topic ippiFilterGaussianBorder in Intel® Integrated Performance Primitives

ippiFilterGaussianBorder

Adriaan_van_Os — Mon, 03 Dec 2018 09:13:56 GMT

The ippiFilterGaussianBorder puzzles me, notably the sigma parameter. Compared to doing the Gaussian Blur with a matrix, ippiFilterGaussianBorder gives me what looks like unprecise results. This is with a typical kernel size 15 or 31. Of course, a Gaussian Blur is separable, so we can replace the matrix with two one-dimensional matrices.

Can you give an example of a matrix or two separable matrices where ippiFilterGaussianBorder is (or should be) equivalent to ippiFilterBorder ?

Regards,

Adriaan van Os

Asking above question again.

Adriaan_van_Os — Mon, 28 Jan 2019 08:58:54 GMT

Asking above question again. Either my understanding of ippiFilterGaussianBorder is wrong, or it has some bugs.

Can you give an example of a matrix or two separable matrices where ippiFilterGaussianBorder is (or should be) equivalent to ippiFilterBorder ?

Regards,

Adriaan van Os

Hi Adriaan van Os,

Igor_A_Intel — Mon, 28 Jan 2019 14:08:49 GMT

Hi Adriaan van Os,

for kernelSize = 15 and sigma = .5.5 coefficients are the next:

k0 = 0.038978182

k1 = 0.048321572

k2 = 0.057956705

k3 = 0.067252662

k4 = 0.075501995

k5 = 0.082006926

k6 = 0.086175894

k7 = 0.087612126

k8 = 0.086175894

k9 = 0.082006926

k10 = 0.075501995

k11 = 0.067252662

k12 = 0.057956705

k13 = 0.048321572

k14 = 0.038978182

the filter itself is separable - therefore row/column coefficients are the same. The only 1 fact that is not reflected in the documentation - that these coefficients are normalized on their initial sum (coeff are obtained according to the formula in the manual and then divided by their sum).

regards, Igor

Thanks.

Adriaan_van_Os — Wed, 30 Jan 2019 12:05:07 GMT

Thanks.

What sigma is ".5.5" ?

Regards,

Adriaan van Os

Hi,

Igor_A_Intel — Wed, 30 Jan 2019 13:43:37 GMT

Hi,

this one (in bold):

IPPAPI(IppStatus, ippiFilterGaussianInit,(IppiSize roiSize, Ipp32u kernelSize, Ipp32f sigma,
IppiBorderType borderType, IppDataType dataType, int numChannels,
IppFilterGaussianSpec* pSpec, Ipp8u* pBuffer))

regards, Igor