Error Concealment | JPEG | MPEG-4 | Wavelet | YUV

Hi all!
I am try to find out the low-pass filter cut-off frequency.
I input an impluse to filter,then got the impulse response.
But,I have a problem about the impulse size. 
when I used one pixel,the result is nothing! 
so,I am try using different impulse size pixels to filter,
then I got many different results. 
I am very confused about this problem ,
Can anyone tell me that I should use which size impulse.

Thank you very much for any help.
Best regards,

ben 
2007.1.7

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Ben-

> Thank you for your reply.
> I use gray image (uint8),the impluse value is 255.
> The image size is 256x256.

Ok.  Are you testing the image with DSP code or MATLAB?  If DSP code, is the
algorithm fixed-point or floating-point?  You should be able to look at intermediate
results and find out why all values are zero.  This shouldn't be hard to debug.

-Jeff

> ----- Original Message -----
> From: "Jeff Brower" <j...@signalogic.com>
> To: "Ben" <g...@ym.edu.tw>
> Cc: <i...@yahoogroups.com>
> Sent: Monday, January 08, 2007 10:54 PM
> Subject: Re: [imagedsp] find out the image filter response...
> 
> > Ben-
> >
> >> I am try to find out the low-pass filter cut-off frequency.
> >> I input an impluse to filter,then got the impulse response.
> >> But,I have a problem about the impulse size.
> >> when I used one pixel,the result is nothing!
> >> so,I am try using different impulse size pixels to filter,
> >> then I got many different results.
> >> I am very confused about this problem ,
> >> Can anyone tell me that I should use which size impulse.
> >
> > What is the value of the impulse pixel?  It should be white; i.e. for an
> > RGB pixel it should be 0x00ffffff.
> >
> > -Jeff
> >

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Ben-

> I am try to find out the low-pass filter cut-off frequency.
> I input an impluse to filter,then got the impulse response.
> But,I have a problem about the impulse size.
> when I used one pixel,the result is nothing!
> so,I am try using different impulse size pixels to filter,
> then I got many different results.
> I am very confused about this problem ,
> Can anyone tell me that I should use which size impulse.

What is the value of the impulse pixel?  It should be white; i.e. for an RGB pixel it should be
0x00ffffff.

-Jeff

(You need to be a member of imagedsp -- send a blank email to imagedsp-subscribe@yahoogroups.com )