Triangle Auto Threshold¶

Creates a binary image from a gray image using adaptive thresholding.

plantcv.threshold.triangle(gray_img, max_value, object_type="light", xstep=1)

returns thresholded/binary image

• Parameters:
  • gray_img - Grayscale image data
  • max_value - Value to apply above threshold (255 = white)
  • object_type - "light" or "dark" (default: "light"). If object is lighter than the background then standard thresholding is done. If object is darker than the background then inverse thresholding is done.
  • xstep - Value to move along x-axis to determine the points from which to calculate distance recommended to start at 1 (default) and change if needed.
• Context:
  • Used to help differentiate plant and background

Grayscale image (green-magenta channel)

from plantcv import plantcv as pcv

# Set global debug behavior to None (default), "print" (to file), 
# or "plot" (Jupyter Notebooks or X11)
pcv.params.debug = "plot"

# Create binary image from a gray image based
thresholded = pcv.threshold.triangle(gray_img=gray_img, max_value=255, object_type='light', xstep=10)

Triangle Auto-Thresholded image (xstep=10)

# Create binary image from a gray image based 
thresholded = pcv.threshold.triangle(gray_img=gray_img, max_value=255, object_type='light', xstep=1)

Triangle Auto-Thresholded image (xstep=1)

Source Code: Here