Add median filter

README.txt

@@ -5,10 +5,10 @@ by Jim Paris <jim@jtan.com>
 Prerequisites:
 
   # Runtime and build environments
-  sudo apt-get install python2.7 python2.7-dev python-setuptools
+  sudo apt-get install python2.7 python2.7-dev python-setuptools python-pip
-  sudo apt-get install python-numpy python-scipy python-matplotlib
+  sudo apt-get install python-numpy python-scipy
 
-  nilmdb (1.5.0+)
+  nilmdb (1.6.3+)
 
 Install:
 

setup.py

@@ -79,6 +79,7 @@ setup(name='nilmtools',
               'nilm-copy-wildcard = nilmtools.copy_wildcard:main',
               'nilm-sinefit = nilmtools.sinefit:main',
               'nilm-cleanup = nilmtools.cleanup:main',
+              'nilm-median = nilmtools.median:main',
               ],
           },
       zip_safe = False,

src/median.py

@@ -0,0 +1,43 @@
+#!/usr/bin/python
+import nilmtools.filter, scipy.signal
+
+def main(argv = None):
+    f = nilmtools.filter.Filter()
+    parser = f.setup_parser("Median Filter")
+    group = parser.add_argument_group("Median filter options")
+    group.add_argument("-z", "--size", action="store", type=int, default=25,
+                       help = "median filter size (default %(default)s)")
+    group.add_argument("-d", "--difference", action="store_true",
+                       help = "store difference rather than filtered values")
+
+    try:
+        args = f.parse_args(argv)
+    except nilmtools.filter.MissingDestination as e:
+        print "Source is %s (%s)" % (e.src.path, e.src.layout)
+        print "Destination %s doesn't exist" % (e.dest.path)
+        print "You could make it with a command like:"
+        print "  nilmtool -u %s create %s %s" % (e.dest.url,
+                                                 e.dest.path, e.src.layout)
+        raise SystemExit(1)
+
+    meta = f.client_src.stream_get_metadata(f.src.path)
+    f.check_dest_metadata({ "median_filter_source": f.src.path,
+                            "median_filter_size": args.size,
+                            "median_filter_difference": repr(args.difference) })
+
+    f.process_numpy(median_filter, args = (args.size, args.difference))
+
+def median_filter(data, interval, args, insert, final):
+    (size, diff) = args
+    (rows, cols) = data.shape
+    for i in range(cols - 1):
+        filtered = scipy.signal.medfilt(data[:, i+1], size)
+        if diff:
+            data[:, i+1] -= filtered
+        else:
+            data[:, i+1] = filtered
+    insert(data)
+    return rows
+
+if __name__ == "__main__":
+    main()