diff --git a/src/org/openstreetmap/josm/plugins/areaselector/ImageAnalyzer.java b/src/org/openstreetmap/josm/plugins/areaselector/ImageAnalyzer.java
index 388aca0..335a4bd 100644
--- a/src/org/openstreetmap/josm/plugins/areaselector/ImageAnalyzer.java
+++ b/src/org/openstreetmap/josm/plugins/areaselector/ImageAnalyzer.java
@@ -606,23 +606,15 @@ public boolean[][] applyKernelDiff(boolean [][] src, int[] kernel){
 		// apply the kernel to get edge pixels
 		boolean[][] dest=applyKernel(src,kernel);
 		
-		
-		
 		// and now erase the found pixels
 		boolean[][] erased=new boolean[src.length][src[0].length];
-		// make a deep copy 
-		for(int y=0;y<src.length;y++){
-			for (int x=0; x<src[y].length; x++){
-				erased[y][x]=src[y][x];
-			}
-		}
-		
-		
 		for(int y=0;y<dest.length;y++){
 			for (int x=0; x<dest[y].length; x++){
 				
 				if(dest[y][x]){
 					erased[y][x]=false;
+				}else {
+					erased[y][x]=src[y][x];
 				}
 			}
 		}