FilterGaussian

Syntax

Include Files

ippcv.h

ippcv_l.h

Domain Dependencies

Headers: ippcore.h, ippvm.h, ipps.h, ippi.h

Libraries: ippcore.lib, ippvm.lib, ipps.lib, ippi.lib

Parameters

Description

This function operates with ROI (see Regions of Interest in Intel IPP).

These functions apply the Gaussian filter to the source image ROI pSrc. The kernel of the Gaussian filter is the matrix of size kernelSizexkernelSize with the standard deviation sigma. The values of the Gaussian kernel elements are computed by the FilterGaussianInit function. Elements of the kernel are normalized. The anchor cell is the center of the kernel.

Before using the ippiFilterGaussian function, compute the size of the Gaussian specification structure using the FilterGaussianGetSpecSize function and the external buffer using the FilterGaussianGetBufferSize function and initialize the structure using the FilterGaussianInit function.

Return Values

Example

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//   A simple example of performing a filtering an image using a general integer rectangular kernel
// implemented with Intel® Integrated Primitives (Intel® IPP) functions:
//     ippiImageJaehne_32f_C1R
//     ippiFilterGaussianGetSpecSize
//     ippiFilterGaussianInit
//     ippiFilterGaussianGetBufferSize
//     ippiFilterGaussian_32f_C1R


#include <stdio.h>
#include "ipp.h"

#define WIDTH  128  /* image width */
#define HEIGHT  64  /* image height */

/* Next two defines are created to simplify code reading and understanding */
#define EXIT_MAIN exitLine:                                  /* Label for Exit */
#define check_sts(st) if((st) != ippStsNoErr) goto exitLine; /* Go to Exit if Intel® IPP function returned status different from ippStsNoErr */

/* Results of ippMalloc() are not validated because Intel® IPP functions perform bad arguments check and will return an appropriate status  */

int main(void)
{
    IppStatus status = ippStsNoErr;
    Ipp32f* pSrc = NULL, * pDst = NULL;     /* Pointers to source/destination images */
    int srcStep = 0, dstStep = 0;          /* Steps, in bytes, through the source/destination images */
    IppiSize roiSize = { WIDTH, HEIGHT };  /* Size of source/destination ROI in pixels */
    Ipp32u kernelSize = 3;
    Ipp32f sigma = 0.35f;
    Ipp8u* pBuffer = NULL;                 /* Pointer to the work buffer */
    Ipp8u* pInitBuf = NULL;                /* Pointer to the Init buffer */
    IppFilterGaussianSpec* pSpec = NULL;   /* context structure */
    int iTmpBufSize = 0, iSpecSize = 0, iInitBufSize = 0;    /* Common work buffer size */
    IppiBorderType borderType = ippBorderRepl;
    Ipp32f borderValue = 0;
    int numChannels = 1;

    pSrc = ippiMalloc_32f_C1(roiSize.width, roiSize.height, &srcStep);
    pDst = ippiMalloc_32f_C1(roiSize.width, roiSize.height, &dstStep);

    check_sts(status = ippiImageJaehne_32f_C1R(pSrc, srcStep, roiSize)) /* fill source image */

    check_sts(status = ippiFilterGaussianGetSpecSize(kernelSize, ipp32f, numChannels,
        &iSpecSize, &iInitBufSize))

    pSpec = (IppFilterGaussianSpec*)ippsMalloc_8u(iSpecSize);
    pInitBuf = ippsMalloc_8u(iInitBufSize);

    status = ippiFilterGaussianInit(roiSize, kernelSize, sigma, borderType,
        ipp32f, numChannels, pSpec, pInitBuf);
    ippsFree(pInitBuf);
    check_sts(status)

    check_sts(status = ippiFilterGaussianGetBufferSize(roiSize, kernelSize, ipp32f,
        numChannels, &iSpecSize, &iTmpBufSize))

    
    pBuffer = ippsMalloc_8u(iTmpBufSize);

    check_sts(status = ippiFilterGaussian_32f_C1R(pSrc, srcStep, pDst, dstStep, roiSize,
        borderType, &borderValue, pSpec, pBuffer))

    EXIT_MAIN
    ippsFree(pBuffer);
    ippsFree(pSpec);
    ippiFree(pSrc);
    ippiFree(pDst);
    printf("Exit status %d (%s)\n", (int)status, ippGetStatusString(status));
    return (int)status;
}