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
find out the image filter response...
Started by ●January 8, 2007
Reply by ●January 9, 20072007-01-09
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"
> To: "Ben"
> Cc:
> 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
> >
> 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"
> To: "Ben"
> Cc:
> 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
> >
Reply by ●January 9, 20072007-01-09
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
> 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
