Fast image coordinate lookup in Numpy

Posted by victor on Stack Overflow See other posts from Stack Overflow or by victor
Published on 2012-10-02T03:34:50Z Indexed on 2012/10/02 3:37 UTC
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numpy

I've got a big numpy array full of coordinates (about 400):

[[102, 234],
 [304, 104],
  ....
]

And a numpy 2d array my_map of size 800x800.

What's the fastest way to look up the coordinates given in that array? I tried things like paletting as described in this post: http://opencvpython.blogspot.com/2012/06/fast-array-manipulation-in-numpy.html but couldn't get it to work.

I was also thinking about turning each coordinate into a linear index of the map and then piping it straight into my_map like so:

my_map[linearized_coords]

but I couldn't get vectorize to properly translate the coordinates into a linear fashion. Any ideas?

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