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
cannyEdges(im, t1, t2, alpha = 1, sigma = 2)
Arguments
im
input image
t1
threshold for weak edges (if missing, both thresholds are determined automatically)
# NOT RUN {cannyEdges(boats) %>% plot
#Make thresholds less strictcannyEdges(boats,alpha=.4) %>% plot
#Make thresholds more strictcannyEdges(boats,alpha=1.4) %>% plot
# }