--- a
+++ b/ants/math/metrics.py
@@ -0,0 +1,43 @@
+
+ 
+
+__all__ = ['image_mutual_information']
+
+
+from ants.decorators import image_method
+from ants.internal import get_lib_fn
+
+@image_method
+def image_mutual_information(image1, image2):
+    """
+    Compute mutual information between two ANTsImage types
+
+    ANTsR function: `antsImageMutualInformation`
+    
+    Arguments
+    ---------
+    image1 : ANTsImage
+        image 1
+
+    image2 : ANTsImage
+        image 2
+
+    Returns
+    -------
+    scalar
+
+    Example
+    -------
+    >>> import ants
+    >>> fi = ants.image_read( ants.get_ants_data('r16') ).clone('float')
+    >>> mi = ants.image_read( ants.get_ants_data('r64') ).clone('float')
+    >>> mival = ants.image_mutual_information(fi, mi) # -0.1796141
+    """
+    if (image1.pixeltype != 'float') or (image2.pixeltype != 'float'):
+        raise ValueError('Both images must have float pixeltype')
+
+    if image1.dimension != image2.dimension:
+        raise ValueError('Both images must have same dimension')
+
+    libfn = get_lib_fn('antsImageMutualInformation%iD' % image1.dimension)
+    return libfn(image1.pointer, image2.pointer)