diff --git a/pixelocr/page.py b/pixelocr/page.py
index 5051fbe..89e99b3 100644
--- a/pixelocr/page.py
+++ b/pixelocr/page.py
@@ -19,7 +19,7 @@ from collections import defaultdict
 
 import numpy as np
 from scipy import ndimage
-from scipy.ndimage import filters
+from scipy.ndimage import filters, grey_closing
 
 from .utils import cached_property, collect_iterable, pairwise, neighbourhood
 from .image import Image, combine, is_nonblank
@@ -158,6 +158,7 @@ class Line(PageObject):
     def baseline(self):
         """Detect baseline height, relative to the top."""
         bitmap = self.image.bitmap
+        bitmap = grey_closing(bitmap, (0, 10), mode='constant')
         histogram = bitmap.sum(axis=1)
         gradient = list(filters.correlate1d(histogram, [-1, 1], axis=0, mode='constant'))
         gradient[0] = histogram[0]