[Image-SIG] Locate The Center of WhiteDot from a Image

[Chris Barker]

On 1/7/2011 8:26 PM, Narendra Sisodiya wrote:
>     If you need more math, numpy can help. Somethign like:
>
>     a = np.asarray(PIL_image)
>     background_color = 0
>     rows, cols = np.where(a <> background_color) # background color a uint32
>     BB = (rows.min(), rows.max(), cols.min(), cols.max())
>
> I am unable to get what that code means ?
> May you explain how I can use above code with getbbox ? Or the above
> code using NumPy is alternate of getbbox method ?

It's an alternative.

> IF yes, then which will be the faster ?

The only way to know is to try it, but I suspect the PIL getbox() is a 
bit faster, as I image it does it all in one C loop. numpy is doing it 
in a couple loops.

The reason to use numpy is if you want to do something more complex that 
is not directly supported by PIL.

you might want to look at the scip ndimage toolbox it has some useful stuff:

http://www.scipy.org/SciPyPackages/Ndimage

though perhaps you've solved you problem.

-Chris


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