Python Point Detect

detect.py

import cv2
import numpy as np
import scipy.ndimage.measurements

cv2.startWindowThread()

for iname,t in (("img",45),("img2",230), ("img3",230), ("img4",250)):
    i = cv2.imread("%s.png" % iname)
    cv2.namedWindow(iname)

    valid = i >= t

    cv2.imshow(iname, i)
    i[~valid] = 0

    lbls,npts = scipy.ndimage.measurements.label(i)
    slcs = scipy.ndimage.measurements.find_objects(lbls)

    #according to the docs, passing None as the last argument should 
    #return all centre of mass. But this doesnt work. So assume the labels start
    #at 1 and increase linearly
    #http://projects.scipy.org/scipy/ticket/1839
    #
    #lets also assume that they are returned in the same order as the slices
    for n in range(1,npts+1):
        slc = slcs[n-1]
        r,c,_ = scipy.ndimage.measurements.center_of_mass(i,lbls,n)

        b = i[slc]
        cv2.namedWindow("%spatch%d" % (iname,n))
        cv2.imshow("%spatch%d" % (iname,n), b)

        print n, " = ", b.sum()/np.count_nonzero(b),"@",r,",",c

        i[r-20:r+20,c,2] = 255
        i[r,c-20:c+20,2] = 255

        cv2.imshow(iname, i)

img.png

img2.png

img3.png

img4.png