Current Version: DLCannyEdgeDetect v1.0
The DLCannyEdgeDetectDOCLIB library offers a complete implementation of the well-known Canny edge detector. It computes both the detected edge magnitude and orientation information. DLCannyEdgeDetectDOCLIB is a DOCLIB add-on module.
Two threshold parameters highT and lowT (i.e. highT > lowT) in the range of [0, 255] control the quality of computed edges as they are used globally at the edge tracking step of the Canny edge detector. Edge tracking starts at a point that has edge magnitude higher than highT and then continues outwards from that starting point until it reaches a point that has an edge magnitude lower than lowT. This hysteresis reduces the chance that noisy edges are broken up into multiple edge fragments.
Users can obtain these information from its member functions dlGetMagnitudeImage() and dlGetOrientationImage(), respectively. Both the edge magnitude and orientation are encoded within the intensity range of grayscale image, i.e. [0, 255].
Reference:
J. Canny, "A Computational Approach to Edge Detection," IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 8, no. 6, pp. 679--698, 1986.