Fix rounding errors (fixes #9)

2019-04-22 17:16:30 +02:00 · 2019-04-22 17:16:30 +02:00 · 52864f2269
parent 2a21c6f2a8
commit 52864f2269
1 changed files with 3 additions and 1 deletions
--- a/stvid/stio.py
+++ b/stvid/stio.py
@ -164,7 +164,9 @@ class fourframe:
        """Create a selection mask"""
        c1 = ndimage.uniform_filter(self.znum, 3, mode='constant')
        c2 = ndimage.uniform_filter(self.znum*self.znum, 3, mode='constant')
-        z = np.sqrt(c2-c1*c1)
+
+        # Add epsilon to keep square root positive
+        z = np.sqrt(c2-c1*c1+1e-9)

        # Standard deviation mask
        c = z < zstd