topic Re: Ippi's example 9-5: Separable kernel convolution in Intel® Integrated Performance Primitives

Ippi's example 9-5: Separable kernel convolution

liorda — Tue, 06 Jan 2009 12:48:22 GMT

Hi, I can't get example 9-5 in the ippi manual to work. my code is as follow:

Ipp16s img[6*6]= { 0, 0, 0, 0, 0, 0,
0, 1, 0,-1, 0, 0,
0, 0,-1, 0, 2, 0,
0, 1, 0,-2, 1, 0,
0, 1, 1, 0, 0, 0,
0, 0, 0, 0, 0, 0 };

Ipp16s output[4*4];
Ipp16s buf[4*4];
Ipp16s kerx[3] = {1, 1, 1};
Ipp16s kery[3] = {1, 1, 1};
IppiSize roi = {4,4};

ippiCopy_16s_C1R(img+7, 6*sizeof(Ipp16s), buf, 4*sizeof(Ipp16s), roi);
Separable_3x3(buf, 4*sizeof(Ipp16s), output, 4*sizeof(Ipp16s), roi, kerx, kery);

can anyone help?

Re: Ippi's example 9-5: Separable kernel convolution

Chao_Y_Intel — Thu, 08 Jan 2009 08:18:14 GMT

Hello,

This looks an image border issue. Image filtering functions assume that for each pixel being processed, adjacent pixels also exist. You may check the following artile for more information on this topic:
http://software.intel.com/en-us/articles/intel-integrated-performance-primitives-intel-ipp-processing-an-image-from-edge-to-edge.

Could you look at if thecode bellow work for u?

Ipp16s img[6*6]= { 0, 0, 0, 0, 0, 0,
0, 1, 0,-1, 0, 0,
0, 0,-1, 0, 2, 0,
0, 1, 0,-2, 1, 0,
0, 1, 1, 0, 0, 0,
0, 0, 0, 0, 0, 0 };

Ipp16s output[4*4];
Ipp16s buf[6*6];
Ipp16s kerx[3] = {1, 1, 1};
Ipp16s kery[3] = {1, 1, 1};
IppiSize roi = {4,4};
IppiSize roi1 = {6,6};

ippiCopy_16s_C1R(img, 6*sizeof(Ipp16s), buf, 6*sizeof(Ipp16s), roi1);
Separable_3x3(buf+7, 6*sizeof(Ipp16s), output, 4*sizeof(Ipp16s), roi, kerx, kery);

Thanks,
Chao

Re: Ippi's example 9-5: Separable kernel convolution

liorda — Fri, 09 Jan 2009 13:43:15 GMT

Quoting - Chao Yu (Intel)

I'm maybe missing something, but I still can't get the code to work as expected. the other convolution methods work normally. the attched example should produce the same output, but the separable method somehow disfunctions...

I'd love to hear what am I doing wrong. my complete test code attached.

Thanks,
--Lior

Re: Ippi's example 9-5: Separable kernel convolution

liorda — Sun, 11 Jan 2009 21:29:06 GMT

can anyone please have a look? I followd the manual example and I can't get right results.

Thanks,
--Lior

Re: Ippi's example 9-5: Separable kernel convolution

Chao_Y_Intel — Tue, 13 Jan 2009 07:43:24 GMT

Hi Lior,

In the file attached, the Separable_3x3 function is using duplicate border (ippBorderRepl), while other two filter functions are using 0 border.

I modified somecode to make that sample more easily to understand ( attached). The code can produce the same output for three filter functions.

Thanks,
Chao