class_docstr: SniperCOCODataSet
class_docstr_tok: ["SniperCOCODataSet"]
code: def init_anno_cropper(self):
      logger.info("Init AnnoCropper...")
      self.anno_cropper = AnnoCropper(
          image_target_sizes=self.image_target_sizes,
          valid_box_ratio_ranges=self.valid_box_ratio_ranges,
          chip_target_size=self.chip_target_size,
          chip_target_stride=self.chip_target_stride,
          use_neg_chip=self.use_neg_chip,
          max_neg_num_per_im=self.max_neg_num_per_im,
          max_per_img=self.max_per_img,
          nms_thresh=self.nms_thresh,
      )
  
imports: import os
  import cv2
  import json
  import copy
  import numpy
  from ppdet.core.workspace import register, serializable
  from ppdet.data.crop_utils.annotation_cropper import AnnoCropper
  from .coco import COCODataSet
  from .dataset import _make_dataset, _is_valid_file
  from ppdet.utils.logger import setup_logger
label_desc: Use image node_id 4 for calling the SniperCOCODataSet obj's underlying member method code with example usage: obj.init_anno_cropper() without return types