| Type: | Package |
| Title: | Implementation of the Canny Edge Detector for Images |
| Version: | 0.1.1 |
| Maintainer: | Jan Wijffels <jwijffels@bnosac.be> |
| Description: | An implementation of the Canny Edge Detector for detecting edges in images. The package provides an interface to the algorithm available at https://github.com/Neseb/canny. |
| License: | GPL-3 |
| URL: | https://github.com/bnosac/image |
| Encoding: | UTF-8 |
| Imports: | Rcpp (≥ 0.12.9) |
| LinkingTo: | Rcpp |
| Suggests: | pixmap, magick |
| RoxygenNote: | 7.1.2 |
| SystemRequirements: | libpng, fftw3 |
| NeedsCompilation: | yes |
| Packaged: | 2023-11-29 13:05:35 UTC; jwijffels |
| Author: | Jan Wijffels [aut, cre, cph], BNOSAC [cph], Vincent Maioli [ctb, cph], IPOL Image Processing On Line [cph] |
| Repository: | CRAN |
| Date/Publication: | 2023-11-29 13:30:02 UTC |
Implementation of the Canny Edge Detector for Images
Description
Canny Edge Detector for Images. See https://en.wikipedia.org/wiki/Canny_edge_detector. Adapted from https://github.com/Neseb/canny.
See Also
Canny Edge Detector for Images
Description
Canny Edge Detector for Images. See https://en.wikipedia.org/wiki/Canny_edge_detector. Adapted from https://github.com/Neseb/canny.
Usage
image_canny_edge_detector(x, s = 2, low_thr = 3, high_thr = 10, accGrad = TRUE)
Arguments
x |
a matrix of image pixel values in the 0-255 range. |
s |
sigma, the Gaussian filter variance. Defaults to 2. |
low_thr |
lower threshold value of the algorithm. Defaults to 3. |
high_thr |
upper threshold value of the algorithm. Defaults to 10 |
accGrad |
logical indicating to trigger higher-order gradient |
Value
a list with element edges which is a matrix with values 0 or 255 indicating
in the same dimension of x. Next to that
the list also contains the input parameters s, low_thr, high_thr and accGrad,
the number of rows (nx) and columns of the image (ny) and the number of pixels which
have value 255 (pixels_nonzero).
Examples
if(requireNamespace("pixmap")){
library(pixmap)
imagelocation <- system.file("extdata", "chairs.pgm", package="image.CannyEdges")
image <- read.pnm(file = imagelocation, cellres = 1)
x <- image@grey * 255
edges <- image_canny_edge_detector(x)
edges
plot(edges)
}
if(requireNamespace("magick")){
##
## image_canny_edge_detector expects a matrix as input
## if you have a jpg/png/... convert it to pgm first or take the r/g/b channel
library(magick)
x <- image_read(system.file("extdata", "atomium.jpg", package="image.CannyEdges"))
x
image <- image_data(x, channels = "Gray")
image <- as.integer(image, transpose = TRUE)
edges <- image_canny_edge_detector(image)
edges
plot(edges)
}
if(requireNamespace("pixmap") && requireNamespace("magick")){
##
## image_canny_edge_detector expects a matrix as input
## if you have a jpg/png/... convert it to pgm first or take the r/g/b channel
library(magick)
library(pixmap)
f <- tempfile(fileext = ".pgm")
x <- image_read(system.file("extdata", "atomium.jpg", package="image.CannyEdges"))
x <- image_convert(x, format = "pgm", depth = 8)
image_write(x, path = f, format = "pgm")
image <- read.pnm(f, cellres = 1)
edges <- image_canny_edge_detector(image@grey * 255)
edges
plot(edges)
file.remove(f)
}
Plot the result of the Canny Edge Detector
Description
Plot the result of image_canny_edge_detector
Usage
## S3 method for class 'image_canny'
plot(x, ...)
Arguments
x |
an object of class image_canny as returned by |
... |
further arguments passed on to plot, except type, xlab and ylab which are set inside the function |
Value
invisible()
Examples
library(pixmap)
imagelocation <- system.file("extdata", "chairs.pgm", package="image.CannyEdges")
image <- read.pnm(file = imagelocation, cellres = 1)
edges <- image_canny_edge_detector(image@grey * 255)
plot(edges)