diff --git a/xray/azav.py b/xray/azav.py
index f6da4af..515cea4 100644
--- a/xray/azav.py
+++ b/xray/azav.py
@@ -95,17 +95,17 @@ def do2d(ai, imgs, mask = None, npt_radial = 600, npt_azim=360,method = 'csr',sa
       out[_i] = i2d
     return q,azTheta,np.squeeze(out)
 
-def getAI(poni,folder=None):
+def getAI(poni=None,folder=None,**kwargs):
   """ get AzimuthalIntegrator instance:
-      → if poni is a dictionary use it to define one
-      → if poni is a string look, it is used as filename to read.
+      → if poni is a string, it is used as filename to read.
         in this case if folder is given it is used (together with all its 
         subfolder) as search path (along with ./ and home folder)
+      → kwargs if present can be used to define (or override) parameters from files,
+        dist,xcen,ycen,poni1,poni2,rot1,rot2,rot3,pixel1,pixel2,splineFile,
+        detector,wavelength
   """
   if isinstance(poni,pyFAI.azimuthalIntegrator.AzimuthalIntegrator):
     ai = poni
-  elif isinstance(poni,dict):
-    ai = pyFAI.azimuthalIntegrator.AzimuthalIntegrator(**poni)
   elif isinstance(poni,str):
     # look is file exists in cwd
     if os.path.isfile(poni):
@@ -130,6 +130,14 @@ def getAI(poni,folder=None):
         else:
           log.debug("Could not poni file %s",fname)
     ai = pyFAI.load(fname)
+  else:
+    ai = pyFAI.azimuthalIntegrator.AzimuthalIntegrator()
+  for par,value in kwargs.items(): setattr(ai,par,value)
+  # provide xcen and ycen for convenience (note: xcen changes poni2
+  # and ycen changes poni1)
+  if 'xcen' in kwargs: ai.poni2 = kwargs['xcen'] * ai.pixel2
+  if 'ycen' in kwargs: ai.poni1 = kwargs['ycen'] * ai.pixel1
+  ai.reset(); # needed in case of overridden parameters
   return ai
 
 g_mask_str = re.compile("(\w)\s*(<|>)\s*(\d+)")