code: def simple_radial_distortion(camera, x):
      return x * (
          1.0 + camera.k1 * np.square(x).sum(axis=-1, keepdims=True)
      )
  
file_path: nerfies/third_party/pycolmap/pycolmap/camera.py
imports: import numpy
  from scipy.optimize import root
label_desc: Use image node_id 1 for calling a global function with example usage: simple_radial_distortion(camera, x) and returns: unknown