration of the values. 1. A method for compressing a sequence (S) of initial digital values (Va , . . . , Vp , Vq , Vr , . . . , Vz) into a compressed sequence (SC) of compressed values (Va , VCp , VCq , VCr , . . . , VCz) , intending to restore these values into a decompressed sequence (S2 ,S4) of decompressed values (Va , . . . , VDp , VDq , VDr , . . . , VDz) , wherein for a first initial value (Va) of the sequence , the compressed value (VCa=Va) of the first initial value is equal to said first initial value (Va) and the decompressed value (VDa=VCa=Va) of said compressed value (VCa) of the first initial value (Va) is equal to said first initial value (Va) , then in that , for each current initial value (Vq) , the following steps are carried out:calculating the difference (Dq=Vq−VDp) between the current initial value (Vq) and the decompressed value (VDp) of the initial value immediately preceding the current value (Vq); then,calculating a compressed value (VCq=f[Dq]) of said difference (Dq) using a complementary compression function (f); then,{'sup': '1', 'calculating the decompressed value (VDq=f[VCq]+VDp) corresponding to said current initial value (Vq); then,'}applying the three preceding steps to the immediately following value (Vr) if there is one; and,constituting the compressed sequence (SC) of the compressed values (Va, . . . , VCp, VCq, VCr, . . . , VCz), each corresponding to a respective initial value (Va, . . . , Vp, Vq, Vr, . . . , Vz).2. The method according to claim 1 , in which the compressed value is rounded to the nearest whole number.3. The method according to claim 1 , further comprising keeping claim 1 , on the compressed value claim 1 , the sign of the difference (if DqO then VCq>O).4. The method according to claim 1 , in which the complementary compression function (f) is an nth root function claim 1 , ...
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