diff --git a/xray/azav.py b/xray/azav.py
index 0f05c0e..693524a 100644
--- a/xray/azav.py
+++ b/xray/azav.py
@@ -121,7 +121,7 @@ def doFolder(folder,files='*.edf*',nQ = 1500,force=False,mask=None,
   if storageFile == 'auto': storageFile = folder + "/" + "pyfai_1d.h5"
 
   if os.path.exists(storageFile) and not force:
-    saved = utils.data_storage(storageFile)
+    saved = storage.DataStorage(storageFile)
   else:
     saved = None
 
@@ -163,7 +163,7 @@ def doFolder(folder,files='*.edf*',nQ = 1500,force=False,mask=None,
     if diagnostic is not None:
       for k in diagnostic:
         ret[k] = np.asarray( [diagnostic[k][f] for f in ret['files']] )
-    ret = utils.data_storage(ret)
+    ret = storage.DataStorage(ret)
     if storageFile is not None: ret.save(storageFile)
   else:
     ret = saved
@@ -224,7 +224,7 @@ def pyFAI_find_center(img,psize=100e-6,dist=0.1,wavelength=0.8e-10,**kwargs):
 
 def average(fileOrFolder,delays=slice(None),scale=1,norm=None,returnAll=False,plot=False,
   showTrend=False):
-  data = utils.data_storage(fileOrFolder)
+  data = storage.DataStorage(fileOrFolder)
   if isinstance(delays,slice):
     idx = np.arange(data.delays.shape[0])[delays]
   elif isinstance(delays,(int,float)):
diff --git a/xray/dataReduction.py b/xray/dataReduction.py
index dad29f0..ff8fba1 100644
--- a/xray/dataReduction.py
+++ b/xray/dataReduction.py
@@ -6,6 +6,7 @@ log.basicConfig(level=log.INFO)
 import numpy as np
 np.seterr(all='ignore')
 from . import utils
+from . import storage
 import os
 
 def subtractReferences(i,idx_ref, useRatio = False):
@@ -61,6 +62,7 @@ def averageScanPoints(scan,data,isRef=None,lpower=None,useRatio=False,\
          function that support axis=0 as keyword argument
 """
   data = data.astype(np.float)
+  avData = np.nanmedian( data , axis = 0 )
   if isRef is None: isRef = np.zeros( data.shape[0], dtype=bool )
   assert data.shape[0] == isRef.shape[0]
 
@@ -110,8 +112,8 @@ def averageScanPoints(scan,data,isRef=None,lpower=None,useRatio=False,\
     err[i] = noise/np.sqrt(shot_idx.sum())
 
   ret = dict(scan=scan_pos,data=ret,err=err,chi2_0=chi2_0,
-             dataInScanPoint=dataInScanPoint)
-  ret = utils.data_storage(ret)
+             dataInScanPoint=dataInScanPoint,avData=avData)
+  ret = storage.DataStorage(ret)
   return ret
 
 
diff --git a/xray/example_main_tiox.py b/xray/example_main_tiox.py
index 364de02..870879f 100644
--- a/xray/example_main_tiox.py
+++ b/xray/example_main_tiox.py
@@ -7,8 +7,8 @@ from mcutils.xray import id9
 id9 = xray.id9
 
 # use npz files (they can handle more stuff (list of arrays,unicode) than h5py)
-id9.storage_extension = '.npz'
-#id9.storage_extension = '.h5'
+id9.default_extension = '.npz'
+#id9.default_extension_extension = '.h5'
 
 def azav(folder,nQ=1500,force=False,saveChi=True,
   poni='auto',storageFile='auto',mask=470):
diff --git a/xray/id9.py b/xray/id9.py
index c51965c..8fead66 100644
--- a/xray/id9.py
+++ b/xray/id9.py
@@ -7,8 +7,9 @@ import numpy as np
 from . import azav
 from . import dataReduction
 from . import utils
+from . import storage
 
-storage_extension = ".npz"
+default_extension = ".npz"
 
 def _conv(x):
     try:
@@ -40,17 +41,17 @@ def doFolder_azav(folder,nQ=1500,force=False,mask=None,saveChi=True,
       the diagnostics.log """
 
   diag = dict( delays = readDelayFromDiagnostic(folder) )
-  if storageFile == 'auto' : storageFile = folder +  "/" + "pyfai_1d" + storage_extension
+  if storageFile == 'auto' : storageFile = folder +  "/" + "pyfai_1d" + default_extension
   return azav.doFolder(folder,files="*.edf*",nQ=nQ,force=force,mask=mask,
     saveChi=saveChi,poni=poni,storageFile=storageFile,diagnostic=diag)
 
 def doFolder_dataRed(folder,storageFile='auto',monitor=None,
                      funcForEveraging=np.nanmean,errFilter=True):
 
-  if storageFile == 'auto' : storageFile = folder +  "/" + "pyfai_1d" + storage_extension
+  if storageFile == 'auto' : storageFile = folder +  "/" + "pyfai_1d" + default_extension
 
   # read azimuthal averaged curves
-  data = utils.data_storage(storageFile)
+  data = storage.DataStorage(storageFile)
 
   
   # calculate differences
@@ -63,6 +64,6 @@ def doFolder_dataRed(folder,storageFile='auto',monitor=None,
   
   # save txt and npz file
   dataReduction.saveTxt(folder,diffs,info=data.pyfai_info)
-  diffs.save(folder + "/" + "diffs" + storage_extension)
+  diffs.save(folder + "/" + "diffs" + default_extension)
 
   return data,diffs
diff --git a/xray/storage.py b/xray/storage.py
index ff49b04..70c4e70 100644
--- a/xray/storage.py
+++ b/xray/storage.py
@@ -1,5 +1,7 @@
-""" hdf5 file based storage; this modules adds the possibility to dump dict as
-    hdf5 File """
+""" npz/hdf5 file based storage; 
+    this modules adds the possibility to dump and load objects in files and
+    a more convenient was of accessing the data via the .attributedict thanks
+    to the DataStorage class """
 import numpy as np
 import os
 import h5py 
@@ -8,12 +10,41 @@ import collections
 import logging as log
 log.basicConfig(level=log.INFO)
 
+def unwrapArray(a,recursive=True,readH5pyDataset=True):
+  """ This function takes an object (like a dictionary) and recursivively
+      unwraps it solving many issues like the fact that many objects are 
+      packaged as 0d array
+      This funciton has also some specific hack for handling h5py limit to 
+      handle for example the None object or the numpy unicode ...
+  """
+  # is h5py dataset convert to array
+  if isinstance(a,h5py.Dataset) and readH5pyDataset: a = a[...]
+  if isinstance(a,h5py.Dataset) and a.shape == (): a = a[...]
+  if isinstance(a,np.ndarray)   and a.ndim  == 0 : a = a.item()
+  if isinstance(a,np.ndarray)   and a.dtype.char == "S": a = a.astype(str)
+  if recursive:
+    if "items" in dir(a): # dict, h5py groups, npz file
+      a = dict(a); # convert to dict, otherwise can't asssign values
+      for key,value in a.items(): a[key] = unwrapArray(value)
+    elif isinstance(a,list):
+      for index in range(len(a)): a[index] = unwrapArray(a[i])
+    else:
+      pass
+  if isinstance(a,dict): a = DataStorage(a)
+  # restore None that cannot be saved in h5py
+  if isinstance(a,str) and a == "NONE_PYTHON_OBJECT": a = None
+  # h5py can't save numpy unicode
+  if isinstance(a,np.ndarray) and a.dtype.char == "S": a = a.astype(str)
+  return a
+
 def dictToH5Group(d,group):
-  """ helper function that transform (recursively) a dictionary into an
-      hdf group """
+  """ helper function that transform (recursive) a dictionary into an
+      hdf group by creating subgroups """
   for key,value in d.items():
-    if not isinstance(value,(dict,collections.OrderedDict)):
-      # hacks for special s...
+    if isinstance(value,dict):
+      group.create_group(key)
+      dictToH5Group(value,group[key])
+    else:
       # h5py can't handle numpy unicode arrays
       if isinstance(value,np.ndarray) and value.dtype.char == "U":
         value = np.asarray([vv.encode('ascii') for vv in value])
@@ -23,9 +54,6 @@ def dictToH5Group(d,group):
         group[key] = value
       except TypeError:
         log.error("Can't save %s"%(key))
-    else:
-      group.create_group(key)
-      dictToH5Group(value,group[key])
 
 def dictToH5(h5,d):
   """ Save a dictionary into an hdf5 file
@@ -35,37 +63,15 @@ def dictToH5(h5,d):
   dictToH5Group(d,h5["/"])
   h5.close()
 
-def h5dataToDict(h5):
-  """ Read a hdf5 group into a dictionary """
-  if isinstance(h5,h5py.Dataset):
-    temp = h5[...]
-    # hack for special s...
-    # unwrap 0d arrays
-    if isinstance(temp,np.ndarray) and temp.ndim == 0:
-      temp=temp.item()
-      # h5py can't handle None
-      if temp == "NONE_PYTHON_OBJECT": temp=None
-    # convert back from ascii to unicode
-    if isinstance(temp,np.ndarray) and temp.dtype.char == "S":
-      temp = temp.astype(str)
-    return temp
-  else:
-    ret = dict()
-    for k,v in h5.items(): ret[k] = h5dataToDict(v)
-    return ret
-
-def h5ToDict(h5):
+def h5ToDict(h5,readH5pyDataset=True):
   """ Read a hdf5 file into a dictionary """
   with h5py.File(h5,"r") as h:
-    ret = h5dataToDict( h["/"] )
+    ret = unwrapArray(h,recursive=True,readH5pyDataset=readH5pyDataset)
   return ret
 
-
 def npzToDict(npzFile):
   with np.load(npzFile) as npz: d = dict(npz)
-  # unwrap 0d arrays
-  for key,value in d.items():
-    if isinstance(value,np.ndarray) and value.ndim == 0: d[key]=value.item()
+  d = unwrapArray(d,recursive=True)
   return d
 
 def dictToNpz(npzFile,d): np.savez(npzFile,**d)
@@ -90,3 +96,34 @@ def save(fname,d):
   else:
     raise ValueError("Extension must be h5 or npz") 
 
+class DataStorage(dict):
+  """ Storage for 1d integrated info """
+  def __init__(self,fileOrDict,default_name='pyfai_1d',default_ext='npz'):
+    if isinstance(fileOrDict,dict):
+      self.filename = None
+      d = fileOrDict
+    else:
+      assert isinstance(fileOrDict,str)
+      if os.path.isdir(fileOrDict):
+        fileOrDict = fileOrDict + "/" + default_name + "." + default_ext
+      self.filename = fileOrDict
+      d = read(fileOrDict)
+
+    # allow accessing with .data, .delays, etc.
+    for k,v in d.items(): setattr(self,k,v)
+
+    # allow accessing as proper dict
+    self.update( **dict(d) )
+
+  def __setitem__(self, key, value):
+    setattr(self,key,value)
+    super().__setitem__(key, value)
+
+  def __delitem__(self, key):
+    delattr(self,key)
+    super().__delitem__(key)
+
+  def save(self,fname=None):
+    if fname is None: fname = self.filename
+    assert fname is not None
+    save(fname,dict(self))
diff --git a/xray/utils.py b/xray/utils.py
index 0f23755..4d80b72 100644
--- a/xray/utils.py
+++ b/xray/utils.py
@@ -97,7 +97,8 @@ def plotdata(q,data,t=None,plot=True,showTrend=True,title=None,clim='auto'):
     plt.title(title)
 
 
-def plotdiffs(q,diffs,t,select=None,err=None,showErr=False,cmap=plt.cm.jet):
+def plotdiffs(q,diffs,t,select=None,err=None,absSignal=None,absSignalScale=10,
+              showErr=False,cmap=plt.cm.jet):
   # this selection trick done in this way allows to keep the same colors when 
   # subselecting (because I do not change the size of diffs)
   if select is not None:
@@ -105,6 +106,10 @@ def plotdiffs(q,diffs,t,select=None,err=None,showErr=False,cmap=plt.cm.jet):
   else:
     indices = range(len(t))
   lines = []
+  if absSignal is not None:
+    line = plt.plot(q,absSignal/absSignalScale,
+                    color='k',label="absSignal/%s"%str(absSignalScale))[0]
+    lines.append(line)
   for idiff in indices:
     color = cmap(idiff/(len(diffs)-1))
     label = timeToStr(t[idiff])
@@ -174,40 +179,6 @@ def saveTxt(fname,q,i,e=None,headerv=None,info=None,overwrite=True):
       x = np.hstack( (headerv[:,np.newaxis],x) )
   np.savetxt(fname,x.T,fmt="%+10.5e",header=header,comments='')
 
-class data_storage(dict):
-  """ Storage for 1d integrated info """
-  def __init__(self,fileOrDict):
-    if isinstance(fileOrDict,dict):
-      self.filename = None
-      d = fileOrDict
-    else:
-      assert isinstance(fileOrDict,str)
-      if os.path.isdir(fileOrDict): fileOrDict = fileOrDict + "/pyfai_1d.h5"
-      self.filename = fileOrDict
-      d = storage.read(fileOrDict)
-
-    # allow accessing with .data, .delays, etc.
-    for k,v in d.items(): setattr(self,k,v)
-
-    # allow accessing as proper dict
-    self.update( **dict(d) )
-
-  def __setitem__(self, key, value):
-    setattr(self,key,value)
-    super().__setitem__(key, value)
-
-  def __delitem__(self, key):
-    delattr(self,key)
-    super().__delitem__(key)
-
-  def save(self,fname=None):
-    if fname is None: fname = self.filename
-    assert fname is not None
-    storage.save(fname,dict(self))
- 
-  #def asdict(self): return dict(self)
-
-
 def reshapeToBroadcast(what,ref):
   """ expand the 1d array 'what' to allow broadbasting to match 
       multidimentional array 'ref'. The two arrays have to same the same