diff --git a/pixelocr/page.py b/pixelocr/page.py
index c6a8aea..4ee5270 100644
--- a/pixelocr/page.py
+++ b/pixelocr/page.py
@@ -104,7 +104,7 @@ class Line(PageObject):
     @cached_property
     def baseline(self):
         """Detect baseline height, relative to the top."""
-        bitmap = self.image.bitmap.astype(np.float)
+        bitmap = self.image.bitmap
         histogram = bitmap.sum(axis=1)
         gradient = list(filters.correlate1d(histogram, [-1, 1], axis=0, mode='constant'))
         gradient[0] = histogram[0]