bug fixes

src/main/java/com/elphel/imagej/orthomosaic/OrthoMapsCollection.java

@@ -2670,10 +2670,10 @@ public class OrthoMapsCollection  implements Serializable{
 					}
 				}
 				System.out.println("Filtered out "+num_removed+
-						" scenes by the main scene filter.");
+						" scenes by the filter.");
 //				remove = new boolean [match_sort.size()];
 			} else {
-				System.out.println("No scenes were filtered out by the main scene filter");
+				System.out.println("No scenes were filtered out by the filter");
 			}
 			System.out.println(match_sort.size()+" candidates remain");
 		}
@@ -2700,6 +2700,10 @@ public class OrthoMapsCollection  implements Serializable{
 			ImagePlus[]           imps_extracted, // may be null - will not be displayed
 			int                   debugLevel
 			) {
+		if (match_sort.isEmpty()) {
+			System.out.println("List of detected objects is empty, nothing to display");
+			return;
+		}
 		PointRoi roi = new PointRoi();
 		roi.setOptions("nolabel"); // label");
 		for (int mn=0; mn < match_sort.size(); mn++) {
@@ -2752,7 +2756,7 @@ public class OrthoMapsCollection  implements Serializable{
 					extr_size,
 					prefix+"-objects_"+scene_num+(remove_dc?"_no-DC":"_with-DC"),				
 					extr_titles); // test_titles,
-			imps_extracted[scene_num].setRoi(roi);
+			imps_extracted[scene_num].setRoi(roi); // null
 			imps_extracted[scene_num].show();
 		}
 	}
@@ -2770,6 +2774,10 @@ public class OrthoMapsCollection  implements Serializable{
 			ImagePlus[]           imps_extracted_corr, // may be null - will not be displayed
 			ImagePlus[]           imps_extracted_corr_half  // may be null - will not be displayed
 			) {
+		if (match_sort.isEmpty()) {
+			System.out.println("List of detected objects is empty, nothing to display");
+			return;
+		}
 		PointRoi roi = new PointRoi();
 		roi.setOptions("nolabel"); // label");
 		for (int mn=0; mn < match_sort.size(); mn++) {