Plot number of black pixels per row using python

I'm working with a binary image in Python and I want to plot a histogram that shows/returns the number of black pixels per row, not the total number. So far this is not working:

hist = cv2.calcHist([binary_image], [0], None, [height], [0, weight])    




I did it in MATLAB and this is works fine

im_hist = hist(t_image, 2);



Assuming that binary_image is a 2D array, this will work:

counts = np.sum(binary_image==0, axis=1)


Your MATLAB function, however, does not do what you describe in a general way. It divides your data into two ranges, then counts how many data points fall into each range. This will only work properly if your image only has two levels. If not, then your "black" will include values other than black. The equivalent python function is this is:

counts = np.sum(binary_image<binary_image.max()/2., axis=1)


Need Your Help

How can I change Mac OS's default Java VM returned from /usr/libexec/java_home

java macos java-home

(Wasn't sure if this should go on SU... migration is certainly an option, but more programmers read questions here, so here goes).

Nested lists in R: extract and combine values according to the name/position of the sublists

r list nested

I store my data in a multilevel nested list. This list may look like this