| Re: CONVOL2D [message #14343] |
Thu, 18 February 1999 00:00 |
David Foster
Messages: 341
Registered: January 1996
|
Senior Member |
|
|
Lisa Bryan wrote:
>
> Hello all,
>
> I had assumed that since the IDL help manual says:
> 'Assume R = CONVOL(A, K, S), where A is an n-element vector, K
>
> is an m-element vector'
>
> the function CONVOL acted in a 1D manner only, i.e. it worked on data
> as vectors and not arrays. Excuse the mistake. On the other hand
> I've decided to bypass colvolutions all together and delve into
> Fourier space (new territory for me so wish me luck!)
And actually you can use convolution to perform Fourier transforms.
Dave
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
David S. Foster Univ. of California, San Diego
Programmer/Analyst Brain Image Analysis Laboratory
foster@bial1.ucsd.edu Department of Psychiatry
(619) 622-5892 8950 Via La Jolla Drive, Suite 2240
La Jolla, CA 92037
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
|
|
|
|
| Re: CONVOL2D [message #14354 is a reply to message #14343] |
Wed, 17 February 1999 00:00  |
lbryanNOSPAM
Messages: 21
Registered: July 1998
|
Junior Member |
|
|
Hello all,
I had assumed that since the IDL help manual says:
'Assume R = CONVOL(A, K, S), where A is an n-element vector, K
is an m-element vector'
the function CONVOL acted in a 1D manner only, i.e. it worked on data
as vectors and not arrays. Excuse the mistake. On the other hand
I've decided to bypass colvolutions all together and delve into
Fourier space (new territory for me so wish me luck!)
On Tue, 16 Feb 1999 16:02:50 -0700, davidf@dfanning.com (David
Fanning) wrote:
> Lisa Bryan (lbryanNOSPAM@arete-az.com) writes:
>
>> I am sure this is out there, I'm just too lazy to find it. I need to
>> convolve a 2D gaussian (not necessarily the same size in each
>> dimension) into an image. Does anyone have a tool I may beg, borrow,
>> or steal?
>
> Do you mean something other than the CONVOL function?
>
> Gaussian kernels to use with the CONVOL function are
> easy to create. You can find them in the back of image
> processing books or even in the image processing
> section (p72) of my book. :-)
>
Lisa Bryan
Arete Associates
Tucson, Arizona
lbryan@arete-az.com
|
|
|
|
| Re: CONVOL2D [message #14363 is a reply to message #14354] |
Wed, 17 February 1999 00:00 |
meron
Messages: 51
Registered: July 1995
|
Member |
|
|
In article <36c9df01.101510033@news1.alterdial.uu.net>, lbryanNOSPAM@arete-az.com (Lisa Bryan) writes:
> Hello all,
>
> I am sure this is out there, I'm just too lazy to find it. I need to
> convolve a 2D gaussian (not necessarily the same size in each
> dimension) into an image. Does anyone have a tool I may beg, borrow,
> or steal?
>
You can use M_CONVOL from my library, but you'll better get the whole
library if you want to do it.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
|
|
|
|
| Re: CONVOL2D [message #14367 is a reply to message #14354] |
Tue, 16 February 1999 00:00 |
David Foster
Messages: 341
Registered: January 1996
|
Senior Member |
|
|
Lisa Bryan wrote:
>
> Hello all,
>
> I am sure this is out there, I'm just too lazy to find it. I need to
> convolve a 2D gaussian (not necessarily the same size in each
> dimension) into an image. Does anyone have a tool I may beg, borrow,
> or steal?
>
> Lisa
uh, how about CONVOL()?
Dave
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
David S. Foster Univ. of California, San Diego
Programmer/Analyst Brain Image Analysis Laboratory
foster@bial1.ucsd.edu Department of Psychiatry
(619) 622-5892 8950 Via La Jolla Drive, Suite 2240
La Jolla, CA 92037
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
|
|
|
|
| Re: CONVOL2D [message #14370 is a reply to message #14367] |
Tue, 16 February 1999 00:00 |
davidf
Messages: 2866
Registered: September 1996
|
Senior Member |
|
|
Lisa Bryan (lbryanNOSPAM@arete-az.com) writes:
> I am sure this is out there, I'm just too lazy to find it. I need to
> convolve a 2D gaussian (not necessarily the same size in each
> dimension) into an image. Does anyone have a tool I may beg, borrow,
> or steal?
Do you mean something other than the CONVOL function?
Gaussian kernels to use with the CONVOL function are
easy to create. You can find them in the back of image
processing books or even in the image processing
section (p72) of my book. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
