Update coco_eval.py (#1894)

* Update coco_eval.py

all the subsequent bbox of current image  will be ignored incorrectly if the conditional in the line 314 met

* fix bug in line 314 of coco_eval.py
Co-authored-by: Nwangguanzhong <jerrywgz@126.com>

ppdet/utils/coco_eval.py

@@ -311,7 +311,9 @@ def bbox2out(results, clsid2catid, is_bbox_normalized=False):
             for j in range(num):
                 dt = bboxes[k]
                 clsid, score, xmin, ymin, xmax, ymax = dt.tolist()
-                if clsid < 0: continue
+                if clsid < 0:
+                    k += 1  #to continue to handle the subsequent bbox of current image
+                    continue
                 catid = (clsid2catid[int(clsid)])
 
                 if is_bbox_normalized: