File "pycocotools/_mask.pyx", line 307, in pycocotools._mask.frPyObjects Exception: input type is not supported.

 mmdetection在訓練有segmentation資料的時候，發生 File "pycocotools/_mask.pyx", line 307, in pycocotools._mask.frPyObjects Exception: input type is not supported.

主要原因為自製的segmentation資料中，可能有不符合規則的資料，coco格式中，segmentation的格式為list(list(x,y,x,y,....))每個seg至少要有四個值且必須為偶數。

下列code移除不符規定的seg

def check_coco_seg_format(json_path):

    """

    check there is invalid segmentation data in coco json file and remove invalid seg then resave it

    Args:

        json_path: path to json file

    Returns: None

    """

    with open(json_path) as fid:

        json_data = json.load(fid)

    annotations = json_data['annotations']

    for annotation in tqdm(annotations):

        segs = annotation['segmentation']

        new_segs = []

        for seg in segs:

            len_seg = len(seg)

            if len_seg % 2 == 0 and len_seg >= 4:

                new_segs.append(seg)

            if len_seg % 2 != 0:

                print('get an annotation not even.')

            if len_seg <= 4:

                print('seg len less than 4: {}'.format(len_seg))

                print('annoation: {}'.format(annotation))

        annotation['segmentation'] = new_segs

    with open(json_path, 'w', encoding='utf-8') as f:

        json.dump(json_data, f, ensure_ascii=False, indent=4)