diff --git a/sgfilter.py b/sgfilter.py
index a3c8681..fca5afb 100644
--- a/sgfilter.py
+++ b/sgfilter.py
@@ -3,10 +3,29 @@
 def sgfilter1d(degree, window_size):
     if not isinstance(degree, int) or degree < 0:
         raise ValueError("Degree of polynomial must be positive integers")
-    if not isinstance(window_size, int) or window_size % 2 == 0 or window_size < 0 :
+    if not isinstance(window_size, int) or window_size % 2 == 0 or window_size < 0:
         raise ValueError("Window size must be positive odd integer")
-    if window_size < degree + 2:
-        raise ValueError("Degree to high for half width")
+    if window_size < (degree + 1):
+        raise ValueError("Degree to high for window size")
     A = np.array([[n ** i for i in xrange(degree + 1)] for n in xrange(-(window_size - 1)/2, (window_size - 1)/2 + 1)])
     Ainv = np.linalg.pinv(A)
     return Ainv[0]
+
+def sgfilter2d(degree, window_size):
+    if not isinstance(degree, int) or degree < 0:
+        raise ValueError("Degree of polynomial must be positive integers")
+    if not isinstance(window_size, int) or window_size % 2 == 0 or window_size < 0 :
+        raise ValueError("Window size must be positive odd integer")
+    if window_size ** 2 < ((degree + 2) * (degree + 1)) / 2.0:
+        raise ValueError("Degree too high for window size")
+    exps = [ {"x": k - n, "y": n } for k in xrange(degree + 1) for n in xrange(k + 1)]
+    n = np.arange(-(window_size - 1) / 2, (window_size - 1)/2 + 1, dtype = np.float64)
+    dx = np.repeat(n, window_size)
+    dy = np.tile(n, [window_size, 1]).reshape(window_size ** 2, )
+    A = np.empty((window_size ** 2, len(exps)))
+    for i, exp in enumerate(exps):
+        A[:,i] = (dx ** exp["x"]) * (dy ** exp["y"])
+    Ainv = np.linalg.pinv(A)
+    return Ainv[0]
+
+print sgfilter2d(3, 5)