cv_sample_connectedComponents2.py

from subprocess import call
from pylab import *
from mpl_toolkits.axes_grid1 import make_axes_locatable
from matplotlib.patches import Rectangle
from time import sleep
import cv2

# Read template image
templateImageGray = cv2.imread("./images/templateImage.png", cv2.IMREAD_GRAYSCALE)
templateImageGray = cv2.resize(templateImageGray, (0, 0), fx=16, fy=16, interpolation=cv2.INTER_CUBIC)

# Convert template image to binary image
_, templateImageBlackWhite = cv2.threshold(templateImageGray, 127, 255, cv2.THRESH_BINARY)

# Convert binary image to labeled image
numOfLabelOfTemplateImage, templateImageLabeled, stats, centroids = cv2.connectedComponentsWithStats(templateImageBlackWhite, connectivity=8)

## Draw rectangle to labeled image
pt1Stats = stats[:, 0:2]
pt2Stats = pt1Stats + stats[:, 2:4]

templateImageLabeledWithRect = np.array(templateImageLabeled)
for pt1, pt2 in zip(pt1Stats, pt2Stats):
    pt1 = tuple(pt1)
    pt2 = tuple(pt2)
    cv2.rectangle(templateImageLabeledWithRect, pt1, pt2, (255, 255, 0), thickness=10)

## Put text to labeled image
#cv2.putText(

print "Number of labeled objects is %d" % numOfLabelOfTemplateImage

################ Plot ################

ax = plt.subplot(411)
plt.title("templateImageGray")
plt.imshow(templateImageGray, cmap="gray", interpolation="nearest")

ax = plt.subplot(412)
plt.title("templateImageBlackWhite")
plt.imshow(templateImageBlackWhite, cmap="gray", interpolation="nearest")

ax = plt.subplot(413)
plt.title("templateImageLabeled")
plt.imshow(templateImageLabeled, interpolation="nearest")

ax = plt.subplot(414)
plt.title("templateImageLabeledWithRect")
plt.imshow(templateImageLabeled, interpolation="nearest")
# Draw rectangle to labeled image
xys = stats[:, 0:2]
whs = stats[:, 2:4]
for n, (xy, wh) in enumerate(zip(xys, whs)):
    ax.text(xy[0], xy[1], str(n), verticalalignment="bottom")
    ax.add_patch(Rectangle(xy, *wh, fill=None, color="#ff0000", linewidth=1))


plt.tight_layout()
plt.show()