Type: Package
Title: Otsu's Image Segmentation Method
Description: An implementation of the Otsu's Image Segmentation Method described in the paper: "A C++ Implementation of Otsu's Image Segmentation Method". The algorithm is explained at <doi:10.5201/ipol.2016.158>.
Maintainer: Jan Wijffels <jwijffels@bnosac.be>
License: MIT + file LICENSE
Version: 0.1
URL: https://github.com/bnosac/image
Imports: Rcpp (≥ 0.12.8)
LinkingTo: Rcpp
Suggests: magick
RoxygenNote: 7.1.0
NeedsCompilation: yes
Packaged: 2020-07-20 19:44:04 UTC; Jan
Author: Jan Wijffels [aut, cre, cph] (R wrapper), BNOSAC [cph] (R wrapper), Juan Pablo Balarini [ctb, cph] (Otsu C++ code), Sergio Nesmachnow [ctb, cph] (Otsu C++ code)
Repository: CRAN
Date/Publication: 2020-07-27 12:30:10 UTC

Image segmentation using Otsu

Description

An implementation of the Otsu's image segmentation algorithm explained at https://doi.org/10.5201/ipol.2016.158.

Usage

image_otsu(x, threshold = 0)

Arguments

x

an object of class magick-image or a greyscale matrix of image pixel values in the 0-255 range

threshold

integer value in range of 0-255. To override the threshold. Defaults to 0 indicating not to override the threshold.

Value

In case x is a matrix, a list with elements x (containing the thresholded image) and threshold is returned
In case x is a magick-image, the thresholded magick-image is returned alongside which also now has an attribute called threshold with the exact Otsu threshold value

Examples

library(magick)
path <- system.file(package="image.Otsu", "extdata", "coins.jpeg")
x    <- image_read(path)
x
img  <- image_otsu(x)
img
attr(img, "threshold")
img  <- image_otsu(x, threshold = 180)
img

img  <- image_data(x, channels = "gray")
img  <- as.integer(img, transpose = TRUE)
img  <- img[, , 1]
img  <- image_otsu(img)
str(img)