Image processing package - morphological functions

[Marius Roets]

Hi,

I have a couple of questions regarding the image processing package's morphological functions. 

1) imerode (and hence imopen and imclose) seems to zero pad the image before the transformation. Matlab does not do this. Example :
octave:88> m5 = magic(5)
m5 =

   17   24    1    8   15
   23    5    7   14   16
    4    6   13   20   22
   10   12   19   21    3
   11   18   25    2    9

octave:89> se = [ 1 1 1 ]
se =

   1   1   1

octave:90> imerode(m5, se)
ans =

    0    1    1    1    0
    0    5    5    7    0
    0    4    6   13    0
    0   10   12    3    0
    0   11    2    2    0

and Matlab gives
ans =

    17    1    1    1    8
    5    5    5    7    14
    4    4    6   13    20
    10   10   12    3    3
    11   11    2    2    2

2) The strel function seems to missing. Not sure if the is part of image processing, but I can't find it anywhere in Octave forge.
3) These functions are very slow. Opening a 600x600 image using a disk shaped structuring element of radius 40 takes 356 seconds.

Thanks
Marius