| Type: | Package |
| Title: | Find Corners in Digital Images with FAST-9 |
| Version: | 0.1.0 |
| Maintainer: | Jan Wijffels <jwijffels@bnosac.be> |
| Description: | An implementation of the "FAST-9" corner detection algorithm explained in the paper 'FASTER and better: A machine learning approach to corner detection' by Rosten E., Porter R. and Drummond T. (2008), available at <doi:10.48550/arXiv.0810.2434>. The package allows to detect corners in digital images. |
| License: | BSD_2_clause + file LICENSE |
| URL: | https://github.com/bnosac/image |
| Imports: | Rcpp (≥ 0.12.8) |
| Suggests: | pixmap, magick |
| LinkingTo: | Rcpp |
| RoxygenNote: | 7.1.0 |
| NeedsCompilation: | yes |
| Packaged: | 2020-07-21 08:01:18 UTC; Jan |
| Author: | Jan Wijffels [aut, cre, cph], BNOSAC [cph], Julien Cayzac [ctb, cph] |
| Repository: | CRAN |
| Date/Publication: | 2020-07-27 12:30:21 UTC |
Find Corners in Digital Images with FAST-9.
Description
An implementation of the "FAST-9" corner detection algorithm explained at <http://www.edwardrosten.com/work/fast.html>. The package allows to detect corners in digital images.
See Also
Find Corners in Digital Images with FAST-9.
Description
An implementation of the "FAST-9" corner detection algorithm explained at <http://www.edwardrosten.com/work/fast.html>.
Usage
image_detect_corners(x, threshold = 50L, suppress_non_max = FALSE)
Arguments
x |
a matrix of image pixel values in the 0-255 range. |
threshold |
positive integer where threshold is the threshold below which differences in luminosity between adjacent pixels are ignored. Think of it as a smoothing parameter. |
suppress_non_max |
logical |
Value
as list of the found corners with the x/y locations
Examples
library(pixmap)
imagelocation <- system.file("extdata", "chairs.pgm", package="image.CornerDetectionF9")
image <- read.pnm(file = imagelocation, cellres = 1)
x <- image@grey * 255
corners <- image_detect_corners(x, 80)
plot(image)
points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5)
##
## image_detect_corners 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", "hall.jpg", package="image.CornerDetectionF9"))
x
image <- image_data(x, channels = "Gray")
image <- as.integer(image, transpose = TRUE)
image <- drop(image)
corners <- image_detect_corners(image, threshold = 80)
plt <- image_draw(x)
points(corners$x, image_info(x)$height - corners$y, col = "red", pch = 20, lwd = 0.5)
dev.off()
plt
## same but now converting to portable grey mab
f <- tempfile(fileext = ".pgm")
library(magick)
x <- image_read(system.file("extdata", "hall.jpg", package="image.CornerDetectionF9"))
x <- image_convert(x, format = "pgm", depth = 8)
image_write(x, path = f, format = "pgm")
image <- read.pnm(f, cellres = 1)
corners <- image_detect_corners(image@grey * 255, 80)
plot(image)
points(corners$x, corners$y, col = "red", pch = 20, lwd = 0.5)
file.remove(f)