topic Re: ippiHistogramEven_8u_C3R in Intel® Integrated Performance Primitives

ippiHistogramEven_8u_C3R

hadipardis — Sat, 15 Dec 2007 08:26:05 GMT

Hi, I use the following Delphi code for calculating the histogram (with 255 bins) of an image using ippiHistogramEven_8u_C3R.

-------------------------

var

LowerLevel,UpperLevel,nLevels:array[0..2] of IPP32s;
pHist,pLevels:array[0..2] of array[0..255] of IPP32s;
begin

LowerLevel[0]:=0;
LowerLevel[1]:=0;
LowerLevel[2]:=0;

UpperLevel[0]:=255;
UpperLevel[1]:=255;
UpperLevel[2]:=255;

nLevels[0]:=256;
nLevels[1]:=256;
nLevels[2]:=256;

.....

ippiHistogramEven_8u_C3R(pSrc,scanline,roisize,@pHist,@pLevels,@nlevels,@LowerLevel,@UpperLevel);

end;

but when I run it I get this message from ippGetStatusString: "Null Pointer Error". But what is the problem? Thanks

Re: ippiHistogramEven_8u_C3R

Vladimir_Dudnik — Sun, 16 Dec 2007 23:28:52 GMT

I may guess the problem is that one of the pointers passed to the function as a parameter is NULL.

Vladimir

Re: ippiHistogramEven_8u_C3R

hadipardis — Mon, 17 Dec 2007 05:20:27 GMT

Thanks,But as you can see from my code, there isn't any NULL pointer. Should I use ippimalloc for creating pHist & pLevel? If so, could you please give me an example. Thanks

Re: ippiHistogramEven_8u_C3R

Vladimir_Dudnik — Mon, 17 Dec 2007 06:16:35 GMT

Please find an example how to callippiHistogramEven function on the page 11-28 of IPP 5.3 manual, volume 2.

Vladimir

Re: ippiHistogramEven_8u_C3R

hadipardis — Mon, 17 Dec 2007 12:14:15 GMT

I am using IPP v5.2 and in its manual there isn't any example to show how to call ippiHistogramEven on multi-channel images. Could you please putthe relevant example of IPP 5.3 here? Anyway, I am wondering why my mentioned code doesn't work!! What do you think? Thanks

Re: ippiHistogramEven_8u_C3R

Vladimir_Dudnik — Wed, 19 Dec 2007 09:22:16 GMT

there is example from IPP 5.3 manual

Example 11-5 Computing the Even Histogram of an Image// Compute histogram of an image for 4 bins in the range [28, 127];
// compute level values for the bins.
{
Ipp8u img[WIDTH*HEIGHT];
IppiSize imgSize = {WIDTH, HEIGHT};
Ipp32s levels[5], histo[5];
ippiHistogramEven_8u_C1R(img, WIDTH, imgSize, levels,
histo, 5, 28, 128);
// When the function completes operation the array histo will // contain a
histogram in specified range, and the array
// levels will contain the level values {28, 53, 78, 103, 128}
}

Regards,
Vladimir

Re: ippiHistogramEven_8u_C3R

hadipardis — Wed, 19 Dec 2007 09:44:10 GMT

Thanks. But I need an exxample for ippiHistogramEven_8u_C3R. Unfortunately, my problem is still remained! If you show me an example in Delphi, it can help me a lot!

Re: ippiHistogramEven_8u_C3R

Vladimir_Dudnik — Wed, 19 Dec 2007 09:56:40 GMT

Please take a look on IPP Delphi sample. Although it does not show you exactly that function, but I think your the main problem is converting memory pointers from Delphi environment to IPP call

Vladimir

Re: ippiHistogramEven_8u_C3R

hadipardis — Fri, 21 Dec 2007 06:59:42 GMT

Thanks Nikolay! Yes, you are right and my problem solved! :)