Developer Reference for Intel® Integrated Performance Primitives 2019
Applies forward Fast Fourier Transform to an image.
Case 1: Not-in-place operation on floating-point data
IppStatus ippiFFTFwd_RToPack_<mod> (const Ipp32f* pSrc, int srcStep, Ipp32f* pDst, int dstStep, const IppiFFTSpec_R_32f* pFFTSpec, Ipp8u* pBuffer);
Supported values for mod:
32f_C1R |
32f_C3R |
32f_C4R |
32f_AC4R |
Case 2: Not-in-place operation on complex data
IppStatus ippiFFTFwd_CToC_32fc_C1R(const Ipp32fc* pSrc, int srcStep, Ipp32fc* pDst, int dstStep, const IppiFFTSpec_C_32fc* pFFTSpec, Ipp8u* pBuffer);
Case 3: In-place operation on floating-point data
IppStatus ippiFFTFwd_RToPack_<mod>(Ipp32f* pSrcDst, int srcDstStep, const IppiFFTSpec_R_32f* pFFTSpec, Ipp8u* pBuffer);
Supported values for mod:
32f_C1IR |
32f_C3IR |
32f_C4IR |
32f_AC4IR |
Case 4: In-place operation on complex data
IppStatus ippiFFTFwd_CToC_32fc_C1IR(Ipp32fc* pSrcDst, int srcDstStep, const IppiFFTSpec_C_32fc* pFFTSpec, Ipp8u* pBuffer);
ippi.h
Headers: ippcore.h, ippvm.h, ipps.h
Libraries: ippcore.lib, ippvm.lib, ipps.lib
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. |
pFFTSpec |
Pointer to the FFT specification structure. |
pBuffer |
Pointer to the external work buffer. |
This function operates with ROI.
This function performs a forward FFT 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 size of ROI is N x M, it is specified by the parameters orderX, orderY.
The function flavor ippiFFTFwd_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 ippiFFTFwd_CToC that operates on images with complex data does not perform any 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 FFT functions, you need to compute the size of the work buffer by ippiFFTGetSize and initialize the context structure by the ippiFFTInit function. The forward FFT functions use the pFFTSpec context structure to set the mode of calculations and retrieve support data.
ippStsNoErr |
Indicates no error. Any other value indicates an error or a warning. |
ippStsNullPtrErr |
Indicates an error condition if pSrc, pDst, or pFFTSpec pointer is NULL. |
ippStsStepErr |
Indicates an error condition if srcStep or dstStep value is zero or negative. |
ippStsContextMatchErr |
Indicates an error condition if a pointer to an invalid pFFTSpec structure is passed. |
ippStsMemAllocErr |
Indicates an error condition if memory allocation fails. |