Distance Transform¶

Perform distance transform on binary image

distance_transform(img, distanceType, maskSize, device, debug=None)

returns device, distance transformed image normalized between 0 and 1

• Parameters:
  • img - Input image
  • distanceType - Type of distance. It can be CV_DIST_L1, CV_DIST_L2 , or CV_DIST_C which are 1,2 and 3 respectively.
  • maskSize - Size of the distance transform mask. It can be 3, 5, or CV_DIST_MASK_PRECISE (the latter option is only supported by the first function). In case of the CV_DIST_L1 or CV_DIST_C distance type, the parameter is forced to 3 because a 3 by 3 mask gives the same result as 5 by 5 or any larger aperture.
  • device - Counter for image processing steps
  • debug - None, "print", or "plot". Print = save to file, Plot = print to screen. Default = None
• Context:
  • Used to perform object segmentation via thresholding and marker-aided watershed segmentation.
• Example use:
  • See below.

Input binary image

from plantcv import plantcv as pcv

# Perform dilation
# Results in addition of pixels to the boundary of object
device, distance_transform_img = pcv.distance_transform(mask, 1, 3, device, debug=None)

Image after distance transform