fix demo confidence filter not to remove mask predictions (IDEA-Resea…

…rch#156)

Co-authored-by: jasam-sheja <jasam-sheja@users.noreply.github.com>

demo/predictors.py

@@ -1,5 +1,6 @@
 import atexit
 import bisect
+from copy import copy
 import multiprocessing as mp
 from collections import deque
 import cv2
@@ -13,19 +14,12 @@
 
 
 def filter_predictions_with_confidence(predictions, confidence_threshold=0.5):
-    preds = predictions["instances"]
-    keep_idxs = preds.scores > confidence_threshold
-    pred_scores = preds.scores[keep_idxs]
-    pred_classes = preds.pred_classes[keep_idxs]
-    pred_boxes = preds.pred_boxes[keep_idxs]
-    return {
-        "instances": Instances(
-            image_size=preds.image_size,
-            pred_boxes=pred_boxes,
-            scores=pred_scores,
-            pred_classes=pred_classes,
-        )
-    }
+    if "instances" in predictions:
+        preds = predictions["instances"]
+        keep_idxs = preds.scores > confidence_threshold
+        predictions = copy(predictions) # don't modify the original
+        predictions["instances"] = preds[keep_idxs]
+    return predictions
 
 
 class VisualizationDemo(object):