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Canny Edge Detector


Canny Edge Detector


Applies a Canny Edge Detector to an image.

The Canny edge detector can detect a wide range of edges in an image.

Dialog box

Canny Edge Detector dialog

Sigma: Standard deviation of the Gaussian filter. Good values to start with are between 0.6 and 2.4. Smaller filters cause less blurring, and allow detection of small, sharp lines. A larger filter increases processing time and causes more blurring.

Low and High thresholds: A threshold set too high can miss important information. On the other hand, a threshold set too low will falsely identify irrelevant information (such as noise) as important. 0.2-0.5 are good starting values for the low threshold; 0.6-0.9 are good starting values for the high threshold.

Click Preview to judge the results.

Click OK to proceed.


Before: After:
Original image Image with Canny Edge Detector filter applied

See also