diff --git a/porespy/metrics/__funcs__.py b/porespy/metrics/__funcs__.py
index <HASH>..<HASH> 100644
--- a/porespy/metrics/__funcs__.py
+++ b/porespy/metrics/__funcs__.py
@@ -443,7 +443,8 @@ def chord_counts(im):
     function is ``sp.bincount`` which gives the number of chords of each
     length in a format suitable for ``plt.plot``.
     """
-    
+    if (im.dtype == bool) or (im.max() == 1):
+        raise Exception ('Image does not have chords')
     labels, N = spim.label(im > 0)
     props = regionprops(labels)
     chord_lens = sp.array([i.filled_area for i in props])
To ensure input image has chords already applied to it.