Re: Inquery(Partial Differentiation)
- To: mathgroup at smc.vnet.net
- Subject: [mg34062] Re: Inquery(Partial Differentiation)
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Wed, 1 May 2002 08:00:33 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <aag9hs$1sb$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
load a picture you like
ll = Import["/export/home/kuska/DigitalImageProcess/tiger.tiff"]
and use a smoothed Sobel filter with
bm = ll[[1, 1]];
sobel = {{1, 0, -1},
{2, 0, -2},
{1, 0, -1}}/8;
gradx = ListConvolve[sobel, bm, {2, 2}];
grady = ListConvolve[Transpose[sobel], bm, {2, 2}];
and here are your derivatives in x and y direction.
ListDensityPlot[gradx, Mesh -> False];
ListDensityPlot[grady, Mesh -> False];
Regards
Jens
Gagan Anand wrote:
>
> I am working to Gray-scale image files(TIFF) , I
> need to calculate the Orientiation of the Pixels , for
> that I need to calculate Directional Filed Estimation.
> For Directional Field Estimation I need to fined the
> Gradient.
> Gradient can be calculated by Partial Differentiation.
> Can you help me out to calculate Partial
> Diffrenetiation at each pixel, I am clear with the
> formulae of Partial Differentiation, but how to
> Implement it.
> Thank You,
> GAGAN ANAND
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Health - your guide to health and wellness
> http://health.yahoo.com