Object detection

[Emmanuelle Gouillart]

Hallo Siggi,

two quick remarks. If you are the one taking the pictures, there is
probably room for improvement concerning the acquisition, and not only
the processing. If your image is taken with scanning electron microscopy,
as it seems to me (but I'm not sure), you might want to combine an
image from secondary electrons as the one you sent, and one image from
back-scattered electrons. These two images should have a different type
of contrast, that you might use for example to remove the background, and
the process only regions corresponding to the spheres.

About the Laplace transform for extracting the edges, you can get more
pixels from the edges by using the canny filter, instead of a simple
sobel filter. I had to use a larger value of sigma (the width of the
Gaussian blurring applied before computing the sobel filter in the
algorithm) than the default value

>>> from skimage import img_as_float
>>> from skimage.filter import canny
>>> edges = canny(img_as_float(data), sigma=3)

Cheers,
Emmanuelle

On Sat, Feb 25, 2012 at 05:50:05AM -0800, Sigmund wrote:
>    Hallo,

>    sorry for being so slow with my answers! I have urgent other tasks right
>    now. I will pick up your hints when I have some time.
>    Thanks for your help.

>    Siggi