Acute vertex

Perform a heuristic search for sharp angles given an object contour and user specified parameters. The acute (sharp) angles are often associated with object tip points. Outputs a python list of points that meet criteria specified in parameters.

acute_vertex(obj, window, thresh, img, device, debug=None)

returns device, list of points that meet specified criteria

  • Parameters:
    • obj - A contour of the plant object (this should be output from the fxn)
    • window - The pre and post point distances on which to calculate angle of focal point (a value of 30 worked well for a sample image) on which to calculate the angle
    • thresh - Threshold to set for acuteness; keep points with an angle more acute than the threshold (a value of 15 worked well for sample image)
    • sep - The number of contour points to search within for the most acute value
    • img - A copy of the original image
    • device - Counter for image processing steps
    • debug- None, "print", or "plot". Print = save to file, Plot = print to screen. Default = None
  • Context:
    • Used to identify tip points based upon the angle between focal pixel and reference points on contour.

Input plant contour


import plantcv as pcv

device = 1

# Identify acute vertices (tip points) of an object
# Results in set of point values that may indicate tip points
device, list_of_acute_points = pcv.acute_vertex(obj, 30, 15, 100, device, debug='print')

Image of points selected