class_docstr: The post process for Differentiable Binarization (DB).
class_docstr_tok: ["The","post","process","for","Differentiable","Binarization","(","DB",")","."]
code: def unclip(self, box):
      try:
          import pyclipper
      except Exception as e:
          raise RuntimeError(
              "Unable to use vehicleplate postprocess in PP-Vehicle, please install pyclipper, for example: `pip install pyclipper`, see https://github.com/fonttools/pyclipper"
          )
      unclip_ratio = self.unclip_ratio
      poly = Polygon(box)
      distance = poly.area * unclip_ratio / poly.length
      offset = pyclipper.PyclipperOffset()
      offset.AddPath(
          box, pyclipper.JT_ROUND, pyclipper.ET_CLOSEDPOLYGON
      )
      expanded = np.array(offset.Execute(distance))
      return expanded
  
imports: import numpy
  import paddle
  from paddle.nn import functional
  import re
  from shapely.geometry import Polygon
  import cv2
  import copy
label_desc: Use image node_id 3 for calling the DBPostProcess obj's underlying member method code with example usage: obj.unclip(box) and returns: expanded