Adapted code from the 'imager' cannyEdges function
without the usage of 'dplyr' and 'purrr'. If the threshold parameters are
missing, they are determined automatically using a k-means heuristic. Use
the alpha parameter to adjust the automatic thresholds up or down. The
thresholds are returned as attributes. The edge detection is based on a
smoothed image gradient with a degree of smoothing set by the sigma
parameter.
Usage
edgeDetection(img, t1, t2, alpha = 1, sigma = 2)
Value
Object of class 'cimg', displaying detected edges.
Arguments
img
image (import by importImage)
t1
threshold for weak edges (if missing, both thresholds are
determined automatically)