diff --git a/converters/detection2panoptic_coco_format.py b/converters/detection2panoptic_coco_format.py
index 5bd4bbc..2320c5a 100644
--- a/converters/detection2panoptic_coco_format.py
+++ b/converters/detection2panoptic_coco_format.py
@@ -47,7 +47,7 @@ def convert_detection_to_panoptic_coco_format_single_core(
         anns = coco_detection.loadAnns(anns_ids)
 
         panoptic_record = {}
-        panoptic_record['image_id'] = img_id
+        panoptic_record['image_id'] = int(img_id)
         file_name = '{}.png'.format(img['file_name'].rsplit('.')[0])
         panoptic_record['file_name'] = file_name
         segments_info = []