Key error when running panoptic2detection_coco_format.py

[Loerbri]

When running the script with the following arguments:

--input_json_file "panoptic_train2017.json"
--segmentations_folder "stuff_train2017_pixelmaps"
--output_json_file "my_folder"
--categories_json_file "~/panopticapi/panoptic_coco_categories.json"
--things_only

I get the following error:

CONVERTING...
COCO panoptic format:
Segmentation folder: stuff_train2017_pixelmaps
JSON file: panoptic_train2017.json
TO
COCO detection format
JSON file: train_semantic_seg
Saving only segments of things classes.

Reading annotation information from panoptic_train2017.json
Number of cores: 8, images per core: 14786
Core: 0, 0 from 14786 images processed
Caught exception in worker thread:
Traceback (most recent call last):
File "/home/nicolas/panopticapi/converters/utils.py", line 14, in wrapper
return f(*args, **kwargs)
File "/home/nicolas/panopticapi/converters/panoptic2detection_coco_format.py", line 61, in convert_panoptic_to_detection_coco_format_single_core
segm_info['segmentation'] = COCOmask.encode(np.asfortranarray(mask))[0]
KeyError: 0
multiprocessing.pool.RemoteTraceback:
"""
Traceback (most recent call last):
File "/home/nicolas/.pyenv/versions/3.6.0/lib/python3.6/multiprocessing/pool.py", line 119, in worker
result = (True, func(*args, **kwds))
File "/home/nicolas/panopticapi/converters/utils.py", line 18, in wrapper
raise e
File "/home/nicolas/panopticapi/converters/utils.py", line 14, in wrapper
return f(*args, **kwargs)
File "/home/nicolas/panopticapi/converters/panoptic2detection_coco_format.py", line 61, in convert_panoptic_to_detection_coco_format_single_core
segm_info['segmentation'] = COCOmask.encode(np.asfortranarray(mask))[0]
KeyError: 0
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/home/nicolas/panopticapi/converters/panoptic2detection_coco_format.py", line 153, in
args.things_only)
File "/home/nicolas/panopticapi/converters/panoptic2detection_coco_format.py", line 109, in convert_panoptic_to_detection_coco_format
annotations_coco_detection.extend(p.get())
File "/home/nicolas/.pyenv/versions/3.6.0/lib/python3.6/multiprocessing/pool.py", line 608, in get
raise self._value
KeyError: 0

I tried to remove the [0] in the line segm_info['segmentation'] = COCOmask.encode(np.asfortranarray(mask))[0] which resulted in

KeyError: 'color'

later on. Any help would be much appreciated.

[kevinj22]

--input_json_file "panoptic_train2017.json"
--segmentations_folder "stuff_train2017_pixelmaps"
--output_json_file "my_folder"
--categories_json_file "~/panopticapi/panoptic_coco_categories.json"
--things_only

Your argument is things only but your segmentation PNG's are for stuff. Perhaps this is the issue?

If so set your segmentations_folder to the results of unzipping the panoptic_train2017.zip file.

Another guess would be to adjust the popping of the color category attribute here:

for category in d_coco['categories']:
        if things_only and category['isthing'] != 1:
            continue
        category.pop('isthing')

        try:
            category.pop('color')
        except:
            pass

        categories_coco_detection.append(category)
    d_coco['categories'] = categories_coco_detection

The key error at this point in time indicates to me there is no need to remove the 'color' key of the current category dictionary. Thus I wrapped it in a try / except block.

[Loerbri]

Thank you very much. I was indeed reading from the wrong segmentation folder.

[ranjiewwen]

i meet another problem int panoptic2detection_coco_format.py funtion : convert_panoptic_to_detection_coco_format() as follow:

    with open(output_json_file, 'w') as f:
        json.dump(d_coco, f)

display error:

   raise TypeError(repr(o) + " is not JSON serializable")
TypeError: b'0b7i51O001O1O1O2N4L2N00000000000000N2N2M3N200O100

i use python3.5 ; i have looked up some information and didn't solve it ; can you help ? thanks!

[kevinj22]

I'm not sure about this but try json.dumps(d_coco_). dumps is for strings I believe: https://realpython.com/python-json/

[ranjiewwen]

i meet another problem int panoptic2detection_coco_format.py funtion : convert_panoptic_to_detection_coco_format() as follow:

    with open(output_json_file, 'w') as f:
        json.dump(d_coco, f)

display error:

   raise TypeError(repr(o) + " is not JSON serializable")
TypeError: b'0b7i51O001O1O1O2N4L2N00000000000000N2N2M3N200O100

i use python3.5 ; i have looked up some information and didn't solve it ; can you help ? thanks!

• thanks: sover my problem : Fix saving of instance data in JSON #7
• 'counts' is returned as binary in Python 3, decode it into a UTF8 string

  for segm_info in annotation['segments_info']:
            if things_only and categories[segm_info['category_id']]['isthing'] != 1:
                continue
            mask = (pan == segm_info['id']).astype(np.uint8)
            mask = np.expand_dims(mask, axis=2)
            mask=COCOmask.encode(np.asfortranarray(mask))[0]
            # 'counts' is returned as binary in Python 3, decode it into a UTF8 string
            mask['counts'] = mask['counts'].decode('utf8')

            segm_info.pop('id')
            segm_info['image_id'] = annotation['image_id']
            segm_info['segmentation'] = mask
            annotations_detection.append(segm_info)

• best way to solve problem: use python2