Developer Reference

  • 2020
  • 07/15/2020
  • Public Content
Contents

WTFwdInit

Initializes the forward wavelet transform context structure.

Syntax

IppStatus ippiWTFwdInit_32f_C1R(IppiWTFwdSpec_32f_C1R*
pSpec
, const Ipp32f*
pTapsLow
, int
lenLow
, int
anchorLow
, const Ipp32f*
pTapsHigh
, int
lenHigh
, int
anchorHigh
);
IppStatus ippiWTFwdInit_32f_C3R(IppiWTFwdSpec_32f_C3R*
pSpec
, const Ipp32f*
pTapsLow
, int
lenLow
, int
anchorLow
, const Ipp32f*
pTapsHigh
, int
lenHigh
, int
anchorHigh
);
Include Files
ippi.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
Parameters
pSpec
Double pointer to the forward wavelet transform specification structure.
pTapsLow
Pointer to lowpass filter taps.
lenLow
Length of the lowpass filter.
anchorLow
Anchor position of the lowpass filter.
pTapsHigh
Pointer to highpass filter taps.
lenHigh
Length of the highpass filter.
anchorHigh
Anchor position of the highpass filter.
Description
This function initializes the specification structure
pSpec
for a one-level wavelet decomposition.
The forward wavelet transform specification structure contains parameters of a wavelet filter bank used for image decomposition. The filter bank consists of two analysis filters and includes the lowpass decomposition filter (or
coarse
filter) and the highpass decomposition filter (or
detail
filter).
The parameters
pTapsLow
and
pTapsHigh
specify coefficients, and
anchorLow
and
anchorHigh
- anchor positions for two synthesis filters. The anchor value sets the initial leftmost filter position relative to image row or column as shown in the figure below:
Anchor Value and Initial Filter Position for Wavelet Decomposition
Here
a
stands for anchor value,
N
is filter length, x
0
is the starting pixel of the processed row or column, and x
-1
, x
-2
,... are the additional border pixels that are needed for calculations. The anchor value and filter length completely determine right, left, top, and bottom border sizes for the source image used in decomposition. The corresponding C-language expressions to calculate border sizes are given in the description of ippiWTFwd
function.
For an example on how to use this function, refer to the example provided with the
ippiWTInv
function description.
Return Values
ippStsNoErr
Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr
Indicates an error when any of the specified pointers is
NULL
.
ippStsNumChannelsErr
Indicates an error when
numChannels
has an illegal value.
ippStsSizeErr
Indicates an error when filter length
lenLow
or
lenHigh
is less than 2.
ippStsAnchorErr
Indicates an error when anchor position
anchorLow
or
anchorHigh
is less than zero.

Product and Performance Information

1

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Notice revision #20110804