Last modified: November 20, 2009
Contents
Image [GreyScale|Grey16|Float] canny_edge_image (float(0.00, 1e+300) scale = 0.80, float(0.00, 1e+300) gradient_threshold = 4.00)
Operates on: | Image [GreyScale|Grey16|Float] |
---|---|
Returns: | Image [GreyScale|Grey16|Float] |
Category: | Edge |
Defined in: | edgedetect.py |
Author: | Ullrich Köthe (wrapped by Robert Ferguson) |
EXPERIMENTAL
Detect and mark edges in an edge image using Canny's algorithm.
Uses code from the VIGRA Computer Vision Library (Copyright 1998-2007 by Ullrich Köthe).
- scale
- The scale relates to the value b of the exponential filter.
- gradient_threshold
- This operator first calls cannyEdgelList() to generate an edgel list for the given image. Than it scans this list and selects edgels whose strength is above the given gradient_threshold.
Example 1: canny_edge_image()
Image [GreyScale|Grey16|Float] difference_of_exponential_crack_edge_image (float(0.00, 1e+300) scale = 0.80, float(0.00, 1e+300) gradient_threshold = 4.00, int(0, 32000) min_edge_length = 0, bool close_gaps = False, bool beautify = False)
Operates on: | Image [GreyScale|Grey16|Float] |
---|---|
Returns: | Image [GreyScale|Grey16|Float] |
Category: | Edge |
Defined in: | edgedetect.py |
Author: | Ullrich Köthe (wrapped by Robert Ferguson) |
EXPERIMENTAL
Detect and mark edges in a crack edge image using the Shen/Castan zero-crossing detector.
Uses code from the VIGRA Computer Vision Library (Copyright 1998-2007 by Ullrich Köthe).
- scale
- The scale relates to the value b of the exponential filter.
- gradient_threshold
- Whenever the gradient at a zero crossing is greater than the given gradient threshold, an edge point is marked in the destination image on the darker side of the zero crossing (the zero crossing occurs between pixels).
- min_edge_length
- Removes all edges shorter than the number of pixels specified (0 retains all edges). Values near 10 are suggested.
- close_gaps
- Close one pixel wide gaps.
- beautify
- See the VIGRA Docs.
Example 1: difference_of_exponential_crack_edge_image()
Image [GreyScale|Grey16|Float] difference_of_exponential_edge_image (float(0.00, 1e+300) scale = 0.80, float(0.00, 1e+300) gradient_threshold = 4.00, int(0, 32000) min_edge_length = 0)
Operates on: | Image [GreyScale|Grey16|Float] |
---|---|
Returns: | Image [GreyScale|Grey16|Float] |
Category: | Edge |
Defined in: | edgedetect.py |
Author: | Ullrich Köthe (wrapped by Robert Ferguson) |
EXPERIMENTAL
Detect and mark edges in an edge image using the Shen/Castan zero-crossing detector.
Uses code from the VIGRA Computer Vision Library (Copyright 1998-2007 by Ullrich Köthe).
Example 1: difference_of_exponential_edge_image()