Index: /fact/tools/pyscripts/sandbox/dneise/fact_compress/diff_wo_offset_sub.py
===================================================================
--- /fact/tools/pyscripts/sandbox/dneise/fact_compress/diff_wo_offset_sub.py	(revision 14215)
+++ /fact/tools/pyscripts/sandbox/dneise/fact_compress/diff_wo_offset_sub.py	(revision 14215)
@@ -0,0 +1,30 @@
+#!/usr/bin/python -tti
+#
+# 
+
+from pyfact   import RawData
+import sys
+from ROOT import TFile, TCanvas, TH2F, TTree, TStyle, TObject
+import numpy as np
+
+data_filename = '/fact/raw/2012/06/06/20120606_116.fits.gz'
+calib_filename = '/fact/raw/2012/06/06/20120606_112.drs.fits.gz'
+
+run = RawData(data_filename, calib_filename, use_CalFactFits = False, do_calibration = False)
+npix = run.npix
+
+rootfile = TFile('20120606_116_diff_wo_offset_sub.root', "RECREATE")
+h = TH2F('h', 'diffs', npix, -0.5, npix-0.5, 4801, -2400.5, 2400.5)
+
+for event in run:
+    index = event['event_id'].value
+    print index, '/', run.nevents
+    cal_data = event['data']
+    
+    
+    for pixel in range(npix):
+        for d in np.diff(cal_data[pixel,:]):
+            h.Fill(pixel, d)
+
+h.Write()
+rootfile.Close()