class_docstr: Class for image processing. Methods for detecting lines in an image and clustering them. Helper methods for
  drawing.
docstr: Load the image file self.imgfile to self.input_img. Additionally set the image width and height (self.img_w
  and self.img_h)
docstr_tok: ["Load","the","image","file","self.imgfile","to","self.input_img",".","Additionally","set","the","image","width","and","height","(","self.img_w","and","self.img_h",")"]
code: def _load_imgfile(self):
      """Load the image file self.imgfile to self.input_img. Additionally set the image width and height (self.img_w
      and self.img_h)"""
      self.input_img = cv2.imread(self.imgfile)
      if self.input_img is None:
          raise IOError("could not load file '%s'" % self.imgfile)
  
      self.img_h, self.img_w = self.input_img.shape[:2]
  
imports: from logging import warning
  from math import degrees
  import numpy
  import cv2
  from pdftabextract.common import ROTATION, SKEW_X, SKEW_Y, DIRECTION_HORIZONTAL, DIRECTION_VERTICAL
  from pdftabextract.geom import normalize_angle, project_polarcoord_lines
  from pdftabextract.clustering import zip_clusters_and_values, find_clusters_1d_break_dist, calc_cluster_centers_1d
label_desc: Use image node_id 13 for calling the ImageProc obj's underlying member method code with example usage: obj._load_imgfile() without return types