Laplace Filter¶

This is a filtering method used to identify and highlight fine edges based on the 2nd derivative.

laplace_filter(img, k, scale, device, debug=None)

returns device, filtered image

• Parameters:
  • img - binary image object. This image will be returned after filling.
  • k - apertures size used to calculate 2nd derivative filter, specifies the size of the kernel (must be an odd integer: 1,3,5...)
  • scale - scaling factor applied (multiplied) to computed Laplacian values (scale = 1 is unscaled)
  • device - Counter for image processing steps
  • debug- None, "print", or "plot". Print = save to file, Plot = print to screen. Default = None
• Context:
  • Used to define edges around objects
• Example use:
  • Use In NIR Tutorial

Input grayscale image

from plantcv import plantcv as pcv

# Apply to a grayscale image
# Filtered image will highlight areas of rapid pixel intensity change
device, lp_img = pcv.laplace_filter(img, 1, 1, device, debug="print")

Image after Laplace filter