message: Update calcBackProject_Demo1.py
  To round a ndarray it's necessary to use np.round() instead to Built-in Python round()
diff: @@ -31,7 +31,7 @@ def Hist_and_Backproj(val):
  histImg = np.zeros((h, w, 3), dtype=np.uint8)
  for i in range(bins):
  - cv.rectangle(histImg, (i*bin_w, h), ( (i+1)*bin_w, h - int(round( hist[i]*h/255.0 )) ), (0, 0, 255), cv.FILLED)
  + cv.rectangle(histImg, (i*bin_w, h), ( (i+1)*bin_w, h - int(np.round( hist[i]*h/255.0 )) ), (0, 0, 255), cv.FILLED)
  cv.imshow('Histogram', histImg)
  ## [Draw the histogram]
  