nice-to-have-function

Image.Image convol(Image.Image i, array(array(array(array(float)))) foo)

Not convolve? (Just trying to avoid new master()->resolv issues... :-)

/ Johan Sundström (Achtung Liebe!)

Previous text:

2004-08-26 05:11: Subject: nice-to-have-function

---

Image.Image->apply_matrix is not always very useful...

I'm a little busy myself, otherwise I would provide a patch, my suggestion is that someone adds a function that does this to Image.Image:

Image.Image convol(Image.Image i, array(array(array(array(float)))) foo) { Image.Image ret;

array(array(array(array(int)))) foo1= ( array(array(array(array(int)))) ) (foo[*][*][*][*]*100000);

for(int x=0;x<3;x++) { array(int) c1=({ 0,0,0 }); c1[x]=255;

array(array(array(int))) foo2=foo1[*][*][x];

for(int y=0;y<3;y++) { array(array(int)) foo3=foo2[*][*][y]; int sum=`+(0, @ foo3*({}));

 array(int) c2=({ 0,0,0 });
 c2[x]=255;

 Image.Image tmp;
 tmp=i->gray(@c1)->apply_matrix(foo3,0,0,0,
                                sum?100000.0/sum:1.0)*c2;

 if(ret) 
   ret+=tmp;
 else
   ret=tmp;

} } return ret; }

I've need a function like this twice now, so I think it would be useful. Also, the implementation above is grossly inefficient..

If anybody knows a faster way to do the same thing with the currently available Image operations, let me know.

Possible extentions to this function: o Add the results to an image to avoid the clipping that would occur if you did the addition afterwards. o Add x-stride and y-stride to allow it to compute only every x:th and y:th pixel to allow scaling in the same step. (Is it even possible to scale an image without averaging right now?)

/ Fredrik (Naranek) Hubinette (T minus 2 weeks)