use numpy. This is taken from a data analysis program I wrote for
analyzing single molecule fluorescent events. So should be similar to
what you want, a white spot of a given intensity surrounded by noise.
array being your image stored as a numpy array, threshhold is your
value to be greater then
self.thresharray = np.where(array>threshhold,array, 0)
for i,v in np.ndenumerate(self.thresharray):
# print i,v
if v > 0:
#find the outside to draw our box around, look
around and color the outside of it green
for k in xrange(-2,2):
for j in xrange(-2,2):
try:
if self.thresharray[i[0]-k,i[1]-j] == 0:
picture.SetRGB(i[1]-j,i[0]-k,0,255,0)
except wx._core.PyAssertionError:
pass
except IndexError:
pass
On Fri, Jan 7, 2011 at 6:41 PM, Garrett Davis <garrettdavis...@gmail.com> wrote:
> Narendra Sisodiya wrote:
>
>> Now, I want to locate the center of whitedot.
>> I want to get center based on density of whitepixel. basically center
>> where white pixel density is very high.
>> Also, I am applying this algorithm on every frame taken from camera at
>> 2fps. So I want a high speed algorithm.
>
> I would recommend using the getbbox() method, as Christopher Barker has
> already pointed out, along with one of these two techniques:
>
> a) shrinking the size of the image to, say, 16x16, so that the smaller
> 'noise' dots disappear or turn into small grey dots, and then apply, or
> re-apply, the 'point' method discussed in an earlier thread to erase them;
>
> b) using a 'centroid' algorithm to determine a 'center of mass' which would
> not be affected much by small amounts of 'noise'.
>
> Fred Lundh had kindly provided this list with such an algorithm, here:
> http://mail.python.org/pipermail/image-sig/2008-August/005149.html
>
> I use both methods in my application - detection of cars on a racetrack for
> timing and scoring purposes - with good results, and with no performance
> problems when processing larger images at 10 frames/second.
>
> Garrett Davis
>
>
> _______________________________________________
> Image-SIG maillist - image-...@python.org
> http://mail.python.org/mailman/listinfo/image-sig
>
_______________________________________________
Image-SIG maillist - Image-SIG@python.org
http://mail.python.org/mailman/listinfo/image-sig
