How to count objects in image using python?

Question

I am trying to count the number of drops in this image and the coverage percentage of the area covered by those drops. I tried to convert this image into black and white, bu

Answer 1

You can fill the holes of your binary image using scipy.ndimage.binary_fill_holes. I also recommend using an automatic thresholding method such as Otsu's (avaible in scikit-image).

from skimage import io, filters
from scipy import ndimage
import matplotlib.pyplot as plt

im = io.imread('ba3g0.jpg', as_grey=True)
val = filters.threshold_otsu(im)
drops = ndimage.binary_fill_holes(im < val)
plt.imshow(drops, cmap='gray')
plt.show()

For the number of drops you can use another function of scikit-image

from skimage import measure
labels = measure.label(drops)
print(labels.max())

And for the coverage

print('coverage is %f' %(drops.mean()))