code: def shrink_polygon_py(polygon, shrink_ratio):
      """
      对框进行缩放，返回去的比例为1/shrink_ratio 即可
      """
      cx = polygon[:, 0].mean()
      cy = polygon[:, 1].mean()
      polygon[:, 0] = cx + (polygon[:, 0] - cx) * shrink_ratio
      polygon[:, 1] = cy + (polygon[:, 1] - cy) * shrink_ratio
      return polygon
  
file_path: PaddleOCR/benchmark/PaddleOCR_DBNet/data_loader/modules/make_shrink_map.py
imports: import numpy
  import cv2
label_desc: Use image node_id 1 for calling a global function with example usage: shrink_polygon_py(polygon, shrink_ratio) and returns: polygon