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Dyadic downsampling



Y = dyaddown(X,EVENODD) where X is a vector, returns a version of X that has been downsampled by 2. Whether Y contains the even- or odd-indexed samples of X depends on the value of positive integer EVENODD:

Y = dyaddown(X) is equivalent to Y = dyaddown(X,0) (even-indexed samples).

Y = dyaddown(X,EVENODD,'type') or Y = dyaddown(X,'type',EVENODD), where X is a matrix, returns a version of X obtained by suppressing one out of two:

Columns of X
If 'type' = 'c'
Rows of X
If 'type' = 'r'
Rows and columns of X
If 'type' = 'm'

according to the parameter EVENODD, which is as above.

If you omit the EVENODD or 'type' arguments, dyaddown defaults to EVENODD = 0 (even-indexed samples) and 'type' = 'c' (columns).

Y = dyaddown(X) is equivalent to Y = dyaddown(X,0,'c'). Y = dyaddown(X,'type') is equivalent to Y = dyaddown(X,0,'type'). Y = dyaddown(X,EVENODD) is equivalent to Y = dyaddown(X,EVENODD,'c').


See Also


Strang, G.; T. Nguyen (1996), Wavelets and Filter Banks, Wellesley-Cambridge Press.

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