Adde binary threshold method.

bbiwarg/Images/DepthImage.cs

@@ -71,6 +71,11 @@ namespace bbiwarg.Images
             }
         }
 
+        public void thresholdBinary(Int16 thresholdDepth)
+        {
+            image = image.ThresholdBinary(new Gray(thresholdDepth), new Gray(Int16.MaxValue));
+        }
+
         public int[] getSmoothedHistogram()
         {
             Int16 minDepth = getMinDepth();