DFTFwd
Applies forward discrete Fourier transform to an
image.
Syntax
Case
1
: Not-in-place
operation on floating-point dataIppStatus
ippiDFTFwd_RToPack_<mod>(const Ipp32f*
pSrc
, int
srcStep
, Ipp32f*
pDst
, int
dstStep
, const IppiDFTSpec_R_32f*
pDFTSpec
, Ipp8u*
pBuffer
);
Supported values for
mod
:32f_C1R |
32f_C3R |
32f_C4R |
32f_AC4R |
Case
2
: Not-in-place
operation on complex dataIppStatus ippiDFTFwd_CToC_32fc_C1R(const
Ipp32fc*
pSrc
, int
srcStep
, Ipp32fc*
pDst
, int
dstStep
, const IppiDFTSpec_C_32fc*
pDFTSpec
, Ipp8u*
pBuffer
);
Case
3
: In-place
operation on floating-point dataIppStatus
ippiDFTFwd_RToPack_<mod>(Ipp32f*
pSrcDst
, int
srcDstStep
, const IppiDFTSpec_R_32f*
pDFTSpec
, Ipp8u*
pBuffer
);
Supported values for
mod
:32f_C1IR |
32f_C3IR |
32f_C4IR |
32f_AC4IR |
Case
4
: In-place
operation on complex dataIppStatus
ippiDFTFwd_CToC_32fc_C1IR(Ipp32fc*
pSrcDst
, int
srcDstStep
, const IppiDFTSpec_C_32fc*
pDFTSpec
, Ipp8u*
pBuffer
);
Include Files
ippi.h
Domain Dependencies
Headers:
ippcore.h
, ippvm.h
, ipps.h
Libraries:
ippcore.lib
, ippvm.lib
, ipps.lib
Parameters
- pSrc
- Pointer to the source image ROI.
- srcStep
- Distance in bytes between starts of consecutive lines in the source image.
- pDst
- Pointer to the destination image ROI.
- dstStep
- Distance in bytes between starts of consecutive lines in the destination image.
- pSrcDst
- Pointer to the source and destination image ROI for the in-place operation.
- srcDstStep
- Distance in bytes between starts of consecutive lines in the source and destination image for the in-place operation.
- pDFTSpec
- Pointer to the previously initialized DFT context structure.
- pBuffer
- Pointer to the external work buffer.
Description
This function operates with ROI.
This function performs a forward DFT on each channel of the source
image ROI
pSrc
(pSrcDst
for
in-place flavors) and writes the Fourier coefficients into the corresponding channel
of the destination buffer pDst
(pSrcDst
for in-place flavors). The function flavor
ippiDFTFwd_RToPack
that operates on images with real data takes
advantage of the symmetry property and stores the output data in RCPack2D format. It supports processing of the 1-, 3-, and 4-channel
images. Note that the functions with AC4
descriptor do not process alpha channel. The function flavor
ippiDFTFwd_CToC
that operates on images with complex data performs no
packing of the transform results as no symmetry with respect to frequency domain
data is observed in this case. Memory layout of images with complex data follows the
same conventions as for real images provided that each pixel value consists of two
numbers: imaginary and real part. Before using the forward DFT functions, you need to compute the
size of the work buffer by
ippiDFTGetSize
and initialize the context structure by the ippiDFTInit
function. The forward
DFT functions use the pDFTSpec
context structure to set the mode of calculations and retrieve support
data.Return Values
- ippStsNoErr
- Indicates no error. Any other value indicates an error or a warning.
- ippStsNullPtrErr
- Indicates an error condition ifpSrc, pDst,orpDFTSpecpointer isNULL.
- ippStsStepErr
- Indicates an error condition ifsrcStepordstStepvalue is zero or negative.
- ippStsContextMatchErr
- Indicates an error condition if a pointer to an invalidpDFTSpecstructure is passed.
- ippStsMemAllocErr
- Indicates an error condition if memory allocation fails.