--- a/python/moving.py	Fri Aug 07 01:05:01 2015 -0400
+++ b/python/moving.py	Fri Aug 07 13:07:53 2015 -0400
@@ -1067,6 +1067,42 @@
             print 'The object does not exist at '+str(inter)
             return None
 
+    def getObjectsInMask(self, mask, homography = None, minLength = 1):
+        '''Returns new objects made of the positions in the mask
+        mask is in the destination of the homography space'''
+        if homography is not None:
+            self.projectedPositions = self.positions.project(homography)
+        else:
+            self.projectedPositions = self.positions
+        def inMask(positions, i, mask):
+            p = positions[i]
+            return mask[p.y, p.x] != 0.
+
+        #subTimeIntervals self.getFirstInstant()+i
+        filteredIndices = [inMask(self.projectedPositions, i, mask) for i in range(int(self.length()))]
+        # 'connected components' in subTimeIntervals
+        l = 0
+        intervalLabels = []
+        prev = True
+        for i in filteredIndices:
+            if i:
+                if not prev: # new interval
+                    l += 1
+                intervalLabels.append(l)
+            else:
+                intervalLabels.append(-1)
+            prev = i
+        intervalLabels = array(intervalLabels)
+        subObjects = []
+        for l in set(intervalLabels):
+            if l >= 0:
+                if sum(intervalLabels == l) >= minLength:
+                    times = [self.getFirstInstant()+i for i in range(len(intervalLabels)) if intervalLabels[i] == l]
+                    subTimeInterval = TimeInterval(min(times), max(times))
+                    subObjects.append(self.getObjectInTimeInterval(subTimeInterval))
+
+        return subObjects
+
     def getPositions(self):
         return self.positions