CODEWITHSUNDEEP
opencvnumpy
Chris
Chris

Reputation: 10041

How to calculate the weighted "center" of a 2d numpy array?

let's say I have some numpy array (in this case it represents a 100x100 binary image)...

img=np.random.randint(0,2,(100,100)).astype(numpy.uint8)

How best to determine the "average position" of the 1 values in the array? For instance, if therer was a cluster of 1's in the array, I would like to find the center of that cluster.

Upvotes: 3

Views: 4683

Answers (1)

Diana
Diana

Reputation: 1321

I'm seeing you tagged this as numpy too, so I'd do this:

x = range(0, img.shape[0])
y = range(0, img.shape[1])

(X,Y) = np.meshgrid(x,y)

x_coord = (X*img).sum() / img.sum().astype("float")
y_coord = (Y*img).sum() / img.sum().astype("float")

That wold give you the weighted average center.

If you want this for every cluster of 1's in the image I suggest you use connected components to mask which cluster you're interested in. Might not be a good idea to repeat this process for as many clusters as you want, but rather compute all cluster averages in the same array traversal.

Upvotes: 1

Related Questions